Company Confidential
24
Raveon Technologies Corp.
11 Tune-up and Alignment
The following table lists the parameters in the modem that are calibrated at the
factory, and the typical values. All modems are shipped from the factory pre-
calibrated and ready to install.
Typical Register Settings
R Register
R0
R5
R8
R9
Function
Peak Deviation
Preamble Length
Frequency Offset
Modulation
Balance
Radio Type 4
(MURS Module)
-280
8
25
65
11.1 Center Frequency
1. Read the deviation setting with the
ATR0
command, and note the
setting.
2.
Temporarily set deviation to 0 by sending this command:
ATR0 0
3. Key the transmitter into a 50 ohm load with the
ATTD 7
command.
4. The modem will now put out CW on the center of the channel.
5. Read the frequency offset with the
ATR8
command.
6. Adjust the frequency to the center of the channel with the
ATR8
command. You can use the “u” key and the “d” key to change the
settings up and down one value in real time.
7. Set the deviation back to the value you read in step 1, using the
ATR0
command.
11.2 TX Deviation
1. Switch to channel 1.
2. Key the transmitter into a 50 ohm load using the ATTD 4 command.
The unit will now transmit, and send a digital 0 continuously. This will
be -2.0kHz low in frequency.
3. Adjust the deviation so that the frequency is exactly 2.0kHz low. The
deviation is set with a digital adjustment. Use the ATR0 command to
read or set the value. This value is negative, and is typically around -
200.
11.3 TX Modulation Balance
1. Transmit random data using the ATTD 1 command.
