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Does such a macro exist?

Discussion in 'Building With Reaktor' started by MackTuesday, Jun 30, 2013.

  1. MackTuesday

    MackTuesday New Member

    Messages:
    13
    I searched the user library but didn't find anything.

    I want something that can take *any* two signals and phase modulate one with the other.

    Help?
     
  2. salamanderanagram

    salamanderanagram NI Product Owner

    Messages:
    3,454
    i'm not sure that one can even identify the phase of an arbitrary signal. like, how do you determine the phase of noise?
     
  3. MackTuesday

    MackTuesday New Member

    Messages:
    13
    Yeah, there's not a good name for what I'm thinking of. Maybe "Time Modulation" or "Scanning Waveshaping" are better names.

    You have a moving window on the carrier signal, however wide you want it. Call that 2 pi radians and pretend the stuff in the window is one period of a periodic function. Then you perform what we commonly call "phase modulation" on that pretend periodic function. You step the moving window forward sample by sample, thereby getting a new pretend periodic function each time.

    I personally wouldn't allow the modulator value to wrap around between 0 and 2 pi, however. You get icky discontinuities that way because the carrier isn't necessarily periodic, and even if it were, the width of the window isn't necessarily the period of the carrier. Instead I'd pass the modulator through some kind of soft clipper or maybe instead apply an envelope on the window, like a Hann function or something.

    It's the same as using the stuff in the moving window as a constantly changing waveshaping function that's applied to the modulator.

    Or you can somehow keep the window in the same place for a while, then make it skip to a new place over and over. I dunno, there are a number of different ways you could do it.

    I call it phase modulation because that's what you get if the carrier is periodic and the window size matches the period.