Piezoelectric oscillator for communications applications, has Colpitts oscillator circuit with piezoelectric resonator and oscillation transistor

摘要

The arrangement includes a Colpitts oscillator with a piezoelectrc resonator and an oscillation transistor. The output is supplied to an amplifier, and the amplifier output is rectified. The rectifier output is fed back to a base of the oscillation transistor to hold the oscillation output level constant. The base bias voltage is adjusted so that the oscillation transistor is offset to a working point near the saturation region. A feedback current is supplied from the rectifier to the oscillation transistor base to maintain the working point to the saturation region, when the saturation output level is high. The working point is distanced from the saturation region when the oscillation output level is low.