Mike, so far as I understand it (limited knowledge) some xtals were specifically manufactured to operate at a particular overtone frequency.
Two modes of operation, series and parallel.
In series mode, shunt capacitance has little effect, at series resonance only the xtals motional inductance and motional capacitance are up for consideration and they are naturally more stable.
In parallel mode, shunt capacitance has an effect and by its nature won't be as stable, the shunt capacitance, including the xtals plates, leads and holder resonates with the Xtals motional inductance, that point lies between the series resonant frequency and the anti-resonant frequency.
The anti-resonant frequency is when the reactance of the xtals motional inductance equals the reactance of the xtals plates, leads and holder.
In frequency progression it's series resonant, parallel resonate and anti-resonant, then overtones etc.
Any errors then guilty as charged.
Lawrence.
Two modes of operation, series and parallel.
In series mode, shunt capacitance has little effect, at series resonance only the xtals motional inductance and motional capacitance are up for consideration and they are naturally more stable.
In parallel mode, shunt capacitance has an effect and by its nature won't be as stable, the shunt capacitance, including the xtals plates, leads and holder resonates with the Xtals motional inductance, that point lies between the series resonant frequency and the anti-resonant frequency.
The anti-resonant frequency is when the reactance of the xtals motional inductance equals the reactance of the xtals plates, leads and holder.
In frequency progression it's series resonant, parallel resonate and anti-resonant, then overtones etc.
Any errors then guilty as charged.
Lawrence.
