High-stable quartz crystal oscillator - has low current consumption and uses controlled reactance compensating frequency drift due to temp. changes

摘要

The quartz crystal oscillator has a voltage-dependent reactance compensating for drift in frequency due to temperature changes. The operating temperature range is divided into intervals. A digital memory stores a tuning voltage for each interval. The tuning voltages are applied to the reactance to maintain the frequency constant. Each temp. interval has a storage address. Each address in the memory contains a digital word describing the tuning voltage associated with that interval. The storage address is a digital work obtained via an A/D converter (4) from a temp./voltage converter (13). The stored word is converted into an analog AFC voltage via a D/A converter (6). The temp. of the oscillator is measured at an appropriate place, i.e. at the crystal itself or at the oscillator casing.