System for evaluation of long-term stability of precision quartz crystal oscillators and results of its use

Long-term stability (aging) is one of the key parameters of quartz crystal oscillator. Approximation and time series prediction methods are used to evaluate it. An improved mathematical model which allows to evaluate quartz crystal oscillators from the point of longterm stability (aging) has been developed. Evaluation of the stabilization of aging process is used as the basis for the model´s algorithm. Basing on such model a software system has been developed. In process of it´s development different approximation functions were considered, including procedure of selection of suitable functions as well as their applicability, forecast accuracy and reliability. Also accuracy of forecast vs. duration of aging testing was studied. In this way the developed software system allowed to reach forecast of 5xE-9 accuracy for long-term stability per year. Also, what is practically important, the developed mathematical model allows to minimize possible human errors in evaluation of subject long-term stability of precision oscillators.