软件实现同步采样的频域误差分析

Frequency-domain error analysis of synchronous sampling realized by software

分析了同步误差产生的原因,导出同步误差引起信号频域分析误差的计算模型,并以标准正弦波信号、含有谐波干扰的信号(电力系统中的实际电流、电压信号)为例,在频域中对软件实现同步采样的误差进行仿真计算与分析.结果表明,由于采样测量中存在同步误差,使信号频率发生偏移,信号幅值减小,信号泄漏增加,降低了微弱信号的分辨率.

The causes of synchronous error were analyzed, and calculation models for the error of signal frequency-domain analysis induced by synchronous error were worked out. The frequency-domain calculation and analysis of the error of synchronous sampling by software were carried out based on a study of standard sine signal and sine signal with harmonic disturbances （the actual current and voltage signal in the power system）. Simulated results show that synchronous error in sampling causes the error in frequency-domain analysis of signals, decrease of amplitude and increase of leakage of signals. These factors including the deviation of signal frequency and reduce the resolution of weak signals.