Company Confidential
36
Raveon Technologies Corp.
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.
TX Modulation Balance
This procedure must be done anytime 4-level modulation is used and the RF
channel frequency y is changed.
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 with the
RF-7800W
, using the
ATDT 1
command.
This command will cause the
RF-7800W
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 and that the transmit
“eye” pattern is as wide as possible.
