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DSP : Flange Effect / Comb Filter - Anyone tried it on the Propeller? — Parallax Forums

DSP : Flange Effect / Comb Filter - Anyone tried it on the Propeller?

bradharperbradharper Posts: 64
edited 2011-07-27 00:37 in Propeller 1
I've seen mention and implementation of several DSP and filtering techniques here, anyone worked through a comb filter or flange effect?

I need to apply it dynamically to a 22khz 16-bit pcm stream.

Comments

  • Mark_TMark_T Posts: 1,981
    edited 2011-07-26 17:53
    The classic 'analog' way to flange was to pass the signal through a bucket-brigade delay chip (charge-coupled delay device) and subtract the input signal from the output (compensating for attenuation). By continusouly varying the clock speed the delay was changed to sweep the comb filter. A rare example of a non-digital sampled signal system.

    This technique uses a varying sampling rate which is a tad tricky for a signal that's already sampled at a fixed frequency... You'd have to fill a buffer at a fixed rate and pull samples out at a varying rate and feed to a DAC run by the same varying clock perhaps? (and prevent the buffer emptying or over-filling).
  • StefanL38StefanL38 Posts: 2,292
    edited 2011-07-27 00:37
    do you know the Open Stomp Coyote?

    I don't know anything about the details. Take a look at it to find out if this device would be suitable for you

    keep the questions coming
    best regards

    Stefan
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