Thermal effects on frequency fluctuations in quartz crystal oscillators

This paper deals with the correlation between the thermal behavior of the oven and phase fluctuations of the oven-controlled oscillator. Experiments to measure the thermal stability of the oven control are presented. A conventional oscillator equipped with a LD-cut quartz resonator is first used in the B-mode in order to measure the temperature fluctuations of its oven. The same resonator is then used in its C-mode to record the phase fluctuations of the oscillator. Obviously, the quartz resonator is previously characterized in terms of temperature dependence. Frequency-temperature curves are given for B and C modes in order to obtain the thermal sensitivity of the resonator. In a first step, thermal fluctuations of the oven are obtained through the measurement of the B-mode oscillator frequency in the time domain, by means of Allan standard deviation. Then, it can be translated into C-mode frequency fluctuations using the thermal sensitivity of the resonator C-mode. At least, power spectral density of phase fluctuations of such an oven-controlled oscillator is related to temperature sensitivity and discussed.