CMOS环形振荡器相位噪声仿真分析

Simulation and analysis of CMOS ring oscillators phase noise

通过分析环形振荡器的一阶线性模型,得到环形振荡器相位噪声的功率谱的近似表达式。为了分析相位噪声的时域特征,引进谱综合法,并利用快速傅立叶变换(FFT),求出了相位噪声的时域采样信号。并进一步分析了相位噪声的采样信号的自相关序列,发现相位噪声是一个长记忆过程,具有非平稳的特征。采用Yule-Walker功率谱估计法,分析了相位噪声的采样信号的功率谱密度,其仿真结果进一步验证了理论分析结果。

The power spectral expression of phase noise in ring oscillator is obtained by analyzing the one order linear model of ring oscillator. In order to analyze the character of phase noise in time domain, spectral synthesis method is introduced. The sampling signal of phase noise in time domain is obtained by fast Fourier transform （FFT） algorithm . The autocorrelation sequence of the sampling signal of phase noise is analyzed, which implies that the phase noise is a long memory process with nonstable character. And then the power spectral density of sampling signal of phase noise is analyzed by Yule-Walker power spectral density estimation method. The simulation result validates the theoretically analyzed result further.