The modulational method of the precision quartz-crystal oscillators and standards frequency stabilization

A new trend in self-contained (without the use of quantum discriminators) frequency stabilization of oven control crystal oscillators (OCXO) and frequency standards is proposed and discussed in this paper. The method developing the trend is called a modulational method and is based on the use of metrological properties of natural volume oscillations of a quartz resonator (double-frequency and multifrequency oscillators are not used in this case). The concept is given of dynamic modulation characteristics of a quartz-crystal oscillator and basic relationships are found for their calculation in the field of unharmonic resonances of a quartz-crystal resonator. The construction principles of frequency stabilization systems are formulated substantiating mathematically the essence of the method. Basic ratios of modulating signals are determined, the solution of which provides a slight influence of the modulation signal on the Allan variance and spectral density of a quartz-crystal oscillator. The results of the practical use of the method are considered with the view of constructing a quartz-crystal oscillator with the adaptation to the environment temperature and a quartz-crystal frequency standard with the long-term frequency instability compensation.