The X-band Sampling Phase-locked Source

With the development of radar and wireless communications, the request for the local oscillator is higher and higher in the system. Seeking the oscillators with lower phase noise, better spectrum purity and higher frequency stability has become to the trend of development. At present, the prevalent frequency-divided PLL oscillators have obtained excellent performance, while sampling PLL oscillator has not been paid enough attention yet, the applications are limited in few special fields such as space exploration and measurement instrument. But that can't obliterate its advantages in phase noise performance. Otherwise, DRVCO is widely used in frequency synthesizers and microwave frequency sources because of its low phase noise, good frequency purity and high frequency stability. This subject is to realize a low phase noise frequency source using both sampling phase-lock technology and DRVCO.This paper researches the X-band frequency source using sampling phase-lock technology, compared with the traditional method known as "lower frequency sampling PLL+frequency multiplying", we realize it by locking the X-band oscillator directly. At the beginning it introduces the theory of sampling phase-locked loop and analyse its characteristics; then it gives the basic conception of DRVCO, the design process and simulation results of DRVCO by EDA software, also along with practical debugging and experimental data of DRVCO which is within our expectation; at last it expatiates on the design procrss of sampling phase-lock loop and makes the practical debugging of the whole PLL circuit including DRVCO. Eventually we realize the X-band sampling phase-locked frequency source with low phase noise. The results show that the output frequency is 10.7GHz, and phase noise is -98.1dBc/Hz@10KHz...