Spectra Engineering MX800 - 5.2 Module Level Test Procedures; Exciter Module Test Procedures

MX800 Transceiver Technical Manual
© SPECTRA ENGINEERING 2006 Revision 4.2.3
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5.1.12 RX Line Output Level Adjustment
The fourth potentiometer RV5 sets the RX Line output level.
Procedure:
5. Disable the repeater (switch SW4/DIP2 OFF).
6. Using a 600ohm termination monitor RX line output level. This output
is located on the rear of the MX800, on the Line I/O connector pin 15 of
the DB15F.
7. Set the receiver modulation frequency to 1kHz and the FM deviation to
nominal for the particular RF receive frequency of the test channel.
8. Adjust Line Output level RV5 to obtain nominal line output level
(-10dBm is the default level).
5.1.13 TX VF Loop Back Level
Under control of the TX VF Loopback Control line (LIFUSEN) the TX line
input may be looped back to the RX Line output. The fifth potentiometer
RV7 sets the loop-back level.
Procedure:
9. Enable the TX VF Loopback using JMP9.
10. Set the transmitter modulation frequency to 1kHz, -10dBm, injected in
through the TX VF input.
11. Adjust RV7 to obtain an RX Line output level of –10dBm.
12. Restore JMP9
5.1.14 Mute Threshold Setting
The Mute Threshold Setting RV6 is used to set the level at which the mute
opens.
Force the mute open using the Remote Screen in MXTOOLS.
Inject the correct RF frequency into the receiver for the test channel.
Set the receiver modulation frequency to 1kHz at nominal deviation.
Alter the amplitude of the RF signal until the RX audio has an 8dB SINAD.
Set the mute back to normal using the Remote Screen in MXTOOLS.
Adjust the mute level potentiometer, RV6, until the mute opens then wind it
back until it just closes.