The application of chaotic oscillator in detecting weak resonant signal of MEMS resonator.

In this paper, a detection model of a chaotic oscillator is applied in the weak signal detection of an electrothermal excitation MEMS resonator, and the maximum Lyapunov exponent is used to obtain the threshold value and monitor the motion transition of a detection system. The phase drift caused by the electrothermal excitation is studied theoretically and experimentally, and according to the results of above study, the phase of a reference current signal is set to eliminate the phase when the resonator is in a resonant state. Then a new detection algorithm is proposed to detect the resonant signal. The simulation experiment on a weak signal under different magnifications and different levels of noises is conducted, after the impact of the quality factor Q of a resonator on detection results is analyzed. Finally, experiments on the output signal of a detected sensor sample are carried out by a proposed algorithm. Simulation and experiment results show that the detection model can effectively detect the weak signal and accurately obtain the resonant frequency, and it is immune to the noises.