一种改善频率合成器相位噪声的方法

A Method to Improve the Phase Noise of Frequency Synthesizer Based on PLL

在现代电子技术中,数字式频率合成器在通信、雷达等系统中得到了广泛的应用,其相位噪声直接影响到系统的整体性能。提出了利用变频锁相方法改善微波波段频率合成器的相位噪声,并进行了频域分析,给出了相应的环路滤波器的设计。最后的实验结果给出了变频锁相与直接锁相的频率合成器相位噪声比较,可以看出采用变频锁相方式的频率合成器的相位噪声有了很大的改善。

The synthesizer,based on digital phase-locked loop(DPLL),has wide yang application in modern electronic technology,shch as communication,radar etc.To reduce phase noise of microwave-band frequency synthesizer,the paper introduces the method of frequency conversion and phase-lock.Then,the compatible loop filter is designed.Finally,the results of experiments prove the phase noise of frequency conversion and phase-locked synthesizer is greatly lower than that of direct phase-ocked synthesizer.