Application of Morlet Combined Wavelets to Signal Process of Torpedo Electromagnetic Fuze

Both infinite impulse response(IIR) and finite impulse response(FIR) digital filters are deficient in filtering the received signals of torpedo electromagnetic fuze. We therefore present a method to construct a band pass filter with Morlet combined wavelets. By appropriately selecting wavelet parameters, the band pass filter is designed with zero phase shift, flat-topped pass-band, and rapid attenuation in transition band. Moreover, the signal envelope can be demodulated by making use of the feature that the imaginary part of the combined wavelets is the Hilbert transform of its real part. According to the representative models of electromagnetic fuze target signal and ambient noise, simulation analysis is carried out in Matlab simulation environment. The results show that our method can effectively eliminate the ambient noise in a low signal to noise ratio(SNR) condition down to-5 dB, and can accurately achieve target signal envelope.