Audio to PWM

Discussion in 'General Electronics Chat' started by M0RFD, Nov 7, 2011.

  1. M0RFD

    Thread Starter New Member

    Nov 7, 2011
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    0
    Hello

    I wish to build an interface which will isolate my laptop from my transceiver. I would like to build an unusual one using PWM. The idea is to take the output from my radio, convert it to PWM which will then, hopefully, drive an opto couple.

    I am not too sure about PWM and would appreciate if someone could tell me the best PWM chip to use. I know that a 555 timer may produce good results, but I just fancy using a dedicated chip.

    Hope this makes sense.


    73
    M0RFD
     
  2. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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  3. M0RFD

    Thread Starter New Member

    Nov 7, 2011
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    Thanks for this. I will give it a try.

    73
     
  4. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    Have you looked at audio transformers?


    The PWM method would be good for Morse Code but not much for fidelity, whereas an audio transformer has a relatively wide frequency response in addition to impedance matching and, of course, isolation.

    Option B if you need fidelity would be a ADC and DAC on either side of the optocoupler.
     
  5. M0RFD

    Thread Starter New Member

    Nov 7, 2011
    3
    0
    Thanks

    Fidelity did worry me as the required bandwidth of the unit has to be 300hz (no problem) to 3Khz which may be a problem for this circuit. I had thought of transformers as well. Most people use them in this circumstance and they work well. I was trying to produce something new, different, better and cheap.

    I think I will stick with TX's. Thanks for the help. It is appreciated.

    73
     
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