[time-nuts] pulling oscillators

[paul swed]

I might ask the question how much pulling are you looking to do???
Regards

On Sat, Mar 5, 2011 at 5:09 AM, J. Forster <jfor at quik.com> wrote:

> Capacitively couple a Varactor (or back biased diode) to the circuit and
> vary the diode bias to tune.
>
> -John
>
> ============
>
>
> > Hello all:
> > I've developed a need for pulling crystal oscillators built in to pll
> > circuits. These are cmos, and have the common style oscillator circuit
> > built in. The crystal is across an inverter in the chip, and there is a
> > small cap between each end of the crystal and ground.
> > The chips are pll's in radio transceivers, early at that.
> > I could carefully remove the crystals and caps, simply driving the
> > non-inverting input on the chip with the reference, but I would rather
> > simply tack on a very small cap and "pull" the crystal oscillator with an
> > external reference signal of the right frequency.
> > Anyone out there tried this?
> > Thanks
> > Don
> >
> >
> >
> > --
> > "Neither the voice of authority nor the weight of reason and argument are
> > as significant as experiment, for thence comes quiet to the mind."
> > R. Bacon
> > "If you don't know what it is, don't poke it."
> > Ghost in the Shell
> >
> >
> > Dr. Don Latham AJ7LL
> > Six Mile Systems LLP
> > 17850 Six Mile Road
> > POB 134
> > Huson, MT, 59846
> > VOX 406-626-4304
> > www.lightningforensics.com
> > www.sixmilesystems.com
> >
> >
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>
>
>
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