Patent ID: 6624708
Filing Date: 2003-09-23
Classification: H03B

Abstract:
A oscillator circuit for operating a piezoelectric crystal at a frequency of oscillation near a series resonance of the crystal, comprising:(a) a tuned gain stage, further comprising a limiting amplifier located in a feedback loop about a transistor, with a non-inverting output of the transistor being connected to drive the crystal at the frequency of oscillation, and with an inverting output of the transistor being connected to a resonant tank to suppress oscillation of the crystal at frequencies other than near the series resonance; and (b) a compensation circuit having an input connected to an output of the limiting amplifier, and further having an output connected to the crystal at the non-inverting output of the transistor for cancelling out any effect on the frequency of oscillation produced by a shunt capacitance associated with the crystal.