Implementing demodulation in a different way

Discussion in 'Wireless & RF Design' started by atferrari, Feb 7, 2012.

  1. atferrari

    Thread Starter AAC Fanatic!

    Jan 6, 2004
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    I revisited the concept of demodulation of an AM signal.

    Isn't the output of the 455 KHz IF filter, similar to a sampled signal as I could get from a DAC process?

    If so (in the hope of not being wrong assuming the above) could I obtain the baseband just by using an active filter implemented with opamps of suitable GBW, surely very expensive/hard to find?

    What are the flaws of my reasoning?
     
  2. crutschow

    Expert

    Mar 14, 2008
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    There is no baseband signal in the 455kHz IF signal. It consists of the 455kHz carrier with sidebands at plus and minus the modulation frequencies around the carrier.
     
  3. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Have a look at this page how a AM signal looks like:
    http://www.williamson-labs.com/480_am.htm

    An other way of demodulation an AM signal is a synchronized demodulator.
    Most times a PLL is used for the synchronized signal needed for the demodulation.

    Bertus
     
  4. atferrari

    Thread Starter AAC Fanatic!

    Jan 6, 2004
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    What about telling if I can recover the audio with what I propose?
     
  5. crutschow

    Expert

    Mar 14, 2008
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    Sorry you didn't understand my answer. It was "NO". :rolleyes:
     
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