Cut Crystal Resonator Research Articles

Ultralow Phase Noise 10-MHz Crystal Oscillators

This paper describes the design and implementation of low phase noise 10-MHz crystal oscillators [using stress compensated (SC) cut crystal resonators] which are being used as a part of the chain of a local oscillator for use in compact atomic clocks. The design considerations and phase noise measurements are presented. The design includes a low-noise transformer coupled differential amplifier, spurious resonance rejection filter, and electronically tuned phase shifter. Phase noise measurements demonstrate a performance of -122 dBc to -123 dBc/Hz at 1-Hz offsets and -148 dBc/Hz at 10-Hz offsets. The phase noise at 1-Hz offset is very similar to the phase noise produced by the low-noise version of a doubled 5-MHz BVA resonator-based oscillators (model number 8607) previously produced by Oscilloquartz. The noise floor of the oscillators presented in this paper is around -161 dBc/Hz. These designs can be used as the reference oscillator to control the timing of many modern electronics systems.

Temperature-compensated crystal oscillator simulation in stress compensated cut crystal resonators

Traditional quartz crystal frequency references include a large, power-starving, oven-controlled crystal oscillator (OCXO), which base stations favor because of their excellent stability. We simulated a temperature-compensated crystal oscillator (TCXO) in the stress-compensated cut (SC-cut) resonator using the C and B mode frequencies. Power-conscious base-station manufacturers use the compensation circuit combination of TCXOs. The large frequency change in the B mode will be employed in temperature compensation for the C mode. First, we examined the circuit that could drive the C mode and B mode by simulation at the same time.