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Q-Lite Satellite Modem Installation and Operating Handbook
7-39
7.11 Antenna Control
Two methods of antenna control are provided by the modem:
•
A scalable (0 to 10V) AGC output is available via the Alarms & AGC serial
connector (the pinout for which is defined in Chapter 10). The AGC output can be
set to represent the demodulator AGC level, the Rx composite power level, the Rx
wanted signal level or the receive Eb/No level (the last two of which are only
available when the demodulator is locked). Other signals on this connector can be
used to infer the demodulator lock status and to mute the modem Tx carrier.
•
The OpenAMIP protocol is supported.
Both of these options are described in more detail below.
Antenna Serial Control
Serial antenna control is supported under
Test->Antenna
(
Figure 7-17
).
Figure 7-17 Antenna Serial Control AGC Output
The AGC output on the Alarms & AGC connector can be set to be driven by various
signals (demodulator AGC, Rx composite power, Rx wanted signal level and Rx Eb/No)
as shown in
Figure 7-18
.
Figure 7-18 Antenna Serial Control Output Source Signal Selection
The AGC output range is 0 to 10V. A scaling factor can be applied to the output. This
controls the slope of the output in order to give the desired range of output values for
supplying to the antenna controller. For example, if the AGC output is set to represent
Eb/No, then a user may decide to set 0V to represent 0dB and 10V to represent 6dB
Eb/No (by entering 0 and 6 respectively to represent the 0 and 10V levels). In this case,
any Eb/No value over 6dB would be represented by a 10V output also.
In addition to the AGC output on pin 8, there is a Tx Mute control and the Rx Lock status
can be obtained on the Alarms & AGC connector as follows: