跳频信号的时频分析

Time-frequency Analysis of Frequency-Hopping Signals

时频分析是跳频信号检测的重要工具之一,获得清晰的时频图是跳频信号参数估计和信号分选的前提。使用各种时频分析工具,包括线性时频表示、二次时频分布、重排类二次时频分布、不同时频分布组合方法对跳频信号进行仿真,在时频聚焦性和抑制交叉项干扰两个方面综合比较各分布之性能,寻找适合针对多个跳频信号同时存在的时频分布,并给出了各分布性能的定量评价。仿真结果表明,谱图、平衡伪Wigner-Ville分布(SP-WVD)、重排类时频分布以及线性与非线性时频分布组合方法能获得较清晰的时频图。

The time-frequency analysis is a powerful tool for the detection of frequency-hopping（FH） signals. A clear time-frequency representation is the precondition of the parameter estimation and the separation of FH signals. To find the appropriate distribution for multiple FH signals, many time-frequency representations, include linear time-frequency representation, bilinear time-frequency distribution, bilinear time-frequency distribution by the reassignment method, different time-frequency analysis synthesis method are simulated and analyzed on the performance of time-frequency concentration and suppression cross-term interference. The results indicate spectrogram, smoothed pseudo WVD （SPWVD） , reassignment distribution, nonlinear and linear time-frequency analysis method synthesis can obtain clear representations.