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M7 GX Technical Manual 52 Raveon Technologies Corp.

in radio test and calibration, the values stored in the R registers should not be

modified.

Improper adjustment of the radio calibration (R0-R9 and RA registers), can

result in failure of the radio modem.

Calibration and alignment values are stored internal to the modem in the “R”

registers. (R0-R9 and RA). For example, to read R5, issue the ATR8 command

without any parameter. To change the setting, issue the ATR8 nn command,

where nn is the new value you would like to store.

Once you read a register using an ATRx command, you may modify its value by

entering a “U” for up or a “D” for down. U or D will change the value by one. Use

this trick carefully, because it modifies the last R register that was read, and it is

easy to unintentionally modify the wrong register.

Periodic Calibration

The only setting that may require adjustment is the center frequency. After years

of operation, all crystals will age and change frequency slightly. The ATR8

command is used to adjust the center frequency. Like all narrow-band radios,

semi-annual checks and adjustment of frequency is recommended.

Center Frequency

1. Key the transmitter with CW output using this command:

ATTD 7

2. The modem will now put out CW on the center of the channel.

3. Read the frequency offset with the ATR8 command.

4. 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.

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.

TX Modulation Balance

This procedure must be done anytime 4-level modulation is used and the RF

channel frequency y is changed.

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Raveon RV-M7 Spezifikationen Seite 52