In order to effectively detect ship shaft-rate(SR) electric signal

the wavelet modulus maximum's scale-distribution characteristics of the measured SR electric signal is analyzed.Based on the analysis result that the intensity and distribution density of noise's wavelet modulus maximum decreases along the scale

a detecting algorithm was proposed to extract the modulus maximum power in the highest scale as feature value to detect the target glidingly.As the wavelet reconstruction is avoided in the de-noising process using wavelet modulus

the detecting algorithm proposed can be easily achieved by hardware.In the end

the effectiveness of the proposed method is verified both using measured data and simulated data

and simultaneity compared with the detecting algorithm based on wavelet packet entropy.The verified result shows that the detecting algorithm provides a better detecting performance

and it can keep detection rate of 79% when the SNR is -10.8dB.