The spectrums of the complicated periodic signals include many harmonic componcnts and their amplitudes are fluctuant.Based on the feature.the period measurement by the harmonic wave method is proposed for the complicated periodic signal.One of the harmonic wave methods,FT-Abs-IFT(FAIF),iS the inverse Fourier transform(IFT)of the spectrum envelope.Then,the output signal is the convolution of the spectrum envelope time domain signal and the periodic impulse signal.The maximum of the convolution output is also the periodic impulse signal with constant amplitude under the noise-free condition,or fluctuant amplitude under the noise condition.The signal period(or frequency)can be obtained by the threshold detection and the period measurement.The simulation comparisons of the harmonic wave method and conventional methods(including homomorphic filtering,autocorrelation and average magnitude difference function(AMDF))are given.The result indicates that the FAIF has high measurement precision,lower error rate,and fine anti-noise performance for period measurement of the complicated periodic signal.%利用复杂周期信号频谱存在大量等间隔幅度起伏的谐波分量.提出了复杂周期信号的谐波法周期测量.谐波法之FT-Abs-IFT(FAIF)是周期信号频谱包络的反傅里叶变换,输出为频谱包络对应时域信号与周期冲击信号的卷积.其最大值是等幅度或起伏幅度(噪声条件下)的周期冲击信号,通过门限栓测和周期测量得到信号周期(或频率).最后通过与常用周期信号测量方法(同态滤波法、自相关法和AMDF)的仿真比较,表明对于复杂周期信号,谐波法之FAIF测量精度高,误差率低和良好的抗噪性能.
展开▼
