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1940Re: [SpectrumLabUsers] FUNcube Dongle and WFM

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  • Jurgen Bartels
    Apr 11, 2014
      > If I have two channels, Left and Right, one carrying centre to +96 kHz and one
      > carrying centre to -96 kHz, but the demodulator only works with 0 to 192 kHz,
      > then if I frequency shift both by +96 kHz. I get them both positive, but I
      > also have to invert the negative frequencies.  I then have to combine the two
      > channels before the demodulator function, which I understand is in the Black
      > Box modules, and I don's see a way of doing that after the filter boxes.

      It is simpler than you may think.

      You have a -96 to +96kHz spectrum.

      In the Filter you shift *that* entire spectrum 96kHz higher.
      (You don't treat the halfs separately.)

      In "filter option"
      enable "reject negative frequencies"
      enable I/Q input

      The filter output will then deliver 0..196kHz with no more negative frequencies

      > Which is why I think that the WFM function is an integral part of the Perseus
      > config and not available to something imitating a sound card.  I guess only

      No there's no Perseus specfic funtion that late in the chain anymore.

      Jurgen Bartels Suellwarden, N. Germany
      Ant. hor: 29-45MHz 7-el, 45-87MHz 11-el, FM 15.11, Band-3:13-el, UHF:48-el
      TV: Winradio G305 / Fly2000 + video noise filter & variable IF BW
      FM: Downconverter + Perseus + Speclab as WFM demod.
      MW: 30 x 4m EWE 320° with JB-terminator, Winradio & Perseus
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