WiNRADiO G33DDC HF Receiver
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Another way of changing the notch filter parameters is by dragging the
stopband of the filter (a blue shaded area) with the mouse. The stopband
width can be adjusted by dragging the edges, while the centre frequency can
be changed by dragging the centre line, which makes it possible to
conveniently position the filter stopband over the interfering signal.
The
Center
button serves to relocate the notch filter stopband to the center of
the demodulator filter passband. This can be useful in situations when the
notch filter is hidden beyond the currently visible demodulator spectrum limits,
in particular when the spectrum is zoomed in.
The following picture shows a signal with a strong interference in the passband
(the large peak right of center, at the cursor position).
In the resulting audio, typically there would be a strong buzzing sound. After
applying the notch filter and adjusting its center and bandwidth (by dragging
the blue area center and edges) to fall exactly over the interfering signal, the
situation will look like this:
