Connect with us

crystal oscillator

Discussion in 'General Electronics Discussion' started by bungy100, Mar 18, 2010.

Scroll to continue with content
  1. bungy100

    bungy100

    3
    0
    Jan 23, 2010
    hi all
    in need of assistance please

    i have a crystal oscillator running at 27 mhz and puts out a nice sine wave

    but i wish to frequency modulate it , i understand the crystal has to be "pulled"

    but not sure of how to inject audio into the circuit

    any ideas ?

    thankyou

    chris
     
  2. neon

    neon

    1,325
    0
    Oct 21, 2006
    you just cannot change the oscillator frequency is fixed that what is good about it. Additional circuitry is required to do what you want.
     
  3. Resqueline

    Resqueline

    2,848
    2
    Jul 31, 2009
    You may not even get narrow-band FM out of it (depends), but capacitance diodes can be used for pulling and frequency-modulating crystals.
    They are placed where the ordinary loading capacitors go, using a couple of extra capacitors to isolate the diode modulating voltage from the oscillator bias.
    The most usual method however is to use a PLL circuit.
     
  4. bungy100

    bungy100

    3
    0
    Jan 23, 2010
    oscillator

    thanks for the replys , if any body has a schematic to hand , id be grateful .
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-