[time-nuts] Notes on the Driscoll VHF Overtone Crystal Oscillator

Bruce Griffiths bruce.griffiths at xtra.co.nz
Mon Dec 28 01:21:06 UTC 2009


Tom Clifton wrote:
> Interesting read on a low phase noise oscillator by Chris Bartram GW4DGU
>
>
> http://www.christopherbartramrfdesign.com/blaenffos/oscillator/VLNO.pdf
>
>    
There are several VHF crystal Oscillators designed by M Driscoll.
The one shown is merely derived from one variant.
It has an unecessary constraint on setting the crystal current.
Much better results are obtained by implementing the diode clamp as a 
capacitively coupled peak to peak detector the output of which is 
connected to a low noise dc source.
The crystal current can then be adjusted by varying the dc source voltage.

Bruce





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