Research on a double phase-locked loop frequency synthesizer

The frequency synthesizer has important influence on the performance of modern radar.The design of a S-band digital phase-locked loop frequency synthesizer is described in detail in this paper.The master-slave double phase-locked loop design is applied in the frequency synthesizer.The frequency-division coefficient of the loop is reduced and the problems such as phase noise,spectrum purity,frequency hopping in large range,and miniaturization are well resolved.The frequency synthesizer is characterized by low cost and high comprehensive performance.The phase noises of the main and assistant loops are analyzed and calculated,and the experimental results are given.The synthesizer has been applied in a modern Doppler radar successfully.