Tx Deviation; Tx Modulation Balance - Raveon RV-D80-EB Technical Manual

10.4. TX Deviation

1. Switch to channel 1.
2. Key the transmitter into a 50 ohm load using the ATTD 3 command. The
unit will now transmit, and send a digital 0 continuously. This should be
+2.0kHz in frequency for narrow-band radios (12.5kHz spaced channels)
and +4.0kHz for wide-band (25kHz channels).
3. Adjust the deviation register setting so that the frequency deviation is
correct. The deviation is set with a digital adjustment. Use the ATR0
command to read or set the deviation level.

10.5. TX Modulation Balance

(Note: This step is not performed on radios with Radio Type 5)
1. Set-up a service monitor to monitor the FM deviation of the transmitted
signal on an oscilloscope. The frequency response of the demodulated
FM signal must be greater than 10Hz to 5kHz without any de-emphasis.
2. Transmit random data on the center of the band, using the ATTD 1
command. This command will cause the RV-D80-EB/RV-M80-EB to
automatically key up, and send random data for one minute.
3. Verify the DC center of the demodulated data is stable. The random data
should be randomly timed 1s and 0s, and have little to no AC component
on them. See pictures below for details.
4. If necessary, change the ATR9 setting so that the long data bit have the
same amplitude and DC value as the shorter ones.
5. On the low end of the band, adjust ATRL so that the modulation is proper.
6. On the high end of the bamd, adjust ATRH so that the modulation is
proper.
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