Oscillator with low noise in the region of its oscillation frequency

摘要

The invention relates to an oscillator with low frequency modulation noise around its carrier frequency. In an oscillator operating by saturation of the current of an amplifier, the low-frequency noise inherent in the semiconductor amplifying device is converted into frequency modulation noise around the carrier. To reduce this FM noise, the oscillator according to the invention includes an amplifier 7 operating in the linear regime, and a negative feed-back loop in which a limiter 8 operates in the non-linear regime. The limiter 8 is linear and comprises two Schottky diodes 16, 17 mounted head-to-tail. A microband filter 11 and dielectric resonator 12, with high quality factor Q reduces the thermal noise of the amplifying transistor 7. Application to microwave frequency oscillators within the band from 1 to 60 GHz. <IMAGE>