Dual-Mode Crystal Oscillator with Simultaneous Excitation of Two Overtones in a Stress Compensated Quartz Resonator

Abstract

The paper introduces novel dual-mode crystal oscillator (DMXO) that employs a standard 10-MHz 3rd overtone stress compensated (SC) quartz resonator. In the DMXO, the two overtones (c-modes) of the SC-cut resonator are simultaneously excited: the 3rd overtone and the 5th overtone. The ability of utilization of the two excited overtones to implement the resonator self-thermometry we have evaluated. The resonator self-temperature-sensing method eliminates temperature offset and lag effects, since no external temperature sensor is used [1], [2], [3]. Eventual applications of the DMXO with excitation of the two overtones include the stabilization of the SC-cut resonator's temperature as well as compensation for frequency shifts due to the variations of the ambient temperature.