The time-frequency characteristics of pulse propagation through plasma

In this paper, propagated δ pulses through different distance of plasma are calculated, and their time-frequency characteristics are studied using CWD (Choi-William distribution). It is found that several horizontal spectra appear at early arrival time like discrete spectrum, at last time a hyperbolic curve lies in the time-frequency spectrum which corresponds to the frequency-group delay curve of plasma. To understand the time-frequency, the property of a signal is helpful for obtaining the plasma parameters.