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                                                        5-1

CHAPTER 5: REVERSE PATH TROUBLESHOOTING

5.0

GENERAL

The following application notes outline some return path
troubleshooting problems and techniques that are useful with
StealthTrak.  For future application notes outlining more techniques,
please see your local Wavetek CATV sales representative.

This table offers some ideas on the best application of StealthTrak’s
capabilities to help you solve troubleshooting problems.

PROBLEM

USE THIS TOOL

INGRESS

SPECTRUM MODE

MODEM CHANNEL HIGH BER

ZERO-SPAN MODE

SIGNAL LEVELS UNBALANCED

REVERSE ALIGNMENT
TECHNIQUES

POOR SIGNAL LEVEL IN SOME
MODEM CHANNELS

REVERSE SWEEP MODE

Summary of Contents for 4040D

Page 1: ...port wavetek com www wavetek com 4 99Rev B Manual Part No 6510 00 0434 Thisdocumentcontainsinformationproprietaryto WavetekWandel Goltermann Theinformationinthisdocument isnottobeusedorduplicatedinanymannerwithout thepriorapproval inwriting ofWavetekWandel Goltermann OPERATION MANUAL MODEL4040D ADVANCED HFC SIGNAL ANALYSIS METER ...

Page 2: ...e caused by improper storage improperinstallation unauthorizedmodification misuse neglect inadequatemaintenance accidentorforanyProductwhichhasbeenrepairedoralteredbyanyoneotherthanWavetek or its authorized representative or not in accordance with instructions furnished by Wavetek The Warranty described above is Buyer s sole and exclusive remedy and no other warranty whether written or oral expres...

Page 3: ... 3 4SystemModesofOperation 3 6 3 5ConfiguringtheSAM4040D 3 8 3 5 1GlobalConfiguration 3 9 3 5 2Diagnostics 3 11 3 5 3MeasurementsConfiguration 3 12 3 5 4SweepConfiguration 3 14 3 5 5 Configuring a Digital Carrier in a Channel Plan 3 14 3 6 SoftIconGuide 3 16 CHAPTER 4 MEASURING SYSTEM PERFOR MANCE 4 1Introduction 4 1 4 2Routine CorrectiveMeasurements 4 1 4 3MeasuringSignalLevels 4 2 4 3 1LevelMeas...

Page 4: ...Editing Test Locations 7 3 7 3 PerformingAutotest 7 5 7 3 1ChooseLocation 7 6 7 3 2 EditLocation 7 6 7 3 3SelectProbePoint 7 7 7 3 4 MeasureVoltage 7 8 7 3 5 Compensation 7 9 7 3 6 ResultsFileName 7 9 7 3 7 TypeofTest 7 10 7 3 8 SetSchedule 7 10 7 3 9 Temperature 7 11 7 3 10 CancelinganAutotest 7 13 7 4 AutotestResults 7 13 CHAPTER 8 FILES 8 1Introduction 8 1 8 2StoringFiles 8 2 8 3Viewing Printin...

Page 5: ...g 9 1 9 4CleaningtheInstrument 9 2 9 5AnnualCalibration 9 2 CHAPTER 10 CHANNEL PLANS 10 1Introduction 10 1 10 2WorkingwithaChannelPlan 10 1 10 3SettingChannelPlanParameters 10 3 APPENDIX A SPECIFICATIONS A 1 APPENDIX B GLOSSARY B 1 ...

Page 6: ...ion of the existing SAM4040 the SAM4040D s new motherboard analysis software and RF design together are the basis of an improved unit that assists the technician in rapid analysis and measurement of CATV broadband system performance Easily and quickly make frequency response checks measure and record signal level performance hum carrier to noise C N ratio depth of modulation and other general perf...

Page 7: ...hTrak and 3SR V T batteries can be used in SAM 4040D 1 3 NEW FEATURES AND BENEFITS IN SAM 4040D Following the existing SAM4040 s capabilities the SAM4040D adds enhanced ingress and noise measurement capabilities digital carrier analysis and increased spectrum analyzer functionality summarized as follows Faster scanning and spectrum analysis for ingress and noise detection catch bursty noise as fas...

Page 8: ...r StealthTrak s built in pre amp allows technicians to clearly see and diagnose noise Easily see the difference between meter induced inter modulation and system inter modulation and common path distortion CPD A built in low pass filter strips away higher power forward path signals to examine just the reverse path Save money connections and time Carry just one box with all the tools needed to find...

Page 9: ...use the manual to best advantage Chapter 4 6 Measurement modes reverse path and digital troubleshooting tools and Spectrum Analysis mode are described Power tools advanced measurement modes and methods and new SAM 4040D capabilities are discussed Chapter 7 9 Automated testing files and data management and StealthTrak maintenance are discussed Chapter 10 Channel Plans Explains step by step the proc...

Page 10: ...ton and packing material for possible future use SAM 4040D Power Requirements The SAM 4040D receiver operates on a 12 VDC battery A desktop extended life battery charger included with the product fully recharges the extended life battery in 5 6 hours Note the extended life battery charger cannot be used with older Stealth batteries Older Stealth batteries may be used with the SAM 4040D and new ext...

Page 11: ...your cable system Level Measurement Mode allows detailed display about a single channel The video and audio levels are displayed both in bar graph and numeric form The delta between audio and video level is also computed Wavetek s digiCheck power measurement algorithms are used to accurately read continuous digital carrier see Section 3 3 4 SCAN mode displays a graph of the level of all channels i...

Page 12: ... the carrier off and then prompt you to turn it back on Carrier to Noise is measured using an advanced quiet line algorithm The SAM 4040D meter searches for a line of video with no active signal This typically happens on one or more lines during vertical sync of an analog video channel This allows the noise measurement to be made in the middle of the channel rather than in an unused side band Thus...

Page 13: ... over the entire 5 1 000 Mhz in frequency range and can be tuned either by channel or frequency Several convenient spans are available Peak hold and dwell time can be varied to track down intermittent signals A low pass filter and preamplifier are available to help find difficult return path problems CSO and CTB can also be measured using the SAM 4040D spectrum mode These can help find the source ...

Page 14: ...gnized Start and stop center or other display settings squeezed or slid off scale or set to a point in the 1 GHz spectrum where no channels are located Connections to splitters couplers diplexers etc in use to patch the SAM 4040D are bad or wrong 2 3 TECHNICAL SUPPORT We ve worked hard to make the SAM 4040D as easy to use as possible If you have a problem using your receiver contact Wavetek s Tech...

Page 15: ...isplayed at any time by pressing Figure 3 1 The Navigator User Interface Use the arrow keys to select a Navigator mode or function followed by the Enter key The Navigator is an easy to use self guided user interface You can use the traditional keystrokes used on older Stealth units at any time NAV Arrow keys used for up down left right scrolling cursor movement etc Title Bar Time Date Battery Stat...

Page 16: ...lpha Numeric Keypad Enter Key Function Key Support Keys Soft keys Note that arrow keys can be cloned and displayed for one hand convenience Measurement Mode Keys Up Down Arrow Keys Soft Keys Note icons See icon reference index or quick guide ...

Page 17: ...ribed in the next section Test for direct access to the Autotest top level Menu PathTrak PathTrak function is not enabled without the PathTrak StealthModem option Four arrow keys for scrolling menu items cursors values etc A sixteen button alpha numeric keypad Menu modes or menu titles are represented in Italics as in Global Measurement and so forth The use of these keys is described as follows So...

Page 18: ... or frequency at a preset frequency offset above the video carrier Press HUM to measure low frequency hum modulation on the selected channel The measurement is presented in dB or as a percentage Select either or dB Press MOD to listen to the audio modulation of tuned channel or frequency and measure the Depth of Modulation on the video carrier Depth is presented as a percentage Press SPECT to acti...

Page 19: ...ts For data fields that accept alpha characters such as test point names technician names or file names enter letters in the edit box field as required Press each key 1 2 or 3 times to choose the letter desired Pressing a key an extra time brings up the number assigned to the key Pressing the space key twice creates a space between letters Use the right and left arrow keys to move the cursor Note ...

Page 20: ...ays a graph of the level of all channels in the current channel plan either with or without audio and digital carriers This mode is very useful when first connecting to a test point It allows a technician to quickly get a general idea of what may be going on with signal levels TILT mode provides the information needed to set the equalization in an amplifier Up to nine selected tilt channels are me...

Page 21: ...troubleshooting and for performing proof of performance tests Carrier to noise hum and depth of modulation are all calculated on analog video channels in service and in channel This allows technicians to measure the performance customers really experience all without any service interruption See Chapter 6 for more details Carrier to noise is measured using an advanced quiet line algorithm The SAM ...

Page 22: ...imum hold and dwell time can be varied to track down intermittent signals A low pass filter and preamplifier are available to help find difficult return path problems The SAM 4040D s spectrum mode includes a very powerful zero span mode display that can be used to measure and analyze TDMA digital channels and difficult ingress signals Zero span mode allows the user to perform in service and in cha...

Page 23: ...3 9 Figure 3 5 CONFIGURE Menu 3 5 1 Global Configuration Select Global and enter appropriate information into the twelve items listed Figure 3 6 GLOBAL Menu ...

Page 24: ...he time in the HH MM SS format 24 hour Date Format Use the UP and DOWN arrow keys to select the date format When you change the date format the new format will appear everywhere the date is displayed or printed The following formats are available MM DD YY DD MM YY YY MM DD Date Use the numeric entry keys to enter the date Select Date Format Next to determine date display format Printer Sets the pr...

Page 25: ...00 4800 9600 and 19 2k Beeps Clicks Use the arrow keys to turn key press clicks and instrument beep functions on off Diagnostics To enter diagnostics mode press the ENTER key 3 5 2 Diagnostics Figure 3 7 Diagnostics In Diagnostics mode you can reset the instrument to original factory configuration test the LCD or when applicable check out the SAM 4040D s internal transmitter functions Default to F...

Page 26: ...right soft key moves to the previous screen Figure 3 7 Display Test 3 5 3 Measurements Configuration With the Setup Menu of Figure 3 4 visible press the soft key on either side of Measurements Seven variables are to be adjusted in this part of the configuration In each case use the up down soft keys to scroll though the list and change the variables as indicated by the Title Bar Press the ENTER So...

Page 27: ...er Supply Scan Rate Two scan rates are available in the Scan mode Normal and Fast The Fast scan feature allows for rapid scan displays but at less accuracy Normal scan rate is slower but more accurate Scan Audio Carriers Omitting the audio carriers during Scan produces a faster scan C N Calibration To increase the accuracy of the carrier to noise measurements the measurement algorithm incorporates...

Page 28: ...e sweep file overlay option is enabled the live response overlays the stored response during viewing Use the up down arrow keys to enable the option Include Audio Carriers This selection allows the audio carriers to be excluded resulting in a faster sweep Use the up down arrow keys to include yes or exclude no audio 3 5 5 Configuring a Digital Carrier in a Channel Plan Follow these instructions to...

Page 29: ...pad type the bandwidth of the digital carrier and then press the Enter button Highlight the Enabled line in the Parameters box Verify that the setting is Yes Press the Exit soft key Highlight the next channel to be configured as digital and repeat this procedure and repeat the procedure ...

Page 30: ...dwidth Sub Menu Limit Check Sub Menu Sweep Enable Video Enable Level Sub Menu Noise Scan Enable Enable Disable Check Limits Frequency Sub Menu Maximum Hold Reference Level Start CSO CTB Test Select High Tilt Pilot Channel A or B Marker Toggle Start Zero Span Tilt Compensation Sub Menu Select Low Tilt Pilot Channel ...

Page 31: ...cription Audio Enable Hysteresis Video Bandwidth Resolution Bandwidth Measurement Bandwidth Scale Return to Last Mode Scan Time Autoscale Restart Maximum Hold Demodulation Toggle Volume Up Volume Down Cancel Restart Center Frequency ...

Page 32: ... Enable Disable Log Linear Toggle Desired Undesired Marker Toggle Low Pass Filter Enable Pre Amp Enable Marker to Peak 1KHz Filter Enable Span Dwell Save This Channel BW Save BW to All Channels Stop Frequency Start Frequency Trigger On Off Manual Trigger ...

Page 33: ...ite Triple Beat CTB 4 2 ROUTINE CORRECTIVE MEASUREMENTS You can start these measurements through the NAV main menu or by simply pressing the Measurement Mode keys During many of the following measurements you will notice that for a given procedure the display remains essentially the same but the Icons that guide you through the test change from screen to screen within the same test Press the soft ...

Page 34: ...annel number by using the numeric keys followed by Chan If you were in Frequency Chan tunes to the nearest channel in the channel plan Frequency To tune by frequency use the numeric keys to enter a frequency followed by Freq See Figure 4 2 Use the left and right arrow keys to decrement and increment the frequency The step size for these frequency changes is programmed during setup NAV Config Measu...

Page 35: ...display of carrier levels dBmV 5 Delta between audio and video levels dB 6 Test point compensation appears only if a non zero value is programmed during setup compensates for the test point loss or probe loss from the measurement result to show the signal level on the system 20 0 dB in this instance Figure 4 2 shows the display for tuning by frequency With only a single frequency involved there is...

Page 36: ...nly Dual audio carrier channels display two audio graphs Digital carriers show as noise Scrambled channels have the same appearance as non scrambled channels You must designate scrambled channels in the Edit Channel Plan sub menu of the Config Channel menu ...

Page 37: ...ou to enter the cable loss for a particular section of coax and then using the scan display adjust the gain of the amplifier to compensate for this loss You can turn Tilt Comp ON OFF in the Tilt sub menu SAM 4040D enables you to designate up to nine Tilt channels Config Channel Plan Edit Channel Plan The slope for Tilt is a straight line from the lowest in frequency to the highest designated Tilt ...

Page 38: ...rence Value level is limited by the units selected and the Scale setting The Tilt adjustment uses amplifier gain to compensate for the attenuation of signals moving through the cable Higher frequencies are attenuated more than lower frequencies This accounts for the slope of the line in Figure 4 3 Tilt mode simplifies the actual balancing by displaying a bar graph with a representation of up to ni...

Page 39: ... the Tilt display and then select the HI Pilot channel Observe the nine Tilt channels by pressing the Tilt Measurement Mode key To include or exclude a channel in the nine Tilt channels you must choose desired video carriers as Tilt Channels in the Edit Channel Plan portion of the Config Channel Plan menus Use the up down arrow keys to adjust the reference level of the graph Adjust amplifier Tilt ...

Page 40: ...ows for rapid scan displays at reduced accuracy as much as 2 dB on scrambled channels Normal scan rate is slower but much more accurate An speeding bullet icon when Fast is selected appears in the upper left hand corner of the Scan display Audio Carriers You can omit audio carriers for a faster scan Select this in the Config Measurement sub menu An X d out audio icon indicator appears in the upper...

Page 41: ...reen Tilt Comp value Immediately below the graph numerical values are displayed The basic display shows the following information Channel number Video carrier frequency and level numerical Audio carrier frequency and level numerical Histogram graph of carrier levels Delta between audio and video levels Selected channel plan Test point compensation appears only if a non zero value is programmed dur...

Page 42: ...ling of the graph Use up down arrow keys to scroll through the available Changing the scale factor changes the display Freq Press to bring up the Freq sub menu then to return to the Main Scan Menu When this is active set Start Freq and press Enter Key When this is active set Stop Freq and press Enter key Pressing this resets the Start Stop Freq to full span Press this to return to values previousl...

Page 43: ...shown as CHAN Adjacent Channel Error VIDEO v Video Level Too High or Low DVA DVA Too High or Low Press to run auto check Figure 4 5 Limits The Limit feature allows for comparison of the current scan measurement with the FCC or other conformance test limits defined during setup and configuration There are two parts to this feature ...

Page 44: ...DEO v Video Level Too High or Low DVA DVA Too High or Low You can display an aggregate result summary by pressing the Limit soft key This performs a limit check of all channels contained within the scan and reports an overall pass fail conclusion The aggregate limit check is not performed with each scan update however you can press the Check soft key to run the test any time When Limit is off the ...

Page 45: ...the frequency offset for the noise measurement from the screen A proprietary DSP technique allows C N measurements on modulated carriers non scrambled channels Th C N measurement requires measuring the video carrier level and then tuning to the offset frequency searching for a quiet line Once a quiet line is found the SAM 4040D measures four consecutive frames then averages the values This value i...

Page 46: ...ass Enter Amplifier Low Pass filter sub menu return to C N main menu Enable or Disable 13 dB Amplifier Enable or Disable 50 mHz Low pass Filter Icon shows Disabled Offset Enter Offset submenu return to C N Main Menu Store current measurement Offset to current channel parameters in current channel plan Store current Measurement Offset to all channels in the current channel plan Enter Bandwidth subm...

Page 47: ... 15 Figure 4 6 Carrier to Noise Measurement NOTE The US FCC specification for C N measurements is a bandwidth of 4 000 MHz CATV organizations outside of the United States may have different requirements ...

Page 48: ...played value between dB and percentage When there is an undetectable level of hum the following message appears on the screen ERROR INSUFFICIENT SIGNAL Level TO PERFORM THE MEASUREMENT Figure 4 7 HUM Measurement To measure Hum simply press the HUM Mode key when tuned to any non scrambled channel Soft keys allow you to select 50 60 100 120 Hz or 1 000 Hz filters for this measurement A 60 Hz modulat...

Page 49: ...hum frequency in the Config Measurement screen to 1 Hz The filter options on the Hum display will then become 1 Hz 50 Hz and 1 kHz NOTE The 1 kHz setting does not include the 1 Hz component it only includes 50 to 1 000 Hz Hum measurements taken while the desktop charger is in use will affect the Hum reading For the most accurate reading disconnect the charger prior to taking Hum measurements ...

Page 50: ...isplay for Video Depth of Modulation which is the ratio of peak downward change in modulation to carrier amplitude expressed as a percentage Pressing the soft key for the Audio icon activates Figure 4 9 Audio Modulation A built in 13 dB amplifier and or 50 MHz low pass filter can also be activated To measure Modulation use the NAV Menu or press the MOD Measurement Mode key Figure 4 8 shows the Vid...

Page 51: ...u press the Speaker icon soft key shown in Figure 4 9 Figure 4 9 Audio Menu Use Icons as follows ENTER Amplifier Low Pass submenu return to main Audio sub menu when appropriate Upper Enable Disable 13dB Amplifier Lower Enable Disable 50 MHz low pass filter Increase speaker volume Decrease speaker volume Switch between FM and AM Demodulation ...

Page 52: ...4 20 Enable Audio Demodulation shown disabled Enable Video modulation measurement shown enabled Note the AM FM indicator in the center of the screen enabled selection is darkened ...

Page 53: ... and correct the cause of this unwanted distortion NOTE Wavetek recommends that a 12 MHz band pass filter be used to limit the amount of intermodulation distortion caused by overload of the RF input of the SAM 4040D If used a preamplifier should be placed between the band pass filter and the receiver In SPECT Mode press the CSO CTB soft key to initiate CSO CTB measurements The SAM 4040D first swit...

Page 54: ...urned off The dark trace represents the distortion products The measurement value is computed by the ratio of the peak level of the video carrier to the peak of the distortion products of the second and third order beats The worst case CSO value is highlighted This is the overall CSO value Notice that CSO and CTB levels are about equal and well below any reasonable minimum Press the CSOCTB Setup s...

Page 55: ...g the UP DOWN arrow keys select the CSO Offset number to change Use the numeric entry keys or the up down arrow keys to enter a new CSO Offset value Upon exiting the CSO CTB measurement the SAM 4040D prompts you to turn the carrier back on ...

Page 56: ...notes outlining more techniques please see your local Wavetek CATV sales representative This table offers some ideas on the best application of StealthTrak s capabilities to help you solve troubleshooting problems PROBLEM USE THIS TOOL INGRESS SPECTRUM MODE MODEM CHANNEL HIGH BER ZERO SPAN MODE SIGNAL LEVELS UNBALANCED REVERSE ALIGNMENT TECHNIQUES POOR SIGNAL LEVEL IN SOME MODEM CHANNELS REVERSE S...

Page 57: ...interference generated at one point in the network affects everyone downstream from the noise source F i b e r Fig 5 1 Customers Affected by forward Path Ingress Source In order to limit these problems hardline and better quality equipment are used at the upstream connections and less expensive equipment is used downstream In the reverse path system however a noise problem affects everyone in the ...

Page 58: ...more varied transmitters of RF energy in the reverse path bands CB radio short wave ham paging and land mobile all use the same frequencies as a cable reverse path Rather than a few transmitters even at high power that are at known locations where better care can be taken with shielding there are lots of transmitters that can be right next to the network and are not controlled Random Noise Noise c...

Page 59: ... forward path technique of walking back up the system and replacing everything until the problem goes away simply doesn t work You now MUST have a tool that accurately indicates whether the problem is here or there The sources of interference come and go CB ham and mobile transmitters are not continuous and they move around Switching noise is transient and may last only a few microseconds but repe...

Page 60: ...amp test point and still see noise accurately Otherwise the reverse network must be taken down to get a high level signal for analysis Ease of use Fewer things to carry means less work long battery life means fewer trips back to the Headend or truck for a new battery light weight means faster time to get connected and less worker s compensation money spent What arms can be used to wage war with re...

Page 61: ...ain processes the voice frequency separate from the other frequencies and delivers the intended message TDMA modems are the same Each modem knows when talk The controller deciphers the messages by knowing when each modem is talking These modems have specific assigned times to send and receive information In fig 5 3 you can see that each user has a time slot assigned for its usage Fig 5 3 Nominal T...

Page 62: ...l is at least a hundred to one One possible answer would be to use a low transfer rate This system would work if no large files need to be transmitted A better answer is variable time TDMA Variable time TDMA gives more bandwidth when needed and takes just a little bandwidth the rest of the time More flexibility can be achieved on cable modems due to the high fidelity connection Therefore unlike IS...

Page 63: ... modems to transmit at the same frequency There are two states to these TDMA signals 1 When all modems are idle there should be low noise at the modem s frequency 2 When a modem is active the power level should be at a predetermined level Both of these states must be met For optimum operation of the modem both of these states must be met Another state occurs in some of the older technology This is...

Page 64: ...wer of the TDMA desired signal The U marker shows the power of the undesired or noise floor Very seldom are 56 dB desired to undesired D U ratios achieved Figure 5 5 Time Domain Signal with No Ingress in ZERO SPAN A more realistic case is shown in fig 5 6 This shows that the noise floor is much higher than in Figure 3 In this case the undesired signal has increased in power from 43 to 30dBmV This ...

Page 65: ... These impulses are a mere 10 uSec every 5 mSec This leaves the probability of catching these in the spectrum graph less than 0 2 They are readily apparent in the ZERO SPAN view Fig 5 7 Time Domain Signal with Intermittent Ingress in ZERO SPAN Looking at TDMA signals can be confusing Implementing return path modem is necessary to keep current customers and attract new revenue Viewing the reverse p...

Page 66: ...e Return Path CED Magazine Oct 1997 4 Ron Hranac Making Two Way Work Cable Tec Exposition Workshop Proceedings 1996 5 Ron Hranac Making Two Way Work Part II Cable Tec Exposition Workshop Proceedings 1997 6 Thomas J Staniec Making Two Way Work Cable Tec Exposition Workshop Proceedings 1996 7 Thomas J Staniec Making Two Way Work A Continuation Cable Tec Exposition Workshop Proceedings 1997 8 Dan Cha...

Page 67: ...lows for comprehensive troubleshooting utility Spect Measurement Mode reveals ingress spikes as brief as 5 µs Zero Span mode of the Spect analyzer displays a single frequency over time You can examine individual TDMA modems most return path signals and continuous carriers digital video most forward path signals with fast sure information about real power and noise levels Pressing the Spect Measure...

Page 68: ...h Return to Menu Note This icon is to return to previous menu mode 6 2 SPECTRUM MODE Amplifier Low Pass Filter sub menu Frequency sub menu Level sub menu A B Markers Soft key to change between marker A and B Select A or B using the right left arrow keys Active marker is emboldened These are two vertical markers on the display The Dotted Line is the active Marker the Solid line does not move This I...

Page 69: ...e user through the measurement of Composite Second Order and Composite Triple Beat products Figure 6 2 SPECT Mode Full Sweep Notice that the REF level value is in dBmV and scale factor is in dB div and are displayed at the top of the graph Figure 6 1 is a graphical display of the instrument s capability as spectrum analyzer The full range is 5 MHz to 1 000 MHz with a span of 1 5 2 5 5 10 or 25 MHz...

Page 70: ...st Ref Level using the up down arrow keys or by entering a numeric value followed by the Enter key Scale The scale parameter 1 2 5 and 10 dB div can be adjusted only with up down arrow keys For example if the reference level is set to 0 dB and the sale is set at 10 dB div the first horizontal grid line above the center equals 30 dB Press the Level soft key to return to the main spectrum analyzer d...

Page 71: ...ter the Frequency sub menu and again to return to the SPECT main menu The Frequency sub menu enables you to select adjust center frequency set the Span and move A B cursors as required to evaluate any part of the display Center Frequency Press to select adjust center frequency Use the numeric keypad then press the Enter soft key to place the frequency you want into the Edit Box that is presented S...

Page 72: ...mSec A B Markers Press to select A B markers and move markers as required with the left right arrow keys Amplifier Low pass Filter Press this to enter the Amp Low pass Filter sub menu then to return to the main SPECT sub menu See specs in the next two icons 3 Amplifier Sub Mode Press to enable disable the 13 dB amplifier as necessary to examine better the signal in the noise Right side darkens whe...

Page 73: ...ency with the greatest amplitude Figure 6 3 Spectrum Analyzer Zero Span 4 Zero Span Press this to enter the Zero Span sub menu In Zero Span mode the instrument displays the trace of one discrete frequency versus time Sweep time is on the x axis and amplitude dBmV is on the y axis You can change the sweep time for a closer or wider look as necessary ...

Page 74: ...e and detector crest factor This will improve the marker accuracy when measuring digital modulated signals and noise floor Amplifier Low pass Filter Press this to enter Amplifier Low pass filter menu then again to return to Zero Span main menu Time Base Press to enter Time base sub menu then to return to Zero Span main menu Use up down arrow keys to scroll through sweep times offered in the Edit B...

Page 75: ...us update When ON the display does not update until incoming signal is above the center line of the graph 5 Amplifier Low pass Filter Press this to enter the Amplifier Low pass sub menu this sub menu allows you to enable and disable the internal low pass filter and amplifier as well as peak search on the markers Amplifier Press to Enable Disable the 13dB amplifier when working with low level signa...

Page 76: ...range Peak Search Press to place the active marker at the time with the greatest amplitude D U Markers Press to toggle the D U markers between active inactive as appropriate Figure 6 4 Noise spike at 45 MHz This is an example of the basic use of the Spectrum Analyzer to view a specific frequency ...

Page 77: ...rosses the horizontal center grid line If signal level never reaches trigger point the Manual Trigger soft key see previous icon can be used Hysteresis Level Adjusts the amount of level the signal must change for a rising edge to cause a trigger event D U Markers Edited with right left arrows Active marker is emboldened Level Reference Level The reference level is located at the top line of the 6 ...

Page 78: ... Desired to Undesired signal quality Bandwidth Press this to enter the Bandwidth sub menu The Bandwidth menu allows you to set the resolution bandwidth video bandwidth and carrier measurement bandwidth Resolution Bandwidth Press to set Resolution Bandwidth 30 kHz 280 kHz or 2 MHz A value of 280 kHz is used as the nominal value 30 kHz or 2 MHz may be used when carrier spacing is very narrow or very...

Page 79: ...ement Bandwidth Any value from 0 01 to 99 999 MHz may be entered This value is used to correct the power level for losses caused by a narrower resolution bandwidth compared to actual signal bandwidth Correction 10log MBW RBW Figure 6 5 Example D U Display ...

Page 80: ...rval or a comprehensive 24 hour report that summarizes data collected from up to four intervals Autotest result files can be uploaded to StealthWare Autotest performs video audio carrier level measurements for each enabled channel Optionally you can select C N hum or mod tests for each channel The unit will run these tests in accordance with your Config setup The basic procedure for initiating an ...

Page 81: ...ta Analysis software and download information to he unit In either case the test location data in the Autotest Reports includes test location data 7 2 1 Parameters and Test Location Types Tables 7 1 and 7 2 provide information about the five types of test locations Headend Trunk Amp Line Extender Fiber Node and Field Test and the parameters that apply to each type Table 7 1 lists the ten Units and...

Page 82: ...rd Equalizer 100 0 100 0 0 0 dB Table 7 2 Parameters versus Test Location Types Parameters Trunk Head Extender Fiber Field 1 Area yes yes yes yes 2 Amp ID yes yes yes 3 Power Configuration yes yes yes 4 Feeder Maker Configuration yes yes yes 5 Trunk Termination yes yes yes 6 Voltage Setting yes yes yes 7 Reverse Pad yes yes yes 8 Reverse Equalizer yes yes yes 9 Forward Pad yes yes 10 Forward Equal...

Page 83: ...ut to overwrite an existing location WARNING a location with this name already exists Overwrite Entering a NEW location To establish a new test location referring to Figure 7 2A on the screen next page 1 Press the Flag soft key The Edit Box appears and the program prompts you to name the location 2 Enter the name and press the Enter soft key Figure 7 2B Edit Locations appears 3 Scroll through the ...

Page 84: ...roll through the list characteristics and make any necessary adjustments 2 When you are satisfied with the adjustments press the OK soft key which re activates figure 7 2A 7 3 PERFORMING AUTOTEST Use the NAV Menu or press the Test support mode key then use the up down arrow keys to select Perform Autotest and press any soft key You are now ready to configure the Autotest ...

Page 85: ...nt you with only the steps required to configure the test Figure 7 3 CHOOSE LOCATION Existing Location Scroll with the up down arrow keys to select test location the press OK New Location Press Flag to create a New Location 7 3 2 Edit Location At this screen enter the information for a new or existing location Use the up and down arrows to select the item to be edited The items that appear in the ...

Page 86: ...to store the only if you think you will return for another test Figure 7 4 New Location 7 3 3 Select Probe Point Some location types have multiple points at which you can make test measurements If you have selected such a type this screen will appear Use the up down arrow keys to choose the appropriate probe point from the list then press the soft key ...

Page 87: ...s 7 3 4 Measure Voltage You can log voltage measurements in the field These will appear when viewing or printing the results of the Autotest When you have finished entering the measurements press the soft key Figure 7 6 Measure Voltage ...

Page 88: ...t is the value specified in the Testpoint screen Enter a different value if necessary Press the soft key to continue Figure 7 7 Compensation 7 3 6 Results File Name Enter the name you want to use for the results file The Autotest software will let you know if you already have used the name You can overwrite an existing file of the same name When you are ready for the next step press the soft key ...

Page 89: ...e Immediate or Scheduled soft 7 3 8 Set Schedule This screen will appear only if you have selected a scheduled test The default schedule will perform four intervals over a twenty four hour period beginning at the present time and date If you require a different schedule use the up and down arrows to edit the schedule and then press the soft key ...

Page 90: ...his purpose If you prefer to use your own thermometer you can manually enter the temperature here NOTE For scheduled tests the manual temperature entry is used for the first interval only Subsequent intervals will record the temperature as measured by the internal sensor For accurate measurements the instrument reads the internal temperature sensor immediately upon power up ...

Page 91: ...egin the test press the soft key While the Autotest is in progress the display indicates the measurement currently being performed level hum or modulation Progress is displayed during the test A bar graph on the display shows the percentage of completion ...

Page 92: ...y is available to print all intervals from all files in the directory 3 The Info soft key displays the test location characteristics for the selected file This is the information that was logged when you configured the test The items presented depend on the location type that you selected 4 Information provided on each interval includes viewing Autotest Files Upon selecting the desired Autotest fi...

Page 93: ... documenting proof of performance compliance measurements Pressing the 24hr Report soft key causes the instrument to automatically format and print the highlighted interval plus the next three intervals The following is an example of a 24 Hour Test Report ...

Page 94: ... 0 0 dB Forward Pad 0 0 dB Forward Equalizer 0 0 dB AC Voltage 110 V DC Voltage reg 14 8 V unreg 20 9 V 1 2 3 4 Date 07 04 95 07 04 95 07 05 95 07 05 95 Time 17 00 00 23 00 00 05 00 00 11 00 00 Temp 75 F 61 F 59 F 83 F Video Video Video Video 24 Hr Chan Level Level Level Level Deviation dBmV dBmV dBmV dBmV dB 2 9 6 8 8 17 7 LO 10 7 28 4 HI 3 9 9 8 6 5 8 LO 8 9 15 7 HI 4 9 2 8 3 2 9 LO 10 1 13 0 HI...

Page 95: ...t If a particular measurement was not within the specified limit a HI LO marker is printed next to the reading indicating the direction that the measurement was out of specification VIEWING INTERVALS To view the measurement data from an interval use the up down arrow keys to highlight the interval then press the soft key The first screen displayed is a tabular list that includes the video and audi...

Page 96: ... level C N hum and modulation measurements 9 When viewing the list of level C N hum and modulation measurements if an error occurred the following symbols replace the measurement value UNDER under range OVER over range E ERROR synthesizer unlocked ...

Page 97: ...ination No Voltage Setting Low Reverse Pad 0 0 dB Reverse Equalizer 0 0 dB Forward Pad 0 0 dB Forward Equalizer 0 0 dB AC Voltage 110 V DC Voltage reg 14 8 V unreg 20 9 V Chan Label Video Audio Delta V A C N Hum Mod dBmV dBmV dB dB 2 QVC 17 7 LO 18 4 0 7 LO 43 9 1 4 86 3 3 TNN 5 8 LO 13 9 8 1 4 USA 2 9 LO 15 6 12 7 0 9 5 ESPN 0 1 16 1 16 2 48 2 6 MTV 7 9 20 3 28 2 HI 88 2 7 FMLY 9 9 10 6 20 5 HI 8...

Page 98: ...H 2 17 7 dBmV Fail Max Delta Video Levels 10 0 CH 2 15 27 9 dB Fail Min Delta V A 6 5 dB CH 2 0 7 dB Fail Max Delta V A 17 0 dB CH 6 28 2 dB Fail Max Delta Adjacent 3 0 Fail Channels Conclusion F A I L Reviewed _______________________________ Date __________________ ...

Page 99: ...oof of performance reports troubleshooting and analysis and for other documentation purposes The following types of measurements can be stored as files Autotests Scans Sweeps including forward sweep reverse sweep reverse amplifier alignment and all sweep references Spectrum scans including regular zero span and CSO CTB measurements Regular measurements can also include peak hold values Tilt measur...

Page 100: ...measurement the measurement can be stored as a file The instrument enters File mode to store this current measurement If you press Function 2 and you are in a mode that does not produce files such as Level the instrument enters View mode to allow you to review existing files 8 2 STORING FILES The Stealth meters enable you to store measurements made with Scan Spect Spectrum Analyzer Mode Tilt and S...

Page 101: ...lready is in use Press the Enter soft key Use the keypad to enter a name then press Enter again The screen displays View Measurement Files the combined file for all three types All stored files except Sweep Reference files can be uploaded to Wavetek s Stealthware PC software Each Sweep Reference file is unique in terms of the meter used location and system conditions at the time of the Sweep The u...

Page 102: ... highlighted marked file The screen displays a graph of printing progress 3 Print all marked files You can print all measurement files except Scan Files 4 Use this to delete marked file s Press the Cancel soft icon to stop 5 Use this to mark files for printing or deletion 1 2 3 5 4 Figure 8 2 View Measurement Files Refer to the file listings shown in Figure 8 2 These types include all types of fil...

Page 103: ...WPLS Sweepless Sweep SAM 4040D 3SR V T StealthTrak units In Sweepless Sweep the instrument is completely passive sweeping its receiver across the allotted spectrum Only active carriers in the CATV system will register in the sweep The Sweep References menu enables you to select store or delete sweep references After making a sweep measurement you can store a sweep reference The instrument must be ...

Page 104: ...elete all the files marked or the current file if none are marked press the Delete button item 3 Different types of sweeps can be stored as references The Stealth instruments mark them differently and displays FDSWP for forward references RVSWP for reverse references and SWPLS for Sweepless Sweep references The file name and date stored are also shown for each file If the channel plan has changed ...

Page 105: ...nt display Refer to Figure 8 4 an example Sweep File The sweep file is displayed as a gray area instead of the usual black and the current sweep response is displayed as a black line in front of the file Figure 8 4 Sweep Reference with Live Sweep In the file shown above a trap was added after the file was stored It is very easy to see the change caused by the trap You can also see the location of ...

Page 106: ...er which the sweep file was stored 2 The channel plans for the stored and live sweep match If sweep overlay is not possible a message appears explaining the situation 3 The names of the file being viewed and the currently selected reference appear beneath the marker information 4 The Level and Frequency adjustments affect both the stored and live sweeps Reference Limits Checking and Tilt Compensat...

Page 107: ...ar on the connectors and they should be replaced To replace the connector 1 Carefully unscrew the connector from the unit using a 7 16 inch wrench 2 Screw the short end of the new connector into the unit A longer connector could cause internal damage to the unit Remember to use a lockwasher 3 Torque the connector to not more than 5 0 6 0 IN LBS 9 4 BATTERY TERMINAL CLEANING Clean the battery termi...

Page 108: ... for best performance accuracy If subjected to difficult conditions temperature humidity physical stress or damage more frequent calibration and service is appropriate See the below for a list of Wavetek Service Centers 9 6 WORLDWIDE SERVICE CENTERS Austria China Tel 3 1 214 5110 Tel 86 10 6592 8044 Fax 43 1 214 5109 Fax 86 10 6500 8199 France Germany Tel 33 01 4 77 47 89 00 Tel 49 89 996 410 Fax ...

Page 109: ...enter the Configure menu either by pressing NAV and using the Navigator menu or by pressing the green Function key and then 3 ghi A Refer to Figure 10 1 The Configure menu includes five categories Global Measurement Channel Plan Sweep Receiver and Diagnostics B Use the up down arrow keys to select Channel Plan and press any soft key The screen displays Figure 10 2 Configure Channel Plan top level ...

Page 110: ...10 2 Figure 10 1 Configure Menu Figure 10 2 Configure Channel Plan ...

Page 111: ... Channel Plan Select the top line which produces Figure 10 3 Select Channel Plan a list of existing channel plans If the Stealth is being used for the first time the only Channel Plan shown is the standard NCTA plan The process in Build Channel Plan text item D below enables you to create name and add to the list new channel plans that meet your requirements Figure 10 3 Select Plan 1 Scroll throug...

Page 112: ...the currently active plan 4 Press X soft key to delete a Plan If you press X you can press STOP or the cancel icon that replaces X to reverse the deletion To accept press OK soft key to confirm it 5 Press Exit soft key to return to Figure 10 2 Channel Plan B Video Signal Type 1 With Figure 10 2 displayed select Video Signal Type and press the Enter soft key The up down arrow keys toggle between NT...

Page 113: ...ress the Enter soft key again then use the up down arrow keys to scroll to the next parameter D Build Channel Plan 1 With figure 10 2 Channel Plan displayed select Build Channel Plan The instrument creates a channel plan by memorizing the active channels in the system and by identifying by default those that are not active CAUTION Be sure that the Stealth Instrument is correctly connected to the c...

Page 114: ...an with that name entered into the meter When you are satisfied with the name press the OK soft key The screen shows Figure 10 6 Build Plan Step 2 Figure 10 6 Build Plan STEP 2 3 At Step 2 select from the menu in the Edit Box a base channel plan to use for building the new plan a Use the up down arrow keys to select a base channel plan to form the basis for the new plan Press the OK soft key when ...

Page 115: ...lan information and the channels being taken into the plan b When building the Channel Plan Stealth sequences through all channels in the selected base plan up to the Stop Frequency To halt the process press the Stop soft key When the Plan is complete you can edit all channels included in the plan c When the Channel Plan is complete the screen displays the name and format for the Plan along with t...

Page 116: ...by the Edit Box Fig 10 8 Edit Channel Plan appears The eight columns of this screen display the following information about each channel in the Plan left to right Enabled Type Channel Label Frequency Sweep Tilt Scrambl ed A Checkmark in the left margin means that the channel is enabled SWP TILT SCR channels have asterisks to indicate that status Figure 10 8 EDIT Channel Plan Press the Edit soft ke...

Page 117: ...ft right arrow keys or the two arrow icons at the upper right corner to scroll through list of channels 3 To make adjustments to the highlighted parameter press the Enter soft key make the changes then press Enter again 4 ADD CHANNEL Press the Add soft key TV lower left to add a new channel to the plan The new channel will be assigned the next channel number from the one being viewed and a frequen...

Page 118: ...hoice For each of the four choices shown below the screen displays the channel parameters applicable for you to examine and edit as necessary Channel type shows in the upper display to the left of the channel number as DIGI DUAL SNG TV or SWP The four choices are discussed below and in Table 10 1 Carrier Types and Parameters Digital Carrier DIGI Can be used for continuous digital carriers Digi is ...

Page 119: ... X Scrambled X X Audio Offset 1 MHz X X DIG DUAL SGNL TV Audio Offset 2 MHz X 3 Frequency MHz The frequency of the carrier for TV and DUAL types this is the frequency of the video carrier Press the Enter soft key and enter frequency by using the numeric entry keys or the up down arrow keys followed again by the Enter soft key 4 Channel Number The channel number of the carrier Change channel number...

Page 120: ...his is the bandwidth of the carrier to be measured 8 Noise Offset MHz The frequency at which the noise level is measured is the Carrier frequency plus the Noise Offset To adjust Noise Offset select Noise Offset MHz Adjust Offset by using the up down arrow keys or by entering a value using the numeric keypad Use the Enter soft key to start and finish 9 Tilt Channel Y N Designates whether or not the...

Page 121: ...hannel Plan menu and press the NEXT soft key as prompted by the Edit Bar 2 The screen warns you that the deletion cannot be undone that ALL channels not enabled will be deleted 3 Press the OK soft key to delete unused channels press the OK soft key to return to Channel Plan menu NOTE SOME CHANNEL PLANS HAVE INTERLACED CHANNELS TO PREVENT STEALTHTRAK FROM INTERFEING DELETE INTERLACED CHANNELS FROM ...

Page 122: ...icon changes to s slotted circle you can use it to cancel all three tests for a selected channel 4 Press the backup icon soft key at the upper left to return to the Channel Plan Menu 5 REMINDER C N hum and modulation cannot be measured on a scrambled channel or a digital carrier Hum measurements include all components 1 kHz Hum is measured in either or dB as established during setup Units cannot b...

Page 123: ...ax 24 hour Level deviation 1 From the Configure Menu select Channel Plan scroll to Edit Limits and press the Edit Box Next icon soft key Fig 10 13 Edit Limits appears Figure 10 11 Edit Limits 2 Use the up down arrow keys to select the limit to be edited 3 Use the numeric entry keys or the up down arrow keys and the Edit Box icon soft key 4 When you have made the adjustment press the Enter hard key...

Page 124: ...ate is set the same for each unit Wavetek recommends a baud of 19 2K for copying plans 2 From the Configure Menu select Channel Plan scroll to Copy Remote Plan and press the Edit Box icon soft key 3 A list of plans located in the remote meter s memory appears on the screen 4 Select the plan that you want to copy and press the Copy soft key 5 The selected plan is transferred from the remote meter a...

Page 125: ...Lo Resolution 0 1dB SCAN Mode All video audio pilot carrier and digital channel levels displayed SWEEP Mode Frequency range 5 1000 MHz Display span user definable Display scale range 6 vertical divisions 1 2 5 or 10 dB division Stability 0 5 dB normalized dependant on stability of referenced carriers Carrier to Noise Measurement Non scrambled channels only No pre selection required for 78 channels...

Page 126: ...aling and Range 0 5 1 2 5 and 10 dB div 6 vertical divisions Dwell programmable 0 25 ms Spurious Free Dynamic Range 60 dB 1 Sensitivity 40 to 60 dBmV without preamp 50 to 50 dBmV with preamp 55 to 55 dBmV typical for f 50 MHz ZERO SPAN Mode Video BW 1MHz 100 kHz 10 kHz 100 Hz Resolution BW 280 kHz 30 kHz Measurement BW compensation Programmable 1 khz 99 MHz Pulse measurement accuracy Nominal level...

Page 127: ...CAN SWEEPLESS SWEEP SPECT regular with max hold ZERO SPAN or CSO CTB TILT Channel Plans Allocated on demand Storage capability simultaneous more of one file type can be traded for less of another typical 78 channel plan all files stored as database not screen picture 8 Channel Plans 100 SWEEP references traces 60 Spectrum SPECT displays 20 Autotests Serial Interface Serial RS232 Epson IBM Printers...

Page 128: ... 5 kg 5 5 lbs Operating Temperature Range 20 to 47 C 4 to 117 F Power Sources Battery 12V 3 5A hr replaceable 4 hours continuous use on a single charge Charger Input 90 265VAC 47 63 Hz Aux out 16V 750 mA Charge 15V 750 mA 1 Typical Specifications 2 Relative to 25 C 3 25 C and 20 dBmV ...

Page 129: ...tion with the 3ST Stealth Headend Transmitter for full forward and reverse alignment 3HRV accommodates up to 10 ten simultaneous reverse sweep inputs 3SR V9 Stealth Sweep Receiver Works with carriers as possible and on Seep frequencies transmitted downstream by the 3ST 3SRT V9 Essentially a portable 3ST 3ST Stealth Sweep Headend Transmitter Used for sweeping the system forward inserting sweeps at ...

Page 130: ...e between the highest and lowest frequencies carried by a channel Also the speed bit rate velocity at which data can be transferred and presented C N also CNR Carrier to Noise ratio normally expressed in dB the ratio of peak carrier power to root mean square RMS noise power noise floor at video bandwidth adjacent to the carrier See Noise Offset CATV Community Antenna Television commonly used to re...

Page 131: ...er steady state conditions successive CW oscillations are identical D U Desired Undesired also called Carrier to Garbage DVA Ratio of video level to audio level expressed in dB Depth of Modulation Ratio of peak downward change in modulation to carrier amplitude expressed as a percentage Roddy Coolen DSP Digital Signal Processor converts digital input into analogue or pulse rate outputs DTV Digital...

Page 132: ...ve multiple hub sites Hum Low Frequency Modulation of a carrier when it passes through an active or passive component Shows on TV screen as bar s scrolling slowly up through the picture Measured in Stealth as dBmV or as a percentage Ingress RF leaking in to a reverse path interfering with transmission Interruption into the cable line by through breaks in the integrity of the cable Inter modulation...

Page 133: ... measure C N ratio at about 2 4 2 5 MHz above the lower band edge between video and chrominance modulation Overlapping Channel Many countries have similar but slightly different frequency allocation for channels To accommodate all possible variations Stealth base channel plans have some overlapping frequencies Carrier frequencies are different but there is some bandwidth overlap if you use one of ...

Page 134: ...se to represent 0 and 1 respectively for digital transmissions QAM Quadrature Amplitude Modulation QAM changes both amplitude and phase simultaneously from symbol to symbol QAM is a special case of pass band pulse amplitude modulation PAM two carriers on the same frequency but 90 degrees out of phase and modulated by the real and imaginary parts of a complex valued baseband signal A polar plot of ...

Page 135: ...between preset or adjustable limits at a rate that is also adjustable Used in conjunction with suitable peripheral equipment the swept signal can be used for comprehensive testing of a CATV plant Sweepless Mode Passive examination of carrier frequencies TASO Television Allocation Study Organization TDMA Time Division Multiple Access an access methodology that assigns bandwidth only when as require...

Page 136: ...r of all LCD screens shows the Name of the Test Measurement on the left and the TIME on the right When Alpha Numeric or Multiple Choice adjustments are offered by the Menu they icon appears in the Title Bar to the Left of the TIME ...

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