Robotron Pty Ltd G9P 用户手册
WiNRADiO G39DDC User’s Guide
63
threshold somewhere between these extreme values. Note that the noise
squelch is particularly effective in the FM mode and its values also depend on
the demodulator bandwidth setting.
squelch is particularly effective in the FM mode and its values also depend on
the demodulator bandwidth setting.
The adjustment procedure for the voice squelch is similar: Tune to an
unoccupied channel first, then to an active voice channel, note the
corresponding Voice content values, and set the voice threshold between
these two extremes.
unoccupied channel first, then to an active voice channel, note the
corresponding Voice content values, and set the voice threshold between
these two extremes.
To enable the squelch action, click the Enable button. Clicking it again
disables it.
disables it.
It is easy to forget that squelch is active. If the receiver doesn’t seem to
be operational (no sound from the speaker), check the squelch and mute
settings first.
be operational (no sound from the speaker), check the squelch and mute
settings first.
Gain
The Gain tab contains several controls to adjust various gain-related settings
of the receiver. The gain is a software parameter, and can be set separately
for each of the two virtual receivers.
of the receiver. The gain is a software parameter, and can be set separately
for each of the two virtual receivers.
AGC
The Automatic Gain Control (AGC) acts upon the digitally down-converted
and filtered demodulator passband, in order to keep the signal coming to the
demodulator at a constant level.
and filtered demodulator passband, in order to keep the signal coming to the
demodulator at a constant level.
This is in fact functionally similar to AGC typically implemented in conventional
receivers, which also works on the IF signal prior to demodulation. The
difference is that in a conventional receiver this is implemented in hardware,
while in the Excelsior it is a software function.
receivers, which also works on the IF signal prior to demodulation. The
difference is that in a conventional receiver this is implemented in hardware,
while in the Excelsior it is a software function.