OSCILLATOR COMPRISING HIGH-FREQUENCY BANDPASS AMPLIFIER HAVING AN ADAPTABLE IMPEDANCE

摘要

The subject of the invention is a high frequency bandpass amplifier with adjustable impedance, in particular for a high frequency quartz resonator. It includes a transistor T connected in common base the emitter of which is connected to ground by a resistive divider bridge (R2, R1) the mid-point of which forms the input of the amplifier. The collector of the transistor (T) is connected to ground by a parallel circuit (LC) having one inductive side (L) and one capacitive side (C), a mid-point of the inductive side (L) or of the capacitive side (C) forming an output (s1 or s2) of the amplifier (A). The base of the transistor is biased and connected to ground via a capacitor (C3) ensuring common base operation in the pass-band of the amplifier. The invention also relates to an oscillator of transmission type including such an amplifier and a resonator (1) connected between the input (e) and one output (s1 or s2) of the amplifier (A). The frequency of resonance of the parallel circuit (LC) is equal to a chosen frequency of the resonator (1).