Frequency generator compensated as a function of at least one physical

Abstract

A frequency generator comprises a quartz crystal controlled oscillator subjected to at least one variable physical parameter such as temperature and has an arrangement for calibrating the frequency with respect to a standard signal with simultaneous compensation for variations of the physical parameter(s). This arrangement comprises a first set of selectable memories storing values to control the division ratio in a dividing chain. These memories are inscribed in a learning period for a few values of the physical parameter(s); simultaneously, digital values supplied by at least one probe, each value corresponding to a range of values of the parameter, are stored in a second set of memories associated with the probe(s). During operation of the generator, a comparator compares the actual digital value supplied by the probe(s) with the values stored in the second set of memories, to select the corresponding memory of the first set for controlling the division ratio, at least one probe sensitive to a physical parameter of the environment, and means associated with each said probe to form selection signals each selection signal representing various possible values of the parameter considered in one of several ranges of values of said parameter, said electrically-alterable memory being arranged in groups to be selected by said selection signals and each corresponding to one of said ranges to memorize values determining the division ratio to be adopted as a function of said signals, the generator further comprising calibration selecting means for connecting the output of the frequency comparator to the inscription input of the selected memory group.