Patent ID: 9077281
Filing Date: 2015-07-07
Classification: H03B

Abstract:
1. An oscillator circuit, comprising: a crystal oscillator; a transistor, a base of the transistor is connected to the crystal oscillator; a first resonance circuit that is between an emitter of the transistor and a ground, the first resonance circuit having a first inductor and a first capacitor; a second resonance circuit that is between the emitter and the ground, the second resonance circuit having a second inductor and a second capacitor; and a third capacitor that is between the base and the emitter, wherein a first resonance frequency of the first resonance circuit is higher than a overtone frequency of a main oscillation of the crystal oscillator, a second resonance frequency of the second resonance circuit is lower than the overtone frequency of the main oscillation of the crystal oscillator, and the oscillator circuit has a negative resistance with a negative value at the overtone frequency of main oscillation of the crystal oscillator, and has the negative resistance with a positive value (i) at fundamental frequencies of the main oscillation and a sub oscillation of the crystal oscillator and (ii) at the overtone frequency of the sub oscillation of the crystal oscillator, the first resonance circuit is a parallel resonance circuit that contains the first inductor and the first capacitor connected in parallel between the emitter of the transistor and the ground, and the second resonance circuit is a serial resonance circuit that contains the second inductor and the second capacitor connected in series between the emitter of the transistor and the ground.