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P300H P300 Series Modem Installation and Operating Handbook Page 205
UNCOMMITTED DAC OUTPUT CONTROL
The output controlled by this selection in only available of the Monitor/AGC option is fitted. Refer to the
Change, User-Opt, AGC Output menu, section 6.10.10 on page 106 for an explanation of this parameter.
This output is updated 10 times per second.
Note: For antenna pointing AGC whilst demod unlocked, see definition of pin 8 on alarms and AGC
connector.
0 Coarse AGC voltage (Rx Signal level), default
Scaled at 1V per 10dB, with extremes of 0V=-100dBm and 10V=0dBm and a 1.0dB resolution.
This signal is forced to 0V when the demod is unlocked. Note that although the scaling extends
from 0 to -100dBm, the actual output range is limited to the range measurable by the software
which is -21dBm to -83dBm (except for when it is forced to 0V if the demod is unlocked).
Note the absolute accuracy of this measured parameter and the unit to unit repeatability is
relatively poor (±4dB), but on any one unit it will be consistent and so show trends accurately.
1 Rx Eb/No Level
Scaled at 1V per 2dB, with extremes of 0V=0dB and 10V=+20dB and a 0.1dB resolution. This
signal is forced to 0V when the demod is unlocked. Note that although the scaling extends from
0 to 20dB, the actual output range is limited to the range measurable by the software which is
approx from a lower limit of 3.0dB (demod unlock threshold) to an upper limit of 13-19dB
(dependent on Modulation scheme, FEC Rate & Data Rate). To Determine the upper limit at any
mix of modulation, FEC, and data rate simply set the modem in IF loopback.
2 Rx IF Offset Frequency
Scaled at 1V per 10KHz, with extremes of 0V=-50KHz and 10V=+50KHz and a 25Hz resolution.
This signal sweeps when the demod is unlocked. The default demod sweep is ±25KHz, with a
maximum of ±32KHz.
3 Fine AGC voltage (Rx Signal level)
In response to customer requests for a finer resolution signal level indicator. Scaled at 3.33V per
10dB, with extremes of 0V=--60dBm and 10V=-30dBm and a 0.1dB resolution. This signal is forced
to 0V when the demod is unlocked.