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

The paper introduces novel dual-mode crystal oscillator (DMXO) that employs a standard 10 - MHz 3^rd overtone stress compensated (SC) quartz resonator. In the DMXO, the two overtones (c-modes) of the SC-cut resonator are simultaneously excited: the 3^rd overtone and the 5^th 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. 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.