一种抗频移的高精度电气信号计算方法研究

Method of High Accuracy Electrical Signal Processing Based on Anti-Frequency Shift Technology

信号的频率偏移给固定采样率下的采样数据精确计算带来困难,而一般数字滤波器带来的幅值衰减和相位偏移对高精度信号计算带来问题。文章从固定采样率下采样数据的信号处理出发,分析信号的频率偏移、数字滤波器的设计对信号计算的影响,并提出一种高精度的信号计算方法。该方法综合FIR滤波器、工频频率测量技术、零相移数字滤波器等信号处理方法以克服谐波和噪声的影响,并采用基于Hanning窗函数的FFT插值算法克服频率偏差的影响。为检验该方法的设计精度,利用5720A多功能校准器,精度达到万分之一,和BHE型标准调相仪,精度在1″之内等高精度的仪器,提出一种幅值和相位精度的检定方案。检定结果表明本文设计的信号计算方法在额定运行状态下幅值测量精度能够达到0.01%,相位测量精度在15″以内。

Asynchronous sampling of input signals brings difficulties to accurate calculation of system parameters, and amplitude attenuation and phase shift of digital filters also bring the same problems as well. So this paper proposes a novel high-precision signal processing method based on analyzing the impact of frequency shift, digital filter with digital signals processing technology. Integrating some digital signal processing technologies, including FIR filter, frequency measurement, and zero-phase digital filter, to overcome the effects of harmonics, the method uses FFT interpolation algorithm of Hanning window to overcome the impact of the frequency shift. The accuracy test scheme of the method is proposed based on FLUKE 5720A, a multifunction calibrator with an accuracy of one per ten thousand, and BHE-I type, the phase-modulation instrument with an accuracy of phase 1＂. Results of accuracy tests and simulation tests show that the method can reach the accuracy of 0.01% in magnitude and 15＂ in phase.