Low temperature quartz crystal oscillator fast warm-up SAW oscillator

The objectives of this program are to: evaluate the frequency instabilities of quartz crystal resonators as a function of temperature and Q-factors, show the feasibility of low temperature quartz oscillators, and determine the dynamic thermal behavior of SAW quartz oscillators and the precise crystal orientation and wave propagation direction with minimized sensitivities. The contribution of impurities to finite Q-factor of quartz resonator at low temperature is studied, both theoretically and experimentally. Short and long term frequency stability measurements are performed at low temperature with a dual crystal passive system adapted to liquid helium. Simultaneously temperature in the bath is controlled and correlation between frequency and temperature fluctuations is studied. Dynamic temperature sensitivity of SAW oscillators is calculated by using a one dimensional thermal model. Crystal cut orientation and wave propagation direction are exploded, at zero first order static temperature coefficient, in search of minimized dynamic thermal sensitivities.