Dynamic Characteristics of Single-frequency Signal after Modulated by Feedback Control System

In order to study the dynamic characteristics of the single-frequency signal through the nonlinear control system, the system control mode, the outer excitation patterns of the model and the amplitude are investigated by using the methods of the nonlinear dynamical analysis. The time-domain diagram, power spectrum, phase diagram and the largest Lyapunov exponent obtained from the process of the signal propagate through different control module are given. The researches on different control systems demonstrate that： after single-frequency signal goes through the nonlinear controller, it is still non-chaotic although the output contains more frequency components; but with the feedback and the external perturbation, the output is a continuous broadband spectrum and the result shows that there is chaos. The energy of the input signal reduces with some appropriate parameters. Therefore, the control system of the nonlinear feedback is a good way to broaden the spectrum of output with inputting a single-frequency signal.