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Need a circuit! Sinewave Generator

Discussion in 'Electronic Basics' started by gmb, Dec 26, 2004.

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  1. gmb

    gmb Guest

    Hi there,

    I am a violin maker, and I need a circuit for a signal generator, to test
    the resonant frequency of my fronts and backs.

    Spec...

    Range 20hz to 10Khz
    With integral digital frequency counter
    Capable of driving a big hefty woofer speaker.

    If any of you experts out there could help, I'd be most appreciative.

    Many thanks, and kindest regards,
    Gordon
     
  2. Dbowey

    Dbowey Guest

    Gordon posted:

    << I am a violin maker, and I need a circuit for a signal generator, to test
    the resonant frequency of my fronts and backs.

    Spec...

    Range 20hz to 10Khz
    With integral digital frequency counter
    Capable of driving a big hefty woofer speaker.

    (snip)
    You aren't going to find an oscillator that can directly drive any speaker very
    well.

    However, you will find some fairly good function generators such as the B&K
    3011B on eBay. They can drive an amp of your choice. Many of them, including
    the 3011B, have a frequency counter, and the bonus is that you can sweep a
    range of frequencys if you like that method. If you have a scope, you can use
    the ramp output of the function generator to drive the horizontal channel so
    you can plot frequency to the horizpntal channel and amplitude to the vertical.
    It gives you some nice options.

    Don
     
  3. Bob Masta

    Bob Masta Guest

    Check out my freeware DaqGen software. It uses the
    sound card in your computer to provide a complete
    low-distortion audio signal generator. Besides pure
    sine waves, you can generate much more complex
    test signals like narrow bands of noise. You can use
    slow frequency sweeps to watch for resonance.

    DaqGen is the signal generator portion of the upcoming
    Daqarta for Windows, which will be released in a few
    months (hopefully!). Daqarta will also allow you view the
    response to the generated signal, so you could have
    the entire resonance analysis in one view, automatically.

    Best regards,


    Bob Masta
    dqatechATdaqartaDOTcom

    D A Q A R T A
    Data AcQuisition And Real-Time Analysis
    www.daqarta.com
     
  4. Louis Bybee

    Louis Bybee Guest

    The software mentioned above is capable of rather complex outputs, patterns,
    and is as good/better than commercial (read: $$$) offerings I've looked at.

    Well worth a look if you need that sort of thing.

    Louis--
    *********************************************
    Remove the two fish in address to respond
     
  5. Guest

    Bob,

    Can you indicate how the Windows versions is coming along? (Or, can
    the DOS version run on Windows XP?)

    Thanks and regards,

    Mark
     
  6. Bob Masta

    Bob Masta Guest

    DaqGen is a Windows-only signal generator program that
    has been available for about a year. It will run fine on XP.

    Daqarta does signal acquisition/analysis as well as signal
    generation.

    Daqarta for Windows does will hopefully be ready in a few months,
    and will run on any Win9x, NT, 2K, XP etc platform.

    Daqarta for DOS will only run on Win9x or earlier because
    it needs real-mode DOS. But the biggest problem is that
    there is no such thing as a standard DOS sound card driver,
    so I have had to write custom drivers for each card
    supported. Since Creative Labs dropped all pretense of
    supporting developers for anything beyond ISA bus,
    that's where I quit. So Daqarta for DOS requires an
    ISA-bus Sound Blaster. (Or one of a huge family of
    legacy ISA-bus lab-type data acquisition boards, or
    a simple 8-bit "board" you can build yourself.)

    I'll post a note here when Daqarta for Windows is ready.

    Best regards,


    Bob Masta
    dqatechATdaqartaDOTcom

    D A Q A R T A
    Data AcQuisition And Real-Time Analysis
    www.daqarta.com
     
  7. gmb

    gmb Guest

    Hi, and thank you all for your information and suggestions. I eagerly await
    the full version of the software, which no doubt will be extremely useful
    for analysing the sound/respose of finished violins.

    Unfortunatley, the 'kit' I need is for my workshop (no computers there).
    Basically, it will be a worktop with a woofer set into it, and the violin
    belly or back supported at nodal points above it. Sprinkled with the fine
    grains of tea from a tea-bag, when cranked up to resonant frequency (with
    quite high amplitude), the plate vibrates and the tea grains form 'Chladni'
    patterns on the plate - it's really the only way there is to determine
    symmetry of vibration across the plates.

    Many thanks,
    Gordon
     
  8. Bob Masta

    Bob Masta Guest

    You may want to consider getting an old "junker"
    computer to keep in the shop, and run Daqarta for DOS
    on it. You can pick these up really cheap, if not for free,
    and the only hitch is finding a compatible sound card.
    Note that the LPTX driver module contains complete
    instructions for a super-simple 8-bit D/A that plugs
    into the printer port... just a handful of resistors. It
    will be roughly comparable to a lab-type function
    generator as far as distortion goes... around 1%.
    It would be just fine for this application, in the event
    that you can't locate a Sound Blaster or other supported card.

    If you can find an ISA-bus Sound Blaster, then the
    Daqarta analysis functions will be really handy as well.

    Best regards,





    Bob Masta
    dqatechATdaqartaDOTcom

    D A Q A R T A
    Data AcQuisition And Real-Time Analysis
    www.daqarta.com
     
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