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Histogram Theory of Operation

An understanding of statistical variations in parameter values is needed for many waveform
parameter measurements. Knowledge of the average, minimum, maximum, and standard
deviation of the parameter are often enough. However, in many cases you may need a more
detailed understanding of the distribution of a parameter's values.
Histograms allow you to see how a parameter's values are distributed over many measurements.
This is done by dividing a range of parameter values into sub-ranges called bins. A count of the
number of parameter values (events) falling within ranges of the bin itself is maintained for each
bin.
While such a value range can be infinite, for practical purposes it only needs to be defined as
large enough to include any realistically possible parameter value. For example, measuring TTL
high-voltage values in a range of ±50 V is unnecessarily large, while one of 4 V ±2.5 V is more
reasonable. It is the 5 V range that is subdivided into bins. If the number of bins used were 50,
each would have a range of 5 V/50 bins or 0.1 V/bin. Events falling into the first bin would be
between 1.5 V and 1.6 V, while the next bin would capture all events between 1.6 V and 1.7 V,
and so on.
After a process of several thousand events, the bar graph of the count for each bin (its histogram)
provides a good understanding of the distribution of values. Histograms generally use the 'x' axis
to show a bin's sub-range value and the 'Y' axis for the count of parameter values within each bin.
The leftmost bin with a non-zero count shows the lowest parameter value measurements. The
highest vertical bin shows the greatest number of events falling within its sub-range.
The number of events in a bin, peak or a histogram is referred to as its population. The following
figure shows a histogram's highest population bin as the one with a sub-range of 4.3 to 4.4 V
(which is expected from a TTL signal).

The lowest-value bin with events is that with a sub-range of 3.0 to 3.1 V. As TTL high voltages
need to be greater than 2.5 V, the lowest bin is within the allowable tolerance. However, because
of its proximity to this tolerance and the degree of the bin's separation from all other values,
additional investigation may be required.

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Содержание SDA

Страница 1: ...SERIAL DATA ANALYZER OPERATOR S MANUAL December 2007 ...

Страница 2: ... their respective holders Information in this publication supersedes all earlier versions Specifications subject to change without notice Manufactured under an ISO 9000 Registered Quality Management System Visit www lecroy com to view the certificate This electronic product is subject to disposal and recycling regulations that vary by country and region Many countries prohibit the disposal of wast...

Страница 3: ...em 29 Jitter Noise Floor 29 Acquisition System 29 Memory 30 SDA 18000 13000 11000 9000 30 Acquisition Modes 30 Acquisition Processing 30 Triggering System 30 Automatic Setup 31 Probes 31 Basic Triggers 31 SMART Triggers 31 SMART Triggers with Exclusion Technology 31 Serial Trigger 32 Clock Recovery 32 Jitter Analysis 32 Math Tools Standard 33 Automated Measure Tools Standard 33 Pass Fail Testing 3...

Страница 4: ...l Reference Receiver with OE425 OE455 39 Software Clock Recovery System 39 Communications Mask Testing 40 Jitter Testing 40 Bit Error Rate optional 41 Safety 42 Safety Requirements 42 Safety Symbols 42 Operating Environment 43 Cooling 44 AC Power Source 44 Power Consumption 45 Power and Ground Connections 45 Standby Power Switch and Scope Operational States 46 Fuse Replacement 46 Calibration 47 Cl...

Страница 5: ... Connecting the Adapters 58 AP 1M Hi Z Adapter 59 Auxiliary Output Signals 60 Auxiliary Output Setup 60 Sampling Modes 61 Sampling Modes 61 Sampling Mode Selection 61 Single shot Sampling Mode 61 Basic Capture Technique 61 Sequence Sampling Mode Working With Segments 62 Sequence Mode Setup 63 Sequence Display Modes 64 Displaying Individual Segments 65 Viewing Time Stamps 66 RIS SAMPLING Mode For H...

Страница 6: ...and Acquisition System 72 Timebase Setup and Control 72 Autosetup 72 SDA DBI Controls 72 SDA18000 DBI Controls 72 SDA 13000 11000 9000 DBI Controls 73 Smart Memory 73 SMART Memory Setup 74 External Timebase vs External Clock 74 Triggering 74 TRIGGER SETUP CONSIDERATIONS 74 Trigger Modes 74 Trigger Types 75 Determining Trigger Level Slope Source and Coupling 76 Trigger Source 77 Level 77 Holdoff by...

Страница 7: ...tence 98 Show Last Trace 99 Persistence Time 100 Locking of Traces 100 Persistence Setup 100 Screen Saver 101 Moving Traces from Grid to Grid 101 Zooming Waveforms 102 Zooming a Single Channel 103 Zooming by Touch and Drag 103 Zooming Multiple Waveforms Quickly 104 Multi Zoom 104 XY Display 105 XY Display Setup 106 Save and Recall 106 Saving and Recalling Scope Settings 106 Saving Scope Settings 1...

Страница 8: ...the Network 113 Windows Setups 113 System Restore 114 Track Views 114 Creating and Viewing a Trend 114 Creating a Track View 115 Histograms 116 Creating and Viewing a Histogram 116 Single Parameter Histogram Setup 116 Viewing Thumbnail Histograms 118 Persistence Histogram 118 Persistence Trace Range 118 Persistence Sigma 118 Histogram Parameters 119 Histogram Theory of Operation 132 DSO Process 13...

Страница 9: ...hmic Parameters 142 Excluded Parameters 142 Parameter Script Parameter Math 143 Param Script vs P Script 143 Parameter Math Setup 144 Parameter Script Math Setup 144 Measure Gate 145 Measure Gate Setup 146 Help Markers 147 Help Marker Setup 149 Turning Off Help Markers 149 Customizing a Parameter 149 From the Measure Dialog 149 From a Vertical Setup Dialog 150 From a Math Setup Dialog 150 Paramete...

Страница 10: ...n 184 How the Instrument Enhances Resolution 184 Enhanced Resolution ERES Setup 187 Waveform Copy 187 Waveform Sparser 187 Waveform Sparser Setup 188 Interpolation 188 Interpolation Setup 188 Fast Wave Port 188 Fast Wave Port Setup Initial 189 Setup Case 1 190 Setup Case 2 190 Setup Case 3 190 Operational Notes 191 Data Length Limitations 191 Performance 191 Choice of Programming Language 191 Exam...

Страница 11: ...Dialog Access 210 Remote communication 210 Remote Communication Setup 210 Configuring the Remote Control Assistant Event Log 211 Hardcopy 211 Printing 211 Clipboard 211 File 211 E Mail 212 Aux Output 212 Date Time 212 Setting the Time and Date Manually 212 Setting the Time and Date from the Internet 213 Setting the Time and Date from Windows 213 Options 214 Preferences 214 Audible Feedback 214 Aut...

Страница 12: ... a File Name 228 Organizing Excel Spreadsheets 229 Setting the Vertical Scale 230 Trace Descriptors 230 Multiple Inputs and Outputs 230 Simple Excel Example 1 231 Simple Excel Example 2 234 Excel Example 1 Exponential Decay Time Constant Excel Parameter 238 Excel Example 2 Gated Parameter Using Excel 239 How Does this Work 241 Excel Example 3 Correlation Excel Waveform Function 242 Excel Example 4...

Страница 13: ...cal Control Variables 268 List of Variables Available to Scripts 268 Communicating with Excel from a VBScript 269 Calling MATLAB from the Instrument 270 How to Select a Waveform Function Call 271 The MATLAB Waveform Control Panel 272 MATLAB Waveform Function Editor Example 272 MATLAB Example Waveform Plot 274 How to Select a MATLAB Parameter Call 274 The MATLAB Parameter Control Panel 275 The MATL...

Страница 14: ...a Notebook Entry 294 Recalling Notebook Entries 298 Creating a Report 299 Previewing a Report 299 Locating a Notebook Entry 299 Creating the Report 299 Formatting the Report 300 Managing Notebook Entry Data 301 Adding Annotations 301 Deleting Notebook Entries 301 Saving Notebook Entries to a Folder 301 Managing the Database 301 Starting a New Database 302 Processing Web Option 302 Using the Web Ed...

Страница 15: ...Jitter Setup 325 SDA DBI Controls 329 SDA 13000 11000 9000 DBI Controls 329 Vertical Noise Calibration 330 Running the Script 330 Using Noise Compensation 331 Jitter Measurements 332 Pj Breakdown 333 Alternate Jitter Breakdown Methods option ASDA J only 333 Effective Jitter 333 MJSQ Jitter 335 Bathtub Curve 336 Jitter Filter 337 TIE Histogram 337 DDJ Synchronous N Cycle Plot 338 DDj ISI plot ASDA ...

Страница 16: ... Transition Eye Diagram 363 Gated Qualified Eye Diagram 364 SDA Theory 365 Clock recovery 365 Eye Pattern 368 Eye Violation Locator ASDA Option 369 Eye Pattern Measurements 370 Eye Amplitude 370 Eye Height 371 Eye Width 371 Extinction Ratio 371 Eye Crossing 371 Average Power 371 Q Factor or BER 372 eyeBER 372 Jitter Measurement 373 Bit Error Rate and Jitter 375 Total Jitter 375 Extrapolating the P...

Страница 17: ...am the Distribution of Edge Transition Times vs Ideal Expected Transition Times 387 Relationship between Histograms and PDF 387 Integrating the PDFs 388 Extrapolation of the Distribution Tails Extremes 389 The Error Function erf x Inverse Error Function erf 1 x and Related Functions 389 The Relationship between the Inverse Error Function and Total Jitter 390 Application of Error Function to Measur...

Страница 18: ...context sensitive Help that is Help related to what was displayed on the screen when you requested Help touch in the drop down menu then touch the on screen control or front panel button or knob that you need information about The instrument will automatically display Help about that control If you want information about something not displayed on the screen touch one of the buttons inside the dro...

Страница 19: ...number clearly on the outside of the shipping carton Return products requiring only maintenance to your local customer service center If you need to return your scope for any reason use the original shipping carton If this is not possible be sure to use a rigid carton The scope should be packed so that it is surrounded by a minimum of four inches 10 cm of shock absorbent material Within the warran...

Страница 20: ...s we must first examine the product and find that it is defective due to workmanship or materials and not due to misuse neglect accident or abnormal conditions or operation LeCroy shall not be responsible for any defect damage or failure caused by any of the following a attempted repairs or installations by personnel other than LeCroy representatives or b improper connection to incompatible equipm...

Страница 21: ... Y RATTACHÉ SOIENT REDIGÉS EN LANGUE ANGLAISE 1 GRANT OF LICENSE 1 1 License Grant Subject to the terms and conditions of this EULA and payment of all applicable fees LeCroy grants to you a nonexclusive nontransferable license the License to a operate the Software Product as provided or installed in object code form for your own internal business purposes i for use in or with an instrument provide...

Страница 22: ...ive with the Software Product e publish benchmark results relating to the Software Product nor disclose Software Product features errors or bugs to third parties or f permit any third party to engage in any of the acts proscribed in clauses a through e In jurisdictions in which transfer is permitted notwithstanding the foregoing prohibition transfers will only be effective if you transfer a copy o...

Страница 23: ...e terms and conditions of this EULA LeCroy may use any technical information you provide to LeCroy during LeCroy s provision of Support Services for LeCroy s business purposes including for product support and development LeCroy will not utilize such technical information in a form that personally identifies you 3 PROPRIETARY RIGHTS 3 1 Right and Title All right title and interest in and to the So...

Страница 24: ...ity of posting any bond As used herein Confidential Information means LeCroy pricing or information concerning new LeCroy products trade secrets including without limitation all internal header information contained in or created by the Software Product all benchmark and performance test results and all Documentation and other proprietary information of LeCroy and any business marketing or technic...

Страница 25: ...ntity or end user subject to U S export restrictions You specifically agree not to export or re export any of the Restricted Components a to any country to which the U S has embargoed or restricted the export of goods or services which currently include but are not necessarily limited to Cuba Iran Iraq Libya North Korea Sudan and Syria or to any national of any such country wherever located who in...

Страница 26: ...PTION OF BUSINESS NOR FOR INDIRECT SPECIAL INCIDENTAL CONSEQUENTIAL OR EXEMPLARY DAMAGES OF ANY KIND WHETHER UNDER THIS EULA OR OTHERWISE ARISING IN ANY WAY IN CONNECTION WITH THE SOFTWARE PRODUCT THE DOCUMENTATION OR THIS EULA SOME JURISDICTIONS DO NOT ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES SO THE ABOVE EXCLUSION OR LIMITATION MAY NOT APPLY TO YOU THESE LIMITATIO...

Страница 27: ...tions hereunder may not be assigned in whole or in part by you except to a successor to the whole of your business without the prior written consent of LeCroy In the case of any permitted assignment or transfer of or under this EULA this EULA or the relevant provisions will be binding upon and inure to the benefit of the successors executors heirs representatives administrators and assigns of the ...

Страница 28: ...ps 75 ps 40 ps 75 ps 49 ps 75 ps Rise Time 20 80 Typical 19 ps 28 ps NA 25 ps NA 28 ps NA NA NA Number of Input Channels 1 1 4 2 or 1 2 or 1 4 or 2 or 1 2 or 1 4 or 2 2 or 1 4 or 2 Bandwidth Limiters Full Full 20 MHz 200 MHz 1 GHz 3 GHz 4 GHz Full 20 MHz 200 MHz 1 GHz 3 GHz 4 GHz Full 20 MHz 200 MHz 1 GHz 3 GHz 4 GHz Full 20 MHz 200 MHz 1 GHz 3 GHz 4 GHz Input Impedance 50 Ω 2 Input Coupling DC GN...

Страница 29: ... 6020 6000x 5000x 4020 4000x 3010 1 ps rms typical External Clock Frequency 30 MHz to 2 GHz 50 Ω impedance applied at the auxiliary input except SDA X000A 30 MHz to 1 GHz 50 Ω impedance applied at the auxiliary input SDA 3010 External Reference Clock Frequency 100 MHz 50 Ω except SDA 11000 and 9000 Trigger and Interpolator Jitter 2 5 ps rms Time per Division Range 20 ps to 1000 s div 10 s div in A...

Страница 30: ...µs div Sequence 2 to 40 000 segments number of segments depends upon memory options Intersegment Time 6 µs typical Acquisition Processing Averaging Summed averaging to 1 million sweeps Continuous averaging to 1 million sweeps Enhanced Resolution ERES From 8 5 to 11 bits vertical resolution Envelope Extrema Envelope floor roof for up to 1 million sweeps Triggering System Modes Normal Auto Single an...

Страница 31: ...l condition SMART Triggers State or Edge Qualified Triggers on any input source only if a defined state or edge occurred on another input source Delay between sources is selectable by time or events Dropout Triggers if signal drops out for longer than selected time between 2 ns and 20 s Pattern Logic Combination AND NAND OR NOR of 5 inputs maximum of 3 or 4 inputs External Trigger not available on...

Страница 32: ... rms typical Recovered CLK and DATA Phase Relationship Data is centered on the rising edge of the clock Source Channel 4 only Trigger Sensitivity 1 division minimum and at least 10 mVp p Clock Recovery custom filter settings damping factor natural frequency number of poles Standard PLL settings FC Golden PCIe DVI Custom Jitter Analysis advanced peak peak rms basic Tj Rj Dj bathtub curve convention...

Страница 33: ...e e log base 10 product x ratio reciprocal rescale with units roof sin x x square square root sum trend datalog of 1 000 events zoom identity Automated Measure Tools Standard These standard tools allow the display of any 8 parameters together with statistics including their average high low and standard deviations Histicons provide a fast dynamic view of parameters and wave shape characteristics a...

Страница 34: ...d datalog of up to 20 000 events Track graphs of any measurement parameter FFT capability added to include power averaging power density real and imaginary components frequency domain parameters and FFT on up to 25 Mpts Narrow band power measurements Auto correlation function Sparse function Cubic and Quadratic Interpolation Jitter and Timing Analysis Package JTA2 Standard This package provides ji...

Страница 35: ... and customize it to meet your unique needs Additional capability provided by XDEV includes The ability to create your own measurement parameter or math function using third party software packages and display the result in the scope Supported third party software packages include VBScript Visual Basic Excel MATLAB Mathcad CustomDSO creates your own user interface in a scope dialog box Supports pl...

Страница 36: ...s data point Or store to any number of files limited only by data storage media Setup Storage Front Panel and Instrument Status Save to the internal hard drive floppy drive or to a USB connected peripheral device Interface Remote Control Via Windows Automation or via LeCroy GPIB command set GPIB Port Optional Supports IEEE 488 2 Ethernet Port 10 100Base T Ethernet interface USB Ports 4 USB ports s...

Страница 37: ...ng 5 to 95 RH non condensing as tested per MIL PRF 28800F Altitude Operating Up to 2 000 m Storage non operating 12 192 m 40 000 ft Certifications CE Compliant UL and cUL Listed CE Declaration of Conformity The oscilloscope meets requirements of EMC Directive 89 336 EEC for Electromagnetic Compatibility and Low Voltage Directive 73 23 EEC for Product Safety EMC Directive EN 61326 A3 2003 EMC requi...

Страница 38: ...eets Performance Criteria C limits during the disturbance product undergoes a temporary degradation or loss of function of performance which requires operator intervention or system reset Low Voltage Directive EN 61010 1 2001 Safety requirements for electrical equipment for measurement control and laboratory use The oscilloscope has been qualified to the following EN 61010 1 limits Installation Ca...

Страница 39: ...00 SONET SDH OC 1 STM0 51 84 Mb s OC 3 STM1 155 52 Mb s OC 12 STM4 622 08 Mb s OC 48 STM16 2488 3 Mb s Fibrechannel FC133 132 7 Mb s FC266 265 6 Mb s FC531 531 2 Mb s FC1063 1063 5 Mb s FC2125 2127 Mb s Gigabit Ethernet 1 25 Gb s InfiniBand 2 25 Gb s 2127 Mb s User Defined Any rate up to 3 5 Gb s Software Clock Recovery System SDA 4000A SDA 5000A SDA 6000A Channel Software based clock recovery usi...

Страница 40: ...E FC1063E IEEE 1394b draft S400 Optical S400b T1 S400b T2 S800 Optical S800b T1 S800b T2 S1600 Optical S1600b T1 S1600b T2 Serial ATA G1 G1 Rx G1 Tx G2 G2 Rx G2 Tx DVI rev 1 0 Transmit normalized Receiver Low high InfiniBand draft 2 5 Gb s Optical 2 5 Gb s Electrical Jitter Testing Data Measurements Period Frequency TIE Clock Measurements Frequency Period Half Period Cycle Cycle N Cycle Positive C...

Страница 41: ...tional SDA 4000A SDA 5000A SDA 6000A Data Rate 2 7 Gb s Maximum capture buffer size bits 20 GS s at 2 5 Gb s data rate 8 samples bit Std VL 32M XL 50M XXL 100M 1M 3M 5M 10M Minimum Detectable BER single acquisition 1 X 10 7 SDA OM E Rev H 41 ...

Страница 42: ... ground connection This symbol is used to denote a grounded frame or chassis terminal This symbol shows that the switch is a Standby power switch When it is pressed the scope s state toggles between operating and Standby mode This switch is not a disconnect device The instrument can only be placed in a complete Power Off state by unplugging the power cord from the AC supply This symbol is used to ...

Страница 43: ...rating environment will be maintained within these parameters Temperature 5 to 40 C Humidity Maximum relative humidity 80 for temperatures up to 31 C decreasing linearly to 50 relative humidity at 40 C Altitude Up to 2 000 m Note Direct sunlight radiators and other heat sources should be taken into account when assessing the ambient temperature WARNING The scope must not be operated in explosive d...

Страница 44: ... Degree 2 Protection Class I Cooling The instrument relies on forced air cooling with internal fans and ventilation openings Care must be taken to avoid restricting the airflow around the apertures fan holes at the sides and rear of the scope To ensure adequate ventilation it is required to leave a 10 cm 4 inch minimum gap around the sides and rear of the instrument CAUTION Do not block the ventil...

Страница 45: ... must be inserted into a mating AC outlet containing a safety ground contact WARNING Electrical Shock Hazard Any interruption of the protective conductor inside or outside of the scope or disconnection of the safety ground terminal creates a hazardous situation Intentional interruption is prohibited In Standby mode the scope is still connected to the AC supply The instrument can only be placed in ...

Страница 46: ...s Properties menu in Windows at the following the path Settings Î Power Î Options It is important to note that the Windows Power Option named Standby only provides control of the scope s computer subsystems CPU hard drive etc and does not affect the other subsystems within the scope In general these other subsystems remain fully powered For additional information on setting these Power Options see...

Страница 47: ...sonnel Abnormal Conditions Operate the instrument only as intended by the manufacturer If you suspect the scope s protection has been impaired disconnect the power cord and secure the instrument against any unintended operation The scope s protection is likely to be impaired if for example the instrument shows visible damage or has been subjected to severe transport stresses Proper use of the inst...

Страница 48: ...se buttons perform the following functions Calls up the Measure menu You can then select a parameter from this menu without leaving the Channel Setup dialog The parameter automatically appears below the grid Creates a zoom trace of the channel trace whose dialog is currently displayed Calls up the Math menu You can then select a math function from this menu without leaving the Channel Setup dialog...

Страница 49: ...pective label to display the setup dialog for that function Channel trace labels show the vertical settings for the trace as well as cursor information if cursors are in use In the title bar of the label are also included indicators for SinX X interpolation waveform inversion INV deskew DSQ coupling DC GND bandwidth limiting BWL and averaging AVG These indicators have a long and short form Besides...

Страница 50: ...e frequency Trace Annotation The instrument gives you the ability to add an identifying label bearing your own text to a waveform display For each waveform you can create multiple labels and turn them all on or all off Also you can position them on the waveform by dragging or by specifying an exact horizontal position 50 SDA OM E Rev H ...

Страница 51: ...ce a label anywhere you want on the waveform Labels are numbered sequentially according to the order in which they are added and not according to their placement on the waveform 2 If you want to change the label s text touch inside the Label Text field A pop up keyboard appears for you to enter your text Touch O K on the keyboard when you are done Your edited text will automatically appear in the ...

Страница 52: ... to activate You can also quickly create traces and turn on the trace label for math functions and memory traces without leaving the Vertical Adjust dialog by touching the icons at the bottom of the Vertical Adjust dialog Whenever you turn on a channel math or memory trace via the menu bar the dialog at the bottom of the screen automatically switches to the vertical setup or math setup dialog for ...

Страница 53: ...s Explorer Default Settings DDA SDA and WaveRunner DSOs On your front panel the DEFAULT SETUP push button does not exist For these instruments therefore to recall a default setup 1 Press the SAVE RECALL push button to the left of the DRIVE ANALYSIS push button Note You can also touch File in the menu bar then Recall Setup in the drop down menu 2 Touch the Recall Setup tab in the dialog 3 Then touc...

Страница 54: ...se the scroll buttons to see the name of the option installed with each key code listed The full array of installed software and hardware options is displayed on the left side of the dialog Restoring Software Restarting the Application Upon initial power up the scope will load the instrument application software automatically If you exit the application and want to reload it touch the shortcut ico...

Страница 55: ...on replaces the standard internal hard drive with a removable hard drive that is installed at the rear of the scope in the slot normally occupied by the CD ROM drive The kit includes two hard drives which can be used interchangeably It also includes a USB CD ROM for loading of new software Caution The Removable Hard Drive Is Not Hot swappable To avoid damage to the drive or the oscilloscope shut o...

Страница 56: ...ically compensates to achieve fully calibrated measurements This intelligent interconnection between your instrument and a wide range of accessories offers important advantages over standard BNC and probe ring connections ProBus ensures correct input coupling by auto sensing the probe type thereby eliminating the guesswork and errors that occur when attenuation or amplification factors are set man...

Страница 57: ...nk BMA to SMA Adapter Installed 3 ProLink BMA to BNC Adapter Installed Note When connecting an active probe to the instrument be sure to use a ProLink BMA to BNC adapter item 3 in the figure Do not plug the probe directly into the front panel connector item 1 without an adapter SDA OM E Rev H 57 ...

Страница 58: ...ht in There will be some resistance and you ll hear clicks as the four clips slide into place Then tighten the captive screws When removing an adapter loosen the two captive screws Push down on the adapter to unseat the clips This will require some force and will be initially noisy but no damage will result to the connector the floating female BMA connector or the pins which can be 15 degrees off ...

Страница 59: ...o ground However for applications that combine one or more high speed signals with slower higher voltage signals the AP 1M provides a 1 M input impedance path and a full scale range of 8 V It is also suitable as an interface for current probes that require a 1 M input path In addition to acting as a ProLink to ProBus adapter the AP 1M also enables a much larger offset voltage range up to 50 V The ...

Страница 60: ...ilities then Utilities Setup in the drop down menu 2 Touch the Aux Output tab 3 If you simply want a 1 kHz 1 V square wave touch the button so labeled 4 If you want a specialized output touch one of the buttons under Use Auxiliary Output For 5 Touch inside the Amplitude data entry field and enter a value using the pop up numeric keypad If you want a TTL level signal touch the TTL Level checkbox Th...

Страница 61: ...associated with a single trigger event The acquisition is typically stopped a defined number of samples after this event occurs a number determined by the selected trigger delay and measured by the timebase The waveform s horizontal position and waveform display in general is determined using the trigger event as the definition of time zero You can choose either a pre or post trigger delay Pre tri...

Страница 62: ...e it for processing with math and measure tools Sequence mode offers a number of unique capabilities With it you can limit dead time between trigger events for consecutive segments The instrument can capture in fine detail complicated sequences of events over large time intervals while ignoring the uninteresting periods between the events You can also make time measurements between events on selec...

Страница 63: ...Sequence mode button 3 Under Sequence Options touch inside the Num Segments data entry field and enter the number of segments you want to display using the pop up keypad 4 Touch inside the Timeout data entry field and enter a timeout value Note The timeout period accounts for instances when a Num Segments miscount occurs for some reason and the scope waits indefinitely for an unforthcoming segment...

Страница 64: ... seg displayed field and enter a value from 1 to 80 using the pop up numeric keypad 9 Touch inside the Starting at field and enter a starting segment number using the pop up numeric keypad Sequence Display Modes The instrument gives you a choice of five ways to display your segments Adjacent Waterfall cascaded Mosaic tiled 64 SDA OM E Rev H ...

Страница 65: ...Math Setup in the drop down menu 2 Touch a function tab F1 to Fx The number of math traces available depends on the software options loaded on your scope See specifications 3 Touch inside the Operator1 field and select Segment from the pop up menu 4 In the right hand dialog touch the Select tab 5 Touch inside the Select data entry field and use the pop up numeric keypad to select the segment you w...

Страница 66: ... the time constraint is a random one The relative time between ADC sampling instants and the event trigger provides the necessary variation measured by the timebase to 5 ps resolution The instrument requires multiple triggers to complete an acquisition The number depends on the sample rate the higher the sample rate the more triggers are required It then interleaves these segments see figure to pr...

Страница 67: ...cs on every step of Roll mode that is valid because of new data Note If the processing time is greater than the acquire time the data in memory gets overwritten In this case the instrument issues the warning Channel data is not continuous in ROLL mode and rolling will start over again VERTICAL SETTINGS AND CHANNEL CONTROLS Adjusting Sensitivity and Position Adjusting Sensitivity 1 Press the approp...

Страница 68: ...ds this limit the coupling mode automatically switches from DC 50 Ω to GROUND You will then have to manually reset the coupling to DC 50 Ω as described next Coupling Setup 1 In the menu bar touch the Vertical button then Channel X Setup in the drop down menu 2 Touch inside the Coupling field and select a coupling mode from the pop up menu Probe Attenuation Setting Probe Attenuation LeCroy s ProBus...

Страница 69: ... to reconstruct straight edged signals such as square waves Sinx x interpolation on the other hand is suitable for reconstructing curved or irregular wave shapes especially when the sample rate is 3 to 5 times the system bandwidth Interpolation Setup 1 Touch the button for the channel you want to set up for example 2 In the dialog area touch inside the Interpolation data entry field under Pre Proc...

Страница 70: ...mV each time you touch the Up Down buttons However when Variable Gain is enabled you can increase or decrease the gain in increments as small as 1 mV depending on the scale of the waveform Enabling Variable Gain 1 Touch the descriptor label for the waveform whose gain you want to vary 2 Touch the Variable Gain check box Channel Deskew Unlike the Deskew math function channel Deskew does no resampli...

Страница 71: ...will be added to the signal The SDA 18000 13000 11000 9000 provides a control in the channel Vertical Adjust dialog that allows you to choose between two group delay compensations Pulse Response minimizes preshoot This selection is preferred in physics applications no prediction of the future event Eye Diagram less overshoot This selection improves the accuracy of serial eye diagrams Flatness like...

Страница 72: ...ned on the first channel in numerical order with a signal applied to it is automatically set up for edge triggering You can perform an autosetup of all these functions together by simply pressing on the front panel or by touching Autosetup in the Vertical Timebase or Trigger drop down menu SDA DBI Controls The SDA 18000 13000 11000 9000 oscilloscopes achieve higher bandwidth and sample rate using ...

Страница 73: ...y s SMART Memory feature ensures the highest time resolution for the time window displayed without aliasing SMART Memory provides these advantages Acquisition memory is automatically allocated as needed Memory size optimization Set Maximum Memory optimizes memory to obtain highest sampling rate reducing the risk of aliasing You can set a maximum memory up to 48 Mpts Fixed Sample Rate allows settin...

Страница 74: ... use 100 MHz 0 001 and the voltage level required is 650 mVpk pk or 0 0 dBm 30 On the other hand the WavePro 7000A series uses an external timebase reference of 10 MHz 0 01 with an amplitude of 650 mVpk pk or 0 0 dBm 30 The external timebase reference is applied to the rear panel BNC connector Note An external timebase reference cannot be applied to the SDA 18000 13000 11000 9000 when operating in...

Страница 75: ...larity positive to positive or negative to negative Use interval trigger to capture intervals that fall short of or exceed a given time limit In addition you can define a width range to capture any interval that is itself inside or outside the specified range an Exclusion trigger by interval The Qualify trigger is an edge qualified SMART Trigger that allows you to use one signal s positive or nega...

Страница 76: ...e zero crossing is used Coupling refers to the type of signal coupling at the input of the trigger circuit Because of the instrument s very high bandwidth there is only one choice of trigger coupling DC 50 Ω However as a visual check of where ground is you may switch the channel to ground coupling at any time while testing With DC coupling all of the signal s frequency components are coupled to th...

Страница 77: ...gain or offset is modified The Amplitude and Range of the trigger level are limited as follows 4 1 screen divisions with a channel as the trigger source 400 mV with EXT as the trigger source 4 V with EXT 10 as the trigger source 40 mV with EXT 10 as the trigger source none with LINE as the trigger source zero crossing is used Note Once specified Trigger Level and Coupling are the only parameters t...

Страница 78: ...igger is generated when the condition is met after the selected holdoff time counted from the last trigger Any time between 2 ns and 20 s can be selected The delay is initialized and started on each trigger Edge Trigger with Holdoff by Time The bold edges on the trigger source indicate that a positive slope has been selected The broken upward pointing arrows indicate potential triggers which would...

Страница 79: ...igger source indicate that a positive slope has been selected The broken upward pointing arrows indicate potential triggers while the bold ones show where triggers actually occur after the holdoff expires Simple Triggers Edge Trigger on Simple Signals The instrument uses many waveform capture techniques that trigger on features and conditions that you define These triggers fall into two major cate...

Страница 80: ... this knob to adjust the level of the trigger source or the highlighted trace Level defines the source voltage at which the trigger will generate an event a change in the input signal that satisfies the trigger conditions Alternatively in the Trigger dialog you can touch inside the Level field and type in a value using the pop up numeric keypad To quickly set a level of zero volts touch the Zero L...

Страница 81: ...op up numeric keypad enter a value in millivolts or use the up down buttons to increase or decrease the value in increments of 1 mV Or touch one of the preset value buttons Max 1 000 V Default 0 mV Min 1 000 V 5 Select the holdoff by touching the Time or Events buttons Using the pop up numeric keypad enter a value and specify the unit of time SDA OM E Rev H 81 ...

Страница 82: ...ments of 200 ps Or touch one of the preset value buttons The preset Time values are as follows Max 20 0 s Default 50 0 ns Min 2 ns The preset Events values are as follows Max 1 000 000 000 events Default 1 event Min 1 event 6 Choose Positive or Negative slope 82 SDA OM E Rev H ...

Страница 83: ... a value using the pop up numeric keypad 5 Select positive or negative slope 6 Touch the LessThan button and enter a pulse width value in the Upper Limit data entry field Or touch the GreaterThan button and enter a pulse width value in the Lower Limit data entry field Or touch the InRange button Touch the Delta button to set up a nominal range plus or minus a delta value in seconds Touch inside th...

Страница 84: ... the glitch s width is narrower than the signal s width set the trigger to a narrower width than that of the signal The signal s width as determined by the instrument trigger comparator depends on the DC trigger level If that level were to be set at the middle of a sine wave for example the width could then be considered as the half period But if the level were higher the signal s width would be c...

Страница 85: ...keypad Interval Trigger How Interval Triggers Work While Glitch trigger performs over the width of a pulse Interval trigger performs over the width of an interval with the signal duration period separating two consecutive edges of the same polarity positive to positive or negative to negative Use Interval trigger to capture intervals that fall short of or exceed a given time limit In addition you ...

Страница 86: ...thin the selected interval Interval Greater Than For this Interval Trigger generated on an interval larger than the one that you set select a minimum interval between two edges of the same slope The instrument generates the trigger on the second edge if it occurs after the set interval The timing for the interval is initialized and restarted whenever the selected edge occurs You can set an interva...

Страница 87: ...e shows where the actual trigger occurs on the positive edge after the selected interval Interval In Range This Interval Trigger is generated whenever an interval between two edges of the same slope falls within a selected range The instrument initializes and restarts the timing for the interval whenever the selected edge occurs You can set an interval from 2 ns to 20 s SDA OM E Rev H 87 ...

Страница 88: ...enu bar touch Trigger then Trigger Setup in the drop down menu 2 Touch the Interval trigger button 3 Touch inside the Trigger On data entry field and select a source on which to trigger Touch inside the Level data entry field and enter a value using the pop up numeric keypad 4 Select positive or negative slope 5 Touch the LessThan button and enter a pulse width value in the Upper Limit data entry ...

Страница 89: ...gnal For State Qualified triggers the amplitude of the first signal must remain in the desired state until the trigger occurs A qualified trigger can occur immediately after the validation or following a predetermined time delay or number of potential trigger events The time delay or trigger count is restarted with every validation Within Time creates a time window within which a trigger can occur...

Страница 90: ...trigger is sufficient to acquire a full sequence Other than in Sequence Mode Qualified First is identical to the Qualified triggers In data storage applications the index pulse can be defined as the qualifier signal and the servo gate signal as the trigger source Edge Qualified Trigger Setup 1 In the menu bar touch Trigger then Trigger Setup in the drop down menu 2 Touch the Qualify trigger button...

Страница 91: ...umeric keypad Then touch the Trigger tab again 5 If you want to set a holdoff in time or events touch one of the Qualify by buttons 6 Touch inside the field below the Qualify by buttons and enter a value using the numeric keypad 7 To set up a Qualified First trigger touch the Qualify first segment only checkbox if you are in Sequence mode State Trigger State trigger is another Qualified trigger ho...

Страница 92: ... has gone data entry field and select a logic level Above or Below Then touch inside the Level field and set a voltage level using the pop up numeric keypad If you want to set a holdoff in time or events touch one of the holdoff buttons 6 Touch inside the field below the holdoff buttons and set a value using the numeric keypad Dropout Trigger Used primarily in single shot applications and usually ...

Страница 93: ...ws show where the trigger occurs Dropout Trigger Setup 1 In the menu bar touch Trigger then Trigger Setup in the drop down menu 2 Touch the Dropout trigger button 3 Select Positive or Negative slope 4 Touch inside the Trigger after timeout data entry field and enter a time window using the pop up numeric keypad SDA OM E Rev H 93 ...

Страница 94: ...CH 2 is low and EXT is irrelevant X or don t care If any one of these conditions is not met the pattern state is considered false You can set holdoff limits from 2 ns to 20 s or from 1 to 1 000 000 000 events Logic Applications Logic Trigger can be used in digital design for the testing of complex logic inputs or data transmission buses Logic Trigger Setup 1 In the menu bar touch Trigger then Trig...

Страница 95: ...trument models give you the capability to trigger on an auxiliary input When you select this option the auxiliary trigger setup is routed to channel 3 and an information icon appears in the Channel 3 descriptor label CAUTION If you select Aux Input trigger on a WavePro 7000 Series scope but do not input an external signal the scope will not operate Aux Input Setup 1 Touch Trigger in the menu bar t...

Страница 96: ...splay 3 Touch inside the grid Intensity data entry field and enter a value from 0 to 100 using the pop up keypad 4 Touch the Grid on top checkbox if you want to superimpose the grid over the waveform Depending on the grid intensity some of your waveform may be hidden from view when the grid is placed on top To undo simply uncheck Grid on top 5 Touch the Axis labels checkbox to permanently display ...

Страница 97: ...stence modes show the most frequent signal path three dimensionally in intensities of the same color or graded in a spectrum of colors You can show persistence for up to eight inputs for any channel math function or memory location M1 to M4 Saturation Level The Persistence display is generated by repeated sampling of the amplitudes of events over time and the accumulation of the sampled data into ...

Страница 98: ...r at the percentage value specified Lowering this percentage causes the pixels to be saturated at a lower population and makes visible those rarely hit pixels not seen at higher percentages 3 Dimensional Persistence By selecting 3d you can create a topographical view of your waveform from a selection of shadings textures and hues The advantage of the topographical view is that areas of highest and...

Страница 99: ...s the shape of the pulses Here is a wire frame view of the same waveform in which lines of equal intensity are used to construct the persistence map Show Last Trace For most applications you may not want to show the last trace because it will be superimposed on top of your persistence display In those cases turn off Show Last Trace by touching the checkbox However if you are doing mask testing and...

Страница 100: ...e same mode saturation level persistence time and last trace display for all input channels Touch the Per Trace button to set these for each input channel individually 4 If you selected All Locked touch one of the mode buttons 5 Then touch the Show last trace checkbox if you want the last trace displayed 6 Touch inside the Saturation data entry field and enter a whole number integer using the pop ...

Страница 101: ...ver is activated the same way as on a standard PC 1 Minimize the instrument display by touching File in the menu bar then Minimize in the drop down menu 2 Touch Start down in the task bar 3 Touch Settings in the pop up menu 4 Touch Control Panel 5 Touch Display 6 Touch the Screen Saver tab Moving Traces from Grid to Grid You can move traces from grid to grid at the touch of a button Moving a Chann...

Страница 102: ...alog The front panel QuickZoom button creates multiple zooms one for each displayed input channel At any time you can also zoom a portion of a waveform by touching and dragging a rectangle around any part of the input waveform The zoom trace will size itself to fit the full width of the grid The degree of magnification therefore will depend on the size of the rectangle that you create When you zoo...

Страница 103: ...ree of magnification will change by a small increment To zoom in or out in large standard increments with each touch of the zoom control buttons leave the Var checkbox unchecked To set exact horizontal or vertical zoom factors touch inside the Horizontal Scale div data entry field and enter a time per div value using the pop up numeric keypad Then touch inside the Vertical Scale div field and ente...

Страница 104: ... disable the zoom trace Multi Zoom The Multi zoom feature creates time locked zoom traces for only the waveforms that you choose to include The zooms are of the same X axis section of each waveform Thus as you scroll through a waveform all included zooms scroll in unison Setting Up Multi zoom 1 In the menu bar touch Math then Math Setup in the drop down menu 2 Verify that the math function selecte...

Страница 105: ...he Auto Scroll buttons at the right of the Multi Zoom dialog to control the zoomed section of your waveforms Turning Off Multi Zoom 1 In the menu bar touch Math then Math Setup in the drop down menu 2 Touch the Multi Zoom On checkbox to turn off Multi zoom XY Display Use XY displays to measure the phase shift between otherwise identical signals You can display either voltage on both axes or freque...

Страница 106: ...cope settings to or from hard disk floppy disk or LAN location Saving Scope Settings 1 In the menu bar touch File then touch Save Setup in the drop down menu Or press the Save Recall front panel button then touch the Save Setup tab 2 To Save To File touch inside the Save Instrument Settings data entry field and use the pop up keyboard to enter the path to the destination folder Or touch Browse to ...

Страница 107: ...r 50 mV div 50 0 ns div DC50 or AC1M model dependent C1 0 mV trigger level 0 V offset 5 0 or 10 0 GS s model dependent edge trigger positive edge 0 s delay Auto trigger mode Saving Screen Images You can send images to a hard copy printer or to storage media Both types of output are done from the same dialog 1 In the menu bar touch Utilities then Utilities Setup in the drop down menu 2 Touch the Ha...

Страница 108: ...ored in non volatile RAM M1M4 4 Touch inside the Trace Title data entry field if you want to change the default name of your waveforms Use the pop up keyboard to type in the new name Note You can change the name but not the sequence number CAUTION If you use a name that ends in a number instead of a letter the instrument may truncate the number This is because by design the first waveform is autom...

Страница 109: ...e pop up menu comma space semicolon or tab 1 Touch the Browse button for the Save file in directory field and browse to the location where you want the file saved The file name is assigned automatically and is shown below the field 2 Touch Auto Save You can also enable Auto Save from this dialog by touching one of the Auto Save buttons Wrap old files overwritten Or Fill no files overwritten CAUTIO...

Страница 110: ...Touch inside the Next file will be recalled from data entry field and enter the path using the pop up keyboard Or touch the Browse button to navigate to the file 5 Touch Disk Utilities Use the Disk Utilities dialog to delete files or create folders Deleting a Single File 1 Touch File in the menu bar then Disk Utilities in the drop down menu 2 Touch the Delete button in the Disk Utilities dialog 3 ...

Страница 111: ...r button PRINTING AND FILE MANAGEMENT Print Plot or Copy The instrument gives you the ability to output files to a printer or plotter to print to file or to e mail your files Any WindowsXP supported printer is supported by your instrument Printing Printer Setup 1 In the menu bar touch File then Print Setup in the drop down menu The Utilities Hardcopy dialog opens 2 In the dialog area touch the Pri...

Страница 112: ...e Default Printer 1 If you want to change the default printer minimize the instrument application by touching File in the menu bar then Minimize in the drop down menu 2 Touch the Start button in the task bar at the bottom of the screen 3 Select Settings then Printers 4 Touch the printer you want to set as the default printer then touch File Set as Default Printer Managing Files Use the instrument ...

Страница 113: ...Guidelines for Working in Windows Although the instrument has an open architecture avoid modifying the Windows operating system since this may cause problems for the instrument s user interface Please follow these recommendations Do not load any version of Windows not provided by LeCroy Windows service packs and critical updates are generally safe and LeCroy does encourage you to install them to k...

Страница 114: ...ically before you install any hardware or software on your instrument LeCroy strongly recommends that you manually create a restore point The restore point resides on the scope s hard drive so no external storage medium floppy disk USB memory stick etc is required Creating a Restore Point 1 From the File menu minimize or Window the scope display to reveal the task bar 2 In the task bar select Star...

Страница 115: ...ple Trend Trace Label for the math function you selected 6 Touch the newly displayed Trend math function trace label if you want to change any settings in the Trend dialog Creating a Track View This feature is available in the XMAP option 1 In the menu bar touch Measure then Measure Setup in the drop down menu 2 Touch one of parameter tabs P1 through Px 3 Touch inside the Source1 data entry field ...

Страница 116: ...y displayed Track math function trace label if you want to change any settings in the Track dialog HISTOGRAMS Creating and Viewing a Histogram Note The number of sweeps comprising the histogram will be displayed in the bottom line of the trace descriptor label Single Parameter Histogram Setup From Measure Dialog 1 In the menu bar touch Measure then Measure Setup 2 Touch the My Measure button 3 Tou...

Страница 117: ...on tabs F1 through Fx The number of math traces available depends on the software options loaded on your scope See specifications 3 Touch the Graph button 4 Touch inside the Source1 field and select a source from the pop up menu 5 Touch inside the Measurement field and select a parameter from the pop up menu 6 Touch inside the Graph with field and select Histogram from the pop up menu 7 In the dia...

Страница 118: ...e Histogram math operation and is not affected by Center and Width settings made there Persistence Histogram Setup 1 In the menu bar touch Math then Math Setup 2 Touch one of function tabs F1 through Fx The number of math traces available depends on the software options loaded on your scope See specifications 3 Touch inside the Source1 field and select a source from the pop up menu 4 Touch inside ...

Страница 119: ...the height of its highest bin population determined for a discussion on how peaks are determined see the pks parameter Description Next the populations of bins to the right and left are found until a bin on each side is found to have a population of less than 50 of that of the highest bin s A line is calculated on each side from the center point of the first bin below the 50 population to that of ...

Страница 120: ...entified and the height of its highest bin population determined see the pks description Next the bin populations to the right and left are found until a bin on each side is found to have a population of less than xx of that of the highest bin A line is calculated on each side from the center point of the first bin below the 50 population to that of the adjacent bin towards the highest bin The int...

Страница 121: ...ould indicate the difference between the binary 1 and 0 voltage values Description The values at the center line dividing the population of peak in half of the two highest peaks are determined see pks parameter description The value of the leftmost of the two peaks is the histogram base see hbase While that of the rightmost is the histogram top see htop The parameter is then calculated as hampl ht...

Страница 122: ...h as TTL voltages where hbase would indicate the binary 0 voltage value Description The two highest histogram peaks are determined If several peaks are of equal height the leftmost peak among these is used see pks Then the leftmost of the two identified peaks is selected This peak s center value the line that divides the population of the peak in half is the hbase Example 122 SDA OM E Rev H ...

Страница 123: ...n The center value of each populated bin is squared and multiplied by the population height of the bin All results are summed and the total is divided by the population of all the bins The square root of the result is returned as hrms Example Using the histogram shown here the value for hrms is hrms 2 87 SDA OM E Rev H 123 ...

Страница 124: ...parameter values such as TTL voltages where htop would indicate the binary 1 voltage value Description The two highest histogram peaks are determined The rightmost of the two identified peaks is then selected The center of that peak is htop center is the horizontal point where the population to the left is equal to the area to the right Example 124 SDA OM E Rev H ...

Страница 125: ...on The count vertical value of the highest population bin in a histogram Description Each bin between the parameter cursors is examined for its count The highest count is returned as maxp Example On the following histogram the maxp is 14 SDA OM E Rev H 125 ...

Страница 126: ...on bin in a histogram Description Each bin between the parameter cursors is examined for its population count The leftmost bin with the highest count found is selected Its center value is returned as mode Example Here the mode is 150 mV 126 SDA OM E Rev H ...

Страница 127: ...ual or exceed xx of the population value is encountered A ratio of the number of counts needed for xx population total bin population is then determined for the bin The horizontal value of the bin at that ratio point of its range is found and returned as pctl Example The total population of a histogram is 100 The histogram range is divided into 20 bins and xx is set to 25 The population sum at the...

Страница 128: ...es above T2 signifies the existence of a peak Scanning continues to the right until one bin or more crosses below T2 However if the bins cross below T2 for less than a hundredth of the histogram range they are ignored and scanning continues in search of peaks that cross under T2 for more than a hundredth of the histogram range Scanning goes on over the remainder of the range to identify additional...

Страница 129: ... between the value of the rightmost and that of the leftmost populated bin Description The rightmost and leftmost populated bins are identified The difference in value between the two is returned as the range Example In this example the range is 2 mV SDA OM E Rev H 129 ...

Страница 130: ... Calculates the total population of a histogram between the parameter cursors Description The count for all populated bins between the parameter cursors is summed Example The total population of this histogram is 9 130 SDA OM E Rev H ...

Страница 131: ...discussion on how peaks are identified see the description for the pks parameter The center of the nth ranked peak the point where the area to the left is equal to the area to the right where n is selected by you is then returned as xapk Example The rightmost peak is the largest and is thus ranked first in area 1 The leftmost peak although higher is ranked second in area 2 The lowest peak is also ...

Страница 132: ...ld have a range of 5 V 50 bins or 0 1 V bin Events falling into the first bin would be between 1 5 V and 1 6 V while the next bin would capture all events between 1 6 V and 1 7 V and so on After a process of several thousand events the bar graph of the count for each bin its histogram provides a good understanding of the distribution of values Histograms generally use the x axis to show a bin s su...

Страница 133: ...tion the display can be turned off to maximize measurement speed Parameter Buffer The oscilloscope maintains a circular parameter buffer of the last 20 000 measurements made including values falling outside the set histogram range If the maximum number of events to be used for the histogram is a number N less than 20 000 the histogram is continuously updated with the last N events as new acquisiti...

Страница 134: ...npts rms sdev dly One event per acquisition Histogram Parameters XMAP and JTA2 Options Once a histogram is defined and generated measurements can be performed on the histogram itself Typical of these are the histogram s average value standard deviation most common value parameter value of highest count bin leftmost bin position representing the lowest measured waveform parameter value rightmost bi...

Страница 135: ... 5 V The adjacent bins signify variation due to noise The graph of the centered bins shows both as peaks Determining such peaks is very useful because they indicate dominant values of a signal However signal noise and the use of a high number of bins relative to the number of parameter values acquired can give a jagged and spiky histogram making meaningful peaks hard to distinguish The scope analy...

Страница 136: ... markers lines cross hairs or arrows that you can move around the grid or the waveform itself Use cursors to make fast accurate measurements and to eliminate guesswork There are two basic types Horiz ontal generally Time or Frequency cursors are markers that you move horizontally along the waveform Place them at a desired location along the time axis to read the signal s amplitude at the selected ...

Страница 137: ... or slope 5 If you chose a Relative mode touch inside the Position 1 and Position 2 data entry fields and type in a value for each cursor You can also use the Cursors knobs on the front panel to place the cursors If you chose an Absolute mode do the same for your single cursor 6 If you chose a Relative mode and you would like both cursors to move in unison as you adjust the position touch the Trac...

Страница 138: ...uickly gain access to a parameter setup dialog by touching the parameter list box below the grid For example touching within P1 below the grid displays the setup dialog for P1 Touching the row titles displays the top Measure dialog 138 SDA OM E Rev H ...

Страница 139: ...a valid value A crossed out pulse means that the scope is unable to determine top and base however the measurement could still be valid A downward pointing arrow indicates an underflow condition An upward pointing arrow indicates an overflow condition An upward and downward pointing arrow indicates an underflow and overflow condition Using X Stream Browser to Obtain Status Information Example Here...

Страница 140: ...to open the browser 3 Touch the left scope icon Connect to a local X Stream DSO device in the X Stream Browser toolbar 4 Select Measure Parameter in error P1 Out Result 5 Read the status information in line StatusDescription 140 SDA OM E Rev H ...

Страница 141: ...t computes on every event the value displayed is equal to the number of events per acquired waveform If x waveforms were acquired the value represents x times the number of cycles per waveform Also the value is equal to the measurement of the last cycle on the last acquisition Applying a Measure Mode 1 In the menu bar touch Measure then Measure Setup 2 Choose a Measure Mode from the dialog The par...

Страница 142: ...eter measurements based on your particular needs Logarithmic Parameters The parameter math feature prevents multiplication and division of parameters that return logarithmic values These parameters are as follows auto correlation signal to noise ratio ACSN narrow band power NBPW media signal to noise ratio MSNR residual signal to noise ratio RSNR top to base ratio when the units are in dB TBR Excl...

Страница 143: ...esult that suits your needs Code entry is done in the Script Editor window directly on the instrument You can also import an existing script Param Script vs P Script Param Script is a VBScript or JavaScript that operates on one or two waveforms and outputs a parameter measurement as shown in the figure below P Script on the other hand is another VBScript or JavaScript that takes as input one or tw...

Страница 144: ... 5 Touch inside the Source1 and Source2 fields and select the parameters you want to apply math to P1 to Px If you are applying math to a single parameter for example invert just touch inside the Source1 field and select a parameter P1 to Px 6 Touch inside the Math Operator field and select a math operation from the Select Measurement menu If you select an operation that requires two input paramet...

Страница 145: ...existing script from a file storage location If you create your script in this window you can then export it and save it to file Measure Gate Using Measure Gate you can narrow the span of the waveform on which to perform parameter measurements allowing you to focus on the area of greatest interest You have the option of dragging the gate posts horizontally along the waveform or specifying a positi...

Страница 146: ... position of the gate posts is shown in the Start and Stop fields in the accompanying dialog Measure Gate Setup 1 In the menu bar touch Measure Setup 2 Touch the Px tab for the parameter you want to gate A mini dialog to the right of the main setup dialog opens Note If you already have the parameter of interest set up you can simply touch the parameter directly below the grid 146 SDA OM E Rev H ...

Страница 147: ...rs Help Markers make it easier to see where your waveform intersects the chosen level This feature also displays the hysteresis band that you have set about that level You also have the option by means of an Always On checkbox to leave the Help Markers displayed after you have closed the Help Markers setup dialog You have a choice of Simple or Detailed views of the markers The Simple selection pro...

Страница 148: ...Standard Horizontal Parameter Help Markers Standard Vertical Parameter Help Markers 148 SDA OM E Rev H ...

Страница 149: ...s band for at level parameters Note The choice of Simple or Detailed is applied to all parameters at the same time That is if you choose Simple markers for one parameter all parameters will be displayed in this mode 5 Touch the Always On checkbox if you want to continuously display Help Markers for this parameter Turning Off Help Markers 1 Touch the Clear All button to turn off Help Markers for al...

Страница 150: ...djust dialog touch the Measure button 2 Select a parameter from the pop up menu The Actions for trace source defaults to the channel or trace whose dialog is open If a parameter it goes into the next available parameter or the last one if all are used 3 Select another parameter or touch Close From a Math Setup Dialog 1 In the Fx dialog touch the Measure button 2 Select a parameter from the pop up ...

Страница 151: ...easily done see previous figure The 90 and 10 threshold levels are automatically determined by the instrument using the amplitude ampl parameter Threshold levels for rise or fall time can also be selected using absolute or relative settings r level f level If absolute settings are chosen the rise or fall time is measured as the time interval separating the two crossing points on a rising or fallin...

Страница 152: ...ing Edge Duration Where Mr is the number of leading edges found Mf the number of trailing edges found the time when rising edge i crosses the x level and the time when falling edge i crosses the x level Determining Time Parameters Time parameter measurements such as width period and delay are carried out with respect to the mesial reference level see Figure 2 as follows located halfway 50 between ...

Страница 153: ...t an integer parameter measurements such as rms or mean are biased However only the last value is actually displayed the mean being available when statistics are enabled To avoid these bias effects the instrument uses cyclic parameters including crms and cmean which restrict the calculation to an integer number of cycles Figure 2 SDA OM E Rev H 153 ...

Страница 154: ...d the boundaries of the hysteresis interval In Figure 3 Delta c2d 1 2 measures the time interval separating the rising edge of the clock trigger from the first negative transition of the data signal Similarly Delta c2d 1 2 measures the time interval between the trigger and the next transition of the data signal Level and Slope For several time based measurements you can choose positive negative or...

Страница 155: ...al to noise ratio for periodic waveforms Available with DDM2 option Standard in DDA 5005A AltNCycle Alternate N Cycle Plot Timing of the transitions in the data waveform is measured for each transition and plotted as a function of the number of unit intervals over which the timing is measured The N cycle plot displays the mean or standard deviation of the edge placement in the waveform relative to...

Страница 156: ...cle begins at first transition after the left cursor Transition may be positive or negative going Number of cycles of periodic waveform Standard parameter cyclic Mean Cyclic mean Computes the average of waveform data Contrary to mean computes average over an integral number of cycles eliminating bias caused by fractional intervals Average of data values of an integral number of periods Choose this...

Страница 157: ...gger and first 50 crossing after left cursor Can measure propagation delay between two signals by triggering on one and determining delay of other Time between trigger and first 50 crossing after left cursor Standard parameter Delta delay delay Computes time between 50 level of two sources Time between midpoint transition of two sources Standard parameter Dj Effective Amount of deterministic jitte...

Страница 158: ...gments of sequence waveforms time from previous segment s to current segment s trigger for waveforms produced by a history function time from first to last accumulated waveform s trigger Time from first to last acquisition for average histogram or sequence waveforms Standard parameter Duty level Percent of period for which data are above or below a specified level Reference levels and edge transit...

Страница 159: ...A100G and WaveExpert scopes Eye BER Bit Error Rate estimated from an eye diagram Available with SDA and SDM options Standard in SDA SDA100G and WaveExpert scopes Eye Bit Rate One over duration of one UI measured on an eye Standard in SDA and WaveExpert scopes Eye Bit Time Duration of one UI measured on an eye Standard in SDA and WaveExpert scopes Eye Crossing Level of the crossing in an eye diagra...

Страница 160: ... jitter measured on eye persistence Standard in SDA and WaveExpert scopes Eye Pulse Wid The width of the eye measured at mid level Standard in SDA and WaveExpert scopes Eye Q Factor Q factor measured within the eye aperture Available with SDA and SDM options Standard in SDA SDA100G and WaveExpert scopes Eye RiseTime Rise time of the mean of persistence data Standard in SDA and WaveExpert scopes Ey...

Страница 161: ...r saw tooth waves for example top and base can default to maximum and minimum giving however less predictable results Standard parameter Fall level Fall at level Duration of pulse waveform s falling edges between user specified transition levels See also Rise level Transition time for or absolute levels of all falling edges Enhanced version sets measurement calculations to use one of the following...

Страница 162: ...largest area histogram peak at half of the population of the highest peak Available with DDM2 JTA2 XMATH XWAV CAN02 SDA and XMAP options Standard in DDA 5005A SDA100G and WaveExpert scopes Half period Half period of a waveform Reference levels and edge transition polarity can be selected Hysteresis argument used to discriminate levels from noise in data Available with JTA2 SDA and XMAP options Sta...

Страница 163: ...of a histogram that divides the population into two equal halves Available with DDM2 JTA2 XMATH XWAV CAN02 SDA and XMAP options Standard in DDA 5005A SDA100G WaveExpert and sampling scopes Hist minimum Value of the lowest left most populated bin in a histogram Available with DDM2 JTA2 XMATH XWAV CAN02 SDA and XMAP options Standard in DDA 5005A SDA100G and WaveExpert scopes Hist Mode Position of th...

Страница 164: ...JTA2 XMATH XWAV CAN02 SDA and XMAP options Standard in DDA 5005A SDA100G WaveExpert and sampling scopes Hist X peak The value of the nth highest histogram peak Applies only to histograms Available with JTA2 XMATH XWAV CAN02 DDM2 SDA and XMAP options Standard in DDA 5005A SDA100G and WaveExpert scopes Hold time Time from the clock edge to the data edge You can set levels slope and hysteresis indepe...

Страница 165: ...cal value of the nearest data point Standard parameter Local base Value of the baseline for a local feature Hysteresis argument used to discriminate levels from noise in data Available with DDM2 option Standard in DDA 5005A Local bsep Local baseline separation between rising and falling slopes Hysteresis argument used to discriminate levels from noise in data Available with DDM2 option Standard in...

Страница 166: ...th DDM2 option Standard in DDA 5005A Local tbt Time between a local feature trough and the next local trough Hysteresis argument used to discriminate levels from noise in data Available with DDM2 option Standard in DDA 5005A Local tmax Time of the maximum value of a local feature Hysteresis argument used to discriminate levels from noise in data Available with DDM2 option Standard in DDA 5005A Loc...

Страница 167: ...DA 5005A WaveRunner 6000A WaveMaster WavePro 7000A and sampling scopes MATLAB must be loaded on the instrument Maximum Measures highest point in waveform Unlike top does not assume waveform has two levels Highest value in waveform between cursors Gives similar result when applied to time domain waveform or histogram of data of same waveform But with histograms result may include contributions from...

Страница 168: ...lable in SDA analyzers NLTS Provides a measurement of the nonlinear transition shift for a prml signal Available with DDM2 option Standard in DDA 5005AA Num Points Number of points in the waveform between the cursors Standard parameter One Level One level of an eye diagram Available with SDA and SDM options Standard in SDA SDA100G and WaveExpert scopes Overshoot Overshoot negative Amount of oversh...

Страница 169: ...me waveform But with histograms result may include contributions from more than one acquisition Standard parameter Percentile Horizontal data value that divides a histogram so the population to the left is xx of the total Available with DDM2 JTA2 XMATH XWAV CAN02 SDA and XMAP options Standard in DDA 5005A SDA100G WaveExpert and sampling scopes Per DCD Amount of jitter due to duty cycle distortion ...

Страница 170: ...Standard in SDA and WaveExpert scopes Persist PkPk Difference between maximum and minimum data values Standard in SDA and WaveExpert scopes Persist RMS Root mean square of persistence data Standard in SDA and WaveExpert scopes Phase Phase difference between signal analyzed and signal used as reference You can set the output type to percent degrees or radians After setting up the reference touch th...

Страница 171: ...A parameter Rise Rise time Duration of rising edge from 10 90 Threshold arguments specify two vertical values on each edge used to compute rise time Formulas for upper and lower values lower lower thresh x amp 100 base upper upper thresh x amp 100 base Time at lower threshold minus Time at upper threshold averaged over each rising edge On signals not having two major levels triangle or saw tooth w...

Страница 172: ...as sdev for a zero mean waveform Where vi denotes measured sample values and N number of data points within the periods found up to maximum of 100 periods Gives similar result when applied to time domain waveform or histogram of data of same waveform But with histograms result may include contributions from more than one acquisition Standard parameter SAS Signal Amplitude Symmetry of a 100Base T s...

Страница 173: ...SC Frequency Frequency of Spread Spectrum Clock signal Available with PCIE option SSC Ratio Calculates the ratio between the maximum and minimum SSC frequencies Available with PCIE option SSC Track Tracks Spread Spectrum Clock Filtered track of frequency at level Available with ASDA option Std dev Standard deviation of the data between the cursors about the same as rms for a zero mean waveform Giv...

Страница 174: ...dge transition polarity can be selected Hysteresis argument used to discriminate levels from noise in data Available with JTA2 ENET SDA and XMAP options Standard in SDA100G WavePro 7000A WaveExpert and sampling scopes Time edge Measures time at each edge on each digital line Available with MS 32 option Time level Time at level Time from trigger t 0 to crossing at a specified level Time from trigge...

Страница 175: ...erence is zero Available with SDA and PCIE options Vdiff Used for V TX DIFFp p and V RX DIFFp p for PCI Express Available with PCIE option VTxDeRatio Ratio between transition and de emphasized bits Available with PCIE option Width Width of cyclic signal determined by examining 50 crossings in data input If first transition after left cursor is a rising edge waveform is considered to consist of pos...

Страница 176: ...n data Available with JTA2 USB2 EMC SDA and XMAP options Standard in SDA100G and WavePro 7000A scopes Enhanced parameter available with EMC option WidthN Width measured at the 50 level and negative slope Standard parameter X max Determines the horizontal axis location of the maximum value between the cursors Restricted to time and frequency waveforms only X min Determines the horizontal axis locat...

Страница 177: ...ange Qualifier Setup 1 From the menu bar select Measure then Measure Setup from the drop down menu 2 Touch a Px tab to open the setup dialog 3 Touch inside the Source field and select a source from the pop up menu 4 Touch inside the Measure field and select a parameter from the pop up menu 5 Touch the Accept tab of the right hand dialog then touch the Values In Range checkbox Depending on whether ...

Страница 178: ...cted state 8 Touch inside the Level Type field and select Absolute or Percent from the pop up menu 9 Touch inside the Level field and enter the crossing level value at which you want measurements to begin Alternatively touch the Find Level button to automatically select the 50 level of your gating waveform WAVEFORM MATH Introduction to Math Traces and Functions With the instrument s math tools you...

Страница 179: ...n display the integral of the averaged difference between Channels 1 and 2 Any trace and function can be chained to another trace and function For example you could make F1 an average of Channel 1 F2 an FFT of F1 and F3 a zoom of F2 Refer to the Specifications to find out which math tools are available in each optional package Setting Up a Math Function Math Setup This setup mode allows you to qui...

Страница 180: ... the software options loaded on your scope See Specifications 3 Touch the single function button 4 Touch inside the Source1 field and select a source channel math trace memory location 5 Touch inside the Operator1 field and select Deskew from the Functions category 6 In the dialog on the right touch the Deskew tab 7 Touch inside the Delay by data entry field and type in a time value using the pop ...

Страница 181: ...hrenheit L Liter M Meter FT Foot IN Inch YARD yard MILE mile N Newton OHM Ohm PAL Pascal PCT Percent POISE Poise PPM parts per million RAD Radian DEG Degree of arc MNT Minute of arc SAMPLE sample SWEEP sweeps SEC Second of arc S Second SIE Siemens T Tesla UI Unit interval V Volt VA Volt amps W Watt WB Weber MIN min HOUR Hour DAY Day WEEK Week ...

Страница 182: ...ry field and select Rescale from the Functions category 6 In the dialog on the right touch the Rescale tab 7 Touch inside the First multiply by checkbox and enter a value for a the multiplication factor 8 Touch inside the then add data entry field and enter a value for b the additive constant 9 Touch inside the Override units checkbox to disregard the source waveform s units using the pop up keybo...

Страница 183: ...l weight of successive source waveforms It is particularly useful for reducing noise on signals that drift very slowly in time or amplitude The most recently acquired waveform has more weight than all the previously acquired ones the continuous average is dominated by the statistical fluctuations of the most recently acquired waveform The weight of old waveforms in the continuous average gradually...

Страница 184: ... Operator menu 5 Touch the Average tab in the dialog to the right of the Fx dialog then touch the Summed button 6 Touch inside the Sweeps data entry field and type in a value using the pop up keypad The valid range is 1 to 1 000 000 sweeps Enhanced Resolution ERES Enhanced Resolution filtering increases vertical resolution allowing you to distinguish closely spaced voltage levels The functioning o...

Страница 185: ...the removal of coherent noise signals feed through of clock signals for example is determined by the fall of the dominant frequency components of the signal in the passband This is easily ascertained using spectral analysis The filters have a precisely constant zero phase response This has two benefits First the filters do not distort the relative position of different events in the waveform even ...

Страница 186: ...e where most of the noise has been eliminated Note Enhanced resolution can only improve the resolution of a trace it cannot improve the accuracy or linearity of the original quantization The pass band will cause signal attenuation for signals near the cut off frequency The highest frequencies passed may be slightly attenuated Perform the filtering on finite record lengths Data will be lost at the ...

Страница 187: ...alculations need to be undone on the copy before additional math can be calculated This benefit of faster throughput however comes at the expense of memory usage Waveform Sparser The Sparse math function allows you to thin out an incoming waveform by skipping points at regular intervals and by starting acquisition at a particular offset point The Sparsing factor specifies the number of sample poin...

Страница 188: ...pad Interpolation Linear interpolation which inserts a straight line between sample points is best used to reconstruct straight edged signals such as square waves Sinx x interpolation on the othe hand is suitable for reconstructing curved or irregular waveshapes especially when the sampling rate is 3 to 5 times the system bandwidth The instrument also gives you a choice of Cubic interpolation For ...

Страница 189: ...ortant to note that the transfer of the results of your processing function back into the X Stream processing stream is optional If performance is the primary goal and display or further processing of the results within the DSO software is not required then this may be skipped Fast Wave Port Setup Initial 1 In the menu bar touch Math then Math Setup in the drop down menu 2 Touch one of the Math fu...

Страница 190: ... GNU s MinGW It should be noted that the optimizer in the GNU C Compiler GCC is less efficient than that in Visual C and results in lower performance 1 Save your application in a text file and copy it onto memory stick or network drive 2 Using Windows Explorer copy the text file to the scope 3 Download and install the compiler onto the scope 4 Configure Environmental Variables as follows A Open St...

Страница 191: ...ected to take Data Length Limitations The size of the memory window is fixed at 80 Mbytes which equates to 40 MSamples Performance This is by far the fastest way to process data using a user defined algorithm on an X Stream DSO Choice of Programming Language The system was designed for use with the C C programming language However it is theoretically possible for the processing to be implemented i...

Страница 192: ...ta starts immediately after the hdr int windowSize total size of the window header data int numSamples total number of samples in the input waveform int segmentIndex index of this segment usually zero when input waveform is not a sequence int numSweeps int _dummy1 not used double verGain scale factor that relates integer sample data values to the vertical units of the waveform double verOffset ver...

Страница 193: ..._hMMFile CreateFileMapping HANDLE 0xffffffff NULL PAGE_READWRITE 0 MEM_MAP_FILE_SIZE szMapFileName if m_hMMFile 0 printf Unable to create file mapping n return 0 Map a view of this file for writing short m_lpMMFile short MapViewOfFile m_hMMFile FILE_MAP_ALL_ACCESS 0 0 0 if m_lpMMFile 0 printf Unable to map view of file n return 0 create open events used for synchronization if the client app was ru...

Страница 194: ...conds and the segment index printf f d d d n sum descHeader numSamples int descHeader trigTime lecTimeStampOneSecond descHeader segmentIndex use to flag that the output is not valid increasing performance when it is not necessary to read data back into the DSO descHeader flags FLAGS_OUTPUT_VALID flag that processing is complete SetEvent m_hProcessingComplete return 0 Header Description int descVer...

Страница 195: ...programming language and all furnished examples use this language It is theoretically possible however for the processing to be implemented in any language that supports Windows named events Mutex and can open a named memory mapped file Nevertheless no guarantee can be given as to the behavior of the system using anything but C C FFT Why Use FFT For a large class of signals you can gain greater in...

Страница 196: ...f acquisition memory available will determine the maximum range Nyquist frequency over which signal components can be observed Consider the problem of determining the length of the observation window and the size of the acquisition buffer if a Nyquist rate of 500 MHz and a resolution of 10 kHz are required To obtain a resolution of 10 kHz the acquisition time must be at least T 1 Delta f 1 10 kHz ...

Страница 197: ...haracteristics Weighting functions control the filter response shape and affect noise bandwidth as well as side lobe levels Ideally the main lobe should be as narrow and flat as possible to effectively discriminate all spectral components while all side lobes should be infinitely attenuated The window type defines the bandwidth and shape of the equivalent filter to be used in the FFT processing In...

Страница 198: ... if the signal noise is uniformly distributed white Low pass filtering should be considered when high frequency components are irrelevant A distinct advantage of this technique is that it works for both repetitive and transient signals The SNR increase is conditioned by the cut off frequency of the ERES low pass filter and the noise shape frequency distribution LeCroy digital oscilloscopes employ ...

Страница 199: ... The real part of Xn is symmetric around the Nyquist frequency that is Rn RN n While the imaginary part is asymmetric that is In IN n The energy of the signal at a frequency n is distributed equally between the first and the second halves of the spectrum the energy at frequency 0 is completely contained in the 0 term The first half of the spectrum Re Im from 0 to the Nyquist frequency is kept for ...

Страница 200: ...o the selected result type using the same formulas as are used for the Fourier Transform Glossary This section defines the terms frequently used in FFT spectrum analysis and relates them to the oscilloscope Aliasing If the input signal to a sampling acquisition system contains components whose frequency is greater than the Nyquist frequency half the sampling frequency there will be less than two s...

Страница 201: ...s An FFT corresponds to analyzing the input signal with a bank of N 2 filters all having the same shape and width and centered at N 2 discrete frequencies Each filter collects the signal energy that falls into the immediate neighborhood of its center frequency Thus it can be said that there are N 2 frequency bins The distance in hertz between the center frequencies of two neighboring bins is alway...

Страница 202: ...n the time domain record the power spectrum obtained with a rectangular window will have a sharp peak corresponding exactly to the frequency and amplitude of the sine wave Otherwise the spectrum peak with a rectangular window will be lower and broader The highest point in the power spectrum can be 3 92 dB lower 1 57 times when the source frequency is halfway between two discrete bin frequencies Th...

Страница 203: ...0 423 0 497 0 079 FFT Setup Setting Up an FFT 1 In the menu bar touch Math then Math Setup in the drop down menu 2 Touch a Math function trace button F1 through Fx The number of math traces available depends on the software options loaded on your scope See Specifications a pop up menu appears Select FFT from the menu 3 Touch the Single or Dual function of a function button if the FFT is to be of t...

Страница 204: ... shortens the record This is commonly encountered in filtering operations like enhanced resolution The missing data points are replaced by data values whose amplitudes are interpolated to fit between the last data point and th first data point in the record This guarantees that there is not a first order discontinuity in the filled data Since the data at the end of the record is filled data it is ...

Страница 205: ...he test will be False if even a single waveform falls outside the mask Masks that you create from your waveform can be confined to just a portion of the trace by use of a measure gate See Measure Gate for an explanation of how this feature works Actions By touching the Stop Test checkbox in the Actions dialog you can set up the test to end after a predetermined number of sweeps that you decide You...

Страница 206: ...Under If touch either the Pass or Fail button to set the actions to occur upon your waveform s passing or failing the test 8 Under Then touch the actions you want to occur stop test sound alarm print result emit pulse or save the waveform If you want to have the results printed and your scope is not equipped with a printer be sure that the it is connected to a local or network printer See Printing...

Страница 207: ...e ParamCompare mini dialog and select a math operator from the pop up menu 7 Touch inside the Limit field and enter a value using the pop up numeric keypad This value takes the dimensions of the parameter that you are testing For example if you are testing a time parameter the unit is seconds If you chose either WithinDeltaPct or WithinDeltaAbs from the Condition menu you also have the choice of s...

Страница 208: ...u 6 Touch inside the Compare Values field and select All or Any from the pop up menu By selecting All the test will be true only if every waveform falls within the limit that you will set By selecting Any the test will be true if just one waveform falls within the limit 7 Touch inside the Condition field in the ParamCompare mini dialog and select a math operator from the pop up menu 8 Touch inside...

Страница 209: ...lse if even a single waveform falls outside the mask 6 From Show Markers choose whether or not to have mask violations displayed 7 If you are loading a pre existing mask touch the Load Mask tab then the File button You can then enter the file name or browse to its location 8 If you want to make a mask from your waveform touch the Make Mask tab 9 Touch inside the Ver Delta and Hor Delta fields and ...

Страница 210: ...ss in the standard Windows 2000 network setup menu The Remote Control Assistant monitors communication between your PC and scope when you are operating the instrument remotely You can log all events or errors only This log can be invaluable when you are creating and debugging remote control applications Remote Communication Setup If you are connecting the scope to a network first contact your Info...

Страница 211: ...nting from the Clipboard 1 In the menu bar touch Utilities then Utilities Setup in the drop down menu 2 Touch the Hardcopy tab 3 Under Colors touch the Use Print Colors checkbox if you want the traces printed on a white background A white background saves printer toner 4 Touch the Grid Area Only checkbox if you do not need to print the dialog area and you only want to show the waveforms and grids ...

Страница 212: ...ou want the traces printed on a white background A white background saves printer toner 5 Touch the Prompt for message to send with mail checkbox if you want to include remarks with the image 6 Touch inside the Hardcopy Area field and make a selection from the pop up menu 7 Touch the Print Now button Aux Output Please refer to Auxiliary Output Signals section of this manual Date Time The instrumen...

Страница 213: ...2 In the menu bar touch Utilities then Utilities Setup in the drop down menu 3 Touch the Date Time tab 4 Touch the Set from Internet button Setting the Time and Date from Windows 1 In the menu bar touch Utilities then Utilities Setup in the drop down menu 2 Touch the Date Time tab 3 Touch the Windows Date Time button 4 Use the Time Date Properties window to configure the time including time zone S...

Страница 214: ...ure If you do not enable this option the scope will only recalibrate at startup and whenever you make a change to certain operating conditions 1 In the menu bar touch Utilities then touch Preferences in the drop down menu 2 Touch the Automatic Calibration Enable checkbox Offset Control As you change the gain this control allows you to either keep the vertical offset level indicator stationary when...

Страница 215: ...ting constant in touch either the Div or Volts button Trigger Counter Checking the Reset trigger counter before starting a new acquisition checkbox clears the trigger counter each time the scope issues an arm acquisition command This applies when you have set a trigger Holdoff condition in the Trigger dialog in either time or events The default condition of this control is off unchecked Performanc...

Страница 216: ...ide the Default Recipient Address To data entry field and use the pop up keyboard to enter the recipient s e mail address 4 If you chose SMTP touch inside the SMTP Server data entry field and use the pop up keyboard to enter the name of your server Touch inside the Originator Address From data entry field and use the pop up keyboard to type in the instrument s e mail address Then touch inside the ...

Страница 217: ...n touch the appropriate shortcut icon Touch Screen Calibration Touching the Touch Screen Calibration button starts the calibration procedure During the procedure you will be prompted to touch the center of a small cross in 5 key locations on the touch screen Because sufficient accuracy cannot be achieved using your finger use a stylus instead for this procedure The calibration has a ten second tim...

Страница 218: ... changing upstream channel controls but includes any upstream processing also 2 Accessing Other Results Access to results waveform measurement etc other than the scripting processor s own inputs may cause incorrect measurements The reason for this is simple the scope contains a complex algorithm to determine in which order results are computed This algorithm ensures that all inputs required by a p...

Страница 219: ...nctions For example you can do an Excel calculation on a result with a MATLAB function applied to it Solutions Engineers do not buy equipment they buy solutions But what solutions can be reached from a set of instrument waveform data The answer is in principle anything that can be logically derived from those data given the limitations of signal to noise ratio and processing time Here are some exa...

Страница 220: ...using VBScript Example 3 as follows doesn t use the input data at all The middle waveform F2 is a golden waveform in this case a perfect sine subject to 16 bit resolution that was created using a VBScript The lower trace F3 is a subtraction of the acquired waveform upper trace and the golden waveform The subtraction of course contains all the noise but it also shows the presence of a very small sq...

Страница 221: ... on the scope as the F2 waveform Example 4 Example 4 is a measurement of DVI Digital Video Interface Data Clock skew jitter measurement using a VBScript to emulate the PLL In this example a customer was not able to probe the desired clock signal The only probing point available was the output differential clock signal C2 However that clock was a factor of 10 slower than the clock embedded in the d...

Страница 222: ...lution has been applied It was created using instrument functions The lower trace is the first lobe of the FFT display But with a logarithmic frequency scale Click here for the VBScript In addition to VBScripting MATLAB Mathcad or Excel can also be used to generate a result The F1 trace shown below in Example 6 was calculated in MATLAB F1 WformOut from C1 WformIn1 and C2 WformIn2 The same calculat...

Страница 223: ...SDA Operator s Manual Example 6 SDA OM E Rev H 223 ...

Страница 224: ...at is MATLAB MATLAB is a software package from MathWorks that provides an environment for work in computation and mathematics An interactive language and graphics are provided What is VBS VBS is a programming language but you don t write it in a special environment such as C or Visual Basic you write it within your own application In the instrument a few clicks or button pushes will get you into a...

Страница 225: ...SDA Operator s Manual SDA OM E Rev H 225 ...

Страница 226: ... scaling factors If the transducers are non linear you can correct for that too You can also transform horizontal scales and vertical scales by manipulating the data Logarithmic scales in amplitude and frequency are often required Squaring and taking square roots are needed in certain applications Here is a picture showing some graphs related to white noise showing ways of detecting small deviatio...

Страница 227: ...s on the software options loaded on your scope See Specifications Excel returns a parameter In both cases one call to Excel can use two separate waveforms as input Please Note the Following Excel has a calculation algorithm of 64 000 points 32 000 if you have created a chart in Excel Therefore make sure that your acquisition has less than this number of points if you are going to use an Excel calc...

Страница 228: ...operties linking cells and scale of the output trace from Excel Entering a File Name If you uncheck the New Sheet checkbox you can enter the file name of an existing file Create Demo Sheet Calls up a default Excel spreadsheet Add Chart Adds charts of your waveforms to Excel You can go into Excel and create as many charts as you want 228 SDA OM E Rev H ...

Страница 229: ...ful to avoid over writing needed information especially when you are using multiple input waveforms As depicted here the instrument panel has been pasted over the Excel Spreadsheet There are three arrays of data for the three waveforms up to two inputs and one output There are corresponding small arrays of information about each trace SDA OM E Rev H 229 ...

Страница 230: ... cell H2 was specified as the top of the data set as depicted below Trace Descriptors The next figure explains the meanings of the descriptors for each trace Multiple Inputs and Outputs If you invoke two or more instrument parameter functions or waveform functions that call Excel you will find that they all refer to the same spreadsheet by default Thus your spreadsheet can use the data from severa...

Страница 231: ...e 1 In this example we use Excel to invert or negate a waveform The first figure shows a part of the screen The upper trace is the original signal The lower is the result from Excel The dialog controls the location of the data in the Excel worksheet The input data are in columns A and B though only the first is used and the output is in column C All have been set to start at row 2 allowing space f...

Страница 232: ...In this figure the panel has been pasted onto the Excel sheet for comparison 232 SDA OM E Rev H ...

Страница 233: ...DA Operator s Manual To get the output values in column C we set C2 A2 and copy this formula down the column This is the only action needed in Excel and can be seen in the next figure SDA OM E Rev H 233 ...

Страница 234: ... result calculated in Excel and displayed on the screen The input data is in columns A and B though by default only a single input column is used and the output is in column C All have been set to start at row 2 which allows for a header in row 1 To create this waveform you would simply do the following 1 Ensure that your acquisition has no more than 64 kpts the Excel calculation limit 234 SDA OM ...

Страница 235: ... a function and select ExcelMath as Operator1 for the function Excel will open automatically in the background 3 Choose File Minimize from the menu bar to minimize the instrument display and open the Excel program SDA OM E Rev H 235 ...

Страница 236: ...program Note that the only action that was needed in Excel was to create the formula in column C for each data point in column A The instrument automatically opens Excel puts the waveform data in the correct columns and returns the calculated data back to the display as the chosen F trace This Excel calculated trace can have further measurements or math calculations performed on it if desired 236 ...

Страница 237: ...w the data there Simply press the Add Chart button in the instrument s Excel dialog and a chart of the input top chart and Excel calculated output bottom chart will be automatically created in the spreadsheet The chart will be updated automatically as the scope is triggered SDA OM E Rev H 237 ...

Страница 238: ...re shows a typical pulse including pseudo random noise generated by a VBScript The pulse was generated by a formula of the form e 1 t TC1 e t TC2 where TC1 and TC2 are time constants The requirement is to measure the time constant TC2 using the portion of the trace where TC1 has negligible effect This was done using Function F1 which is not a part of the measurement process 238 SDA OM E Rev H ...

Страница 239: ...a in column B with a time scale in A created using the contents of cell F9 Horizontal Per Step The logarithmic data are in column D with the time scale repeated in C The output appears in cell H3 using the formula 1 SLOPE D21 D51 C21 C51 Excel Example 2 Gated Parameter Using Excel This example calculates a parameter of a waveform in a region of interest defined by the leading edges of two pulses i...

Страница 240: ...tions to produce different data Script F1 generates pulses having widths that are multiples of a set clock period F2 generates one pulse in the first half of the time window and one pulse in the second half Both pulses are constrained to coincide with the clock pulses of F1 F1 and F2 are used here only as simulations and are not part of the measurement process which only uses P1 The call to Excel ...

Страница 241: ... the sources were defined to be A10 and B10 This means that the first point on the waveform will be read into A10 and since the waveform has 500 points the last point will be read into A510 The same holds true for F2 and column B since F2 is assigned as Source2 and data is defined to write into column B starting with cell B10 To create the gating function in column C the cell C10 was given the fol...

Страница 242: ... The correlation trace is of necessity shorter than the input traces The noise was generated using pseudo random numbers Randomize Timer was included in the VBScript to ensure that the two traces differed and that subsequent acquisitions differed Functions F1 and F2 are included only to simulate signals and are not part of the measurement process which is performed by F3 242 SDA OM E Rev H ...

Страница 243: ...SDA Operator s Manual This example used the CORREL Array1 Array2 function of Excel as depicted below SDA OM E Rev H 243 ...

Страница 244: ...Depicted below is an example from an Excel spreadsheet Here is an original instrument trace The method is very simple First the waveform is transferred to an Excel spreadsheet by means of an instrument Excel call Second two operations are needed in Excel placing a simple formula in one cell and copying that formula into a range of cells 244 SDA OM E Rev H ...

Страница 245: ...art at cell B134 The traces repeat at intervals of 250 cells Let us call this interval R If we require a horizontal displacement D then in cell CN we write B N R D In this example D is 10 Finally we may want a vertical displacement V and we write B N R D V In this example V is 0 02 D and V can be zero if required as depicted below All that remains is to copy the formula to the required range of ce...

Страница 246: ...246 SDA OM E Rev H ...

Страница 247: ...SDA Operator s Manual Excel Example 5 Using a Surface Plot SDA OM E Rev H 247 ...

Страница 248: ...ng the script separately as well because it is saved in a suitable format for printing or off line editing with Notepad Note that in both these examples the input data are referred to as InResult DataArray You can also write InResult1 DataArray and InResult2 DataArray which refer to the two input traces InResult DataArray always refers to input trace 1 These remarks hold for any script that you wr...

Страница 249: ...n script explanatory notes InResult Samples is the number of points in the incoming waveform InResult DataArray Boolean or InResult1 DataArray or InResult2 DataArray is the array of input data If the Boolean is True you get scaled real data in the units of the trace If the Boolean is false you get unscaled integer data in the range 32768 to 32767 The value of InResult Samples is the total number o...

Страница 250: ...ray False means that the data are signed integers in the range 32768 to 32767 False is a Boolean value applying to the property Scaled Scaled data are specified in the units of the vertical scale such as volts You get these by putting True instead of False If you want to make a section of the output trace invisible you simply set the data values to full scale or bigger top or bottom You can start ...

Страница 251: ...ult DataArray are inputs and their values cannot be changed OutResult Samples and OutResult DataArray are outputs and can be changed but not directly through their individual elements The default parameter function script explanatory notes The default parameter script is similar to the default waveform script but there are subtle differences First the size of the data array is the same as the nomi...

Страница 252: ...le material that is usually used to clarify the workings of the script For example RMSMax 32767 Sqr 2 RMS of the largest sinusoid that can be fitted into the screen in unscaled mode To continue a comment on to another line another quotation mark is required on the new line Variable Types VBS supports the following variable types Integer signed 16 bit value in the range 32768 to 32767 Long signed 3...

Страница 253: ...tants give them sensible names just like variables For example do not write _If RMS 23169 Then OutputY Y Its meaning may not be obvious to someone else It is better to write something like this FullScale 32767 RootTwo Sqr 2 0 MaxRMS FullScale RootTwo If RMS MaxRMS Then But to keep your scripts fast leave definitions like this outside your loops General usage Note that white space has no effect so ...

Страница 254: ...ning by making suitable tests before the calculation is performed The other is to let it happen and use an error handling routine This will be discussed later Normally in VBScript you will know the range of the data since all the incoming data are by definition integer unscaled data or real scaled data and they must fit into the screen of the instrument Results of Calculations Sometimes you may se...

Страница 255: ...y other operations are performed Use brackets to force the result you want and also to clarify a calculation A 1 1 1 1 1 1 1 1 255 0 1 0 1 1 0 1 0 90 B OR C AND D OR E B 1 1 1 1 0 0 0 0 240 0 0 0 0 0 0 0 0 0 B OR C AND D OR E C 1 0 1 0 1 0 1 0 130 1 1 1 1 1 0 1 0 250 B OR C AND D OR E D 0 1 0 1 0 1 0 1 85 0 1 0 1 1 1 1 1 95 B OR C AND D OR E E 0 0 0 0 1 1 1 1 15 F 0 0 0 0 0 0 0 0 0 A 7 315 A B C D...

Страница 256: ...riodOfSinusoid End If End If is needed to terminate the construction The If statement is very often used with the following Boolean expressions A B A is greater than B A B A is greater than B or equal to B A B A is equal to B A B A is less than B A B A is less than B or equal to B A B A is not equal to B These statements are not like the usual program statements such as A B These statements are Bo...

Страница 257: ...g End If If you write a list like this all the Booleans will be evaluated whether you want that or not If A 9 Then VBScripting1 If A 7 Then VBScripting2 If A 6 Then VBScripting3 If A 4 Then VBScripting4 If A 3 Then VBScripting5 If A 1 Then VBScripting6 Be very careful when testing for equality There will be no trouble with Integers Long Integers and Strings but Real numbers are different Because t...

Страница 258: ...e 4 9 16 25 36 Y Sqr Sin A Z Sqr Cos A Case 7 15 31 63 127 Z Y X Case Else Z 3 End Select Case N assumes that the value of N has already been set Case Else is included to cover other cases whether foreseen or not It should always be included Select Case is much neater than a string of Ifs and Elses but remember You cannot use Select Case unless you are sure of exact equality which allows you to co...

Страница 259: ...0 0 Do Loop Until Timer NewTime Where Timer is a clock function in the PC which has a resolution of one second While Wend This is similar to Do While Loop You can write things like While A 2 And C 92677663 AnyVBCalculation Wend For Next Sometimes you know or you think you know the number of times that you want to do a job For this case a For loop is ideal especially when you have an array of numbe...

Страница 260: ...r Atn Make tan 1 of a value Result in range from π 2 to π 2 radians Cdbl Convert a value to double precision floating point Chr Create a character from an integer in range 0 to 255 Cint Convert a value to nearest integer in the range 32768 to 32767 Clng Convert a value to nearest long integer in the range 231 to 231 1 Close Close a file Cos Make the cosine of an angle expressed in radians Csng Con...

Страница 261: ...the square root of a positive number Str Make a string from a numerical value Timer Time since midnight in seconds with a resolution of one second Trim Remove leading and trailing spaces from a string Val Get the ASCII value of a string beginning with numerical characters Other VBS Words Const Define a constant value Dim Dimension a variable Redim Dimension a variable again Boolean Boolean variabl...

Страница 262: ... Cos Cos A calculates the cosine of any integer or real number giving an output that is never greater than plus one or less than minus one CSng CSng A calculates a single precision real variable equal to A Exp Exp A calculates the value of eA Int Cint A calculates the integer value next below A which can be any acceptable VBS number Int 7 4 8 Log Log A calculates the natural logarithm to base e of...

Страница 263: ...ke a script that takes a long time to run go back to the default setup before quitting or powering down or you will have a long wait next time you power up Always use a recursive calculation when this will speed things up Keep everything outside a loop that does not have to be inside to speed things up Make your scripts clear not only by indenting and commenting but by structuring neatly as well S...

Страница 264: ...give some values as examples and explain how the script would have to change if the variables changed Errors The instrument VBS tries hard to help you when errors occur Errors may be of two main types The script may not be usable because the interpreter cannot construct a logical structure from it The script may be usable but may fail while running because an incomputable function has been request...

Страница 265: ... following example the red trace has gone outside the allowed range at the beginning resulting in the message at the bottom of the instrument screen This array is fixed or temporarily locked OutResult DataArray SDA OM E Rev H 265 ...

Страница 266: ...ciple has an infinite range or a finite range which is wider than the signed 16 bits allowed check each value If a value falls outside the range you could set it to the maximum or generate another example You can however use one of the following On Error Resume Next Followed by some code that may make some attempt to deal with the problem or at least to allow execution to continue On Error GoTo 0 ...

Страница 267: ...nterleaved You can even create output data that are not related to the input The output data need not even be in the same domain as the input data because the system treats them as pure numbers So you can create your own transforms into the frequency domain for example Debugging Scripts Until we have integrated a more comprehensive debugger for VBScript there is a workaround 1 Download the Windows...

Страница 268: ...een successive possible levels in the output waveform memory 1 65536 of vertical full scale InResult VerticalResolution Double precision Difference between successive possible physical levels in the input waveform OutResultVerticalResolution Double precision Difference between successive possible physical levels in the output waveform 1 256 of vertical full scale for channel waveforms 1 65536 of v...

Страница 269: ... pVal VerticalFrameStop in double newVal VerticalResolution out retval double pVal VerticalResolution in double newVal VerticalPerStep out retval double pVal VerticalPerStep in double newVal VerticalOffset out retval double pVal VerticalOffset in double newVal VerticalMinPossible out retval double pVal VerticalMinPossible in double newVal VerticalMaxPossible out retval double pVal VerticalMaxPossi...

Страница 270: ...instrument application Restarting the application is necessary in order to update the system registry MATLAB can be directly called from the instrument in two ways Using a function F1 through Fx The number of math traces available depends on the software options loaded on your scope See Specifications MATLAB returns a waveform Using a parameter P1 through Px MATLAB returns a parameter In both case...

Страница 271: ... The MATLAB Waveform functions are selected from the Select Math Operator menu Please note that once you have clicked on MATLAB Wave there will be a slight pause before MATLAB starts Source 1 and Source 2 are the waveforms that MATLAB will use SDA OM E Rev H 271 ...

Страница 272: ... fit the grid or use the text boxes to choose a scale MATLAB Waveform Function Editor Example By touching Edit Code you can reach the MATLAB Editor where you will see the default waveform function If you are familiar with MATLAB you might prefer to launch MATLAB and create a MATLAB function that performs your task Your program in the instrument could then be a one line call of your MATLAB function...

Страница 273: ...isible MATLAB Response From this panel you can save your code load a previous code and edit your function A powerful feature of MATLAB is that you can refer to an entire waveforn as a vector The two input waveforms are WformIn1 and WformIn2 while the output is WformOut You can also refer to individual samples such as WformIn1 34 and sequences of samples such as WformIn 55 89 You can write statemen...

Страница 274: ...Waveform Plot If you touch the MATLAB Plot checkbox you will see a MATLAB plot like this one How to Select a MATLAB Parameter Call Menu position for MATLAB parameter call in Select Measurement menu 274 SDA OM E Rev H ...

Страница 275: ...s getting a result in the instrument The MATLAB Parameter Editor By touching Edit Code you can reach the MATLAB Editor This simple example shows the MATLAB function Standard Deviation acting on input channel 1 and the result would be shown in the MATLAB Response pane for an amplitude of 0 15 volt You can load an existing MATLAB program using the Load Code button and you can save the current progra...

Страница 276: ...ATLAB you might prefer to launch MATLAB and create a MATLAB function that performs your task Your program in the instrument could then be a one line call of your MATLAB function MATLAB Example Parameter Panel 276 SDA OM E Rev H ...

Страница 277: ...lculates the ratio of the number of data points that are above a given level to the number of points below the level in this case one half of the amplitude More Examples of MATLAB Waveform Functions Negating the input signal SDA OM E Rev H 277 ...

Страница 278: ...Squaring the input signal Creating pulses from a sinusoid Creating pulses at the zero crossings of the signal 278 SDA OM E Rev H ...

Страница 279: ...SDA Operator s Manual Convolving two signals SDA OM E Rev H 279 ...

Страница 280: ...editor and save it as a MATLAB m file by giving it a name of the form Filename m Call the function using the MATLAB math editor or the MATLAB parameter editor as appropriate A simple example is shown below function out negatewf wf1 NEGATEWF changes the sign of all the data out wf1 280 SDA OM E Rev H ...

Страница 281: ... that can set up all or part of the scope and do many other things Another more powerful feature is the PlugIn which allows you to add your own ActiveX controls to a setup These controls are powered by routines written in Visual Basic With ActiveX controls you can create your own user interfaces to suit your own preferences A large number of interactive devices are available button checkbox radio ...

Страница 282: ... file that is named in the Setup file to recall field and not the file of the setup that the instrument is currently in unless these happen to be the same In the example used here three setup files were made called CustomA lss CustomB lss and CustomC lss Fragments from all three are shown below 1160 Set CustomDSO XStreamDSO CustomDSO 1161 CustomDSO Setup A lss 1162 CustomDSO ActionScript1 c LeCroy...

Страница 283: ...etup will be called when the button is pressed The boolean in blue decides whether the action button will invoke the setup or remain inactive For example in setup B A lss and C lss can be invoked but not B which is already in place As you see from the line numbers in the program fragments the setup files are rather long because they include all the information needed to set the DSO to the required...

Страница 284: ...n the Properties window set Width 11940 B In the Properties window set Height 2475 3 Place two buttons on the control A Double click on the command button at left of screen left arrow below B Move and resize the resulting button as required using the handles right arrow below C Repeat for the second button D In the Properties window set the Name properties to SingleButton and AutoButton respective...

Страница 285: ...iveDSO in the Analysis Menu C Select PlugIns mode D Type Project1 UserControl1 in the COM ProgID of Plug In text box E Click the Install button under the text box 8 Now Click the new Auto and Single buttons to see their effects Properties of the Control and its Objects Using the View Properties button in Visual Basic you can customize your PlugIn to your exact requirements Among the most useful pr...

Страница 286: ...mmand button a picture box a list box and a Tabbed Dialog Control The Tabbed Control arrow is not in the basic tool box To gain access to it right click in the tool box at left but not on an icon You will see this menu 286 SDA OM E Rev H ...

Страница 287: ...ct the Microsoft Tabbed Control as shown below and click on Apply The control will be added into the toolbox at the left of the screen where you can double click on it as usual The new control is shown below arrow SDA OM E Rev H 287 ...

Страница 288: ...ol Look in the properties window to see how you can customize your tabs illustrated as follows Removing a PlugIn To remove a plug in click on Remove in the PlugIn dialog as follows Close the CustomDSO dialog and then reopen it At this point the plug in should be removed 288 SDA OM E Rev H ...

Страница 289: ...on Set acq wm Acquisition To save typing Set mat wm Math To save typing Dim t 16 As Object Create an array of objects to allow looping Set t 1 acq C1 Set t 2 acq C2 Set t 3 acq C3 Set t 4 acq C4 Set t 5 mat F1 Set t 6 mat F2 Set t 7 mat F3 Set t 8 mat F4 Set t 9 mat F5 Set t 10 mat F6 Set t 11 mat F7 Set t 12 mat F8 Dim trace As Integer trace 0 views 0 Exchange the traces on the grids Do trace tra...

Страница 290: ... has been set to 0 in the Properties Window thus defining the initial value Here is the result after seven swaps The counting method could be useful in any routine where numerous operations such as triggers have to be performed In fact the caption of the button could have been used to show the number of operations ActiveX offers a large range of standard controls including list boxes for selection...

Страница 291: ...n the second the FFT was zoomed vertically The graph has a red line to represent the theoretical envelope for the peaks This has great potential for testing the transmission characteristics of amplifiers and filters since the output can be compared with a theoretical curve Furthermore if the output is divided by the curve the result for a perfect DUT would be a horizontal line which is easy to ins...

Страница 292: ...op Bot As Single Top WM Math F1 Out Result VerticalFrameStop Bot WM Math F1 Out Result VerticalFrameStart Picture1 Scale 0 Top Samples Bot Dim Wave Wave WM Math F1 Out Result DataArray Dim Black White Blue Red As Long Black 0 White HFFFFFF Blue HFF4444 Red HFF Draw a theoretical curve for the peaks StartPoint Top 20 EndPoint 54 5 Picture1 Line 0 StartPoint Samples EndPoint Red Draw the plot with l...

Страница 293: ... your panel setups and parameter measurements You have the capability to back up the database to external media The Flashback feature allows you to recall the state of the DSO at a later date including the saved waveforms and the DSO setup so that you can make additional measurements A keyword filter makes it easy to find the correct notebook entry to recall You can choose which notebook to use fo...

Страница 294: ...py report Touch inside Hardcopy Area to determine how much of the screen image to include in the report grid area only grid area plus dialog whole screen E mail Setup You can e mail just the pdf or html report or you can include additional files trace data trc for each waveform in the report a screen dump a scope setup file and an xml report record Touch the checkbox to enable the extra report seg...

Страница 295: ...d A drawing toolbar appears at top The pen tool enables you to write or draw in freehand You can use a mouse or a stylus to do this using the touch screen Once you click off you can drag your note anywhere on your waveform The circle tool enables you to create a circle around a waveform feature that you want to point out Once you click off the circle is drawn and you can drag it anywhere on the sc...

Страница 296: ...lect for shapes lines and text To use additional colors touch More When you touch More a Custom box opens with the default color yellow displayed Touch the yellow button to open the full color palette When you have chosen a custom color touch Add to Custom Colors the color will appear in the Custom Colors palette 296 SDA OM E Rev H ...

Страница 297: ...n objects and text Touch Undo to discard the last object drawn The Move Toolbar button enables you to place the toolbar anywhere on the screen Touch the button a second time to return it to its original fixed location Touch Done when you are finished annotating the notebook entry The name of the entry will appear in the list box in the LabNotebook dialog You can now create a hardcopy report of it ...

Страница 298: ...to a trace file and recalled during flashback they are clipped to 16 bits Floating point waveforms Certain math operations result in the creation of floating point waveforms with much higher resolution than can be stored in a 16 bit waveform file This extra resolution will not be preserved when traces are recalled using flashback Cumulative Measurements Any measurements that are on when the Lab No...

Страница 299: ...g Locating a Notebook Entry A search filter is provided to help you locate the notebook entry you want to make a report of You can search by date or keyword Touch the Filter button A search dialog box opens Touch inside the Day Month and Year fields and enter a date Or touch inside the Keyword field and enter a keyword or phrase Touch Find Now Only the entries fitting the date or keyword criteria ...

Страница 300: ... template however you can use your own format including company logo 1 Touch the Advanced tab 2 Touch inside the Directory field and navigate to a folder to contain the reports 3 Touch the Browse button next to Template to navigate to an existing report format that you want to use Or touch inside the Template field and enter the name and path to the template using the pop up keyboard Otherwise tou...

Страница 301: ...ry in the list box then touch the Delete button to discard just that one entry Saving Notebook Entries to a Folder You can save notebook entries to a folder other than the default 1 Touch the tab bearing the name of the notebook entry 2 Touch the Save Data to button A navigation window opens which provides the opportunity also to open Windows Explorer to navigate to the folder 3 Touch the Zip chec...

Страница 302: ...es a graphical way to quickly and easily set up math functions and parameter measurements Using the Processing Web you can chain together many more math on math functions than you can using the Math Setup dialog where you are limited to two functions In addition you can insert a parameter measurement for any math output waveform anywhere in the web The web analogy derives from the nodes and connec...

Страница 303: ...nu 2 Touch the Math tab and select a math location F1 to Fx The number of math traces available depends on the software options loaded on your scope See Specifications for the new math function that you are about to create by touching the Web Edit button Once you select a math location for web editing it cannot be used for another math function and will appear as unavailable in the Math Setup dial...

Страница 304: ...ton and select a math function from the Add Math Processor menu The math function icon will appear on the web setup field Touch and drag the icon to the desired location 5 If you are using channel inputs touch the arrow of a channel input icon Then drag a line from the channel to the input of the math function icon If your math function is a dual input function such as ratio select a second input ...

Страница 305: ...nected to any math function in the web Adding Previews 1 Touch the Add Preview button A scope like icon will appear 2 Touch the output arrow on the math function or parameter icon and drag a line to the input arrow of the preview icon A thumbnail view of your signal will appear if the preview icon is connected to a channel output or math function output If it is connected to a parameter output a n...

Страница 306: ...n to all the standard WaveMaster scope measurement functions the SDA provides two other types of measurements jitter and eye pattern The ASDA J option also adds bit error rate analysis to the SDA These measurements are available together in the summary screen as well as in individual modes Measurements on the SDA are performed on long continuous acquisitions of the signals under test All jitter me...

Страница 307: ...nistic components as well as the breakdown of deterministic jitter into periodic data dependent and duty cycle distortion Option ASDA J adds the following analysis features Mask violation location This is the ability to list and view the individual bits that violate the selected mask Mask violation location takes much more time than jitter testing acquisition size should be just a few thousand UI ...

Страница 308: ...d jitter X ISI plot X Edge to edge jitter X Effective and MJSQ jitter breakdown X Bit error testing with error map X N cycle jitter parameter data X X Eye Pattern Measurements Average power X X X Bit rate X X X Extinction ratio X X X Eye amplitude X X X Eye bit error rate X X X Eye crossing X X X Eye height X X X Eye width X X X One level X X X Zero level X X X Q factor X X X Table 1 Measurements ...

Страница 309: ...5Gb s TX long haul short haul Rx SONET OC 1 OC 3 OC 12 OC 48 STS 1 eye STS 3 transmit STS 3 interface SDH STM 1 STM 4 STM 16 PCI Express TX add in transition TX add in de emphasized TX system transition TX system de emphasized RX Serial ATA 1 5 Gb s TX connector RX connector USB2 0 TX near end far end RX near end far end TX driver output RX receiver input XAUI Driver far Driver near Table 2 Standa...

Страница 310: ...The jitter wizard is accessed from the Analysis drop down menu 310 SDA OM E Rev H ...

Страница 311: ...isplayed until the instrument is restarted The remainder of the jitter setup wizard guides you through a series of dialogs that request input concerning the signal type and measurement method that is desired Explanations of the various choices that can be made are also provided Each dialog has a default selection that represents the most common configuration You can accept the defaults by simply t...

Страница 312: ... option If this option is not present the two mode buttons are not displayed The Edge Edge mode is explained separately in this manual the information presented here applies mainly to the standard Edge Reference mode 2 Touch inside the Data Source field and select a data source then touch inside the Clock Source field and select a clock input If you want to recover the clock from the signal touch ...

Страница 313: ... the Percent level field and enter a percentage value using the pop up keypad The level is automatically set to the selected percentage on each acquisition Note The absolute level setting should be used for jitter measurements over several acquisitions because the relative setting can potentially remove jitter by tracking slowly thereby varying level shifts that could occur between acquisitions 5 ...

Страница 314: ...k edges relative to the data signal It shifts the clock signal relative to the data signal A clock signal goes through one complete cycle during each bit interval The edge timing can be measured relative to the rising or falling slope of the clock by means of the Clock Slope setting The Tx Density control indicates the ratio of transitions in the data record to the total number of bits in the sign...

Страница 315: ...L is set to a cutoff frequency of 1 1667 times the bit rate of the signal under test This ratio can be adjusted from 1 10 to 1 1e6 The PCI Express PLL uses a filter that approximates the PCI SIG compliance requirement The PCI SIG compliance procedure describes a processing algorithm that measures the average bit rate over 3500 consecutive unit intervals UI or bit intervals The 250 UI in the center...

Страница 316: ...rum clocking because it accurately tracks and removes the low frequency clock spreading while allowing the signal jitter to be measured The natural frequency is somewhat lower than the actual 3 dB cutoff frequency given by the following equation The quantity is the damping factor and is the natural frequency For a damping factor of 0 707 this relationship is fc 2 06 fn 3 Settings for the FC Golden...

Страница 317: ...htub curve near the edges of the graph where the curves are at their highest amplitude while random jitter determines the shape of the curve near the middle TIE trend This is a trend of the time interval error measurements between the data transitions and the reference clock This is the time record of the information contained in the TIE histogram and TIE histogram A histogram of the time interval...

Страница 318: ...s you to select different modes for the selected standard Individual modes for a given standard define specific masks for example transmit or receive 6 Under Measure touch inside the Type field then select a set of parameter measurements from the pop up menu 6 The Sequential eye pattern is created using a long acquisition of waveform data that is then processed to generate a recovered bit clock an...

Страница 319: ...e Slice Width The slice width is a percentage of the duration of a single bit i e the part of the pattern over which the extinction ratio is measured By setting a percentage value you indicate how much of the central portion of the bit width to use Slice width is marked by the dashed vertical lines on the display field and enter a value from 0 to 100 Mask Margin 1 Touch inside the X field and ente...

Страница 320: ...p up keypad enter the number of failures after which data accumulation will end up to 10 000 Multiple failures can occur on each bit so the value of N failures will always be equal to or greater than the number of failed bits 7 ASDA J option only Touch inside the Bits in Locater field and using the pop up keypad enter the number of bits to be displayed in the bad bits trace This trace shows the pa...

Страница 321: ...Header or Size and Header touch inside the Frame header field and enter a hexadecimal number representing the prefix before the actual data This prefix will be ignored and only the data will be examined If you selected Size or Size and Header touch inside the Frame size field and enter the number of bytes in the frame using the pop up keypad Frame size divides your waveform into equal pieces of th...

Страница 322: ...m two different menus By touching the Trigger descriptor label then the Serial Trigger button you can access the trigger phase locked loop and set the data pattern on which to trigger It is also accessible from the channel 4 Vertical Adjust dialog 322 SDA OM E Rev H ...

Страница 323: ...tting the Data Pattern The 32 bits in the pattern are set using the controls on the right half of the CDRSerialTrigger dialog Using the matrix of buttons you can set the value of each bit in the pattern to 1 0 or X dont care The values are selected by touching each button and cycling through to the desired value The buttons are arranged in four rows each row corresponding to an 8 bit word with cor...

Страница 324: ...up of buttons is provided to quickly set the pattern to all 1s all 0s or all Xs And a fourth button is provided to invert the entire data pattern Example Bit Pattern and Resulting Waveform 324 SDA OM E Rev H ...

Страница 325: ...nob can be used to position the trace in the same way as for other trigger modes The trigger can be set to single normal or auto In auto mode the scope will arm and trigger itself even if the selected pattern is not detected However serial pattern triggering is only valid in the normal or single trigger modes Jitter Setup Jitter measurements are enabled by touching the Jitter button once the signa...

Страница 326: ...to form an estimate of the histogram for a population of 1016 measurements The extrapolated histogram is then integrated to determine the cumulative distribution function which forms the sides of the bathtub curve The bathtub curve gives the eye opening or 1UI Tj UI for all bit error rates down to 10 16 The total jitter for a given bit error rate is found by measuring the width of the bathtub curv...

Страница 327: ...SDA Operator s Manual SDA OM E Rev H 327 ...

Страница 328: ...328 SDA OM E Rev H ...

Страница 329: ...d the active channels are C1 C3 and C4 The 11 GHz channel provides 40 GS s sampling while the 6 GHz channels provide 20 GS s sampling When 11 GHz is selected the active channels are C1 C3 and C4 The 11 GHz channel provides 40 GS s sampling while the 6 GHz channels provide 20 GS s sampling When 6 GHz is selected all 4 channels are active each providing 20 GS s When 6 GHz is selected all 4 channels ...

Страница 330: ... SDA accounts for vertical noise when calculating jitter This feature applies only in Jitter mode If your SDA does not have X Replay loaded this free utility is available for download from www lecroy com Running the Script 1 Minimize the scope application by selecting File Minimize 2 Open Windows Explorer and navigate to D Applications VerticalNoiseCal VerticalNoiseCal irt The X Replay window open...

Страница 331: ... the previous step each channel is tested at two offset positions for each volts div setting Then a second dialog box opens which prompts you to attach any probes desired Touch OK when done or you may Skip this test group 7 When testing is finished notification is given in the lower right hand pane of the X Replay window Using Noise Compensation 1 Maximize the scope application window by touching ...

Страница 332: ...d from the equation Rj Tj BER Dj Tj 1 sigma BER where the value for BER is typically 10e 12 i e Rj is not a function but a single value The bit error rate is selected in the BER pow 10 control in the jitter menu Rj is expressed in terms of an rms value whereas Tj and Dj are expressed as peak to peak values Dj Deterministic jitter is the peak to peak non random part of the total jitter This paramet...

Страница 333: ...e instrument has the ASDA J option present The Effective and MJSQ methods provide alternate ways of determining the random and deterministic jitter but do not include the breakdown of deterministic jitter into periodic and data dependent parts When either of these modes is selected the jitter breakdown button the jitter menu becomes grayed unavailable and only the basic jitter display is shown The...

Страница 334: ...ed histogram of TIE as a function of BER fitting the form Tj BER Dje Tj sigma 1 BER Rje EffeDj Effective Deterministic Jitter is one of the two constants used to estimate the function Tj BER for very low BER Rje is obtained through the analysis of the growth of the extrapolated histogram of TIE as a function of BER fitting the form Tj BER Dje Tj sigma 1 BER Rje 334 SDA OM E Rev H ...

Страница 335: ...standard deviations so that they best fit the tails of the measured pdf The difference between their mean values is the Dj and the average of their standard deviations is the Rj This method is shown as follows MJSQRj MJSQ Random Jitter is determined by finding the average of the two standard deviations of the best fit Gaussian distributions to the left and right sides of the measured jitter probab...

Страница 336: ...button or touch Analysis in the menu bar then Serial Data in the drop down menu The display defaults to the Scope dialog which enables you to set up SDA measurements while you continue to view currently displayed waveforms 2 Touch the Jitter button The Jitter Bathtub setup dialog is displayed You can enable several parameter measurements from this dialog 3 For basic measurements touch the Basic bu...

Страница 337: ...nd enter a value using the pop up keypad To realize a low pass filter select Set to min in the pop up keypad In this case the lower frequency cutoff will be set by the PLL cutoff frequency 3 Touch inside the Upper Limit field and enter a value using the pop up keypad TIE Histogram A TIE histogram is often useful to display the raw measured histogram of the measured jitter values because it can giv...

Страница 338: ...e data pattern and comparing this to the nominal crossing time based on the expected bit rate of the signal under test This measurement requires a repeating data pattern to operate If the data pattern in the signal does not repeat at least once in the acquired data record the DDj parameter will indicate zero even though this type of jitter is present A graphical display of the DDj can be viewed by...

Страница 339: ...e to the first transition in the data pattern D Check the Show Graphic Bit Pattern checkbox to display a trace showing the bit pattern in the grid with the synchronous n cycle plot The transitions of the pattern line up with the measurement points in the plot DDj ISI plot ASDA J Option Only A repeating data pattern is not always present in cases where there is no ability to program the PHY under t...

Страница 340: ... the length specified in the ISI N Bits field Only the patterns that exist in the acquired data stream is shown Touch any bit pattern in the list then touch Add to display that trace Up to seven patterns can be placed in the box at the right and displayed as traces Clear any pattern and trace from the screen by touching the pattern in the list box on the right then touching Remove Touch Clear all ...

Страница 341: ...s automatically set to the selected percentage on each acquisition 3 If you selected absolute touch inside the Abs level field and enter a voltage value Alternatively you can touch the Find Data Level or Find Clock Level button If you selected Percent touch inside the Percent level field and enter a percentage value using the pop up keypad The level is automatically set to the selected percentage ...

Страница 342: ...y 50 of the bit intervals have transitions so the Tx density is 500e 3 The actual acquired data set may have a transition density different from 50 however The total jitter measurement uses this transition density to normalize the measured histogram into a pdf probability density function Many instruments simply assume 50 when performing this normalization which can lead to errors These errors are...

Страница 343: ...population of 1016 measurements The extrapolated histogram is then integrated to determine the cumulative distribution function which forms the sides of the bathtub curve The bathtub curve gives the eye opening or 1UI Tj UI for all bit error rates down to 10 16 The total jitter for a given bit error rate is found by measuring the width of the bathtub curve at the y axis value corresponding to the ...

Страница 344: ...tter menu Rj is expressed in terms of an RMS value whereas Tj and Dj are expressed as peak to peak values Dj Deterministic jitter is the peak to peak non random part of the total jitter This parameter is the sum of the measured peak to peak values of periodic jitter Pj and data dependent jitter DDj The DDj includes the effects of both inter symbol interference and duty cycle distortion Pj Pj is th...

Страница 345: ...easured from the data record because there is no timing reference on which to base the Fourier transform The SDA employs a function called the Alternate N Cycle plot to measure periodic jitter on edge to edge TIE values The plot displays the standard deviation of a histogram of the timing variations for transitions in the data signal that are spaced n UI apart Each Y value in this plot represents ...

Страница 346: ...gram of time interval error measurements to the desired bit error rate This function creates the bathtub and total jitter curves Total jitter as well as the effective and MJSQ breakdowns use the output of this function Jitter filter Filter the trend of jitter values with the specified band pass filter This function expects a trend of jitter values as an input It is further required that the measur...

Страница 347: ... describe the function in detail The N cycle plot displays the mean or standard deviation of the edge placement in the waveform relative to each other data to data or to a reference clock clock to data The N cycle plot displays the mean or standard deviation of the distribution of timing for edges spaced n UI apart as a function of n The value of n can vary from 1 to some maximum value including a...

Страница 348: ...standard deviation for each edge for each value of N relative to the reference clock DDmean gives the mean value of each edge relative to the first edge normalized to a unit interval for each N DDsdev gives the standard deviation for each edge relative to the first edge normalized to a UI for each N Length UI The maximum N value This field displays the pattern length if Sync to Pattern is selected...

Страница 349: ...m On off Averages the N cycle plots measured on successive acquisitions This is especially useful for removing random effects from standard deviation plots Use PLL On off Use the software golden PLL to generate the reference clock for edge timing This setting is ignored when DDmean or DDsdev is selected Cutoff Div PLL cutoff divisor When the PLL is selected this control sets the loop bandwidth as ...

Страница 350: ...pulation of at least 100k and a minimum of 500 bins The histogram should also be completely contained on the instrument screen it may be necessary to set the horizontal scale to do this The table below outlines the settings for this function Output Format Waveform Type TjGaussian The total jitter curve for a Gaussian with zero mean and unity standard deviation LogEstTIE The log of the estimated ex...

Страница 351: ...xtrapolated to a population of 1016 LogTIE The log of the TIE histogram Bathtub The bathtub curve This is a an alternate version of the total jitter curve scaled horizontally to 1 UI The right hand side of the curve is taken from the left hand side of the total jitter curve and the left hand side comes from the right hand side of the total jitter curve Frequency 100 kHz to 4 5 GHz The bit rate of ...

Страница 352: ...the TIETrend trace generated by the SDA The low frequency corner is limited by the record length longer records are required for lower cutoff frequencies If an invalid lower cutoff frequency is chosen the filter reverts to low pass Bit Frequency 100 kHz to 4 5 GHz The bit rate of the signal under test Low Pass Frequency Set by record length and sample rate bit rate The lower corner frequency of th...

Страница 353: ...unction can only be used in the Web Edit mode available with the XWEB option The Include virtual edges checkbox must be checked in the TIE lvl parameter dialog to include both transition and non transition edges in the eye pattern SDA OM E Rev H 353 ...

Страница 354: ...t stream should have a clock input consisting of the numbers 0 4e 10 8e 10 12e 10 which increase at a 400 ps per UI rate The clock signal is derived from the output of the TIE lvl parameter which contains a sequence of adjustment values that are added to the nominal bit period for each UI These correction values allow the TIE lvl parameter to act as a phase locked loop The web edit setup is shown ...

Страница 355: ...splay Scale Bottom to 4 V to 4 V Scales the zero level to a specific voltage on the display MULTI EYE MEASUREMENTS Overview of Multi Eye Measurement Tools The Multi Eye Measurement Tool is designed to improve the analysis and processing of serial data signals in high speed buses and interfaces commonly used in desktop server and storage applications It is available with version 4 3 of X Stream sof...

Страница 356: ...arry out the eye diagram measurements as described in the example below The Gated Eye Diagram requires at least two inputs The Data and the Gate signal The Transition Mode requires at least one input the Data Stream but depending on the specific serial data standard a clock input may also be required to recover the clock information These signals except for the strobes are differential signals so ...

Страница 357: ...Data2 Channel 4 M4 Serial Data Analysis Setup 1 Select Signal Type FSB 533MHz 667MHz or 800MHz 2 Uncheck Recover Clock No clock recovery is required in FSB case 3 Select Eye Diagram Tab then configure the screen as follows Mode FSB Data Source 2 Channel 4 M4 DSTBP Channel 1 M1 DSTBN Channel 2 M2 The screen should look like this SDA OM E Rev H 357 ...

Страница 358: ...e one or several types of serial data masks available 2 Select a Mask Margin as of the nominal mask size if desired 3 Select a Measurement Type There are three groups of parameters Amplitude Eye Height One Level Eye Zero Level Eye Eye Amplitude Timing Eye RiseTime Eye FallTime Eye Eye Width Eye RMS Jit Eye BER Eye Crossing Avg Pwr Eye ...

Страница 359: ...de Bus FSB Introduction to FSB Front Side Bus is also known as the processor bus memory bus or system bus The FSB connects the processors to the main memory and is used to connect to other resources within the computer The FSB can range from speeds of 66 MHz 133 MHz 100 MHz 266 MHz 400 MHz and higher The FSB speed can generally be set either using the system BIOS or with jumpers located on the com...

Страница 360: ...he transmitter and A is the receiver The bus clock BCLK signal is formed by a differential pair BCLK0 and BCLK1 running at 533 MHz This is the trigger signal for the bit transactions with the strobe signals as the qualifiers for the actual bit transfers Data Bus Characteristics Refer to Figure During every period of BCLK 4 bits are sent or there s an idle state high voltage on both strobes and rel...

Страница 361: ... state high voltage on both strobes and relevant data Bit transfers occur in double multiples of bits only 2 4 6 There s sampling of address bits on both falling and rising edges of ADSTB Falling edge ASTB samples address bit 0 Rising edge ASTB samples address bit 1 Address Bus Timing Diagram Intel Corporation SDA OM E Rev H 361 ...

Страница 362: ...eristics Refer to Figure During every period of BCLK 1 bit is sent or there s an idle state meaning high voltage on the signal BCLK is a differential signal Common Clock Bus Timing Diagram Intel Corporation 362 SDA OM E Rev H ...

Страница 363: ...ransition Mode For example Section 4 3 3 1 of PCI Express Specification defines the requirements for Transition and Non transition eye diagrams There are two eye diagrams that must be met for the Transmitter Both eye diagrams must be aligned in time using the jitter median to locate the center of the eye diagram The different eye diagrams will differ in voltage depending whether it is a transition...

Страница 364: ...sed on the polarity of the Gate Here s an example of a gated eye diagram Channel 1 M1 contains the raw data and Channel 2 M2 contains a Gate signal While the Gate signal is high the UIs will transfer to Eye display When the Gate signal goes low the UIs will transfer to Eye2 display Data M1 and Gate M2 signal sources 364 SDA OM E Rev H ...

Страница 365: ...ern computation jitter measurement and bit error testing All of these operations are performed on the same data record The processes are described in detail in this section Clock recovery An accurate reference clock is central to all of the measurements performed by the SDA The recovered clock is defined by the locations of its crossing points in time Starting with zero the clock edges are compute...

Страница 366: ...ossing are interpolated for the measurement A cubic interpolation is used followed by a linear fit to the interpolated data to find the crossing point This is shown in Figure 1 Figure 1 SDA Threshold Crossing Algorithm Clock recovery implementation in the SDA is shown in Figure 2 This algorithm generates time values corresponding to a clock at the data rate The computation follows variations in th...

Страница 367: ...cutoff frequency is Fd n where Fd is the data rate This filter is related to its analog counterpart through a design process known as impulse invariance and is only valid for cutoff frequencies much less than the data rate For this reason the minimum PLL cutoff divisor setting is 20 in the SDA The factor n determines the number of previous values of the correction value y that is used in the compu...

Страница 368: ... to the trigger or data clock As many data points are collected the eye pattern fills in with multiple occurrences of time and amplitude values counted by incrementing counters in each x y bin Timing jitter is indicated by the horizontal distribution of the points around the data crossings The histogram of the bins around the crossing points provides the distribution of jitter amplitude A recovere...

Страница 369: ...s rms Eye Violation Locator ASDA Option The eye pattern is measured by overlaying segments of a continuous acquisition Since the complete data record is available the location of individual bits can be determined by comparing each bit interval in the original waveform to the selected mask The mask is aligned horizontally along the mean bit interval and vertically along the mean one and zero level ...

Страница 370: ...ude is a measure of the amplitude of the data signal The measurement is made using the distribution of amplitude values in a region near the center of the eye normally 20 of the distance between the zero crossing times The simple mean of the distribution around the 0 level is subtracted from the mean of the distribution around the 1 level This difference is expressed in units of the signal amplitu...

Страница 371: ...l to electrical converters on the front end of the SDA Any DC offset in the O E must be removed prior to measurement of the extinction ratio This procedure is known as dark calibration The output of the O E is measured with no signal attached i e dark and this value is subtracted from all subsequent measurements Eye Crossing Eye crossing is the point at which the transitions from 0 to 1 and from 1...

Страница 372: ...lues standard deviations of the 1 and 0 levels All of these measurements are taken in the center usually 20 of the eye eyeBER EyeBER is the estimated bit error rate from an eye diagram It is calculated using the intersection of the distribution of the one and zero levels EyeBER differs from BER in that eyeBER is calculated from Q factor and is therefore based on signal to noise ratio BER on the ot...

Страница 373: ...ons within the setup and hold time gray area will result in bit errors Time interval error TIE is the time difference between clock and data edges The PDF of TIE is a measure of the probability of an edge occurring during the setup and hold time The processes that make up jitter are complex and come from many different random and non random deterministic sources The PDF of the jitter is the convol...

Страница 374: ... error rate The process of determining Rj and Dj involves finding the best fit values that solve equation 1 There are many possible ways to fit Rj and Dj to 1 and since it is a simplification no single set of solutions can completely describe the behavior of actual jitter completely It is for this reason that the SDA uses two separate methods to measure Rj and Dj effective and direct and presents ...

Страница 375: ... contribution due to jitter The total jitter gives a confidence interval for the jitter in that it will not exceed a certain value to a confidence of 1 BER The term bit error rate is commonly used in this context to refer to the jitter confidence interval in many specifications EyeBER differs from BER in that eyeBER is calculated from Q factor and is therefore based on signal to noise ratio BER on...

Страница 376: ... desired bit error rate These jitter values can be measured by finding the intersection between a horizontal line at the bit error rate and the total jitter curve The horizontal spacing between these two points is the total jitter Figure 9 Total jitter curve The vertical values of this curve represent the probability of a data transition occurring at a time represented by the horizontal axis The h...

Страница 377: ...e right half of the total jitter curve The bathtub curve corresponding to the total jitter curve in Figure 9 is shown in Figure 10 Extrapolating the PDF Measuring the total jitter requires that the probability density function PDF of the jitter be known exactly The SDA measures the jitter PDF by collecting a histogram of TIE measurements This histogram approximates the PDF by counting the number o...

Страница 378: ... and above the 90th percentile The log of the histogram is used to simplify this process to a quadratic fit Figure 12 Logarithm of the measured TIE histogram superimposed on the extrapolated curve in yellow The extrapolation uses a quadratic curve fit to the histogram bins at the extremes 378 SDA OM E Rev H ...

Страница 379: ... error in the fit The second method of fitting Rj and Dj to the measured data is based on direct measurements of the deterministic jitter Random jitter is the difference between this value and the total jitter at the selected bit error rate measured from the total jitter curve This of course exactly matches the measured total jitter at the selected bit error rate but is a poor predictor of the jit...

Страница 380: ...he two classes of deterministic jitter are periodic and data dependent Data dependent jitter is caused by system effects that are dependent on the data pattern A common source of data dependent jitter is the frequency response of the channel through which the serial data signal is transmitted In this case data patterns with many transitions such as a 101010 pattern contain more high frequencies in...

Страница 381: ...re Averaged waveform segments for each pattern in the data stream are overlaid by lining up the first data transition The curve above shows all of the transitions between the next to last bit and the last bit on the right side The DDj is measured by examining the width of this crossing point at the selected threshold level Periodic jitter is measured by examining the spectrum of the trend of TIE v...

Страница 382: ...the total jitter at error rates below the specified one and overestimates the jitter above this Note that the effective parameters underestimate the jitter for high bit error rates The three curves in Figure 15 show the resulting bathtub curves from the measured signal blue line and the two models Hj BER for the direct Dj method red line and Hje BER for the effective jitter method green line Figur...

Страница 383: ...available through the bit error map This display is a view of the bit errors in the data stream relative to any framing that may be present in the signal There are several options for framing that may be set The general form of the data signal is shown here The header portion is a fixed pattern that can be set to any pattern The header must be one or more bytes if it is present The software search...

Страница 384: ...Figure 16 Bit Error Map for 127 Bit Pattern Containing Random Errors White Squares Figure 17 Bit Error Map for 127 Bit Pattern Containing Pattern Dependent Errors 384 SDA OM E Rev H ...

Страница 385: ... also interpret this as jitter Any noise added by the test system should however not be included as this will overestimate the jitter The SDA includes a feature that removes the system noise from the instrument which uses the rms noise of the oscilloscope and probe if present This section explains the theory of operation of the noise compensation Signal Slew Rate and How Vertical Noise Converts to...

Страница 386: ...se contribution from the instrument can be compensated as follows So if the dv dt can be well estimated by the instrument and if the instrument s contribution to vertical noise is known and incoherent with the signal which is nearly always the case this compensated Rj figure can be reported As such the LeCroy SDA software has been equipped to perform this compensation and applies it to the Rj figu...

Страница 387: ...l The PDF is a continuous function and reflects integrals of the probability see http en wikipedia org wiki Probability_density_function over each interval of measurem value x ent That is to say the density of probability as a function of the measured quantity when integrated over a given region gives the probability that any measurement value will be within that region The process of forming a hi...

Страница 388: ...presentation We are interested in variations in timing jitter before and after the mean timing value or to left or right of the mean As such and in order to view the timing errors in a symmetric fashion we paste together two halves the right hand and the left hand parts of the EDF where the left hand part is summed from the left increasing bin index starting with leftmost bin and the right hand pa...

Страница 389: ... is even beyond where we have real observed data To this end we strive to fit the data at the extremes of the EDF to plausible mathematical forms suggested by the underlying physics One such mathematical form is the error function which is closely related to the CDF of a Gaussian distribution The Error Function erf x Inverse Error Function erf 1 x and Related Functions Where the error function its...

Страница 390: ...function erf 1 n help to put the general er not to confu The Relationship between the Inverse Error Function and Total Jitter It is noteworthy that the inverse error function has no closed analytical form It is also noteworthy that the heuristic jitter equation is linearly related to this inverse error function Recall this equation 390 SDA OM E Rev H ...

Страница 391: ...f the problem are well chosen An example is Kepler s Laws When expressed in the usual Cartesian coordinate system those laws are rather obscure but expressed in polar coordinates they are quite simple The problem of analyzing the EDF in order to predict a CDF is best served by a coordinate transformation for the variable BER The subject of Q Scale has been proposed and described by several sources...

Страница 392: ...ion This is all common treatment so r All is well for a single Gaussian distribution Now enter the idea that this coordinate transformation should have a variable normalization s normalization is such that when the area of an un normalized Gaussian is ρnorm then 0 fa factor Thi that resulting CDF manifests as straight lines with slope revealing sigma and intercept with Q giving the mean of the Gau...

Страница 393: ... equal to the reciprocal of the slope obtained from the best linear fit and amplitude area equal to the best normalization factor itself 4 Under the assumption of symmetric noise jitter contributions a single ideal normalization may be obtained and used however ideally both extremes of the EDF must be treated the same sum contributing to the estimate of EDF in this case Upper and lower values of B...

Страница 394: ...394 SDA OM E Rev H ...

Страница 395: ...SDA Operator s Manual SDA OM E Rev H 395 ...

Страница 396: ...e detailed differences between this and other approaches for obtaining Rj and Dj the most important figure we need to establish is total Jitter Referring roughly back to the heuristic jitter equation we rewrite this as Where Dj is the separation between the two means of the distributions 396 SDA OM E Rev H ...

Страница 397: ...e traditional Dj and Rj value we are still using the separation of the outermost means and approximating Rj by the mean of the two sigmas We do however calculate Tj from the most precise estimation of the CDF from the renormalized Q scale fit using correct weights and sigmas to reconstruct a theoretical PDF using the central region of the histogram as is and the extremes replaced by theoretical Ga...

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