WiNRADiO G33DDC HF Receiver
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UDM Mode Selection
If the UDM mode is selected, the AMS band selection controls are replaced
with the
Mode
selector for the user-defined mode:
The UDM mode can utilize the AM, USB, LSB, CW or FM modes.
Audio Tab
The
Audio tab
contains functions specific to the parameters of the output
sound, for example volume and audio filtering.
Audio Filter
The
Filter
button turns on the
Audio filter
. The audio filter is a bandpass filter
with continuously adjustable lower and upper cut-off frequencies:
When the audio filter is enabled, its low and high cut-off frequencies can be
adjusted using the
Low
and
High
controls. The
De-em
control is used to
adjust
de-emphasis
, relating to the filter’s slope from the highest frequency to
the lowest, which is particularly important for FM signals (a typical de-
emphasis value for narrow-band FM-modulated signals is 6.0 dB/oct).
However, it can be also useful for AM signals: Gently sloping the filter
passband can sometimes make the signal easier on ears and avoid operator
fatigue.
