On Fri, 17 Feb 2006 10:21:19 GMT, "W3JDR" wrote:

As a generalization, I think that any circuit that excites the crystal's
series resonant mode will probably outperform a circuit that excites the
parallel resonant mode, because the series resonance is higher Q and is less
affected by external influences.

Joe, a minor issue.

Frerking,"Crystal Oscillator Design and Temperature Compensation" (and
a lot of other folks) says the Q of the crystal is: Q = Xl / R,
where Xl is the motional inductance and R is the ESR. Thus the Q of
the -crystal- is not a function of the mode of operation. Short of
drastically changing R, the crystal Q is unaffected by external
circuitry.

If we speak of overall -circuit- Q then that is a different can of
worms.



Joe
W3JDR


"Tim Wescott" wrote in message
...
JJ wrote:
I am fimilar with Colpitts, Harley, Clapps, Bulter, Piece oscillators?

Which configuration with JFET or BJT would yield the highest performance
and least jitter?

JJ

AFAIK a well-designed Butler oscillator will have the lowest jitter, but I
doubt that you could do the "well designed" part without a lot of bench
work.

Any of the rest (considering a "Clapp" oscillator to mean a crystal
oscillator with rubbering) are good enough for communications work.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

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