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Raveon Technologies Corp.
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.
