Yes, the R's have no effect on resonant frequency.
They do lower the Q.
More interesting is the model of the quartz crystal resonator,
consisting of a series R,Lm,Cm in parallel with a Cp
The R,Lm,Cm are due to the physical properties of the quartz,
with Lm being extremely huge, perhaps a Henry or so, and Cm being very small.
That is the primary series resonance of the quartz.
Cp is a few pF, due to the plates on each side of the quartz for the electrical connection,
plus any packaging and wiring and IO cells at any device IC it is hooked up to.
I recently spent half a day scratching my head figuring out why
the parallel resonance came about, and why it was so near the series resonant frequency.
When the frequency rises a little bit from series resonance, there's a uH or so
of Lm that does not get canceled out by Cm, and that uH becomes resonant
with Cp to create the parallel resonant frequency.
Jerry, KE7ER
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On Tue, Sep 8, 2020 at 06:55 AM, John Baines wrote:
My first guess was that the resonant frequency is unchanged by any value of R,
though Q is certainly changed.
A quick drawing of the vector diagram seems to agree with this.
