频率均匀随机波动信号采样方式对谱分析的影响

Influence of the Sampling Method of Signal with Uniform Random Fluctuation Frequency on Spectrum Analysis

采用等时隙和等位置(相位)两种采样方法,对具有频率均匀随机波动的简单正弦信号进行了谱分析仿真对比.研究结果发现:采用等位置采样方法整周期采样,频率随机波动的大小不会产生谱分析误差;采用等时隙采样方法,频率随机波动的大小则会严重影响谱分析的结果.当频率随机波动水平较小时,会导致谱峰值的降低,当频率随机波动水平较大时,不仅会导致谱峰值的显著降低,而且会引起谱线漂移和许多虚假的谱线;通过提高等时隙采样方法的采样率,可以减小谱分析的误差.

The authors simulate the spectrum analysis of signals with uniform random fluctuation frequency by means of uniform time sampling and uniform space sampling. The results show that (1) For uniform space sampling, whether the frequency fluctuation level is high or small, there are no errors of spectrum analysis; (2) For uniform time sampling, the level of frequency fluctuation will greatly influence the results of spectrum analysis. If the level is low, it causes to drop the peak value of the spectrum. If the level is higher, it not only causes to drop the peak value and also to drift the spectrum line or to create more false spectrum lines. (3) Increasing the sampling rate of uniform time sampling, the errors of spectrum analysis can be reduced.