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ZETRON Viavi 3920 Maintenance Manual

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Appendix C: Viavi
3920 Test Procedures
MAINTENANCE GUIDE
www.zetron.com

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Summary of Contents for ZETRON Viavi 3920

  • Page 1 ™ Appendix C: Viavi 3920 Test Procedures MAINTENANCE GUIDE www.zetron.com...

  • Page 2: Table Of Contents

    Adapters, Cables and Extender Cards � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 3 Zetron MT-4E Radio System Test Sheet � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 3 Turning OFF the MT-4E Receiver and Transmitter Modules �...

  • Page 3: Appendix C: Viavi 3920 Test Procedures

    Radio Systems with the 3920 Service Monitor by Viavi. This Chapter is intended as an aid to configuring and testing Zetron MT-4E radios using the Viavi 3920. Neither Zetron or Viavi Solutions assume responsibility for damage caused to either unit as a result of misinterpretation or misuse of this procedure.

  • Page 4: General Set-Up And Connections

    Management. The Internal directory should be selected as Stores:/ and the External directory should be selected as USB. Select the Internal Directory you would like to copy the files to (suggest Zetron, then select the files on the USB and click File Copy. To select multiple files at once, hold the HOLD key.

  • Page 5: Radio Service Software (Rss)

    (RF frequency, wide / narrowband, digital / analog, CTCSS / NAC, etc.). Control Cards Some Zetron MT-4E radio systems may have an AC-3E Audio Control Card or CI-BC-4E Base Control Card for use in the radio system. The Control Cards connect to the receiver and transmitter balanced audio lines with an unbalanced load, which could cause some measurements to be in error.

  • Page 6: Turning Off The Mt-4E Receiver And Transmitter Modules

    RJ45 cables, rather than turning the front panel switch to the OFF position. All Zetron modules are hot swappable. There is no need to disconnect the power supply when inserting or removing the modules from the subrack.

  • Page 7: Audio Connections

    Appendix C: Viavi 3920 Test Procedures Audio Connections The Receiver, Transmitter and Auxiliary Balanced audio lines are available for connection on Zetron extender cards or by connecting to the optional back panel A-PNL-AUX96-3 screw-type terminal connector. The extender cards have solder points available on each signal line that can have a small test point (5059- TP110300) that is supplied with the extender card, soldered to them for easy connection with clip-on type clips.

  • Page 8: System Regulator Testing

    System Voltage Testing The first stage of testing a Zetron MT-4E radio system is to perform a basic system check on the supply and regulated voltages. The System Regulator module is designed with a convenient and easy test point built into the front panel.

  • Page 9: Receiver Testing

    Figure C-3: Receiver Analog Testing On the 3920, recall Zetron setup 01 (Rx Analog) from your internal drive. Enter the correct RF frequency and ensure that the deviation level of the 1.0 KHz tone is set correctly for your receiver (wide/narrow). Enter the correct CTCSS tone (if used) and deviation level for the tone.
  • Page 10 Appendix C: Viavi 3920 Test Procedures Audio Distortion: To check receiver distortion, inject -70 dBm RF carrier level into the receiver and measure the audio distortion on the meter as shown in Figure C-5. The high limit is set to 2.0 %.
  • Page 11 Enter the Reference Sensitivity (12 dB SINAD) reading on the MT-4E Test Sheet. If the distortion or reference sensitivity measurements are not within Zetron published specifications, the RF Preselector may need re-alignment. Refer to the Receiver RF Preselector Alignment and Tuning section.
  • Page 12 Appendix C: Viavi 3920 Test Procedures Audio Level: The audio level adjustment is not required when connecting the receiver in a repeater configuration using LVDS Serial Data. The audio level adjustment can be done on both the Rx Balanced Audio Output and the Auxiliary Balanced Output (1 and 2).

  • Page 13: Receiver Digital Testing

    Figure C-8: Receiver Digital Testing On the 3920, recall Zetron setup 02 (Rx Digital) from your internal drive. Enter the correct RF frequency, and ensure that the RF Control is set to Phase 1 and it is set for the STORED SPCH test pattern (or optionally the 1011 test pattern)�...
  • Page 14 Appendix C: Viavi 3920 Test Procedures Inject the correct NAC (and TGID if programmed) and ensure that the receiver is operating as shown in Figure C-9. There are no specific measurements to make on this test, just verify that the receiver is operating.

  • Page 15: Receiver Bit Error Rate Testing

    Figure C-10: Receiver Bit Error Rate Testing On the 3920, recall Zetron setup 02 (Rx Digital) from your internal drive. Enter the correct RF frequency, and ensure that the RF Control is set to Phase 1 and it is set for the STD 1011 test pattern (the 1011 test pattern will not operate correctly for this test) as shown in Figure C-11.
  • Page 16 Enter the Reference Sensitivity (5% BER) reading on the MT-4E Test Sheet. If the BER measurements are not within Zetron published specifi cations, the RF Preselector may need re- alignment. Refer to the Receiver RF Preselector Alignment and Tuning section.

  • Page 17: Receiver Rf Preselector Alignment And Tuning

    filter (typically 5 - 7 MHz in a VHF or UHF 400 MHz receiver). The UHF 700 / 800 / 900 MHz receiver RF Preselector is Full Band and does not require any tuning� Connect the 3920 and Zetron Radio as shown in Figure C-13. RF Preselector output from Receiver...
  • Page 18 Appendix C: Viavi 3920 Test Procedures On the 3920, recall Zetron setup 03 (Rx Preselector Tune) from your internal drive. If Trk Gen does not appear on the lower left corner of the display, then the 3920 does not have the tracking generator option. Enter the correct RF frequency as the Center Frequency (CF) and ensure the receiver is turned on.

  • Page 19: Receiver Reference Oscillator Adjustment

    Appendix C: Viavi 3920 Test Procedures Receiver Reference Oscillator Adjustment Connect the 3920 and Zetron Radio as shown in Figure C-16. Computer running RSS Synthesizer L.O. output from Receiver to ANT input on 3920 HELP SELECT 150 V MAX CAT II...
  • Page 20 3920 Figure C-18: UHF 700 / 800 / 900 MHz Receiver Reference Oscillator Connection On the 3920, recall Zetron setup 04 (Rx Reference) from your internal drive as shown in Figure C-19. Figure C-19: Receiver Reference Oscillator Measurement MAINTENANCE GUIDE | MT-4E ANALOG & P25 DIGITAL RADIO SYSTEMS...
  • Page 21 Appendix C: Viavi 3920 Test Procedures In the receiver RSS, enter the Service section and click on “Ref Oscillator”. The reference oscillator frequency is shown as the “Target Synthesizer RF OUT”. Enter this RF frequency into the Analyzer RF Freq on the 3920. The receiver generates this frequency out of the Synthesizer into the 3920.

  • Page 22: Transmitter Testing

    Figure C-21: Transmitter Analog Testing On the 3920, recall Zetron setup 05 (Tx Analog) from your internal drive. Enter the correct RF frequency on the 3920, set the MIC MODE switch on the front panel of the transmitter to Analog, and flip the other switch to KEY TX (or set the switch to NORM and key the transmitter through the RSS).
  • Page 23 Appendix C: Viavi 3920 Test Procedures Audio Distortion: The distortion meter will read demodulated audio and give you a transmitter demod distortion reading as shown in Figure C-22. The high limit is set to 3.0 %. Figure C-22: Transmitter Distortion and Power Measurements Enter the Audio Distortion reading on the MT-4E Test Sheet.
  • Page 24 Appendix C: Viavi 3920 Test Procedures RF Power: Monitor the RF power output of the transmitter as shown in Figure C-22. In the Power Level area of the Service section on the RSS, click on the “Key Tx” button and adjust the Transmitter Output Power adjustment as shown in Figure C-23 to change the RF output power.
  • Page 25 Appendix C: Viavi 3920 Test Procedures Deviation Level: The deviation level adjustment is not required when connecting the transmitter in a repeater configuration using LVDS Serial Data. The audio level/deviation level adjustment can be done on both the Tx Balanced Audio Input and the Auxiliary Balanced Input (1 and 2).
  • Page 26 Appendix C: Viavi 3920 Test Procedures Deviation Level If the transmitter has CTCSS encode (internal or external), temporarily reprogram the transmitter for no tone. Check the repeater deviation level. Ideally the deviation level out of the transmitter should match the input to the receiver.
  • Page 27 Appendix C: Viavi 3920 Test Procedures In the Deviation Levels area of the Service section on the RSS, click on the “Key Tx” button and adjust the Tx Balanced Audio Input level adjustment as shown in Figure C-25 until a deviation of +/- 1.5 KHz (narrowband) or +/-3.0 KHz (wideband) is measured on the 3920.

  • Page 28: Transmitter Ctcss Testing

    Figure C-27: Transmitter CTCSS Testing On the 3920, recall Zetron setup 06 (Tx CTCSS) from your internal drive. Enter the correct RF frequency on the 3920, set the MIC MODE switch on the front panel of the transmitter to Analog and flip the other switch to KEY TX (or set the switch to NORM and key the transmitter through the RSS).
  • Page 29 Appendix C: Viavi 3920 Test Procedures Audio Generator 2 (if used) is confi gured to inject a 100 Hz tone at -18.0 dBm (0.098 Vrms or 0.277 Vpp) into the Tx Subtone input as shown in Figure C-28. If the internal programming is used to generate the CTCSS tone, the Audio Generators are not used and the CTCSS tone is generated internally in the transmitter.
  • Page 30 Appendix C: Viavi 3920 Test Procedures In the Subtone Levels area of the Service section on the RSS, click on the “Key Tx” button and adjust the Narrow and/or Wide Internal and/or External Subtone Deviation level adjustment as shown in Figure C-29 until a deviation of +/- 0.35 KHz (narrowband) or +/-0.5 KHz (wideband) is measured on the 3920.

  • Page 31: Transmitter Digital Testing

    Figure C-30: Transmitter Digital Testing On the 3920, recall Zetron setup 07 (Tx Digital) from your internal drive as shown in Figure C-31. Enter the correct RF frequency on the 3920, set the MIC MODE switch on the front panel of the transmitter to Digital and fl ip the other switch to KEY TX (or set the switch to NORM and key the transmitter through the RSS).
  • Page 32 Appendix C: Viavi 3920 Test Procedures Audio Generator 1 is configured to inject a 1.0 KHz tone at -8.0 dBm (0.308 Vrms) into the transmitter balanced input. A continuous tone injected into the transmitter will be demodulated as a “fluctuating” audio level and tone on older P25 radio systems.
  • Page 33 Appendix C: Viavi 3920 Test Procedures Modulation Fidelity Testing In the transmitter RSS, enter the Service section and click on “Test Patterns”. Ensure the transmitter frequency is in the frequency box. In the Select Pattern window select “C4FM Modulation Fidelity”. Click on the “Key Tx”...
  • Page 34 Appendix C: Viavi 3920 Test Procedures Measure the Modulation Fidelity of the transmitter as shown in Figure C-34. The transmitter should not read more than 5% Modulation Fidelity. If the Modulation Fidelity is more than 5%, the transmitter will need to be returned to the factory for service.

  • Page 35: System Testing

    Figure C-35: System Duplex Analog Testing On the 3920, recall Zetron setup 08 (Duplex Analog) from your internal drive as shown in Figure C-36. Enter the correct RF frequencies for the receiver and transmitter and ensure that the deviation level of the 1.0 KHz tone is set correctly for your receiver (wide / narrow).
  • Page 36 Appendix C: Viavi 3920 Test Procedures Ensure that the receiver and transmitter are connected to the repeater controller via the RJ45 cables on the front panel. In some systems, the receiver and transmitter may be connected directly together using the RJ45 cables�...
  • Page 37 Appendix C: Viavi 3920 Test Procedures Deviation Level: Check the deviation level. Ideally the deviation level out of the transmitter should match the input to the receiver. The repeater deviation level matching is adjusted by the analog LVDS level adjustment that is available in both the receiver and transmitter (only one needs to be adjusted).

  • Page 38: Duplex Digital Testing

    Figure C-38: System Duplex Digital Testing On the 3920, recall Zetron setup 09 (Duplex Digital) from your internal drive as shown in Figure C-39. Enter the correct RF frequencies for the receiver and transmitter, and ensure that the RF Control is set to Phase 1 and it is set for the STORED SPCH test pattern (or optionally the 1011 test pattern).
  • Page 39 Appendix C: Viavi 3920 Test Procedures On the 3920, recall Zetron setup 09 (Duplex Digital) from your internal drive as shown in Figure C-39. Enter the correct RF frequencies for the receiver and transmitter, and ensure that the RF Control is set to Phase 1 and it is set for the STORED SPCH test pattern (or optionally the 1011 test pattern).
  • Page 40 Appendix C: Viavi 3920 Test Procedures There are no specific measurements to make on this test, just verify that the system is operating correctly. NAC: Check to make sure your receiver unsquelches on the proper NAC. If the NAC is set for $F7F in the receiver, ensure that the system transmits the NAC it receives.
  • Page 41 Appendix C: Viavi 3920 Test Procedures To check the TGID, Unit ID and Emergency Bit, click on the Message Encode menu expansion to show all of the P25 Message Encode information as shown in Figure C-40. Close the Message Encode window then click on the Data Link menu expansion to open the full Data Link window.
  • Page 42 E: uk@zetron.com ©Zetron, Inc. All rights reserved. Zetron® and Zetron and Design® are registered trademarks of Zetron, Inc. All other trademarks are properties of their respective owners. See Zetron price list for option pricing. Specifications subject to change without notice.

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