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Fm receiver circuits

  1. Dec 2, 2008 #1
    I want to design a fm receiver circuit for the frequency range of 144-146Mhz.Kindly suggest me a suitable ic for the same.
  2. jcsd
  3. Dec 2, 2008 #2
    One IC for a complete receiver in this range? What kind of receiver performance are you looking for? It just so happens I have a bit of experience in this area.
  4. Dec 3, 2008 #3
    Because narrow band FM (NBFM) is used on 144 MHz you can't use the standard 10.7 MHz IF directly.

    I think all 'proper (sensitive)' NBFM receivers use double conversion to 10.7 MHz and then 455 KHz. You need a 11.155 MHz Xtal oscillator (10.7 + 0.455) OR 10.245 (10.7 - 0.455)

    There is a circiuit here... Based on the MC3359 chip.


    Also you need a narrow 10.7 MHz filter and a suitable 455 KHz one. As it is narrow band you need a much more stable first conversion oscillator...either Xtal controlled or synthesised. You need a 455 KHz quadrature coil for the de-modulation.

    All in all it will be a far more complicated receiver than an FM broadcast one and cost considerably more.
    Last edited: Dec 3, 2008
  5. Dec 4, 2008 #4
    i need to design the circuit to decode a morse code which will be transmitted in this range,the IC TDA 7000 does not satisfy the frequency range criteria.It works in the range of 70 to 120 MHz range. Can i use a mixer to lower the incoming frequency to this range and than use it?
  6. Dec 4, 2008 #5
    Also check out the SA605 it's very similar to MC3359. It has a nice LNA on board, oscillator, mixer, and FM demodulator if needed.
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