CONTROLLED FREQUENCY-MULTIPLYING CRYSTAL OSCILLATOR Russian patent published in 1999 - IPC

FIELD: radio engineering; self-excited crystal oscillators producing high-stability frequency-modulated waves. SUBSTANCE: oscillator incorporates provision for doubling frequency of crystal-cavity first mechanical harmonic. Main part uses Colpitts oscillatory circuit arrangement with varicap introduced to produce frequency-modulated waves. Oscillator collector circuit producing second harmonic possesses zero impedance at first harmonic which maintains self-excited oscillations and stable oscillations at first harmonic thereby reducing impact of load impedance on oscillation frequency. Oscillator can dispense with additional buffer stages when used as part of multistage radio transmitter and can be directly connected to antenna, if necessary, without apprehending noticeable effect of its mismatch on pitch frequency. EFFECT: reduced dependence of oscillator frequency on load impedance. 1 dwg