Re: LF: Soundcard bandpass filter?

[DL4YHF@aol.com]

Hello David and group,


> Would the new 'filter' incorporated into  V2.3 spectrum Lab do this?

Yes, it does. In fact the 'new filter' uses FFT and inverse FFT to produce any filter response as you like. You may use a standard bandpass with adjustable center frequency and bandwidth, or 'draw' the desired frequency response with the mouse. All this is in the "Filter Control Window" which pops up when you click on the filter block in the center of the test circuit diagram. 

For a relatively easy start, load the file "VlfLsn2.usr" which contains all necessary settings for a stereo filter with FFT, originally used for listening to signals in the VLF range. You may turn of one channel to reduce the CPU load, or reduce the sampling rate from 44kHz to 11kHz which is appropriate for typical SSB bandwidths.

If you need more info please ask, because the documentation of some of the special functions (like autonotch and denoiser) is very sparse.

Regards and seasons greetings from cold and misty DL,

Wolf DL4YHF.


P.S: Hope to be back on LF soon. At the moment, neither antenna nor transmitter in functional state...