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Re: AM demodulation (or a sort of it) using MC3359P, is it possible?

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  • th3ad10
    ... Hello Paul. Thank you a lot for the help. Sadly it is not so easy as I hoped. I understand what you wrote. Only things I can add are the second conversion
    Message 1 of 16 , Nov 19, 2012
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      --- In Electronics_101@yahoogroups.com, Paul Read <paulr@...> wrote:
      >
      > Hi TF,
      >
      > It sounds like you may need to have a bit more gain before the detector, which probably won't be small.
      > Most of the gain in an FM receiver is in the limiting amplifier, there is 10 to 20 dB in the front end.
      > In an AM receiver there is quite a lot if Linear gain (without distortion). This will almost always be controlled by an AGC system (automatic gain control), so that strong signals don't overload it, but ensuring that weak signals can be heard. This might be getting beyond the space you have available.
      > There are some AM receiver chips that will be useable at 455kHz (I assume that is the frequency at pin 5).
      > If the AM signals you are trying to receive are strong then you won't need so much gain and might still get results with the system we have discussed.
      > I'll have more thinks
      >
      > Cheers
      >
      > Paul

      Hello Paul.
      Thank you a lot for the help.
      Sadly it is not so easy as I hoped.
      I understand what you wrote.
      Only things I can add are the second conversion (MC3359P's pin 5) is 450kHz and about the strenght of the signals I'd like to hear, it depend due the fact sometimes they are strong but other times they are faint...
      Listen them in FM (in the case they are AM stations) make them also a bit fainter, beyond that listening in FM in any case they are almost incomprehensible expecially when they are faint.
      I already wrote about my intention of use a high impedence headphone, I have to make a chance.
      Thanks again Paul.
      Regards,
      TF
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