OSCILLATOR CHARACTERISTIC AUTOMATIC COMPENSATOR, CHARACTERISTIC AUTOMATIC COMPENSATING METHOD, CHARACTERISTIC AUTOMATIC COMPENSATING PROGRAM, AND POSITION MEASURING SIGNAL RECEIVER

摘要

An oscillator having a given characteristic in the relation between a physical quantity and the drift value of the oscillation frequency. The variation of the characteristic is adaptively corrected, and the oscillation frequency drift value can be always deduced. The oscillator comprises a reference oscillator (17) for outputting an oscillation signal the oscillation frequency of which is dependent on temperature, a TCO (16) for detecting the temperature of the reference oscillator (17), characteristic determining means for measuring the oscillation frequency drift value of the reference oscillator (17) while changing the temperature and determining in advance the coefficient of an approximate expression representing the temperature frequency characteristic in the relation between the temperature measured by the TCO (16) and the oscillation frequency drift value, a memory (13) for storing the determined coefficient of the approximate expression, drift value deducing means for deducing the drift value on the basis of the measured temperature, and characteristic updating means for updating the coefficient of the determined approximate expression according to the measured drift value and the then measured temperature.