基于窗函数设计的跳频信号时频分析

Time-frequency analysis of frequency-hopping signals based on window function design

基于抑制交叉项,提高信号分量时频聚集性的考虑,提出一种基于可调窗函数进行平滑伪维格纳分布核函数设计的时频分析方法:在保持平滑伪维格纳分布中核函数宽度不变的情况下,根据核函数自项和互项能量分布比,通过调整窗函数中的扩展因子改变核函数形状,获取跳频信号优良的时频表示。与固定窗函数方法相比,应用该时频表示,可以有效估计跳频信号的时频参数,而且有很好的抗噪声干扰能力。

To suppress the cross-term and increase aggregation of time-frequency signal components, a new timefrequency analysis method for frequency-hopping signals was proposed based on adjusted window for kernel function design of Smoothed Pseudo Wigner Ville Distribution （SPWVD）. According to the auto-term energy and cross-term energy ratios in the time-frequency plane, the shape of kernel function of SPWVD was adjusted through changing spread factors of window function to obtain excellent time frequency representation in fixed-kernel width. Compared with the fixed window function, using the proposed time frequency representation, time frequency parameters of frequency hopping signals can be estimated efficiently and good noise immunity can be got.