Specifications

M7 GX Technical Manual 53 Raveon Technologies Corp.
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 RV-M7, using the ATDT 1 command. This
command will cause the RV-M7 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.
10.8. RS232 Serial Port Options
Flow Control
If large amounts of data will be sent with the RV-M7, it may be possible to overflow
the internal data buffer. To ensure the transmit buffer does not overflow, enable
and use hardware flow control. Hardware flow control is enabled with the ATCH 1
command. Note that the RV-M7 modem will always indicate the status of its
internal buffer using the CTS signal on the DB-9 serial connector. When CTS is
negated, the internal buffers are more than 80% full. When it is asserted and it is
“Clear to Send”, the buffers are less than 80% full.
RX Carrier Detect
The DCD signal from the modem may be generated by detection of RF, using an
internal signal called RSSI (Receive Signal Strength Indication). The RSSI signal
is an analog signal representing the strength of the RF carrier. It is compared with
a pre-set value, and if it is above this value, Carrier Detect is asserted. The pre-set
value may be change with the ATRA command.
When the modem is used in the Streaming Mode (non-packetized operation, you
may wish to configure the modem to require RF carrier detect to be active for the
modem to receive data. Use the ATRF command to enable/disable this feature.
To set the RF carrier detect level, perform the following steps:
1. Generate a test signal, 1kHz tone, 1.5kHz deviation, on the receive frequency.
Connect the signal generator to the antenna input. Turn the RF level off.
2. Watch the RSSI DAC value by issuing the AT$5 command. The current
reading will be sent out the serial port.
3. Adjust the RF level to a point where you would like the RSSI to trigger the CD
signal. This is factory-set to -110dBm.
4. Send the ATRA nnn command. Set nnn to be equal to the RSSI setting you
would like the CD signal to trip at. The BUSY LED will also indicate an RF
carrier when the RF carrier is above the threshold set with the ATRA command.