[time-nuts] Low noise quartz crystal oscillator by Bruce Griffiths
Richard (Rick) Karlquist
richard at karlquist.com
Tue Oct 27 12:43:07 UTC 2015
On 10/26/2015 9:15 PM, Bruce Griffiths wrote:
> The 10811A ocxo uses an oscillator of this type albeit with a lower crystal current, an overtone crystal. However the output stages spoil the PN floor..Cascaded transformer coupled CB stages are somewhat quieter.
> Bruce
>
That's right. Burgoon (10811 designer) told me he had to meet other
requirements besides noise floor. He had a special
one-off version of the 10811 without these compromises
that he built to provide a reference source to use
for phase noise measurements. In the 10816 rubidium,
I used 3 common base transistors in cascade as
the output buffer and got similar results to
his special version.
>
> Driscoll developed various high frequency crystal oscillators employing MMICs RF splitters together with a crystal, various matching circuits and a diode limiter.
>
Yes, he did, but long before that work he championed
his 2 transistor circuit that was extensively copied
by many other designers.
Rick
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