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DDS Signal generation

Discussion in 'Electronic Design' started by [email protected], Feb 16, 2007.

  1. Guest

    Hello,
    I would like to design a signal generator.
    the signal as the following form : cos(cos w1).sin(w2)
    with w1~ 10Mhz and w2~50kHz
    amplitude and frequency of the signal have to be digitally controlled.
    I thought about DDS's (AD) to design this.
    What do you think about such a solution?

    Thank you.
    y.
     
  2. Rich Grise

    Rich Grise Guest

    Depends on what the teacher wants.

    Good Luck!
    Rich
     
  3. John Larkin

    John Larkin Guest

    Easy in an FPGA. Two phase accumulators, two sine lookup tables, one
    multiplier, all feeding a dac. I did a similar thing recently, 8
    channels, 32 MHz Nyquist, but the multiply was just used as a slow
    gain scaler.

    John
     
  4. Guest

    Actually, this is not a student project!
    I'm not familiar with using discussion groups, and perhaps is my
    problem not very well explained!

    Thank you for yout suggestion.
    Yes, I was thinking about a FPGA, but I'm not familiar with this
    technology, since I usually work with uC's. I think I'll study this
    option a bit further!
    In fact, DDS seems not to be really done for a "real-time" modulation
    as I wouls like to design.
     
  5. Tom Bruhns

    Tom Bruhns Guest


    You should look at the Analog Devices web site. They make several DDS
    chips, and some of them integrate most (or perhaps all) of what you
    want into one part. I assume that the function you originally posted
    is not quite correct, and that you want to amplitude modulate one
    sinusoid (high frequency) by another (much lower frequency). Or did
    you really mean the cosine of a cosine wave, times a sine wave?

    DDS is most certainly done for real-time modulation. It's done for
    arbitrary modulating waveforms as well as for sinusoids or other
    repetitive waveforms.

    Cheers,
    Tom
     
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