Signal generation and enhancement in a delayed system

We present an effective way to generate periodic signal in a delayed nonlinear system. The generated signal at a desired frequency can be enhanced greatly by a nonlinear term. Specifically, the amplitude of the generated signal can be much larger than that of the input signal by the cooperation of an appropriate time delay and a nonlinear term. When the primary, subharmonic or superharmonic resonance occurs, the desired signal is improved significantly. Further, the delay time that induces the resonance behavior can be analytically predicted. The result herein is different from the phenomenon of stochastic resonance or vibrational resonance observed in time delayed systems. Compared with the stochastic resonance or vibrational resonance, the method used here is much simpler and the desired signal can be generated in a much wider scope without changing the excitation. We believe that our results might be useful for the signal processing research.