WiNRADiO G305 VHF/UHF Receiver
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If you have a preference for particular IF bandwidths, you can associate them
with any of the ten preset buttons (located at the bottom of the demodulator
front panel) by double clicking the Bandwidth column of the IF bandwidth
presets table, and then typing in the numerical bandwidth value in Hz. The
buttons are numbered (1 to 10) from left to right. The factory default values
can be restored at any time, by pressing the
Restore default settings
button.
Each modulation mode has a separate set of IF bandwidth presets.
The audio filter’s length is adjustable under the
Audio filter length
parameter.
Note how this parameter influences the actual filter passband (represented by
the blue graph under
Audio filter settings
), compared to the ideal passband
(represented by red lines). The
Audio filter settings
make it possible to adjust
audio filtering separately for each demodulation mode. The
On
button either
enables or disables filtering, and is tied to the
AF Filter
button in the
demodulator front panel.
The
Band-pass
and
Low-pass
buttons make it possible to select the desired
type of filter. The filter cut-off frequencies can be either entered numerically, or
the filter edges can be dragged with the mouse. For the band-pass filter, the
entire filter passband may be shifted left or right by dragging the top horizontal
red line. With a band-pass filter, suitable low and high cut off values for good
intelligibility of voice communications are 300 and 3000 Hz, respectively.
De-
emphasis
is usually necessary for use with FM modulation only. The typical
value is -6dB/octave.
Finally, all demodulated audio output is scaled up by an
Audio gain
factor.
The scaled audio signal level is further adjusted with the
Volume control
in
the demodulator main panel. However, when the
Software AGC
is active, the
fixed
Audio gain
setting is ignored, and the software will automatically adjust
the audio level according to the
SAGC reference level
setting.
If you are experiencing audio distortion when using the Software AGC,
this is probably because the SAGC reference level is set too high.