Basics of oscillators and VCOs

Discussion in 'General Electronics Chat' started by midrees, Sep 8, 2010.

  1. midrees

    Thread Starter New Member

    Aug 22, 2010
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    0
    Dear All!
    Can some body help me in learning the basics of Oscillators, VCO and Phase detectors.
    Thanks
     
    Last edited: Sep 8, 2010
  2. marshallf3

    Well-Known Member

    Jul 26, 2010
    2,358
    201
    That's too complex to sit here and spend hours writing about.

    See top of page, note links in light blue:

    Vol. I - DC
    Vol. II - AC
    Vol. III - Semiconductors
    Vol. IV - Digital
    Vol. V - Reference
    Vol. VI - Experiments
    Worksheets
    Videos

    Of course theres always this link: http://tinyurl.com/23uo7gs
     
  3. bertus

    Administrator

    Apr 5, 2008
    15,647
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  4. Potato Pudding

    Well-Known Member

    Jun 11, 2010
    684
    92
    The basics?

    Oscillators are circuits that create an AC signal. They ussually do this by inverting and delayed feedback - which is feeding the circuit its own output as an input.

    A Voltage controlled Oscillator will have elements Like a reverse bias high capacitance diode or varactor that are changed by application of a control voltage. These changes will cause a shift in the oscillators frequency tuning.
     
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  5. Potato Pudding

    Well-Known Member

    Jun 11, 2010
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    A phase detector looks at two signals (one of them its own VCO for a PLL) and outputs the difference frequency. A phase locked loop or PLL is the normal method of doing this. It is a VCO that feeds back the phase difference as its control voltage. This allows it to demodulate FM radio signals.

    Another use is clock syncing. If the clock drifts it creates a phase difference that controls the VCO back towards sync. The synced clocks willl have a flat 0 volt signal for the phase detected.
     
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