FM Demodulator

Discussion in 'Wireless & RF Design' started by Xwingz87, Apr 8, 2010.

  1. Xwingz87

    Thread Starter New Member

    Apr 8, 2010
    Does anyone know of FM Demodulator chip that can output a 35kHz sine wave AFTER the demodulation process. We are currently using a receiver from an FM radio, but it seems to cut off frequencies over 10kHz. I need to be able to see the 35kHz signal at amplitude of at least 100mV (200mV peak-to-peak).

    Also, since we're powering this chip with battery, it will be extremely helpful if it's as low powered as possible and can run off a 3V power supply.

    Thank you
  2. bertus


    Apr 5, 2008
  3. AlexR

    Well-Known Member

    Jan 16, 2008
    You are going to need to do more than just soup up your discriminator. You will need to re-design the receiver RF and IF sections to accommodate the extra bandwidth.
    While you are about it you will probably also have to re-design the transmitter, increase the deviation and ensure that the modulator can cope with the high audio frequencies.
  4. rogs

    Active Member

    Aug 28, 2009
    Have a look at the 4046. It can be used to both modulate and demodulate FM signals. The 74HC4046 will work at much higher frequencies than the stabdard 4046, if you need that option.

    Page 17 of this data sheet gives some details of the FM demodualtion type of application:
  5. Audioguru

    AAC Fanatic!

    Dec 20, 2007
    An FM radio has equalization called de-emphasis that rolls of high audio frequencies above 2133Hz in North America at 6db/octave to reduce hiss and the transmitter has a complementary pre-emphasis (high frequencies boost).

    FM Stereo radios have a detector that is flat to 53kHz or higher and the demodulated stereo channels have the de-emphasis roll-off at their outputs.