Frequency Detection of Weak Signal in Narrowband Noise Based on Duffing Oscillator

Duffing oscillator is used to detect weak signal in strong noise because traditional linear methods cannot work correctly in this situation. Normal Duffing oscillator is used under broadband noise because it is immune to broadband noise. But it is not suitable in narrowband noise because zero expectation of noise is damaged in narrowband noise. In this paper, the difference influence to Duffing oscillator between broadband noise and narrowband noise is analyzed and the resistance of Duffing oscillator to narrowband noise is proved. Then a new frequency detection method based on higher initial driving force amplitude and duration of cycle state is developed. Finally, the appropriate initial amplitude needed in this method is confirmed and the method is verified that it can detect frequency in narrowband noise by simulation.