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Low phase noise VCO

Discussion in 'Electronic Components' started by [email protected], Dec 15, 2006.

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  1. Guest

    Hi,

    In my project, I drive an oscillating device (oscillator) with an VCO
    reference signal. In order to lock the oscillator's frequency, a PLL is
    employed. To keep the device oscillating the input frequency needs to
    be hit at least as precise as 0.005 Hz.

    The problem, though, when the oscillator is changed, its center
    frequency changes, too. It can be in the range between 11.75kHz-12kHz.

    Because of other clocks that need to be synchronized and generated, the
    VCO's output frequency must be in the range 13.865-14.16 MHz. Actually,
    a VCXO would fit my needs best to tune the frequency as accurate as 5.9
    Hz at 14 MHz (0.005 Hz at 12kHz). However, if I pick a VCXO for say
    14.1 MHz that is +/-100ppm pullable, it may work with some oscillators,
    but not with all possible.

    So, I need a VCO whose center freqency is coarse adjustable in a
    relatively wide band (13.8-14.2 MHz) and it should have a fine
    frequency tuning resolution using the input voltage.

    Has anyone an idea what VCO could fit for this?

    Thanks,

    Stefan
     
  2. maxfoo

    maxfoo Guest

    Check out Randy Rhea's VCO design book, has a nice colpitts oscillator in there
    that would work.
     
  3. maxfoo

    maxfoo Guest

    I posted a pdf file on oscillator design in alt.binaries.schematics.electronic
    written by Dr. Rhodes.
     
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