[time-nuts] How can I generate a very clean 1 W signal @ 116 MHz ?

Richard (Rick) Karlquist richard at karlquist.com
Tue May 31 13:33:28 UTC 2016



On 5/31/2016 3:30 AM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote:
>
> Please excuse my ignorance,  but how would one lock a 116 MHz 5th overtone
> crystal oscillator to 10 MHz with no difficulty?  Do you have a circuit you
> share that would give low phase noise, and if so how low?

If you extract the signal from the oscillator through the
crystal (as done in the 10811), the oscillator will be
inherently low phase noise, plenty good enough for your
ham radio application.  Hard to screw it up.

If you phase lock the oscillator to 10 MHz using a very
narrow bandwidth phase locked loop, say 10 Hz, you will
not contaminate the crystal oscillator with reference
noise.  The purpose of the PLL here is not to "clean
up" the XO, but to merely remove drift.  Again, hard to
screw it up.

I can't quote exact phase noise numbers from 40 years ago,
but the Zeta Labs sources were sold to very demanding
aerospace customers, all big names you would have heard
of.

Rick N6RK



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