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Appendix H: Viavi CX300 Tests
MAINTENANCE GUIDE | MT-4E ANALOG & P25 DIGITAL RADIO SYSTEMS
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 H-22 until a deviation of +/- 1.5 KHz (narrowband)
or +/-3.0 KHz (wideband) is measured on the CX300. The high and low limits are set at +/-1.4 KHz to +/- 1.6 KHz
deviation�
Figure H-22: RSS Transmitter Audio Level Adjustment
Enter the Transmitter Deviation Level reading on the MT-4E Test Sheet.
Configure AF Generator A1 to inject a 300 Hz tone at +10.0 dBm (2.500 Vrms) into the Tx Balanced audio input
and adjust the audio frequency from 300 Hz to 3400 Hz in increments of 100 Hz and check that the transmitter
deviation does not rise above +/- 2.5 KHz (narrowband) or +/-5.0 KHz (wideband). The MT-4E Transmitter will
transmit a maximum deviation at an audio frequency of approximately 1300 Hz.
Enter the Transmitter Maximum Deviation Level reading on the MT-4E Test Sheet.
To adjust the auxiliary balanced audio input, plug the AC-3E Control Card or CI-BC-4E Base Control Card
into the subrack using an extender card, disconnect the Tx Balanced audio input and connect the Auxiliary
Balanced audio input to the AF OUTPUT on the CX300. Auxiliary 1 audio input is available on pins C19 and C20,
and Auxiliary 2 audio input is available on pins B14 and A14. Ensure that NO external devices (eg. tone remote
adapter or IP router) are connected to the auxiliary audio input. Configure AF Generator A1 to inject a 1.0 KHz
tone at 0.0 dBm (0.775 Vrms) into the Auxiliary Balanced audio input. Adjust the Auxiliary Balanced Audio Input
level adjustment (R120 for Aux In 1, R123 for Aux In 2) for deviation of +/- 1.5 KHz (narrowband) or +/-3.0 KHz
(wideband)�
Enter the Auxiliary Deviation Level (if used) reading on the MT-4E Test Sheet.
