Weak Signal Detection by Duffing Oscillator Based on Improved Circle Zone Partition Method

To solve the complex computation and time consuming problem when determining the threshold value of chaos state of Duffing oscillator using Melnikov method and Lyapunov exponent method, improved circle zone partition (ICZP) method is presented to identify the phase state. ICZP method uses phase point percentage within the circle area to determine the phase state, which will change dramatically when the state changes from chaos to periodic state. This characteristic is used to perform weak signal detection. The radius of the circle zone may take different values, which makes it more flexible. The simulation shows that the detection accuracy can reach 89% even when the signal to noise ratio (SNR) gets as low as-60dB, which proves the validity of the proposed method.