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HP 54710A, User'S Reference Manual

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Summary of dc Errors

You can minimize the effects of dc errors on time-interval measurements by
observing these guidelines when feasible:

•

Measure between identical edges—same slew rate, amplitude, and offset.

•

Use the same dc level to reference each endpoint of the interval.

•

Reference the measurement to the fastest-slewing portion of each edge.

•

Operate the oscilloscope in a mode that gives the best vertical resolution.

Signal edges having faster slew rates minimize the effects of dc errors on the
time interval measurement.

Dynamic Response Errors

Whenever the input voltage of an oscilloscope changes with respect to time,
there is some transient error in the oscilloscope’s reproduction of the input
signal.

The probe also has some non ideal transient response that contributes to the
overall system error.  Additionally, the probe and the circuit under test form
a circuit that behaves differently from the circuit without the probe; the
signal at the probe tip is not the same as the signal that is present when the
probe is removed.  Probe loading often has a more significant effect on the
measurement than the transient response of the oscilloscope, and must be
included in the analysis of time-interval measurement errors.  See "Probe
Capacitive Loading" for more information.

At the very high bandwidth of the HP 54720 oscilloscope, the transient

response of 50 

Ω

 coaxial cables can be significant.  You must use good quality

cables and keep them as short as possible for best accuracy.

Measurements

Time-interval measurements

13–37

Summary of Contents for 54710A

Page 1: ...rmware revision 4 XX For Safety information Warranties and Regulatory information see the pages behind the index Copyright Hewlett Packard Company 1992 1995 All Rights Reserved HP 54710A 54710D 54720A and 54720D Oscilloscopes Advanced Test Equipment Rentals www atecorp com 800 404 ATEC 2832 Established 1981 ...

Page 2: ...sales and service contact information in this manual may be out of date The latest service and contact information for your location can be found on the Web at http www agilent com find assist If you do not have access to the Internet contact your field engineer or the nearest sales and service office listed below In any correspondence or telephone conversation refer to your instrument by its mode...

Page 3: ...in the 54720D The HP 54720 also has firmware modularity by having a 3 1 2 inch disk drive and flash ROMs which allows for upgrades of the system firmware features in the oscilloscope The plug ins provide analog signal conditioning for the A D converters that are inside the mainframe This performance and flexibility provide you with the most accurate analysis of single shot phenomena found in any l...

Page 4: ...can damage the oscilloscope HP 54710 68703 Opt 907 Rackmount kit handles only Includes M4 X 0 7 X 12 mm flat head screws HP part number 0515 2227 HP 54710 68704 Opt 908 Rackmount kit ears only Includes M4 X 0 7 X 14 mm flat head screws HP part number 0515 0435 HP 54710 68705 Opt 909 Rackmount kit with ears and handles Includes M4 X 0 7 X 20 mm flat head screws HP part number 0515 0456 HP 54720 687...

Page 5: ... the Acquisition hardkey on the front panel The remaining chapters contain additional information about the oscilloscope For example Measurements discusses how the oscilloscope calculates the measurement results when you select an automatic measurement You will find it easier to use this reference book if you are at least a little familiar with how to use the front panel The best way to learn how ...

Page 6: ...e Works 1 Front Panel Features 2 Acquisition Menu 3 Applications 4 Calibration Overview 5 Channel Menu 6 Define Measure Menu 7 Disk Menu 8 Display Menu 9 Messages 10 Marker Menu 11 Math Menu 12 Measurements 13 Setup 14 v ...

Page 7: ...vi ...

Page 8: ...tup Print Menu 15 Specifications and Characteristics 16 Time Base Menu 17 Trigger Menu 18 Utility Menu 19 Waveform Menu 20 FFT Menu 21 Limit Test Menu 22 Mask Menu 23 Histogram Menu 24 Glossary Index vii ...

Page 9: ...viii ...

Page 10: ...1 32 2 Front Panel Features Autoscale Key 2 3 Clear Display Key 2 3 Display 2 4 Entry Devices 2 7 Fine Mode 2 8 Help Menu 2 9 Indicator Lights 2 10 Local Key 2 12 Run Key 2 13 Stop Single Key 2 14 3 Acquisition Menu Sampling Mode 3 4 Digital BW Limit 3 6 Interpolate 3 6 Sampling Rate 3 12 Record Length 3 14 Averaging 3 19 Completion 3 20 4 Applications Contents 1 ...

Page 11: ...8 6 Channel Menu Display 6 4 Scale 6 5 Offset 6 6 Input 6 6 Probe 6 7 Calibrate 6 10 7 Define Measure Menu Define Measure Menu 7 2 Thresholds 7 4 Top Base 7 6 Define time 7 8 Statistics 7 9 8 Disk Menu Disk Menu 8 2 Directory 8 3 Load 8 5 Store 8 6 Delete 8 8 Format 8 9 Type 8 10 File Format 8 12 From File To File or File Name 8 20 To Memory 8 21 Contents Contents 2 ...

Page 12: ... 9 5 Draw Waveform 9 6 Graticule 9 10 Label 9 13 Color 9 17 10 Messages 11 Marker Menu Off 11 3 Manual 11 3 Waveform 11 5 Measurement 11 7 Histogram 11 8 Marker Hints 11 8 12 Math Menu Function 12 3 Define Function 12 4 Display 12 7 Contents Contents 3 ...

Page 13: ...Standard Waveform Definitions 13 21 Voltage Measurements 13 21 Timing Definitions 13 24 Some Important Measurement Considerations 13 26 Making Automatic Measurements from the Front Panel 13 27 Increasing the accuracy of your measurements 13 29 Measuring time intervals 13 30 Statistics 13 34 Time interval measurements 13 38 14 Setup Menu Setup Memory 14 3 Save 14 3 Recall 14 4 Default Setup 14 4 15...

Page 14: ... Position 17 3 Reference 17 4 Windowing 17 5 18 Trigger Menu Trigger Basics 18 4 Sweep 18 6 Mode 18 7 Source 18 20 Level 18 20 Slope 18 20 Holdoff and Conditioning 18 21 19 Utility Menu HP IB Setup 19 3 System Configuration 19 4 Calibrate 19 10 Self Test 19 14 Firmware Support 19 14 Service 19 16 20 Waveform Menu Waveform 20 3 Pixel 20 6 Contents Contents 5 ...

Page 15: ...2 4 Fail When 22 5 Upper Limit 22 7 Lower Limit 22 7 Run Until 22 7 Fail Action 22 9 23 Mask Menu Polygon Masks in the Oscilloscope 23 4 Test 23 6 Scale mask 23 7 Edit Mask 23 9 Run Until 23 18 Fail Action 23 20 24 Histogram Menu Histograms in the oscilloscope 24 3 Mode 24 6 Axis 24 6 Histogram Window 24 7 Histogram Scale 24 8 Run Until 24 10 Contents Contents 6 ...

Page 16: ...Glossary Index Contents Contents 7 ...

Page 17: ...Contents 8 ...

Page 18: ...1 Hardware Architecture 1 3 Data Flow 1 8 Sampling Overview 1 11 Choosing Plug ins 1 17 Choosing Probes 1 20 System Bandwidth 1 25 How the Oscilloscope Works ...

Page 19: ...ubleshooting purposes but rather to give you an idea of the basic hardware inside the oscilloscope so you can make better decisions about configuring the oscilloscope when you are making measurements The following topics are discussed Hardware Architecture Data Flow Sampling Overview Choosing Plug ins Choosing Probes System Bandwidth 1 2 ...

Page 20: ... the oscilloscope You will find a complete block diagram of the oscilloscope in the Service Guide that is supplied with the oscilloscope Figure 1 1 is a functional block diagram of the hardware in the oscilloscope Figure 1 1 How the Oscilloscope Works Hardware Architecture 1 3 ...

Page 21: ...22A plug in uses four slots which interleaves four hybrids in time to give you 8 GSa s sample rate and 64K 256K on the D models of memory In the equivalent time sampling mode the 500 MSa s samplers are synchronized and the voltage reference of the ADCs is shifted in voltage by one quarter of a least significant bit to achieve higher vertical resolution This process results in 500 MSa s and 16K 64K...

Page 22: ... the oscilloscope because the CPU now reads calibrated data and does not have to explicitly correct it This is faster than using a software solution Microprocessors and coprocessors There are two 32 bit microprocessors one 32 bit coprocessor and one 16 bit coprocessor in the mainframe Motorola 68020 A 32 bit microprocessor that controls the system hardware and also acts as a traffic controller on ...

Page 23: ...stem firmware into the flash ROMs load applications save screen dumps in a TIFF GIF or PCX format or as additional storage space for saving waveforms and front panel setups User Interface Hardware The user interface hardware is the keyboard and the hardware that interfaces the keyboard and knob with the system bus FIFO and HP IB Hardware The FIFO is a first in first out memory that transfers wavef...

Page 24: ... high speed port feature is not implemented at this time Video RAM This is 1 MByte of fast video RAM for storing the display image The video RAM also contains the pixel memory Display The display is a 9 inch high resolution color display See Also Display in Chapter 2 for additional details How the Oscilloscope Works Hardware Architecture 1 7 ...

Page 25: ...data and when the post acquisition signal processing is applied to the data Figure 1 2 is a data flow diagram of the oscilloscope The diagram is laid out serially to give you a visual perception of how the data is affected by the oscilloscope Figure 1 2 How the Oscilloscope Works Data Flow 1 8 ...

Page 26: ...real time data after it has gone through postprocessing Therefore you can make measurements on the data and you can turn on or off digital bandwidth limit or interpolation without having to reacquire the data This is important because the real time sampling mode is primarily used on events that happen either once or infrequently and reacquiring the data may not be one of your options Also turning ...

Page 27: ...d the data is sent through the display portion of the oscilloscope Notice that connected dots is a display feature and that it has no influence on the measurement results The pixel memory is also part of the video RAM which is past the point where the measurements are performed on the data Therefore you cannot make measurements on data in the pixel memory But you can make measurements on data stor...

Page 28: ...ug in like the HP 54721A uses two plug in slots for a maximum sampling rate of 4 GSa s A four wide plug in like the HP 54722A uses four plug in slots for a maximum sampling rate of 8 GSa s Also this sampling mode is typically used on signals that happen either once or infrequently Because you may have only one chance to capture the data you will want to use the maximum sampling rate available A si...

Page 29: ...them may represent the signal You can say that the signal in figure 1 3 is undersampled because not enough data was acquired on each time base sweep for the oscilloscope to accurately reconstruct the waveform on the display Also notice the measurement results at the bottom of the picture The question marks indicate that there was insufficient data to make the measurements Figure 1 3 How the Oscill...

Page 30: ...ill enough differences among each of the ten waveforms that you can say the signal is undersampled Notice that figure 1 4 gives you more information about the signal than figure 1 3 The oscilloscope has enough data to make the measurements but the statistics results show that there is a wide variation in the measurement results Figure 1 4 How the Oscilloscope Works Sampling Overview 1 13 ...

Page 31: ...o that it can more faithfully reconstruct the signal Also notice that the statistics results indicate that the measurements are much more repeatable Use the real time sampling mode when The signal occurs once or infrequently The sample rate is four times or greater than the highest frequency components that you are interested in in the signal Figure 1 5 How the Oscilloscope Works Sampling Overview...

Page 32: ...ple rate You can still use the equivalent time sampling mode for single shot applications Because the interpolation filter is not available in the equivalent time mode the maximum single shot frequency you can reasonably view and also avoid aliasing is about one tenth the sample rate or 50 MHz The HP 54711A and HP 54712A plug ins are best suited for equivalent time sampling because they allow acce...

Page 33: ...in excellent reconstruction of the signal Compare the similarity between figures 1 5 and 1 6 Also notice that the statistical results indicate very repeatable measurement results Use the equivalent time sampling mode when The signal is repetitive The signal contains frequency components that you are interested in greater than one fourth maximum the sample rate of the oscilloscope Figure 1 6 How th...

Page 34: ...the rise time of the oscilloscope compared to the rise time of the signal you are measuring The oscilloscope rise time is about Scope Rise Time 0 35 Bandwidth To obtain a rise time measurement accuracy of 5 percent the rise time of the oscilloscope should be one third the rise time of the signal you are measuring To obtain a rise time measurement accuracy of 1 percent the rise time of the oscillos...

Page 35: ...50 Ω 50 Ω 1 M Ω 50 Ω 1 M Ω 50 Ω 50 Ω 50 Ω Slots used 1 1 1 1 2 4 The standard 1 2 5 sequence in the 54722A plug in which is selected by the mainframe s front panel knob does not correspond exactly to the attenuator ratios in the hardware Refer to the HP 54722A Attenuator Plug in User s Reference for more information about the attenuator ranges Use the HP 54711A plug in when The signal is repetitiv...

Page 36: ... up to 8 channels Use the HP 54721A plug in when The signal happens once or infrequently and you are using the real time sampling mode You need the 1 1 GHz real time bandwidth rise time is slower than 1 ns You need the 4 GSa s sample rate You need 32K memory depth Use the HP 54722A plug in when The signal happens once or infrequently and you are using the real time sampling mode You require the 8 ...

Page 37: ...rement system response degrading measurement accuracy The probe is a part of the circuit under test Suppose that you are trying to debug an intermittent failure in a state machine that is implemented in high speed CMOS logic You know that you need a high performance digitizing oscilloscope but you don t know which probe gives the best results There are two major factors influencing probe selection...

Page 38: ...hed to indicate the principal loading effects The probe load has both resistive and capacitive components In addition to this the inductance in the probe ground lead can cause ringing Simplified equivalent circuit of DUT and probe Figure 1 8 How the Oscilloscope Works Choosing Probes 1 21 ...

Page 39: ...e of the circuit under test the amplitude is reduced by about 10 percent See figure 1 9 The frequency independent amplitude errors and dc offset errors introduced by probe resistive loading are approximately proportional to the ratio of the probe s resistance to ground and the equivalent output resistance of the circuit under test Reduced amplitude and dc offset caused by probe loading Figure 1 9 ...

Page 40: ... time of a simple RC circuit is 2 2 RC Thus for an output resistance of 100 Ω and a probe tip capacitance of 8 pF the real rise time at the node under test cannot be faster than approximately 1 8 ns Although it might be faster without the probe If the output of the circuit under test is current limited as is often the case for CMOS the slew rate is limited by the relationship dV dT I C See figure ...

Page 41: ...of PC board traces and so on The ringing frequency of this circuit is F 1 2 π LC If the rise time of the signal is sufficient to stimulate this ringing then it can appear as part of the captured signal An approximation of the bandwidth of the signal is Signal Bandwidth 0 35 Signal Rise Time To calculate the ringing frequency you can assume that the probe ground wire has an inductance of approximat...

Page 42: ...rizing First the combined system rise time oscilloscope and probe should be less than 1 3 the rise time of the measured signal for an error of less than 5 percent or less than 1 7 of the rise time of the measure signal for an error of less than 1 percent Second rise time and bandwidth are inversely related as shown in equations 5 and 6 Third rise times add approximately as the square root of the s...

Page 43: ...mpedance The tip of the probe has a 450 Ω or 950 Ω series resistor The cable is designed for a 50 Ω transmission line Because the cable is terminated in 50 Ω at the oscilloscope input it looks like a purely resistive 50 Ω load when viewed from the tip Therefore the resistive divider is flat over a wide range of frequencies limited primarily by the parasitic capacitance and inductance of the 450 Ω ...

Page 44: ...uit under test might affect the circuit s behavior This type of probe is the best choice for minimum disturbance probing of ECL circuits and 50 Ω transmission lines The 1 kΩ divider probes are also usually suitable for high speed CMOS circuits If you are interested in troubleshooting CMOS consult the data sheet for the particular CMOS part to make sure that it can drive a 1 kΩ load and to determin...

Page 45: ...put capacitance One of the compensating capacitors is made adjustable so you can optimize the step response flatness because the input capacitance of the oscilloscope is unknown The HP 54720A provides a square wave at the calibrator output for this purpose Compensated passive divider probe Figure 1 12 How the Oscilloscope Works System Bandwidth 1 28 ...

Page 46: ...edance of an 8 pF capacitance is 10 kΩ and at 100 MHz it is only 200 Ω This type of probe is often referred to as a high impedance probe This is a misnomer because they exhibit high impedance only at relatively low frequencies Figure 1 13 shows a plot of the impedance of a typical 1 MΩ 8 pF probe as a function of frequency Some applications where 1 MΩ or higher probes are appropriate include high ...

Page 47: ...omewhat limited input dynamic range Previous active probe designs were more susceptible to damage particularly to ESD and required careful handling The HP 54701A is designed to withstand 200 V peak ac and 12 kV of ESD so it functions reliably in adverse conditions The HP 54701A has sufficient bandwidth 2 5 GHz sufficiently small capacitive loading 0 6 pF and sufficiently high resistance 100 kΩ to ...

Page 48: ...e using SPICE This discussion assumes a simple resistance as the equivalent circuit for the circuit under test For an actual measurement a more complete model is useful in evaluating the effects of the probe Some knowledge of the expected signal particularly its rise time or spectral content is also useful in making a probe choice Finally it s important to know what parameter voltage or time you n...

Page 49: ...mV div HP 54713B 500 MHz 10 mV div HP 54721A 1 GHz 10 mV div HP 54006A Passive 50 Ω Divider Probe Input resistance 500 Ω 10 1 or 1000 Ω 20 1 Input capacitance Typically 250 fF Division Ratio 10 1 or 20 1 When used with Bandwidth Maximum sensitivity HP 54711A 1 5 GHz 20 mV div 10 1 or 40 mV 20 1 HP 54712A 1 1 GHz 10 mV div 10 1 or 20 mV 20 1 HP 54721A 1 1 GHz 10 mV div 10 1 or 20 mV 20 1 HP 10430A ...

Page 50: ...2 Autoscale Key 2 3 Clear Display Key 2 3 Display 2 4 Entry Devices 2 7 Fine Mode 2 8 Help Menu 2 9 Indicator Lights 2 10 Local Key 2 12 Run Key 2 13 Stop Single Key 2 14 Front Panel Features ...

Page 51: ...the front panel interface is in the User s Quick Start Guide that is supplied with the oscilloscope The two types of keys on the front panel are hardkeys and softkeys A hardkey has text numbers or graphics printed on it or it is blue in color Softkeys are to the right side of the display and the label for a softkey is displayed on the screen next to that softkey These labels are referred to as men...

Page 52: ...is happens you can use the Undo Autoscale key to return the oscilloscope to the settings prior to pressing the Autoscale key To undo an Autoscale Press the blue shift key then press the Autoscale key again Clear Display Key The Clear display key erases all channel and function waveform data from the graticule area and it resets all associated measurements and measurement statistics When the oscill...

Page 53: ...messages warnings acquisition status sample rate in the real time mode and the number of averages when averaging is turned on in the equivalent time mode Time base position setting Time base reference indicator Channel and measurement results area Time base area Memory bar Softkey menu area Status area Graticule area Marker results and statistics results area Figure 2 1 Front Panel Features Displa...

Page 54: ...el and measurement results area The channel settings and measurement results share the same area The channel settings are displayed only when the measurements are off When you make an automatic measurement the results are displayed in place of the channel settings To get the channel settings back on the display Press the blue shift key then press the Clr meas clear measure key When a channel numbe...

Page 55: ...press The Quick Start Guide contains an explanation of how the softkeys operate Memory bar The memory bar represents the entire waveform record The highlighted part of the memory bar represents the portion of the waveform record that is currently on the display When possible the acquisition hardware is set up so that all of the waveform record is displayed on the screen When the waveform record co...

Page 56: ...list of choices When you use the entry devices to scroll through a list of choices you may notice that the background color of each item changes as scroll through the list Occasionally a particular feature may not be available with a specific plug in model In this case the background color of that feature will not change as you scroll through the list Front Panel Features Entry Devices 2 7 ...

Page 57: ...mV and 500 mV In the fine mode the knob changes the channel scale in smaller increments like 100 mV 101 mV 102 mV To put the oscilloscope in the fine mode press the blue key on the keypad then press the down arrow key with the word Fine written above it Repeat the process to exit the fine mode You can tell when the fine mode is active because the screen displays the word FINE at the top right corn...

Page 58: ...r example to move a signal vertically on the display you can look up Channel vertical position in the help menu list The middle column indicates that you press the Channel hardkey and the right column indicates that you also press the Offset softkey Offset allows you to move waveforms vertically on the display When possible the feature is listed under different names This allows you to look up a f...

Page 59: ...ny data the lack of data indicates that you need to change the channel and time base menus to properly display the signal Also you may have to reacquire the data after changing the setup conditions on the ocilloscope to display the signal Triggered When the triggered light is on it indicates that the oscilloscope accepted a trigger event Every time the oscilloscope accepts a trigger event it makes...

Page 60: ...he trigger level half way between the two thresholds Auto Triggered When the auto triggered light is on it indicates that the oscilloscope is not seeing any valid trigger events and that the oscilloscope is forcing itself to trigger every 30 ms If you see that the auto triggered light is on you know that the oscilloscope is triggering and that the screen should display data If the screen is not di...

Page 61: ...scilloscope to return control to the front panel This is the only active key when the oscilloscope is under remote control The exception occurs when the controller sends a local lockout command The local lockout command prevents the local key from causing control of the oscilloscope to return to the front panel Front Panel Features Local Key 2 12 ...

Page 62: ...ts Press the Autoscale key unless the signal is single shot Make sure that a signal is connected to one of the channels and that the display for that channel is turned on Make sure that the offset does not have the trace clipped off the display Check the trigger setup conditions to make sure that the trigger conditions are valid for the signal Set the trigger sweep mode to Auto Auto sweep forces t...

Page 63: ...shot events Single shot events are waveforms that occur only once or infrequently Some examples of single shot events are a switch closure a power supply turnon the impact of an object on the floor or an errant pulse that causes your system to fail In order to capture a single shot event you need to have some knowledge of the waveform you are trying to capture You must know the approximate amplitu...

Page 64: ...ay key This erases any previously acquired data from the display and resets any measurement results 8 Press the Stop Single key again This rearms the trigger circuit The next event that meets the trigger criteria specified in step 4 is captured by the oscilloscope If the channel and time base controls are set correctly the signal is displayed on the screen and any measurement results are recalcula...

Page 65: ...2 16 ...

Page 66: ...3 Sampling Mode 3 4 Digital BW Limit 3 6 Interpolate 3 6 Sampling Rate 3 12 Record Length 3 14 Averaging 3 19 Completion 3 20 Acquisition Menu ...

Page 67: ... acquisition menu allows you to customize the way the oscilloscope acquires the data Some of your choices are selecting the sampling mode number of averages sample rate and record length Acquisition menu map Figure 3 1 3 2 ...

Page 68: ...y the sampling mode you select determines which of these two softkey menus is displayed The menu on the left is for the real time time sampling mode while the menu on the right is for the equivalent time sampling mode Acquisition Menu 3 3 ...

Page 69: ... all the data points that make up a waveform come from one trigger event Therefore you want the highest sample rate possible to better reconstruct the signal The real time sampling mode has the following features 8 bits of vertical resolution Fast waveform throughput Ability to turn on or off the bandwidth limit filter Ability to turn on or off the interpolator Selectable sample rate Selectable re...

Page 70: ... the waveform is reconstructed from data points that are acquired from multiple trigger events The equivalent time sampling mode has the following features 8 bits of vertical resolution Averaging of acquired data points to achieve vertical resolutions of up to 12 bits Maximum sampling rate of 500 MSa s on each plug in slot Maximum system bandwidth Ability to turn on or off averaging Selectable rec...

Page 71: ...s or memories Interpolate Interpolate is a finite impulse response FIR digital filter that makes the best possible reconstruction of the waveform This reconstruction is done by using digital signal processing DSP to add data points between the acquired data points The interpolated data points are used in calculating measurement results which usually improves the accuracy of your measurements The b...

Page 72: ...Interpolation turned off Interpolation turned on Figure 3 2 Figure 3 3 Acquisition Menu Interpolate 3 7 ...

Page 73: ...ith the data that is in memory rather than what is on the display Figure 3 4 shows the same rising edge except that interpolate is turned off and connected dots is turned on For the best measurement results leave interpolation turned on all the time Only turn interpolation off when you want to see the actual acquired data points or when you want to increase the throughput of the oscilloscope Conne...

Page 74: ...nterpolation of the clipped data The following two pages show some examples of clipped waveforms Figure 3 5 shows a signal that is not clipped Figure 3 6 shows the same signal when it is clipped Notice that connect the dots is used instead of interpolation When filters are turned on like bandwidth limit it is even more difficult to determine if the applied signal is clipped Figure 3 7 shows the sa...

Page 75: ...Applied signal is not clipped Applied signal is clipped Figure 3 5 Figure 3 6 Acquisition Menu Interpolate 3 10 ...

Page 76: ...Applied signal is not clipped and bandwidth limit is turned on Applied signal is clipped and bandwidth limit is turned on Figure 3 7 Figure 3 8 Acquisition Menu Interpolate 3 11 ...

Page 77: ... length to automatic the oscilloscope picks an optimum sample rate and record length that gives the best waveform reconstruction and measurement speed for the time base scale setting you selected However you may want to make the trade off decisions yourself by selecting a sample rate and record length that fits your application You may prefer to sacrifice measurement throughput by selecting a high...

Page 78: ... 4 GSa s or up to 8 GSa s That is because even though the two wide plug in or the four wide plug in is turned off if it is used as an operand in a waveform math function it is acquiring data at the selected sample rate Automatic Automatic lets the oscilloscope select the sampling rate for you The advantage is that the oscilloscope selects a sample rate that optimizes the way the waveform is displa...

Page 79: ... Time Duration of the Record There are some points you should remember when you are mixing plug ins using both single wide plug ins and a two wide plug in The maximum record length is 16K per plug in slot on the A model mainframes and up to 64K per plug in slot on the D model mainframes A two wide plug in like the HP 54721A uses two plug in slots which allows a maximum record length of 32K on the ...

Page 80: ...isplay waveform histogram or mask testing modes an optimum number of points for the database is selected It is recommended that the auto record length be used for the above three modes Manual Manual lets you pick a record length from 16 to 16K points with single wide plug ins in the A model mainframes from 16 to 65K points in the D model mainframes up to 32K or 128K points with a two wide plug in ...

Page 81: ...to display 1 2 GSa s 256 Points 128 ns of data Because the time base is set to 50 ns div and the screen is 10 divisions wide the screen can display up to 500 ns of data In this example there is 128 ns of data in the waveform record which is not enough data to fill the screen In order to fill the screen either increase the waveform record length to 1000 to capture more data or change the time base ...

Page 82: ...ower sample rate in order to optimize the amount of data stored in memory to fill up the screen Notice that more data is displayed 1 500 MSa s 256 Points 512 ns of data Because the screen can display up to 500 ns of data about 97 7 percent of the waveform record is displayed on the screen The arrow on the right side of the memory bar indicates that the data in the waveform record that is not prese...

Page 83: ...ope while still displaying most of the waveform record on the screen Notice that the oscilloscope picked a sample rate of 2 GSa s and increased the waveform record to 1001 points 1 2 GSa s 1001 Points 500 5 ns of data The same amount of data is stored in the waveform record as figure 3 10 except that in figure 3 11 the data was acquired at 2 GSa s instead of 500 MSa s Automatic sample rate and aut...

Page 84: ...eraging significantly reduces noise on the displayed waveform improves resolution of the displayed waveform and increases measurement repeatability all due to a more stable displayed waveform However averaging slows down the throughput of the oscilloscope Also the waveform is less responsive to changes especially when you select a high number of averages The vertical resolution can be improved to ...

Page 85: ...by the number of averages control After the measurement is made the data in the waveform record is erased and the acquisition process starts over Due to the nature of the real time acquisition mode 100 of the waveform record bins are filled after each trigger event and all of the old data in the record is replaced by new data Hence the Completion control really has no effect and the behavior is ex...

Page 86: ...4 Applications ...

Page 87: ...disk into the disk drive 2 Press the Application key at the bottom of the display 3 Press the Install Application softkey If the scope is turned off 1 Place the disk into the disk drive 2 Turn on the scope The application will load automatically as the scope powers up and will remain loaded in RAM as long as the scope is left turned on To access the application press the application key at the bot...

Page 88: ...5 Mainframe Calibration 5 3 Plug in Calibration 5 4 Normal Accuracy Calibration Level 5 5 Best Accuracy Calibration Level 5 6 Probe Calibration 5 8 Calibration Overview ...

Page 89: ...It is intended to give you or the calibration lab personnel an understanding of the various calibration levels available and how they were intended to be used Also this section acquaints you with the terms used in this manual the help screens and the data sheet as they apply to calibrating the oscilloscope 5 2 ...

Page 90: ...nt Frame Temperature _ C The equipment needed to perform mainframe calibration is HP 54717A Calibration Plug in Three BNC cables 1 to 2 ft two cables must be the same length 20 dB BNC attenuator BNC Tee When the calibration is initiated instructions appear on the screen on how to connect the various pieces of equipment to perform the calibration Note you can use the 20 dB attenuator as a 50 Ω term...

Page 91: ...d The equipment needed to perform a plug in calibration is a BNC cable 1 to 2 ft Because the intent is for the oscilloscope to determine the calibration factors for the plug in only you should perform plug in calibrations right after calibrating the mainframe That way any drifts in the mainframe calibration due to time or temperature will not cause drift in the calibration factors assigned to the ...

Page 92: ...plug in to be inserted in any mainframe slot and still achieve a typical vertical accuracy of 3 For two wide plug ins like the HP 54721A the interleaving of the two mainframe slots is performed during the best accuracy calibration Therefore the real time sampling mode is typically not useful in the normal accuracy mode For accurate results a best accuracy calibration must be performed to use two w...

Page 93: ...for a plug in slot combination until a plug in with a different serial number is calibrated to best accuracy in that slot This means that a plug in that was calibrated to best accuracy in a particular mainframe slot can be removed and reinstalled later in that slot and the best accuracy calibration is still in effect as long as no other plug in was placed in that slot and calibrated to the best ac...

Page 94: ... for all plug ins under the Utility Calibrate Cal status on menu and for each plug in under the Channel Calibrate Cal status on menu In order for a channel to meet the specifications listed under Best Accuracy in chapter 16 both the Current frame Temp and the Best Accuracy Temp must be between 5 C In other words the oscilloscope must be within 5 C from the temperature that the mainframe was calibr...

Page 95: ...ven if a probe calibration is not performed For passive probes or nonidentified probes the oscilloscope adjusts the vertical scale factors only if a probe calibration is performed If you do not perform a probe calibration but want to use a passive probe the attenuation factor can be entered in the Channel Probe Probe atten menu You can use the probe calibration to calibrate any network including p...

Page 96: ...6 Display 6 4 Scale 6 5 Offset 6 6 Input 6 6 Probe 6 7 Calibrate 6 10 Channel Menu ...

Page 97: ...ovides a trigger sync signal to the time base trigger board inside the mainframe This chapter treats the channel menus generically Specific details about each menu operating ranges and specifications depend on which plug in you are using Figure 6 1 is the channel menu map for the HP 54712A Amplifier plug in The other plug ins may have specific features that are not shown on this menu map The purpo...

Page 98: ...Channel menu and menu map for the HP 54712A plug in Figure 6 1 Channel Menu 6 3 ...

Page 99: ...are the same area of the display as the channel setups When the channel display is off the waveform display for that channel is turned off Also acquisition on that channel is stopped unless it is needed as an operand for waveform math functions and any pulse parameter measurements are stopped Even though the channel display is off you can still use the plug in as a trigger source as a function sou...

Page 100: ...en the fine mode is on the knob and arrow keys change the vertical scaling in smaller increments You can always use the keypad to enter values in 1 mV increments independent of the fine mode Software expansion is used to obtain the scale values between the hardware scale selections The scale range depends on the plug in you are using and the probe attenuation factor The units that the scale is dis...

Page 101: ...ule area and the range of offset depends on the scale setting You can use the knob arrow keys or keypad to change the offset setting The fine mode also works with offset Input Input coupling for the plug in is set by this softkey The available input coupling choices depend on which plug in you are using Refer to the User s Reference for the plug in that you are using for more information about thi...

Page 102: ...probe or device connected to the oscilloscope When the probe attenuation is set correctly the oscilloscope maintains the current scale factors if possible All marker values and voltage measurements will reflect the actual voltage at the tip of the probe The probe attenuation range is from 0 0001 1 to 1 000 000 1 When you connect an active probe power connector to the plug in the oscilloscope autom...

Page 103: ...ified lightwave converter whose ideal characteristics are 300 V W with 0 V offset But its actual characteristics are 324 V W with 1 mV of output offset Therefore set the external gain to 324 V W and the external offset to 1 mV Example Voltage probes Because the CAL signal on the mainframe is a voltage source you can let the oscilloscope compensate for the actual characteristics of your probe by le...

Page 104: ...u how to do this 1 Set Atten units to ratio 2 Set Probe atten to 1 1 3 Set Units to Ampere Watt or unknown 4 Set Ext gain to the actual gain characteristics of your probe or device 5 Set Ext offset to the offset that is introduced by your probe or device Calibrate probe Connect a voltage probe from the plug in to the CAL signal on the mainframe then press the Calibrate probe softkey The oscillosco...

Page 105: ...ference between them If you are more interested in comparing the shapes of two waveforms rather than the actual timing difference between them you can use Skew to overlay one waveform on top of the other waveform To skew two channels 1 Turn both channels on and overlay the signals vertically 2 Expand the time base so that the rising edges are about a 45 degree angle 3 Adjust the skew on one of cha...

Page 106: ...formed in that slot the original best accuracy calibration factors are retained The best accuracy calibration factors for a two wide plug in are stored in the left slot For example if you performed a best accuracy calibration on a two wide plug in in slots 2 and 3 the best accuracy calibration factors are stored in the memory behind slot two You can remove the two wide plug in and install a single...

Page 107: ...t Date This is the current date and time You can compare this to the last best accuracy calibration time or the last plug in calibration time That way you will know how long it has been since the last best accuracy calibration or normal plug in calibration was performed Figure 6 2 Channel Menu Calibrate 6 12 ...

Page 108: ... within 5 degrees and no more than 24 hours has elapsed since the best accuracy calibration was performed Normal means that the plug in is not calibrated for best accuracy Either the calibration factors were cleared from the memory in the mainframe or that a best accuracy calibration was not performed on this plug in in this slot Also Normal indicates that the normal plug in calibration is still v...

Page 109: ...ected before continuing with the calibration The best accuracy calibration switch on the rear panel is normally left in the unprotected position This allows you to perform a best accuracy calibration at any time without having to change the switch setting Plug in This lists the model number serial number date time and temperature delta The temperature is the temperature change from the temperature...

Page 110: ...7 Thresholds 7 4 Top Base 7 6 Define time 7 8 Statistics 7 9 Define Measure Menu ...

Page 111: ...se the standard IEEE measurement points or by allowing you to customize the measurements with the user defined selections Figure 7 1 is a waveform drawing that shows some of the standard measurement thresholds See Also Chapter 13 Measurements for details about the algorithms used to calculate the thresholds for the automatic measurement feature Standard measurement thresholds Figure 7 1 7 2 ...

Page 112: ...Define measure menu and menu map Figure 7 2 Define Measure Menu 7 3 ...

Page 113: ...n the display Make sure that the waveform is expanded vertically and horizontally so that the oscilloscope can accurately determine the top and base values of the waveform However if too much of the top and base of the waveform is on the display it may reduce the number of sample points on the edge of interest which may reduce the repeatability of your measurements A good rule of thumb is to have ...

Page 114: ...eshold If the threshold you are using for the measurement is not positioned on the waveform then that threshold followed by a question mark is displayed in place of the automatic measurement result When Units is set to Volts user defined simplifies the threshold detection algorithm The result is that the measurement throughput of the oscilloscope is increased because the oscilloscope does not have...

Page 115: ...curately determine the top and base values of the waveform However if too much of the top and base of the waveform are on the display it may reduce the number of sample points on the edge of interest which may reduce the repeatability of your measurements A good rule of thumb is to have two divisions of top and two divisions of base User Defined User defined lets you set the top and base to a spec...

Page 116: ...rement mode 3 Press the blue shift key V amptdV amptd then select channel you are using 4 Press the Define meas key 5 Set Top base to User defined As you adjust the values of Top and Base the markers give you a visual indication of where you are positioning them on the waveform If the marker values are much greater than the top base values the markers may be clipped off the screen Define Measure M...

Page 117: ...to 65 534 The selection affects all time measurements The automatic measurements are made on waveforms that are on the display If you select an edge that is not on the display Edge is displayed instead of the measurement results To get a time measurement you must either select an edge that is already on the display or reduce the time base scale setting so the selected edge is on the display Edge t...

Page 118: ...turn statistics on the mean standard deviation minimum and maximum values start to accumulate at the same time All results are continuously updated even though only one pair of results is currently displayed For example if you select minimum and maximum the minimum and maximum values are displayed on the screen and they are updated as the results change The mean and standard deviation results are ...

Page 119: ... position reference or resolution number of points Changing the channel state scale or offset Changing the trigger definition Changing the sampling mode between real time and equivalent time Redefining the waveform math function if the measurement is calculated on a function Storing to memory if the measurement is calculated on a memory Changing the filter bandwidth if measuring filtered data Clea...

Page 120: ... is the statistical average of all results for a particular measurement Standard deviation measures the dispersion of those measurement results Figure 7 3 shows the mean and standard deviation more graphically Standard deviation is represented by the Greek letter sigma σ For a gaussian distribution two sigma 1σ from the mean is where 67 percent of the data points reside and six sigma 3 σ from the ...

Page 121: ...tandard deviation is calculated as σ n x2 x 2 n n 1 1 2 2 n 65 534 µ2 n µ2 n 1 n 1 x2 n n 65 535 σ n µ2 n µn 2 n 1 1 2 n 65 535 σ standard deviation n count since last statistics reset x measurement result min max Min minimum and max maximum are the absolute extremes of the automatic measurement Define Measure Menu Statistics 7 12 ...

Page 122: ...8 Directory 8 3 Load 8 5 Store 8 6 Delete 8 8 Format 8 9 Type 8 10 File Format 8 12 From File To File or File Name 8 20 To Memory 8 21 Disk Menu ...

Page 123: ...te files from a disk format a disk or obtain a directory listing of a disk In other menus you can use the disk drive to load applications load new system firmware or save a copy of the display information in a TIFF GIF PCX or printer specific format You can choose from five different disk operations directory load store delete and format Disk menu and menu map Figure 8 1 8 2 ...

Page 124: ... available space left on the disk When you press the Disk hardkey to enter the disk menu the oscilloscope checks to see if a disk is in the drive If there is a disk in the drive you will see a directory listing of all the files on the disk If there is no disk in the drive the screen displays the message There is no disk in the drive Then the disk softkey menu is displayed Figure 8 2 Disk Menu Dire...

Page 125: ...isk If the type of file is not recognized by the oscilloscope the type field is left blank Also the oscilloscope lists only those files that are in the root directory of the disk All other directories on the disk are listed like files except that a file extension is not appended to the filename and the file size is listed as 0 bytes Any files that are not in the root directory are not included in ...

Page 126: ...text files are loaded into one of the four waveform memories by overwriting any data previously stored in that waveform memory Database files are read into directly into the scope by overwriting the previous database Pixel files are loaded in the pixel memory by overwriting any data previously stored in the pixel memory Setup files are immediately activated as the new front panel setup by overwrit...

Page 127: ... that allows you to enter a file name When you execute the store function the oscilloscope stores the information to whichever file name is listed under the To file softkey If the file already exists on the disk you are prompted to press the continue key before the file on the disk is overwritten You can either press the continue key to overwrite the file or you can press the To file softkey and e...

Page 128: ...executed the message The disk is full is displayed on the status line which is near the upper left corner of the display If there is a file on the disk with the same name and of the same file type the oscilloscope prompts you with the message File already exists press continue to overwrite the file Press the Continue softkey to overwrite the file Press the Cancel softkey to prevent the oscilloscop...

Page 129: ...oftkey displays another softkey menu that allows you to enter a file name As a safeguard the oscilloscope prompts you to press the continue key before deleting the selected file from the disk This is to make sure you are not deleting a file from the disk by accident If you select continue then the selected file is deleted from the disk After the file is deleted the directory listing on the display...

Page 130: ...ecause some computers and disk drives format disks with a different disk interleave factor than that used by the oscilloscope The interleave factor used when the oscilloscope formats a disk maximizes the data transfer rate to and from the internal disk drive As a safeguard the oscilloscope prompts you to press the continue key before formatting the disk This is to make sure you are not formatting ...

Page 131: ...ernal waveforms TXT for text waveforms PIX for pixel memories SET for front panel setups MSK for masks The PCL TIF GIF and PCX file extensions are used by the Setup print menu Waveform The waveform file type is for storing waveforms to a disk or loading waveforms from a disk The three file formats for storing waveforms to a disk are internal text verbose and text Y values The format you select det...

Page 132: ...d a pixel file into the oscilloscope it is loaded into the pixel memory by overwriting all data that was previously stored in the pixel memory Setup A setup file is a copy of the front panel setups and it has a SET file extension Saving setups to a disk allows you to save more front panel setups than the ten available in the oscilloscope Ten front panel setups may not be adequate for a group of wo...

Page 133: ...mat which if you try to read it in a word processing program it will give you meaningless information However this is the preferred waveform storage method because the files take up one third as much disk space as text files You can always convert them to text files at a later date Internal format files have a WAV file extension Waveform files stored using the internal format contain the vertical ...

Page 134: ...that the X data is listed before the Y data in the waveform text file Because the oscilloscope converts all characters to uppercase the header information can be a mix of uppercase and lowercase characters Also there must be at least one space between a header and its corresponding data For example there must be at least one space between Type and raw If you have modified the header information an...

Page 135: ... Type raw Points 16 Count 1 XInc 1 24999524625E 007 XOrg 9 99996197003E 007 XRef 0 YData range 1 70000E 000 YData center 1 71800E 001 Coupling dc 50 Ohms XRange 2 00000E 006 XOffset 9 99999997475E 007 YRange 1 60000E 000 YOffset 1 71800E 001 Date 11 JAN 1993 Time 12 34 04 Frame 54720A 3207A00101 Module 54712A 3207A00112 Acq mode equivalent time Completion 100 X Units second Y Units Volt Max bandwi...

Page 136: ...00E 000 YOffset 1 71800E 001 Date 11 JAN 1993 Time 14 29 15 Frame 54720A 3207A00101 Module 54712A 3207A00112 Acq mode equivalent time Completion 100 X Units Volt Y Units Volt Max bandwidth 1100000000 Min bandwidth 0 Data X Data 2 725E 001 6 613E 001 4 496E 001 1 827E 001 3 027E 001 Y Data 2 725E 001 6 613E 001 2 208E 001 2 808E 001 5 610E 001 Partial listing of the text verbose format for a versus...

Page 137: ...equal to the YData range value for versus waveforms The default value is 2 441000000000000E 005 XOrg X origin is the x value of the first data point in the data record X origin is equal to the YData center value for versus waveforms The default value is 5 00000000000000E 002 XRef X reference is always set to zero when it is read back into the oscilloscope The default value is 0 YData range Y data ...

Page 138: ...eform either real time or equivalent time The default value is real time Completion Completion represents the percent of the time buckets in the waveform record that contain data The number of time buckets is equal to the number of points in the waveform record Completion is ignored when it is read back into the oscilloscope The default value is 0 X Units X units is the horizontal scaling units se...

Page 139: ...5E 002 3 147E 001 3 057E 001 4 77E 002 5 280E 001 6 296E 001 6 296E 001 2 297E 001 1 259E 001 3 147E 001 3 147E 001 9 40E 002 Text Y values format X Data 4 757E 002 5 117E 002 1 885E 002 5 07E 003 2 916E 002 3 979E 002 3 649E 002 5 82E 003 2 880E 002 4 727E 002 4 230E 002 2 318E 002 3 91E 003 2 568E 002 3 931E 002 2 178E 002 Y Data 4 757E 002 5 117E 002 1 885E 002 5 07E 003 2 916E 002 3 979E 002 3...

Page 140: ... s Physical Electrical Characteristics of Hierarchical Digital Interface Geneva 1972 further amended Recommendation G 703 Level1 Peak 2 37V Level2 0 00V Delta X 244 ns Top Polygon 1 Number of vertices 9 0 5 Max Top of screen left side 0 5 0 1 0 0512 0 5 0 0512 1 2 0 5 1 1 1 0512 1 2 1 0512 0 5 1 5 0 1 1 5 Max Top of screen right side _______________________________________ Bottom Polygon 2 Number ...

Page 141: ... file name field You can also use the keypad to enter numbers into the filename The arrow keys move the cursor forward and backward through the file name The Backspace softkey backspaces over characters in the file name The Delete softkey deletes characters from the file name Press the Clr clear key on the keypad to erase the file name from the menu You do not add a file extension in this menu bec...

Page 142: ...aveform memories you want to load a waveform into The To memory softkey comes up when you have selected waveform with the Type softkey The oscilloscope overwrites any data that was previously stored in the waveform memory Disk Menu To Memory 8 21 ...

Page 143: ...8 22 ...

Page 144: ...9 Persistence 9 3 Color Grade 9 5 Draw waveform 9 6 Graticule 9 10 Label 9 14 Color 9 17 Display Menu ...

Page 145: ...a is displayed on the screen You can select the graticule settings and you can change the color of most of the items that are displayed on the screen You can also annotate waveforms by using the Label softkey menus to add text to the waveform viewing area Display menu and menu map Figure 9 1 9 2 ...

Page 146: ...ence time the previous data points are kept on the display depending on the persistence time you have selected Therefore the longer the persistence time the longer each data point is left on the display before it is erased from the display You can change the persistence time with the knob arrow keys or keypad The variable persistence mode has a feature called gray scaling On older digitizing oscil...

Page 147: ... with low repetition rates Because all of the data points acquired from a specific trigger event are displayed at the same intensity the gray scaling feature gives you several benefits that are listed below You can associate various points on the display to determine which points make up individual waveforms You can determine the relative ages of waveforms You can determine the direction in which ...

Page 148: ... time a pixel is hit by data the counter for that pixel is incremented The maximum count for each counter is 65 536 The color graded display feature uses seven colors to show the number of hits per pixel over the graticule area Each color represents a range of counts and the range depends on the total number of hits As the total count increases the range of hits represented by each color also incr...

Page 149: ...astest throughput If oscilloscope speed is what you need use the fast mode In the equivalent time sampling mode you may find that fast is your preferred choice because of the high sample rate and display persistence of the oscilloscope When the waveform record length is less than 1000 points the throughput of the oscilloscope is fast enough that you can use the other display modes without noticing...

Page 150: ...n the real time sampling mode a better solution is to turn on the interpolator The interpolator reconstructs the waveform much better than connected dots and the interpolator also improves the measurement repeatability of the oscilloscope Figure 9 4 shows the same waveform as figure 9 3 except that the interpolator is turned on Interpolate is only available in the real time sampling mode so you us...

Page 151: ...Connected dots instead of interpolation Interpolation instead of connected dots Figure 9 3 Figure 9 4 Display Menu Draw Waveform 9 8 ...

Page 152: ...ually has When the data point lies between adjacent pixels the oscilloscope lights up both pixels but varies the brightness of each pixel The brightness of each pixel is proportional to how close it is to the data point Your eye is then drawn to a point between the two pixels to the data point However this increased vertical resolution does take microprocessor time which slows down the display upd...

Page 153: ...hat has ten major horizontal divisions and eight major vertical divisions There are also tic marks on the axis to indicate minor divisions Vertically one minor division is one quarter of a major division and horizontally one minor division is one fifth of a major division Figure 9 5 shows the screen in the grid mode Screen in grid mode using one graph Figure 9 5 Display Menu Graticule 9 10 ...

Page 154: ... printer so that the graticule lines do not obscure the waveform data Intensity Intensity controls the brightness of the horizontal and vertical graticule markings You can vary the brightness from 0 off to 100 very bright Use the knob arrow keys or keypad to set the intensity level of the graticule You can also change the color of the graticule in the color menu Screen in frame mode using one grap...

Page 155: ...o graphs The upper graph is channel 1 while the lower graph is waveform memory 1 Waveform Waveform lets you select from channels functions or memories Whatever is selected with the Waveform softkey is placed into the graph chosen by the Location softkey Location Location lets you select either the upper or lower graph When you select upper or lower whatever you selected with the Waveform softkey i...

Page 156: ...a setup memory or to a disk For positioning the first character of the label the waveform viewing area is divided into 19 vertical rows 0 18 and 64 horizontal columns 0 63 Label position 0 0 is the upper left hand corner and position 18 63 is the lower right hand corner Display The display softkey allows you to turn the labels off and on Define new label The Define new label softkey allows you to ...

Page 157: ...aracter list To move the cursor through the file name use the arrow keys To erase the entire file name press the clear Clr key on the keypad To move the cursor one character to the left in the file name and to also delete that character use the Backspace softkey To delete a character from the file name use the arrow key to position the cursor over that character then press the Delete softkey If la...

Page 158: ...abels until you end up on the first label again You must select a label highlighted before you can change its position or modify its text Row The Row softkey allows you to select one of the 19 vertical rows where you want the label to move to Column The Column softkey allows you to select one of the 64 horizontal columns where you want the label to move to Label text The description of the Label t...

Page 159: ...t to delete When you enter the menu the first label you defined is highlighted Each subsequent press of the softkey rotates through the remaining defined labels until you end up on the first label again Delete The Delete softkey erases the the selected label from the display You must select a label highlighted before you can delete it Display Menu Label 9 16 ...

Page 160: ...s from the plug in installed in slot 1 and also the color of function 1 when when it is turned on Plug in 2 The color of waveforms from the plug in installed in slot 2 and also the color of function 2 when it is turned on Plug in 3 The color of waveforms from the plug in installed in slot 3 and the color of the FFT waveform when it is turned on Plug in 4 The color of waveforms from the plug in ins...

Page 161: ...rder Menu background The color of the softkey s background and scale readout background in the graticule border Menu outline The color of the screen s background Menu highlight The color of the outline around the softkeys that have an entry field Menu shadow The color of the outline around the softkeys that have an entry field which also gives the softkey a 3 dimensional effect Memory bar backgrou...

Page 162: ...se the knob arrow keys or keypad to vary the percentage from 0 to 100 The 0 setting is black and the 100 setting is maximum brightness Default colors The Default colors softkey sets the oscilloscope to the default colors The default display colors were selected for the following reasons Improve the appearance of the display Help you discern which waveform is on which channel by making each channel...

Page 163: ...9 20 ...

Page 164: ...10 Messages ...

Page 165: ...ages needing explanation are contained in this chapter Other messages that are the result of an action you have taken and explain what the instrument is doing or tell that the action you have requested has occurred are not listed here Each message listed here has an explanation and if necessary the action you should take to remedy the condition 10 2 ...

Page 166: ... hardware For example slots 3 and 4 of an HP 54710A or 54710D Busy timeout occurred with plug in Try reinstalling plug in The plug in busy signal was present too long The indicates which plug in had the timeout Check the following Reinstall the plug in Finger tighten the knurled screw on the front panel of the plug in If these actions do not solve the problem there must be a hardware problem in ma...

Page 167: ...dware The indicates which plug in has the Id error This is a special case of memory error Check the following Reinstall the plug in Finger tighten the knurled screw on the front panel of the plug in If these actions do not solve the problem there must be a hardware problem in mainframe or plug in Call Hewlett Packard service Incompatible setup It is possible that due to a system firmware change a ...

Page 168: ...d not all have overload protection Please correct overload condition then press Overload Cleared This is further prompting that occurs when the menu of an overloaded channel is selected Actions to take include the following Removing the input signal Reducing the amplitude of the input signal Decreasing the channel sensitivity Changing the input coupling from dc to ac if the signal has a large offs...

Page 169: ...en new system firmware is installed or when the memory is declassified in the utility menu System firmware error occurred This is a defect diagnostic that should be reported to Hewlett Packard service Normally the address where the error occurred is also displayed Record the address to help in servicing the instrument The instrument is still operable System load failed System firmware is unchanged...

Page 170: ...11 Off 11 3 Manual 11 3 Waveform 11 5 Measurement 11 7 Marker Hints 11 8 Histogram 11 8 Marker Menu ...

Page 171: ... different color in the display menu You can use the markers to make custom measurements to use as visual reference points on the display or to show you where the last automatic measurement was made on the signal There are four marker modes and each mode is discussed in this chapter off manual waveform and measurement Marker menu and menu map Figure 11 1 11 2 ...

Page 172: ...tom measurements As long as you do not press the Autoscale key the manual markers stay in the position where you placed them which allows you to make accurate delay measurements without having both markers on the display Also they are not tied to the waveform data they are just positions on the display The position readout is based on the scale factors of the srouce waveform X1 Y1 Source and X2 Y2...

Page 173: ...he 1 delta X value If you are measuring the period of a signal with the X markers then 1 delta X is the frequency of the signal You can also make a channel to channel skew measurement by placing the X1 marker on one channel and the X2 marker on another channel Y1 Position and Y2 Position Y1 Position moves the Y1 marker vertically and Y2 Position moves the Y2 marker vertically Use the knob arrow ke...

Page 174: ... accurate delay measurements without having both markers on the display Source and X Source You can set the marker sources as channels functions or memories For example you can set the source to a waveform memory and the X source to a channel The scale used to position each marker on the display is based on the scale of the waveform source that the marker is tied to You can select a marker source ...

Page 175: ... an X position Vertical measurements are made with the Y positions and delta Y is the difference between the Y positions Timing measurements are made with the X positions and delta X is the difference between the X positions Also notice 1 delta X If you are using the markers to measure the period of a signal then 1 delta X is the frequency of that signal See Also Making Accurate Time Interval Meas...

Page 176: ...ement key on the keypad The measurement markers are not displayed if you do not make an automatic measurement sometime prior to selecting the measurement markers The markers follow the last measurement and the last measurement is displayed in the same color as the markers Readout The Readout softkey determines whether or not the measurement marker positions are shown at the bottom of the display I...

Page 177: ... sources are set to when you are making marker measurements You may find yourself in a situation when the markers are turned on but they are positioned off the display You may notice that it can take a long time to bring the markers back onto the display with the knob If you set the marker position to the time base position value this will snap the marker to the same location as the time base refe...

Page 178: ...12 Function 12 3 Define Function 12 4 Display 12 7 Math Menu ...

Page 179: ... either one or two operands A function is calculated on data adjusted by the calibration factors and a new waveform called a function is generated by the computation You can place markers on functions make measurements on functions or store functions to waveform memories Waveform math menu and menu map Figure 12 1 12 2 ...

Page 180: ... or function two f2 You can display both functions on the screen at the same time Even though a channel display is set to off you can still use that channel as part of a function and see the results of the function on the display Math Menu Function 12 3 ...

Page 181: ...be shown similar to the time base windowing feature Invert Inverts the waveform on operand 1 Add Adds point by point operand 1 and operand 2 Use add to compare two waveforms Simply invert one of the waveforms Make sure that the vertical sensitivity and offset settings are identical for both waveforms Then use the add function to add the waveforms together Subtract Subtracts point by point operand ...

Page 182: ...quired in each time bucket on operand 1 Max Maximum stores the maximum value acquired in each time bucket on operand 1 The results for minimum and maximum are recalculated when any of the following occurs Time base scale position or reference is changed Channel state scale or offset is changed Trigger definition is changed Acquisition mode record length or sampling rate is changed Additional data ...

Page 183: ...rms have different record lengths the function uses the shortest record If two operands have the same time base scale the resulting function has the same time scale which results in the proper time scale for the function Constant operands have the same time scale as the associated waveform operand A waveform function operand is acquired even if its display is turned off Function 1 is allowed as an...

Page 184: ... the data When display is set to on the function is calculated and displayed Turning the display to off ends function computation and erases the function from the display Function 1 is displayed in the same color that is used to display signals from slot 1 and function 2 is displayed in the same color that is used to display signals from slot 2 Vertical You can set the scale to track the source wa...

Page 185: ...elect either track source or manual Track source makes the function use the same vertical scale and offset of the function s waveform source Manual allows you to set the vertical scale and offset independently of the waveform source Horizontal Horizontal allows you to select either track source or manual Track source allows the function to use the same horizontal scale and position as the waveform...

Page 186: ...13 Measurements ...

Page 187: ...ike any tool it is important to understand how to use the tool its limitations and methods that may overcome some of the shortcomings The waveform in figure 13 1 shows the pulse parameters that the oscilloscope measures Hewlett Packard has been using these parameters in its measurements for the past 10 years This chapter defines these parameters and discusses how they are measured Pulse parameters...

Page 188: ... recording how many times each q level a q level is an internal voltage representation is present in the data record From the histogram and from the data record the absolute maximum and minimum voltage levels as well as relative maximum top and minimum base voltage levels are determined Using the top and base levels threshold levels are calculated The data record is again analyzed using the thresh...

Page 189: ...a must be acquired before the measurement process starts as shown in figure 13 3 This feature keeps an interrupt over the bus from stopping the data collection before enough data has been collected to make accurate measurements The completion criterion for measurements over the bus can be controlled using the completion criterion command ACQUIRE COMPLETE The data record used for making measurement...

Page 190: ...own in figure 13 4 The histogram does not represent the full resolution of the data however as this would result in a very large histogram array The oscilloscope uses the histogram to determine the statistical maximum top and minimum base of the data record Some measurements are made from the histogram Figure 13 4 Measurements Then the System Builds a Histogram 13 5 ...

Page 191: ... this information is also recorded After the minimum and maximum measurements are complete the Vmin Vmax Vp p Tmin Tmax and Tvolt measurements can be made The remaining primitives of the measurement process calculate thresholds find edge and period are executed only if other measurements such as fall time frequency or delta time are requested Measurements The System Calculates Min and Max From the...

Page 192: ...op 40 percent is scanned for the top and the bottom 40 percent of the histogram is scanned for the base The center portion of the histogram is not searched to prevent a baseline value from being chosen as the top or base as shown in figure 13 5 The middle 20 percent of the waveform is ignored Figure 13 5 Measurements Then It Calculates Top and Base 13 7 ...

Page 193: ...lue the base defaults to the value of the absolute minimum This may be the case for very irregular waveforms or those in which the voltage rises or falls slowly over time This selection technique prevents the top and base from jumping around on waves with even histogram distributions such as triangle waves It also allows the detection of the top and base for low duty cycle signals The oscilloscope...

Page 194: ...all timing measurements as they are needed to determine the presence of a rising or falling edge In addition the thresholds are used by various measurements For example rise time is measured from the lower threshold to the upper threshold of a rising edge Period and frequency measurements use the middle threshold as shown in figure 13 6 See also Chapter 8 Define Measure Menu for information on man...

Page 195: ... a transition that passes through the upper middle and lower threshold levels For an edge to be present and defined it must complete the transition through all three threshold levels Once the transition points and edges are identified the instrument next calculates timing measurements rise time fall time and frequency Finally it calculates voltage measurements that need timing information Vrms cyc...

Page 196: ...rm data point does not exactly correspond to the threshold level value the system interpolates between the two points about the threshold Then the location of the transition point is recorded in an edge array The system ignores incomplete transitions and glitches as shown in as shown in figure 13 8 The system ignores incomplete transitions when defining edges Figure 13 8 Measurements Finally Risin...

Page 197: ...igure 13 9 it is clear that measuring the rise time from the first point crossing the lower threshold to the last point through the upper threshold gives a different answer than the shaded line that uses the edge definition given in the previous paragraph The points in a period are defined to be the midpoint between the first point before crossing the middle threshold to the last point after cross...

Page 198: ...top and base calculations area completed most of the voltage measurements can be made Vmin voltage of the absolute minimum level Vmax voltage of the absolute maximum level Vp p Vmax Vmin Vbase voltage of the statistical minimum level Vtop voltage of the statistical maximum level Vamp Vtop Vbase Vbase may be equal to Vmin for many waveforms such as triangle waveforms Likewise Vtop may be equal to V...

Page 199: ...Waveform definitions used to make voltage measurements Figure 13 10 Measurements Voltage Measurements 13 14 ...

Page 200: ...local max top else overshoot base local min Preshoot a distortion which precedes a major transition If first edge is falling then preshoot base local min else preshoot local max top The oscilloscope computes a local minimum and maximum when computing preshoot and overshoot The local minimum or maximum occurs before the first transition in the case of preshoot or in the first 50 percent of the time...

Page 201: ...ssing of first rising edge else period mid threshold crossing of second falling edge mid threshold crossing of first falling edge Frequency 1 period Width if first edge is rising then width mid threshold crossing of first falling edge mid threshold crossing of first rising edge else width mid threshold crossing of second falling edge mid threshold crossing of first rising edge Width if first edge ...

Page 202: ... the second source s edge This gives flexibility in defining time measurements between channels or on a single channel between edges To avoid confusing the delay measurement with time base delay and trigger delay the delay measurement has been called time as shown in figure 13 11 See also Chapter 7 Define Measure Menu for information on delay measurements You may define time Figure 13 11 Measureme...

Page 203: ...id in windowing the signal for measurement Statistics are available on the oscilloscope so you may display the mean standard deviation min and max for each measurement result In the user defined mode you may also define some of the measurement you want to make Specify your own thresholds rather than using the standard 10 50 and 90 percent levels Specify the IEEE standard definitions of thresholds ...

Page 204: ...automatic measurements You will get a warning or error message if this occurs Period and Frequency Measurements At least one full cycle of the waveform with at least two like edges must be displayed for period and frequency measurements Additionally you can increase the accuracy of frequency measurements by windowing on multiple pulses Automatic waveform measurements use a single pulse and may hav...

Page 205: ...d rising edge preshoot and overshoot measurements The trailing falling edge of the waveform must be displayed for fall time and falling edge preshoot and overshoot measurements Remember that an edge must pass through all three thresholds to be recognized as an edge Therefore it is important that the pulse be positioned so that all three thresholds are displayed on the screen Rise time fall time pr...

Page 206: ...ous methods for making time interval measurements and the pros and cons of each The second section introduces the concept of statistical analysis of time intervals The third section explores errors in time interval measurements that are not related to the time base accuracy including the response of the oscilloscope s vertical channels and the effect of probes The fourth section discusses various ...

Page 207: ...imilar In all cases you measure the time between two events where an event is defined as a voltage transition of a specified polarity through a specified level When measuring the width of a pulse these two events are the leading edge and the trailing edge The concepts developed here can be applied to any other time interval measurement For two channel measurements you must take care to deskew the ...

Page 208: ...Both edges of the pulse must be on the screen and at the same time there must be sufficient baseline or top for a negative pulse for the top and base algorithm to reliably determine the voltage level of the base or top Refer to the discussion on page 5 describing the algorithm the oscilloscope uses to determine the top and base levels If the baseline is distorted prior to the initial transition of...

Page 209: ... menu and set the memory to the maximum 16384 points for single width plug ins The double width plug in HP 54721A gives you twice the memory depth because it uses two of the mainframe s digitizing channels and associated memory Therefore in some situations it is better to use the HP 54721A plug in for increased memory though you may not need the higher sampling rate it provides The HP 54720 has au...

Page 210: ... the difference set up a pulse generator for a pulse width of 100 ms and a rise time of 1 ns or as small as the pulse generator will allow Then measure the width both by using the oscilloscope s automatic measurement and by using the markers Channel to Channel Measurements To make channel to channel measurements such as propagation delay setup time or hold time you must remove any systematic diffe...

Page 211: ...scope s time interval measurement varies statistically because this affects measurements of the statistical behavior of your system Jitter introduced by the oscilloscope has two components a fixed part and a variable part The fixed component of jitter is the same at all points on the time base including the trigger point The variable component increases as the delay from the trigger point increase...

Page 212: ...iable jitter set the Position in the Time Base menu to a large number relative to the Scale setting As you increase the value of Position you will see the jitter increase The HP 54720 s variable jitter is on the order of 10 to 20 ppm so you must use a large value of Position and a fast setting of Time Base Scale to see it You can use the automatic measurements in the oscilloscope to measure the ji...

Page 213: ... Jitter and Averaging Vertical averaging removes the apparent jitter on the display but may give misleading information about the true behavior of the signal For example consider measuring rise time Figure 13 12 shows a rise time measurement on a jittering signal with averaging turned on Erroneous Rise Time Measurements Due to Jitter Figure 13 12 Measurements Statistics 13 28 ...

Page 214: ...tervals on jittering signals In the real time acquisition mode a complete record of each transition is acquired on every trigger The oscilloscope can make accurate measurements on these records and can calculate and display the statistics of measurements on many transitions Measurements Statistics 13 29 ...

Page 215: ...ndistorted replica of the board This section examines the distortions introduced by the vertical channels the probes and connecting cables and it shows how these distortions affect the accuracy of time interval measurements Errors introduced by the vertical channels of the oscilloscope and by the probe can be divided into the following categories dc errors These include offset level error gain err...

Page 216: ...lope of the transfer function Linearity error variations in the slope of the transfer function Random errors that can t be repeated from measurement to measurement Figure 13 13 shows how vertical dc errors affect time interval accuracy The linearity of the HP 54720 is typically better than 1 2 LSB so the error is dominated by the offset and gain errors Effect of Vertical dc Errors on Measurement A...

Page 217: ...y to single channel measurements For channel to channel measurements the dc errors on each channel could be different so the errors may not cancel If the slew rates of the edges are different as in figure 13 there may still be a time error introduced by the dc level error though both times are referenced to the same dc level and both edges have the same amplitude and polarity Measurements Time int...

Page 218: ...sed by dc level errors add rather than cancel as shown in figure 13 14 The time errors in locating the leading edge and trailing edge of the pulse reinforce rather than cancel Edges of Opposite Polarity Reinforce dc Errors Figure 13 14 Measurements Time interval measurements 13 33 ...

Page 219: ...ty as well as for channel to channel measurements as illustrated by figure 13 15 If the edges have a non uniform slew rate with fast and slow regions try to reference the time interval measurement to the fastest changing region as shown in figure 13 16 Faster Transitions Decrease Effect of dc Offset Errors Figure 13 15 Measurements Time interval measurements 13 34 ...

Page 220: ...Measure Time Intervals at Fastest Changing Part of Transition Figure 13 16 Measurements Time interval measurements 13 35 ...

Page 221: ...g rate and the sampling mode If the resolution is 8 bits the vertical scale factor is set to 1 V div and the input slew rate is 1 V s then the best timing resolution is 31 2 ns Therefore for slowly varying edges where sampling rate and bandwidth are not the dominant influence on accuracy increasing the vertical resolution at the expense of bandwidth may improve time interval measurement resolution...

Page 222: ...illoscope s reproduction of the input signal The probe also has some non ideal transient response that contributes to the overall system error Additionally the probe and the circuit under test form a circuit that behaves differently from the circuit without the probe the signal at the probe tip is not the same as the signal that is present when the probe is removed Probe loading often has a more s...

Page 223: ...The rise time of the HP 54720 depends on which plug in is used and on whether real time or equivalent time sampling is used Table 13 1 gives the rise time for various combinations of plug in and sampling technique Table 13 1 Rise Time Response Plug In Real time rise time Repetitive rise time HP 54711A 233 ps HP 54712A 318 ps HP 54713A 700 ps 700 ps HP 54721A 318 ps 318 ps Not recommended for singl...

Page 224: ...ombined rise time of 330 ps the error will be reduced to approximately 5 percent Measured rise time 1 ns 2 330 ps 2 1 05 ns Table 13 2 shows the error for other ratios of oscilloscope rise time to signal rise time Table 13 3 shows the approximate error in measuring rise times with various plug in and probe combinations with the HP 54720 Table 13 2 Rise Time Measurement Errors Signal rise time Osci...

Page 225: ...54713A 72 22 5 9 2 7 HP 54713A and 54701A 72 22 5 9 2 7 HP 54713A and 10430A 72 22 5 9 2 7 HP 54721A 18 5 4 9 1 3 0 6 HP 54721A and 54006A 18 5 4 9 1 3 0 6 HP 54721A and 54701A 22 5 9 1 5 0 7 You can apply the concepts of rise time measurement to measuring the interval between two identical edges at different levels The error in measuring the interval from the 10 percent level on one edge to the 9...

Page 226: ... 54720 the waveform is affected in three ways the height is incorrect the 50 percent width is incorrect and the peak is shifted relative to the pulse as shown in figure 13 17 Narrow Pulse Applied to an Oscilloscope Figure 13 17 Measurements Time interval measurements 13 41 ...

Page 227: ... logic threshold the peak height error might make you believe that it does not Figure 13 18 shows pulse height error as a function of oscilloscope rise time and input pulse width Errors in Pulse Height Measurement Figure 13 18 Measurements Time interval measurements 13 42 ...

Page 228: ...the error in peak height measurements will also be less than 5 percent You can extend this concept to channel to channel time interval measurements between edges of opposite polarity Measuring the time interval between two closely spaced edges of opposite polarity on two channels is equivalent to measuring the width of a narrow pulse as shown in figure 13 19 Error in Pulse Width at 10 Level is App...

Page 229: ... a simple RC circuit is 2 2RC Thus for an output resistance of 100 W and a probe tip capacitance of 8 pF the real rise time at the node under test cannot be faster than approximately 1 8 ns Without the probe the rise time might be faster If the output of the circuit under test is current limited as is often the case for CMOS the slew rate will be limited as shown by equation 2 as shown in figure 1...

Page 230: ... of Transient Response Errors Minimize the effects of transient response on time interval measurements by following these guidelines Choose an oscilloscope and probe with a combined rise time less than 1 3 the fastest rise time or pulse width to be measured Consider probe loading effects particularly capacitive loading The RC time constant of the output impedance of the circuit under test and the ...

Page 231: ...ntages of each mode Real Time Sampling In real time sampling all the samples are acquired and digitized on every trigger as shown in figure 13 21 There is a simple direct correspondence between the samples and the time that they were acquired Single shot measurements require real time sampling Sampling Techniques Figure 13 21 Measurements Time interval measurements 13 46 ...

Page 232: ... constantly sampled and digitized at a rate determined by the oscilloscope s sampling clock see figure 21 Whenever a trigger event occurs the oscilloscope measures the time from the trigger event to the next sample Knowing this time relationship allows the oscilloscope to assign the samples to the correct time relative to the trigger After enough acquisition cycles have occurred the waveform is co...

Page 233: ...ution and accuracy for time interval measurements Of course equivalent time sampling cannot be used for single shot measurements Bandwidth affects the accuracy of time interval measurements and the HP 54720 has the highest bandwidth when operated in the equivalent time sampling mode with the HP 54711A plug in Advantages of equivalent time sampling include the following Higher bandwidth than real t...

Page 234: ...states that complex signals such as square waves or triangular waves can be represented mathematically as the sum of a series of sine waves If you know the phase frequency and magnitude of every sinusoidal component you have all the information about the complex signal The Shannon sampling theorem says that if you sample a signal that contains no frequencies higher than half the sampling rate all ...

Page 235: ...e is very different as shown in figure 13 23 Only one sine wave will fit all the sample points Therefore for this sine wave sampled at greater than frequency 2f you know everything about it just as Shannon s theorem predicted Sine Wave Having Frequency f and Sampled at Frequency 2f Figure 13 23 Measurements Time interval measurements 13 50 ...

Page 236: ...nal were not a sine wave What if it were a square wave or a triangular wave as shown in figure 13 24 Samples Might Represent a Sine Wave of Some Complex Waveform Figure 13 24 Measurements Time interval measurements 13 51 ...

Page 237: ...quare wave you must sample it at a rate at least twice the highest frequency in its Fourier expansion Aliasing The effect of sampling rate is the same as bandwidth loss of high frequency information in the signal However there is an additional complication associated with sampling a signal If the signal contains frequencies higher than half the sampling rate then there will be errors due to aliasi...

Page 238: ...accurate time interval measurements on them requires a filter with the following characteristics The step response should be monotonic with no preshoot or overshoot There should be no ringing in the step response or impulse response The group delay should be constant This simply means that all frequencies in the signal should be delayed by the same amount of time If the higher frequency components...

Page 239: ...Response of a Gaussian Filter Versus Frequency Figure 13 26 Measurements Time interval measurements 13 54 ...

Page 240: ...B frequency to 1 4 the sampling rate Then the response will be down 12 dB at the Nyquist frequency The bandwidth of the HP 54720 depends on the plug in selection You must consider the characteristics of the signals you want to measure before selecting the appropriate plug in for single shot measurements When using the HP 54711A or HP 54712A plug ins the bandwidth is greater than 1 4 the sampling r...

Page 241: ... rise time with an error of less than 5 percent The Shannon sampling theorem states that if you sample the same signal at 4 GSa s you are assured of having all the information contained in the signal up to 1 GHz with plenty of margin As a result you could measure the rise time with an error of less than 5 percent At first this conclusion may seem counter intuitive At 4 GSa s the time between sampl...

Page 242: ...error could be as much as 125 ps which is 12 5 percent of the actual rise time and the resolution could not be better than 250 ps You could get a better estimate of the rise time by simply interpolating between the sample points with a straight line Linear Interpolation Between Samples Improves Accuracy of Rising Edge Measurement Figure 13 28 Measurements Time interval measurements 13 57 ...

Page 243: ... contains higher frequency components and it would not be seen on any oscilloscope with 1 GHz bandwidth analog or digitizing To see the glitch you need an oscilloscope with higher bandwidth and a higher sampling rate A Glitch Between Samples Figure 13 29 Measurements Time interval measurements 13 58 ...

Page 244: ...n But is it valid Does reconstruction add new information that was not contained in the original samples The Shannon sampling theorem assures you that reconstruction is valid if you do not violate the Nyquist criterion The time base accuracy and resolution specified for the HP 54720 digitizing oscilloscope in real time sampling mode is much better than the 250 ps sampling interval Reconstruction i...

Page 245: ...13 60 ...

Page 246: ...14 Setup Memory 14 3 Save 14 3 Recall 14 4 Default Setups 14 4 Setup Menu ...

Page 247: ...n use the setup memories for rapidly recalling setups for production test environments or when you are comparing waveforms by using more than one setup You can also set the oscilloscope to its default settings These settings set the oscilloscope to a known operating condition Setup menu and menu map Figure 14 1 14 2 ...

Page 248: ...in case someone else changes the setup when they are using it In situations where you need more than ten front panel setups or in work groups where you want to make sure that someone does not accidentally overwrite your saved setups you can save setups to a disk See Also Chapter 7 Disk for information on saving to a disk Save Save stores the present front panel setup to a selected setup memory Any...

Page 249: ...his known operating condition is used as a starting point in the service procedures You may find it helpful to use this known operating condition as a starting point when setting up the oscilloscope to view signals Table 14 1 Default setups Global Run Stop Run Menu Time base Time base Scale 20 µs div Windowing Disabled Position 0 s Window scale 10 µs Reference Center Window position 0 s Trigger Mo...

Page 250: ...lable channel Waveform X source First available channel X2 position 0 s Waveform X position 0 s Y2 position 0 V Define measure Thresholds percent 10 50 90 Delta time Thresholds volts 0 0 1 6 5 0 Start edge Rising 1 middle Top base Standard Stop edge Falling 1 middle Statistics Off Waveform Pixel memory Off Memory display Off Waveform save format internal Y Scale 20 mV div Byte order MSB first Y Of...

Page 251: ...0 Offset log 80 dB Scale type Linear Scale linear 25 Scale mode Auto Offset linear 0 Utility CRT pattern Off Light output Off Color purity Off Limit test Test Off Run until Forever Measurement None Run until failures 1 failure Fail when Outside Run until waveforms 100000 waveforms Upper limit 10000 Store summary Off Lower limit 10000 Store screen Off Store waveforms Off Mask test Test Off Run unti...

Page 252: ...15 Print Format 15 4 Destination 15 6 Data 15 8 Setup Factors 15 8 TIFF and GIF files on the Apple Macintosh Computer 15 9 Setup Print Menu ...

Page 253: ...ice selected in the setup print menu If that device is not connected to the oscilloscope the screen displays the message Print canceled Printer is not responding When you are printing to a printer the time and date of the printout is also printed at the top of the printed data The date and time are the same as the oscilloscope s If they are incorrect you can change the date and time in the Utility...

Page 254: ...is displayed Which menu is displayed depends on the selected print format The default format is ThinkJet The PaintJet LaserJet DeskJet and Epson menus are similar to the ThinkJet menu and the PCX color TIFF and GIF menus are similar to the TIFF menu Setup Print Menu 15 3 ...

Page 255: ...image at 256 colors Also the TIFF and color TIFF files comply with the TIFF 5 0 file format Even though you select a printer as a print format you can still select the disk as the destination instead of a printer The resulting file is in the format for the selected printer If a printer is not connected to the oscilloscope you can print the data to a disk Then you can take that disk to a computer o...

Page 256: ...form feed command to the printer after the printing of the data is complete Media Media allows you to select either paper or transparency as the printing material The media softkey is displayed when the DeskJet and PaintJet printers are selected Background The background softkey is displayed when PaintJet color is the selected printer Background allows you to select either a normal or white backgr...

Page 257: ...ress for the printer Disk Disk prints to the disk drive in the oscilloscope When disk is selected an additional softkey is displayed that specifies the file name If that file already exists on the disk you are prompted to press the continue key before the file on the disk is overwritten You can either press the continue key to overwrite the file or you can press the To file softkey and enter a new...

Page 258: ...st To move the cursor through the file name use the arrow keys To erase the entire file name press the clear Clr key on the keypad To move the cursor one character to the left in the file name and to also delete that character use the Backspace softkey To delete a character from the file name use the arrow key to position the cursor over that character then press the Delete softkey You do not need...

Page 259: ...en area to a printer or a disk If you turn on setup factors the channel time base and trigger setups are also printed Factors Factors prints only the channel time base and trigger setups to the printer or to the disk Setup Factors Setup factors is available when the Data softkey is set to either graticule or screen When set to on Setup factors prints the channel time base and trigger setups along ...

Page 260: ...iting utility like ResEdit 2 1 available from Apple Computer Inc Macintosh ftp archive sites or a local Macintosh User s group to open the TIFF file that you translated from MS DOS format to the Macintosh computer To use ResEdit choose Get File Folder Info from the File menu Change the Type field to TIFF for TIF files or change the Type field to GIF for GIF files The Type filed must contain four c...

Page 261: ...15 10 ...

Page 262: ...16 Specifications 16 3 Characteristics 16 4 Product Support 16 9 General Characteristics 16 10 Specifications and Characteristics ...

Page 263: ... the specifications and characteristics for the HP 54710 and HP 54720 that are not dependent upon the plug in that you are using The specifications and characteristics for a specific plug in are in the User s Reference that is supplied with the plug in 16 2 ...

Page 264: ...brator dc Output Adjustable output range 2 5 V to 2 5 V when terminated into 50 Ω Output Delta Voltage Accuracy 0 2 of delta voltage output 1 Time interval measurement accuracy includes error sources such as time base inaccuracy aperture uncertainty sample clock phase jitter reconstruction filter uncertainty real time only trigger interpolation jitter and channel to channel skew Real time time int...

Page 265: ...quires a specific plug in to stay installed in a specific mainframe slot Channel Skew Adjustment The time skew between channels can be manually eliminated all the way to the probe tip to 1 ps resolution Probe Calibration A probe calibration routine automatically computes the offset and the attenuation created by the probe attached to the channel input Time base Time Base Scale 100 ps div to 20 s d...

Page 266: ...Trigger A pattern is specified on any three of the four inputs with the fourth input used as a clock Trigger occurs on the rising or falling edge of the input specified as the clock and when the pattern is present or is not present Setup time for the pattern with respect to the clock is 10 ns or less hold time is zero Event Delayed Trigger The trigger is qualified by an edge The delay can be spec ...

Page 267: ...solution 0 00007 signal frequency Magnitude Specifications Magnitude Accuracy Flattop window 0 26 dB 3 Near dc 3 dB at maximum bandwidth Signal to noise Ratio 55 to 65 dB typical Controls Span Sets the maximum frequency Resolution Sets the spacing between points in the frequency domain Magnify Controls For zooming in on a portion of the frequency record up to an expansion factor of 200 The magnify...

Page 268: ...etween bins The scallop loss determines the amplitude accuracy of a window It measures the attenuation of a signal that falls between frequency bins versus one that is exactly on a frequency bin FFT Measurements FFT Freq Frequency of a peak TMin Frequency at minimum point FFT Mag Magnitude of a peak VMax Maximum amplitude FFT Freq Magnitude between peaks VMin Minimum amplitude FFT Mag Frequency be...

Page 269: ...h off and one channel acquisition Vp p does not require threshold detection but period does Throughput Waveforms second Measurements second Measurement Vp p Period Front Panel Capture and Transfer Rate 170 44 39 HP IB Capture and Transfer Rate 50 33 31 Front Panel Calibrator ac Output A 2 kHz or 500 kHz square wave with approximately 1 6 ns transitions can be used for probe compensation and system...

Page 270: ...f performance at the time of measurement Low Cost of Ownership The HP 54700 Series including plug ins and probes include a one year return to HP warranty To minimize the mean time to repair and the calibration time the series was designed with no periodic hardware adjustments HP s board exchange program assures economical and timely repair of units reducing the cost of ownership Reliability Under ...

Page 271: ...Non operating 40 C to 70 C 40 F to 158 F Humidity Operating up to 95 relative humidity non condensing at 40 C 104 F Non operating up to 90 relative humidity at 65 C 149 F Altitude Operating up to 4 600 meters 15 000 ft Non operating up to 15 300 meters 50 000 ft Vibration Operating Random vibration 5 500 Hz 10 minutes per axis 0 3 grms Non operating Random vibration 5 500 Hz 10 minute per axis 2 4...

Page 272: ... kg 58 lb Shipping 31 8 kg 70 lb 33 6 kg 74 lb Dimensions Refer to the outline drawings to the right Notes 1 Dimensions are for general information only If dimensions are required for building special enclosures contact your HP field engineer 2 Dimensions are in millimeters and inches Specifications and Characteristics General Characteristics 16 11 ...

Page 273: ...ss A equipment SABS RAA Act No 24 1990 Immunity EN50082 1 Code1 Notes2 IEC 801 2 ESD 4kV CD 8kV AD IEC 801 3 Rad 3 V m IEC 801 4 EFT 1kV 1 2 1 1 Performance Codes 1 PASS Normal operation no effect 2 PASS Temporary degradation self recoverable 3 PASS Temporary degradation operator intervention required 4 FAIL Not recoverable component damage 2 Notes None Specifications and Characteristics General C...

Page 274: ...17 Scale 17 3 Position 17 3 Reference 17 4 Windowing 17 5 Time Base Menu ...

Page 275: ...pter contains a description of the time base menu and how it controls the horizontal portion of the display The topics covered are horizontal scale position reference and windowing Time base menu and menu map Figure 17 1 17 2 ...

Page 276: ...play you can see what portion of memory you are zooming on Position Position moves the sweep horizontally When position is set to zero the trigger point corresponds to the reference point The position range depends on the scale selection and reference selection Positive position values indicate time after the trigger point posttrigger and negative position values indicate time before the trigger p...

Page 277: ...er reference The data is acquired evenly on both sides of the reference point The data in the waveform record is centered around the reference point and changing the scale expands or contracts the signal about the reference point Left reference The data is acquired starting at the reference point and the data in the waveform record is all postreference Right reference The data is acquired ending a...

Page 278: ...dual events on the display for the automatic measurement View View lets you select main or window When you select window the softkey menu at the left is displayed Main Main displays the signal according to the scale and position settings and a window marker is placed on the signal The window marker defines the portion of the signal you plan to expand However the color highlight is not available wh...

Page 279: ...rmines how much of the signal is expanded in the window mode Increasing the window scale decreases the amount of expansion Window Position Window position moves the intensified marker horizontally across the main sweep It allows you to precisely pick the segment of the main sweep you wish to expand for further analysis Time Base Menu Windowing 17 6 ...

Page 280: ...18 Trigger Basics 18 4 Sweep 18 6 Mode 18 7 Source 18 20 Level 18 20 Slope 18 20 Holdoff and Conditioning 18 21 Trigger Menu ...

Page 281: ...orms two functions It locates the waveform of interest and it synchronizes the oscilloscope measurement and display to the waveform The trigger menu that is displayed when you enter the trigger menu depends on the selected trigger mode The menu for each trigger mode is included with the discussion of that mode Edge is the default trigger mode 18 2 ...

Page 282: ...Trigger menu and menu map Figure 18 1 Trigger Menu 18 3 ...

Page 283: ...ll of the available trigger sources Rather than clutter up the waveform record with useless data that you have to shift through you can use logic triggering to pick out the area of the signal you are most interested in viewing Then you can use time base delay to view what happened before and after the trigger event Although previous digital oscilloscopes offer you logic triggering this oscilloscop...

Page 284: ...it is in the Auto sweep trigger mode The trigger specifications and the available trigger features depend on the plug in you are using Refer to the User s Reference for the plug in you are using for details on the trigger specifications and available features For example logic triggering capabilities are not available with the HP 54711A plug in If you have an HP 54711A plug in installed in the mai...

Page 285: ...d for the next trigger event Auto After the trigger circuit is armed the oscilloscope waits for up to 30 ms for a trigger to occur If a trigger does not occur within 30 ms the oscilloscope triggers itself and the data that is acquired with the trigger is displayed on the screen It also lights the Auto Triggered LED Use the Auto sweep mode when you are unsure how to setup the trigger menu to trigge...

Page 286: ...e trigger on a voltage either slightly higher or lower than the trigger level The arming voltage is set slightly lower than the trigger level for a positive slope and slightly higher than the trigger level for a negative slope Then a signal with the correct slope and voltage level triggers the oscilloscope You can use the edge trigger mode to easily detect logic level transitions In the menu at th...

Page 287: ... the selected width but wider than 500 ps depending on the plug in you are using Source Selects which trigger source the oscilloscope uses as it searches for a glitch Level Sets a voltage level the glitch must cross before the oscilloscope triggers on the glitch Polarity Select either a positive or negative polarity glitch The oscilloscope triggers on the falling edge of positive polarity glitches...

Page 288: ... the oscilloscope to detect the glitch If a negative polarity glitch was selected then the signal must be above the trigger level for at least 5 ns The opposite polarity of the glitch must be present for at least 5 ns If the selected glitch width is from 3 ns to 19 ns the time between similar edges must be greater than the selected glitch width Figure 18 3 illustrates the timing between like edges...

Page 289: ...e trigger level on channel 1 to a TTL high and channel 2 to an ECL low When Selects when the trigger is to occur The choices are listed below Entering a pattern the trigger occurs on the edge of the source that is the last edge to make the pattern true Exiting a pattern the trigger occurs on the edge of the source that is the first edge to make the pattern false A pattern is present greater than a...

Page 290: ...wo channel timing diagram and where the trigger occurs for a few patterns Also shown is the logic gate equivalent of the each pattern Examples of when a trigger occurs for pattern trigger Figure 18 4 Trigger Menu Mode 18 11 ...

Page 291: ...lock The trigger source can be a channel or external trigger source State Sets the other slots to form a trigger pattern An arrow indicates which trigger source is the clock You can select the polarity of the clock edge as either rising or falling You can also select the pattern on the remaining slots and independently set the trigger level on each slot Pattern Sets the oscilloscope to trigger whe...

Page 292: ... channels 1 and 2 You may notice that channels 1 and 2 are both high during clock pulses A B and C In the state mode the pattern is checked for validity only on the selected clock edge On the rising edge of clock pulses A and B channel 2 is a low level Therefore the pattern is valid only on the rising edge of clock pulse C Example of a when a trigger occurs on a state timing diagram Figure 18 5 Tr...

Page 293: ...because it moves the trigger event closer to the point of interest which reduces any jitter on long delay measurements For example a disk drive motor does not spin at a constant speed all the time If you use time base delay to look at a pulse separated from the trigger event by a long time period the jitter on the pulse caused by variations in the motor s speed can make it almost impossible to see...

Page 294: ...nnel 2 By changing the amount of delay you can look at various events in a pulse train without the effects of jitter The first event to satisfy the trigger conditions after the delay timer times out triggers the oscilloscope Example of a when a trigger occurs on a delay by time timing diagram Figure 18 6 Trigger Menu Mode 18 15 ...

Page 295: ...n the pulse can make it almost impossible to see the desired pulse Delay by events allows you to delay out to the pulse of interest then trigger on that pulse Because you are triggering on the pulse of interest jitter is not a factor in viewing the pulse For example you may want to look at the 97th pulse out of 100 pulses You can arm on the first pulse then delay out 95 events then trigger on the ...

Page 296: ...By changing the number of events you can consecutively look at pulses in a pulse burst without the effects of jitter The first event to satisfy the trigger conditions after the number of events are counted triggers the oscilloscope Example of a when a trigger occurs on a delay by events timing diagram Figure 18 7 Trigger Menu Mode 18 17 ...

Page 297: ...ield you want the oscilloscope to trigger on The trigger is generated on the selected line The range of lines you can choose from depends on what the standard and field softkeys are set to When the standard softkey is set to 525 lines 60 Hz which is compatible with broadcast standard M field 1 allows a range of lines from 1 to 263 and field 2 allows a range of lines from 1 to 262 When the standard...

Page 298: ...gger on softkey allows you to set the oscilloscope to trigger on a positive or negative slope Negative polarity means that the scope arms on a high state and triggers on a negative slope Positive polarity means that the scope arms on a low state and triggers on a positive slope Edge Number Softkey The Edge number softkey allows you to select an edge number from 1 to 16 million to trigger the oscil...

Page 299: ... the trigger level You can adjust the trigger level from within any of the trigger submenus The trigger level setting also determines what the oscilloscope uses as a reference to determine a high or low A high is a voltage above the trigger level and a low is a voltage below the trigger level On plug ins that have internal triggering there is a horizontal line on the display with a T on the right ...

Page 300: ...r to trigger the oscilloscope If the trigger signal is very small then you want less hysteresis If the trigger signal is very large then you want more hysteresis so that the trigger circuit is less sensitive to noise The oscilloscope offers three Hysteresis selections noise reject normal and high sensitivity The specifications for each of these selections depends on the plug in you are using Refer...

Page 301: ...ws a pulse burst with the holdoff time represented as T1 You may notice that holdoff keeps the trigger circuit from rearming until after the pulse burst is over That way the first pulse in the next burst is the trigger event The advantage of digital holdoff is that it is a fixed number As a result changing the time base settings does not affect the holdoff number and the oscilloscope remains trigg...

Page 302: ...19 HP IB Setup 19 3 System Configuration 19 4 Calibrate 19 10 Self test 19 14 Firmware Support 19 14 Service 19 16 Utility Menu ...

Page 303: ...ity Menu The utility menu allows you access to these six additional softkey menus HP IB setup System configuration Calibrate Self test Firmware support and Service Utility menu and menu map Figure 19 1 19 2 ...

Page 304: ...g address so that the computer or controller can communicate with only one instrument at a time The HP IB setup menu lets you select an address from 0 to 31 The address number you select is the address that a computer or controller uses to communicate with the oscilloscope The default HP IB address for oscilloscopes is 7 Utility Menu HP IB Setup 19 3 ...

Page 305: ...ed The system configuration menu gives you information about the mainframe and plug ins It allows you to set the date and time on the clock inside the mainframe It also allows you to update the system firmware and to declassify the memory in the mainframe Figure 19 2 Utility Menu System Configuration 19 4 ...

Page 306: ...me set the switch to the unprotected position Make sure you that you return it to the protected position after completing the calibration Power On Test Indicates if the power on self tests passed or failed These power on tests verify that the six boards are in the mainframe five boards in the HP 54710 mainframe A Failed message indicates that at least one board is loose or defective The power up r...

Page 307: ...er on The time that the oscilloscope has been turned on since it was manufactured Length Last Pof Power off The time that the oscilloscope was off the last time it was turned off Time Since on Power on The time that the oscilloscope has been turned on since the last time it was turned on Power Cycles The number of times that the oscilloscope has been turned off and on since it was manufactured Uti...

Page 308: ...log bandwidth of the plug in when used with the mainframe Using probes and bandwidth limit filters can result in a lower system bandwidth for the associated channel Calibration Memory Indicates the position of the memory protect switch inside the plug in This switch is for the memory in the plug in that contains the calibration factors from the last plug in calibration This switch is normally set ...

Page 309: ... the proper clearance Declassifying the mainframe places zeros in the oscilloscope s RAM memory This clears all the setup memories waveform memories pixel memories front panel setups channel memories and function memories Declassify the mainframe in situations when you are concerned about the security of the work you are performing For example you would declassify the mainframe when you are going ...

Page 310: ...ware for the graphics processor All measurements are turned off The default setup condition is stored in all of the setup memories The oscilloscope is placed in the default setup condition See Also Chapter 14 Setup for the default setup conditions Update system firmware The operating system for the oscilloscope is located in the system ROM inside the oscilloscope The oscilloscope does not need a d...

Page 311: ... softkey is set to on a screen similar to figure 19 3 is displayed Current Temperature This is the temperature change inside the instrument between the last mainframe calibration and now A positive number indicates how many degrees warmer the mainframe is now compared to the temperature of the mainframe at the last mainframe calibration If the current temperature delta is more than 5 C you have to...

Page 312: ... to the protected position after completing the calibration Frame Calibration Status Indicates the calibration status of the mainframe which is either calibrated or uncalibrated Below the Frame Calibration Status line is a display of each slot and whether the slot passed or failed the calibration If any part of the calibration process fails then the Frame Calibration Status line also displays fail...

Page 313: ...emory in the plug in that contains the calibration factors from the last plug in calibration This switch is normally set to the protected position so before calibrating a plug in make sure that the memory protect switch in the plug in is in the unprotected position Make sure you return it to the protected position after completing the calibration Date and Time Indicates the date and time of the la...

Page 314: ...te to best accuracy softkey 4 Follow the instructions on the display Uncalibrated indicates that the calibration factors in the plug in are set to the default state See the Service Guide that is supplied with the plug in for calibration information Best accuracy Temp Indicates the temperature change from the temperature that the last best accuracy calibration was performed at Output Output lets yo...

Page 315: ...mware support softkey lets you print a copy of the problem report form or the firmware request form You may not have originally purchased the oscilloscope or you may share the oscilloscope with several coworkers These forms are your way of communicating with the manufacturer of the oscilloscope Hewlett Packard Because both forms reside in the memory of the oscilloscope you can print out a copy of ...

Page 316: ...r this oscilloscope and who would like Hewlett Packard to notify them of all future software and hardware upgrades that become available If you signed up for option NA0 you do not need to fill out this form because you will automatically be notified of future firmware upgrades Keep in mind that this form provides notification of upgrades only If an upgrade has already occurred and you want a copy ...

Page 317: ...Service The Service menu is for performing service work on the oscilloscope Refer to the Service Guide supplied with the oscilloscope for details on the features in this menu Utility Menu Service 19 16 ...

Page 318: ...__________ _________________________________________________________________________________________ _________________________________________________________________________________________ System Description Remote controller Software Printer Cables _________________________________________________________________________________________ __________________________________________________________...

Page 319: ...19 18 ...

Page 320: ...untry Code _________________________________ Phone Number_______________ Street Address _______________________________________________ Fax Number _________________ Mail Stop ____________________________________________________ Department _________________ City ________________________________________________________ Prov State___________________ Postal Zip ________________________________________...

Page 321: ...____________________________________________ _________________________________________________________________________________________ _________________________________________________________________________________________ What are you making measurements on ______ Computers ______ Disk Drives ______ Tape Drives ______ ICs ______ Lasers ______ Fiber Optics ______ Instrumentation ______ Video ___...

Page 322: ...20 Waveform 20 3 Pixel 20 6 Waveform Menu ...

Page 323: ...a waveform to a waveform memory or to the pixel memory When you recall a waveform from a waveform memory or the pixel memory it is displayed in the default color blue However you can change the default color in the display menu Waveform menu map Figure 20 1 20 2 ...

Page 324: ...4K but less than 128K the available memories are grouped together in pairs The three possible memory pairs are m1 and m2 m2 and m3 and m3 and m4 If the waveform is greater than 128K but less than 256K the available memories are grouped together into one large memory When the display for an available memory is turned on the bar below the memory fills in and turns blue The default color is blue If t...

Page 325: ... knob arrow keys or keypad to change the values of the four scaling softkeys Y scale changes the vertical scaling of the waveform and Y offset moves the waveform vertically up and down X scale expands and contracts the waveform horizontally while X position moves the signal horizontally From waveform From waveform allows you to choose the source of the waveform you intend to save You can choose be...

Page 326: ...utoscale softkey turn off the power or set the oscilloscope to the default settings A waveform memory contains a single waveform record including the horizontal and vertical scaling parameters Therefore you can make parametric measurements on stored waveforms or use them as operands in a function You can also recall the waveform for future comparison or analysis print it save it to a disk or load ...

Page 327: ... have different time base and channel scale factors Display Display turns on and off the pixel memory When the pixel display and the channel display are both on the oscilloscope displays any trace overlap in a different color The default color is pink however you can change the default color in the display menu Add to memory Add to memory places additional snapshots of the graticule area in the pi...

Page 328: ...21 Display 21 3 Source 21 3 Window 21 3 FFT Scaling 21 4 FFTs and Automatic Measurements 21 8 FFT Basics 21 10 FFT Menu ...

Page 329: ...you to see the frequency content of a signal FFT functionality added to an oscilloscope allows you to analyze a signal from two different but complimentary points of view the frequency domain and the time domain FFT menu and menu map This softkey is displayed when the top softkey Display is set to on To enter the FFT menu Press the blue shift key on the keypad then press the Math hardkey Figure 21...

Page 330: ...akage In order to minimize spectral leakage windows that approach zero smoothly at the beginning and end of the record are employed as filters to the FFT Windows work by weighting points in the middle of the waveform record higher than those at the ends of the record For example a Hanning window looks like the first half of a sine wave The Hanning window multiplies the points in the center of the ...

Page 331: ...splayed when the FFT Display softkey is set to on Pressing the FFT Scaling softkey brings up either of the two following softkey menus The setting of the Magnify softkey determines which of the two menus is displayed FFT Menu FFT Scaling 21 4 ...

Page 332: ...elow the span frequency selection In the equivalent time mode the effective sample rate is displayed It is equal to one divided by the time between points and this number can be much larger than the oscilloscope s maximum sample rate You can only change the span for channel operands in the real time acquisition mode Because the keypad does not have keys for entering kHz or MHz use the enter expone...

Page 333: ...at way the oscilloscope can automatically pick the sample rate and record length to optimize the display of signals on the display You can either press the Autoscale key or set the record length and sample rate to automatic in the acquisition menu An FFT performed on a small number of points is computed faster than those performed on a large number of points An FFT performed on a large number of p...

Page 334: ...e vertical scaling of the FFT function It does not affect the hardware settings in the plug ins The scaling units are in dB per division For example if the scale is set to 10 dB div and a peak is two divisions high you know that the amplitude of the frequency peak is 20 dB Offset The Offset softkey uses software expansion to move the FFT function vertically on the screen Offset is the value at the...

Page 335: ...FT when you are making measurements on an FFT function selected in the FFT menu and function 1 or function 2 when making measurements on an FFT function selected in the Math menu Otherwise you will be making measurements on something other than the FFT function Peak Number Peak Number selects which peak the oscilloscope uses for the measurement For example a peak number of 2 indicates that the mea...

Page 336: ...evel and must go up and down at least one eighth of full scale one division Other FFT measurements There are a number of time domain measurements that you can make on FFT waveforms Tmin Tmax Vp p Vmin and Vmax The Tmax measurement is particularly useful because it returns the frequency of the highest peak on the display FFT Menu FFTs and Automatic Measurements 21 9 ...

Page 337: ...to the frequency domain The fast Fourier transform FFT was developed as a special algorithm that speeds up the discrete Fourier transform DFT by reducing the large number of calculations that are required by DFTs Because an FFT runs 10 to 100 times faster than the traditional DFT Fourier transform calculations typically use FFTs in place of DFTs Oscilloscopes operate in the time domain and display...

Page 338: ...es on every cycle of the input signal Signals above the Nyquist frequency become aliased which means that they appear as signals of a lower frequency The reason is that there are not enough sample points on each cycle of the signal to determine the correct frequency It turns out that the points above Fs 2 are a mirror image of the points below Fs 2 The points above Fs 2 are not displayed because t...

Page 339: ...ourier transform The third line lists the vertical scale and offset settings of channel 1 Because the frequency domain may be new to you lets look at the second line of numbers The first number is the vertical scale in dB div The second number is the offset in dBm at the center of the lower graticule area The third number is the horizontal scale in frequency div The fourth number is the center fre...

Page 340: ...o wide plug in or as high as possible if computation time is a consideration A higher number of points results in more accurate measurements but also takes more computation time Depending on your application you can balance between the need for accuracy and computation speed of the FFT Frequency Accuracy The frequency accuracy is the sum of two terms The first term is supplied because there are a ...

Page 341: ...ctly for your application 2 In the acquisition menu set the Sampling mode to real time and set Interpolate to off 3 In the channel menu set the Scaling for almost full scale deflection 4 In the FFT menu use the flattop window 5 Press the shift key then the More meas key on the keypad Then make an FFT magnitude measurement FFT Menu FFT Basics 21 14 ...

Page 342: ...log Vp 0 316228V The bottom term 0 316228 Volts is the peak voltage of a 1 mW signal into a 50 Ω resistor The calculation is VP Vrms 0 707107 P R 0 707107 1 mW 50 Ω 0 707107 0 316228V If you are measuring the power of a signal then terminate the source into 50 Ω in order to get the correct dBm reading However if you are measuring voltage then you do not need to terminate source impedance into 50 Ω...

Page 343: ... signal is greater than or equal to the Nyquist frequency sample frequency divided by 2 When a signal is aliased it shows up in the FFT spectrum as a signal of a lower frequency Because the frequency span goes from 0 to the Nyquist frequency the best way to prevent aliasing is to make sure that the frequency span is greater than the frequencies present in the input signal Keep in mind that most pe...

Page 344: ...22 Test 22 4 Measurement 22 4 Fail When 22 5 Lower Limit 22 7 Upper Limit 22 7 Run Until 22 7 Fail Action 22 9 Limit Test Menu ...

Page 345: ...tly tracks up to four measurements and you can determine the fail action the oscilloscope takes Figure 22 1 shows a functional view of the limit test You may notice that the test summary screen dumps and waveforms can each be sent to different destinations To enter the Limit test menu Press the blue shift key on the keypad then press the Define meas hardkey Figure 22 1 22 2 ...

Page 346: ...Limit test menu and menu map Figure 22 2 Limit Test Menu 22 3 ...

Page 347: ...cope stops the test and stops acquiring data If you set the Test softkey to off after completion of the test the test results are removed from the screen Measurement The limit test runs on all active measurements The Measurement softkey allows you to select each of the measurements and configure the Fail when Upper limit and Lower limit softkeys for that measurement This allows you to individualiz...

Page 348: ...n the measurement results is greater than the upper limit or is less than the lower limit Always Fail always causes the oscilloscope to fail on a test every time the measurement is executed and the parameters set by the Lower limit and Upper limit softkeys are ignored Use the fail always mode when you want to log the action each time the measurement is executed Fail always allows you to monitor tr...

Page 349: ...present but is not found The fail mode is used for most applications The total number of waveforms is incremented and the total number of failures is incremented Pass You might use the pass parameter when triggering on one event and measuring another event that may not occur on every trigger For example in a communications system you may want to trigger on the clock and test the rise times of edge...

Page 350: ...when the oscilloscope should stop running the limit test The Run until selections are global for all measurements Mode Mode allows you to configure when the limit test should stop The three choices are run the test forever run until a set number of failures occurs or run until a set number of waveforms occurs Forever Forever runs the limit test until you turn the test off Use the forever mode when...

Page 351: ...constructed from several trigger events The limit test operates in conjunction with the completion softkey in the acquisition menu If the Completion softkey is set to off measurements and limit test consider each trigger event as a waveform Older data from previous triggers is still retained in memory and the latest trigger may or may not add additional data points to the waveform When Completion ...

Page 352: ... measurement parameters at the time of the failure are logged to the summary After the limit test is complete the summary contains a log of all the measurement results at each failure When a failure does not occur during a set of measurements the header information is updated to show that the measurements passed but measurement results are not logged to the summary file unless a failure occurred W...

Page 353: ... started Selecting a measurement Turning on the display of the signal under measurement Changing the channel state scale or offset for the measurement on that channel Redefining a waveform math function if the measurement is calculated on that function Storing to memory for the measurements calculated on that memory Change the upper or lower limits Change the fail when mode The store summary choic...

Page 354: ...t limit is with MS DOS itself MS DOS limits the root directory to 224 entries an entry is either a file name or subdirectory Because the oscilloscope can only access files in the root directory that limits the maximum number of files the oscilloscope can store to a disk to 224 The second limit is the potential size of a summary file The size of the summary file depends on how many measurements are...

Page 355: ...e that is stored Off Off means that the an image copy of the entire screen area is not stored printed or retained Pixel memory Pixel memory stores an image copy of the entire screen area to the pixel memory the same pixel memory that is accessed by the Waveform menu Additional failures are added to the composite data stored in the pixel memory The only way to clear the pixel memory is from the Wav...

Page 356: ...ntains the vertical and horizontal scaling factors which allows you to bring the waveform back into the oscilloscope for measurement or rescaling Waveforms are stored on a source by source basis For example you can store channel 1 to a file and channel 2 to a memory Off Off means that the waveform data is not stored printed or retained Memory Memory stores a copy of what the Source softkey is set ...

Page 357: ...22 14 ...

Page 358: ...23 Polygon Masks in the Oscilloscope 24 4 Test 23 6 Scale Mask 23 7 Edit Mask 23 9 Run Until 23 18 Fail Action 23 20 Mask Menu ...

Page 359: ...can have from 3 to 512 sides Because of the flexibility polygons give you to design a mask the polygon method is typically used for telecommunications data communication and general purpose digital design and test For example you can construct very complicated masks with polygons or you can place polygons within polygons Placing polygons within polygons allows you to test waveform failure rates to...

Page 360: ...Mask menu map Figure 23 1 Mask Menu 23 3 ...

Page 361: ...as of the display The data base continues to build until the oscilloscope stops acquiring data or all three functions color graded display mask testing and histograms are turned off The oscilloscope stops acquiring data when the power is cycled the Stop Single hardkey is pressed or the run until softkey in the mask limit test or histograms menus is set to stop acquiring data after a specified numb...

Page 362: ...s building because color graded display is turned on When mask testing is turned on it takes advantage of the information already established in the data base as if it had been turned on the entire time The results are updated automatically from the existing data base which allows you to modify the mask or to load a new mask without having to reacquire the data You will know how many waveforms and...

Page 363: ...est is turned off the Stop Single hardkey is pressed power is cycled or the conditions set by the run until softkey are met Also if the data base for the mask test is not already built histograms and color graded display turned off on starts building the data base If the data base is already built on automatically updates the mask test results as if mask testing had been on all the time You will k...

Page 364: ...istance between the markers depends on the vertical scaling of the source If the source is set to 100 mV div the markers will be two divisions apart If the source is set to 1 V div the markers will be about a minor division apart With a channel as the source the scaling of the X1 and X markers is set by the time div setting in the time base menu With a function or memory as the source the scaling ...

Page 365: ...2 The 1 level Y2 softkey moves the Y2 marker that defines the horizontal line or 1 level where Y 1 Moving the Y1 marker moves all mask points that do not have a Y value of 0 The Y2 marker tracks the 1 level softkey 0 Level Y1 The 0 level Y1 softkey defines the horizontal line where Y 0 The Y1 marker tracks the Y1 Position softkey This control is typically set to the value that corresponds to a log...

Page 366: ...y allows you to select one of the eight polygons that you want to edit or create If the mask does not have a polygon with the selected number you can create that polygon using the edit polygon menu If a polygon is scaled off of the screen the number of that polygon is still displayed on the screen However it is possible that a polygon number can obscure another polygon number Also if a polygon is ...

Page 367: ...id line when you exit the menu Also you cannot cross lines as this turns one polygon into multiple polygons For example in figure 23 6 A requires two polygons while B is not a legal construction because B requires lines to cross X Moves the cursor horizontally across the display allowing you to define a point Y Moves the cursor vertically on the display allowing you to define a point Insert Insert...

Page 368: ...n the cursor to the location on the screen where you want to place point number 2 7 Press the Insert softkey The scope draws a line from point 1 to point 2 and the Point softkey increments to the number 2 Repeat steps 5 and 6 to add more points up to 512 You can also use the Delete softkey to remove a point or the Move softkey to change a point s location You may notice that after you define point...

Page 369: ...n figure 23 3 looks like both points are off the screen However rescaling the polygon by changing the 1 level Y2 value from 3 V to 2 V shrinks the polygon in figure 23 4 You may notice that the top left point stayed fixed to the top of the screen while the top right point moved into the graticule area To keep a point fixed to a side of the graticule area set the point s value to either minimum or ...

Page 370: ...Figure 23 3 Figure 23 4 Mask Menu Edit Mask 23 13 ...

Page 371: ...tional A title can be up to 20 characters long and it must be enclosed in quote marks Polygon number A number 1 through 8 Number of vertices Number of vertices in the polygon up to 512 Vertices Pairs X Y pairs separated by new lines spaces tabs or commas Fixed point numbers are allowed plus the special values of min or max Min fixes a vertex to either the left edge or bottom edge of the graticule ...

Page 372: ...s Top Polygon 1 Number of vertices 9 0 5 Max Top of screen left side 0 5 0 1 0 0512 0 5 0 0512 1 2 0 5 1 1 1 0512 1 2 1 0512 0 5 1 5 0 1 1 5 Max Top of screen right side _______________________________________ Bottom Polygon 2 Number of vertices 11 0 5 Min Bottom of screen left side 0 5 0 1 0 05123 0 2 0 05123 0 5 0 10246 0 8 0 5 0 9 Figure 23 6 Figure 23 7 Mask Menu Edit Mask 23 15 ...

Page 373: ...he point on the polygon you wish to edit The scope will not let you select a point that is not defined 6 Edit the selected point To delete the selected point press the delete softkey To insert a point or move a point use the X and Y softkeys to move the cursor to the desired location Then press the Insert softkey to insert a new point or press the Move softkey to move the selected point to the new...

Page 374: ...depends on the vertical scaling of the source If the source is set to 100 mV div the markers will be two divisions apart If the source is set to 1 V div the markers will be about a minor division apart The source selection also defines the waveform the scope generates the mask from Units Units allows you to define X and Y in divisions or current source settings Current is typically in volts and se...

Page 375: ... not stop after a fixed number of failures or acquisitions For example you may want the mask test to run overnight and not be limited by a number of failures or acquisitions Failed Waveforms Failed waveforms runs the mask test until a set number of failed waveforms are acquired When failed waveforms is selected another softkey is displayed that allows you to set the number of failures Failed Sampl...

Page 376: ...ents the counters on each trigger event For example older data may have incremented some of the counters to a thousand When Completion is on Completion acts like a holdoff control because the test is held off until after the completion criteria is met For example if completion is set to 95 then the counters are incremented after 95 of the waveform record is filled with data The counters will have ...

Page 377: ... to the summary The first part is a header that is a running total of the number of failures The second part is the log of the results on each failure When a failure does not occur during a set of measurements the header information is updated to show that the measurements passed but the results are not logged to the summary file unless a failure occurred When the screen or a waveform is logged to...

Page 378: ...nging the filter bandwidth if measuring filtered data Changing the record length Changing the interpolator setting Clearing the display Off Off means that the summary data is not printed or stored Printer Printer sends the summary to the destination determined by the Print selections The destination can be one of several printers The printer selection gives you a hardcopy of the summary informatio...

Page 379: ...he first limit is with MS DOS itself MS DOS limits the root directory to 224 entries an entry is either a file name or subdirectory Because the oscilloscope can only access files in the root directory that limits the maximum number of files the oscilloscope can store to a disk to 224 The second limit is the potential size of a summary file The size of the summary file depends on how many tests are...

Page 380: ...mage that is stored Off Off means that the an image copy of the entire screen area is not stored printed or retained Pixel memory Pixel memory stores an image copy of the entire screen area to the pixel memory The same pixel memory that is accessed by the Waveform menu Additional failures are added to the composite data stored in the pixel memory The only way to clear the pixel memory is from the ...

Page 381: ...contains the vertical and horizontal scaling factors which allows you to bring the waveform back into the oscilloscope for measurement or rescaling Waveforms are stored on a source by source basis For example you can store channel 1 to a file and channel 2 to a memory Off Off means that the waveform data is not stored printed or retained Memory Memory stores a copy of what the Source softkey is se...

Page 382: ...24 Histograms in the Oscilloscope 24 3 Mode 24 6 Axis 24 6 Histogram Window 24 7 Histogram Scale 24 8 Run Until Mode 24 10 Histogram Menu ...

Page 383: ...ents The two most common uses for histograms are measuring and characterizing noise or jitter on displayed waveforms Noise is measured by sizing the histogram window to a narrow portion of time and observing a vertical histogram that measures the noise on an edge Jitter is measured by sizing the histogram window to a narrow portion of voltage and observing a horizontal histogram that measures the ...

Page 384: ...e stops acquiring data or all three functions color graded display mask testing and histograms are turned off The oscilloscope stops acquiring data when the power is cycled the Stop Single hardkey is pressed or the run until mode softkey in the mask limit test or histograms menus is set to stop acquiring data after a specified number of waveforms or samples are acquired You can clear the data base...

Page 385: ...he display as opposed to the center of the display Mean Mean is the average value of all the points in the histogram Median 50 of the histogram samples are above the median and 50 are below the median Std dev The Standard deviation σ value of the histogram Hits The total number of samples included in the histogram P P The width of the histogram For horizontal histograms width is the difference tim...

Page 386: ...To enter the histogram menu Press the blue shift key on the keypad then press the Display hardkey Figure 24 2 Histogram Menu Histograms in the oscilloscope 24 5 ...

Page 387: ...e and the histogram If the data base is already built waveform displays a histogram of the data in the data base that is windowed by the histogram markers The data base may be reset by pressing the Clear display hardkey Axis The axis softkey orients the histogram vertically or horizontally Vertical places the histogram at the left side of the graticule which allows for voltage measurements Horizon...

Page 388: ...eys allow you to use the histogram markers to select a region of the data base X1 and X2 position move the vertical histogram markers vertically across the display while Y1 and Y2 position move the horizontal histogram markers horizontally across the display Because the data base that the histogram is derived from is limited to the size of the graticule area placing the histogram markers beyond th...

Page 389: ... scale is in decibels per division The histogram is plotted according to the following formula dB 20 log X peak where X is the number of hits in a histogram row for vertical histograms or the number of hits in a histogram column for horizontal histograms Peak is the number of hits in the largest histogram column or row dB is the log value that gets plotted Linear offset For linear scale type the o...

Page 390: ...splayed on the screen If the axis softkey is set to horizontal auto sets the base of the histogram to the bottom of the graticule area and displays the histogram using half of the graticule height If the axis softkey is set to vertical auto sets the base of the histogram to the left edge of the graticule area and displays the histogram using half of the graticule width Manual lets you window in on...

Page 391: ...f forever is selected you must press the stop single hardkey to stop the acquisition of data If either waveforms or samples is selected after the number of waveforms or samples are met then the acquisition is stopped as if you had pressed the stop single hardkey Histogram Menu Run Until 24 10 ...

Page 392: ... perform a best accuracy calibration before just prior to making critical measurements See chapter 5 Calibration Overview for additional details about the calibration levels of the oscilloscope Bit map A two dimensional array in which each element stores the state of a corresponding pixel dot on a video display Typically there is one bit in the array for each pixel on the display The bit indicates...

Page 393: ...isplay that uses the full resolution of the data in the waveform memory making the display appear to have a higher vertical resolution When a data point lies between two adjacent pixels the oscilloscope lights up both pixels but varies the brightness of each pixel The brightness of each pixel is proportional to how close it is to the data point Your eye is then drawn to a point between the two pix...

Page 394: ...ration Offset Offset moves the waveform vertically on the display It is similar to the vertical position control on analog oscilloscopes except that it is precisely calibrated The offset voltage is the voltage at the center of the graticule area Pattern triggering Pattern triggering qualifies the trigger event by having the oscilloscope search for a 4 bit pattern across the oscilloscope inputs You...

Page 395: ... or infrequently Reconstruction Also known as interpolation Sampling theory indicates that if a signal is bandwidth limited to less than half of the sampling frequency the Nyquist frequency the continuous signal can be determined exactly from the sequence of samples Two problems exist in the real world to prevent exact determination of the continuous input First many signals are not bandwidth limi...

Page 396: ...w Skew changes the horizontal position of a waveform on the display independent of any other waveforms on the display The time base position control moves all of the waveforms on the display at the same time whereas skew moves individual waveforms Skew is typically used for overlaying waveforms or eliminating timing difference caused by diverse cable and probe lengths Slot There are four slots on ...

Page 397: ...h waveform sample is stored in a specific time bucket within the waveform record based upon its time relationship to the other samples The waveform record length number of points determines the number of time buckets in a record A time bucket is considered full if it contains a waveform data sample Trigger event A change of some type in the trigger source waveform which causes the acquisition syst...

Page 398: ...ftkey 6 12 CAL calibration table 1 12 Cal status softkey 19 10 Calculated softkey 7 6 calculations dBm 21 15 dBV 21 16 including new data with existing 3 19 mean 7 12 rise time 1 24 standard deviation 7 12 Calibrate frame softkey 19 10 Calibrate plug in softkey 19 10 Calibrate probe softkey 6 9 Calibrate softkey menu 6 10 19 10 Calibrate to best accuracy softkey 6 11 calibration memory screen mess...

Page 399: ...ng files 8 8 Delta X 11 4 Delta Y 11 4 Destination softkey 15 6 diagram of data flow 1 15 digital BW bandwidth limit 3 6 digital holdoff 18 22 digitizer 1 16 dimensions of instrument 16 11 directory disk operation 8 3 files 15 6 listing of files on disk 8 3 to 8 4 listing screen 8 3 scrolling 8 5 disk compatibility 8 9 formatting 8 9 loading waveforms 8 10 menu map 8 2 storage 22 11 storing wavefo...

Page 400: ...l remote control lockout 2 12 setup 14 3 setup file 8 11 setups 14 4 storing setups to disk 8 6 front panel calibrator characteristics 16 8 front panel calibrator specifications 16 3 Function scaling softkey 12 8 Function softkey 12 3 G gain errors 13 39 general characteristics 16 10 to 16 12 glitch 13 66 polarity 18 8 pulse 13 50 timing requirements 18 9 width 18 8 Glitch trigger softkey 18 8 Gra...

Page 401: ...8 on screen 11 5 results area 2 6 usage 13 33 Marker hardkey 11 2 Marker menu map 11 2 mask constructing 23 9 scaling 23 7 to 23 8 mask data base 23 4 mask editing 23 9 mask file format 8 19 Mask menu map 23 3 mask testing 23 2 Math hardkey 12 2 math menu 12 2 Max maximum softkey 7 12 12 5 maximum memory depth 13 32 mean calculation 7 12 Mean softkey 7 11 Meas Measurement not found softkey 22 6 me...

Page 402: ...calibration level 5 5 recommendations when mixing 3 14 Plug in screen message 6 14 19 7 points in a period defined 13 20 points of reference 17 4 Polarity softkey 18 8 polygon creating 23 11 editing 23 16 Polygon softkey 23 9 polygons in masks 23 2 23 4 port centronics 1 14 high speed 1 14 Position softkey 17 3 position value 17 4 positive position 17 3 positive time 18 4 postprocessing 1 16 postt...

Page 403: ...tioning 1 12 drift 9 4 infrequent 1 18 infrequent viewing 1 11 output selection 19 13 reconstructing 1 18 repetitive viewing 1 11 sampling 1 11 zooming 17 3 single shot bandwidth 3 5 events 2 14 to 2 15 Skew softkey 6 10 slew rate 13 35 Slope softkey 18 20 slot screen message 19 6 softkey Position 11 6 Source 11 5 0 level 23 8 1 level 23 8 Add 12 4 Add to memory 20 6 Arm on 18 14 18 16 18 19 Atten...

Page 404: ... 9 15 Run until 22 7 23 4 saturation 9 19 Save 14 3 20 5 Scale 6 5 12 7 17 3 21 7 Scale mask 23 7 Scale source 23 7 Select next label 9 15 to 9 16 Setup menu 14 3 skew 6 10 Slope 18 20 source 18 8 18 20 21 3 21 8 Span 21 5 Standard 18 18 Start edge 7 8 State 18 12 Statistics 7 9 13 34 stddev standard deviation 7 11 Stop edge 7 8 Store 8 6 Store summary 22 9 Store waveforms 22 13 Subtract 12 4 Swee...

Page 405: ...rval measurement accuracy 16 4 Time softkey 19 8 time division 13 32 timing measurements 11 6 13 18 To file softkey 8 6 To memory softkey 8 21 20 5 Top base softkey 7 6 top base values setting manually 7 7 track source 12 8 transient errors 13 45 response 13 45 response errors 13 53 trigger delay 18 14 delay by events 18 16 event 13 55 event defined 18 4 features 18 4 holdoff 18 21 to 18 22 hyster...

Page 406: ...and 12 6 patterns 18 10 18 19 reconstructing 3 6 9 7 record 2 6 3 12 12 5 record discontinuity 21 3 rescaling 20 4 source selecting 20 4 storage 22 12 to 22 13 storing setups to disk 8 6 storing to disk 8 10 top calculation 13 15 to 13 16 track source 12 8 transitions 13 19 vertical movement 6 6 Waveform hardkey 20 3 waveform math menu map 12 2 Waveform menu map 20 2 Waveform softkey 9 12 22 8 wav...

Page 407: ...Index 10 ...

Page 408: ... Class A IEC 801 2 1991 EN 50082 1 1992 4 kV CD 8 kV AD IEC 801 3 1984 EN 50082 1 1992 3 V m 1kHz 80 AM 27 1000 MHz IEC 801 4 1988 EN 50082 1 1992 0 5 kV Sig Lines 1 kV Power Lines Supplementary Information The product herewith complies with the requirements of the Low Voltage Directive 73 23 EEC and the EMC Directive 89 336 EEC and carries the CE marking accordingly This product was tested in a t...

Page 409: ......

Page 410: ...acement Parts Section for the proper HP part number Number of German License BW 218 86 ROE Während des Betriebs erzeugt dieses Gerät Röntgenstrahlung Das Gerät ist so abgeschirmt daß die Dosisleistung weniger als 36 pA kg 0 5 mR h in 5cm Abstand von der Oberfläche der Kathodenstrahlröhre beträgt Somit sind die Sicherheitsbestimmungen verschiedener Länder u A der deutschen Röntgenverordnung eingeha...

Page 411: ...d Service instructions are for trained service personnel To avoid dangerous electric shock do not perform any service unless qualified to do so Do not attempt internal service or adjustment unless another person capable of rendering first aid and resuscitation is present If you energize this instrument by an auto transformer for voltage reduction make sure the common terminal is connected to the e...

Page 412: ... s sole and exclusive remedies Hewlett Packard shall not be liable for any direct indirect special incidental or consequential damages whether based on contract tort or any other legal theory Assistance Product maintenance agreements and other customer assistance agreements are available for Hewlett Packard products For any assistance contact your nearest Hewlett Packard Sales Office Certification...

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