广义S变换及其时频滤波

首先从基于高斯窗函数的短时傅里叶变换推导出了一种广义S变换,分析了它与S变换及小波变换的关系,给出了它的运算实现.理论分析与仿真实验表明,广义S变换的时频窗口不仅能够随着频率尺度自适应地调整,而且克服了S变换中时窗函数的变化趋势固定不变的问题,使广义S变换在应用中具有更高的实用性和灵活性.利用其高质量的时频分布,在时频平面中设计时频滤波器,用于非平稳信号中特定信号分量的提取,展示了广义S变换在这一应用中的有效性.

Generalized S Transform and Its Time-Frequency Filtering

A Generalized S transform(GST)is derived theoretically from the short-time Fourier transform(STFT)with Gaussian window in the paper.The paper analyzes the relationship between GST and S transform(ST)and wavelet transform(WT).The numeri- cal implementation of GST is introduced later.The detailed analyses beth in theory and in the simulation indicate that the time-frequency window of GST can not only varying adaptively with the frequency,but also avoid the unchangeable and fixed varying pattern of the win- dow in ST.GST possesses adjustable time-frequency resolution with higher practicability and adaptability than ST in actual application. A time-frequency filter on the time-frequency plane based on its excellent time-frequency distribution is presented,which is used to ex- tract specific signal components and filter noise on the particular time-frequency plane.The simulation demonstrates that the filter based on GST is effective in signal extracting.