中文摘要：

根据时域连续有限冲激响应滤波器的原理设计了短窗窄带带通连续滤波器。该滤波器通过处理输入离散采样信号获得连续信号并抑制谐波噪声，改进了过零测频方法。对含有40％低频和高频谐波的500kV线路的故障电压进行仿真，试验结果表明当采样数据的窗长为4个工频周期时，该方法的测频误差小于0．05Hz，且延时仅为2个工频周期，其抗谐波、抗噪声和动态响应特性优于傅氏测频法，能够满足电子式互感器应用环境下实时测频的要求。

英文摘要：

Based on the principle of time-domain continuous finite impulse response （TCFIR） filter, a short window narrow band pass continuous filter is designed. The filter processes input discrete sampling signal to recover continuous signal and suppress harmonic noise, and the zero-crossing frequency measuring method is improved. By detecting the zero-crossing points of the continuous signal, the frequency of input signal can be calculated. The fault voltage with 40% low frequency harmonics and high frequency harmonics in 500 kV transmission line is simulated, test results show that under the data window of four power frequency periods the frequency measurement error of the proposed method is less than 0.05Hz and the time delay is only two power frequency periods, its anti-harmonic and noise-proof performance and dynamic response characteristic is superior to Fourier frequency measurement method, so the proposed method can meet the requirement of real-time frequency measurement under application environment of electronic instrument transducers.