Research on Time-Frequency Analysis Algorithm of Heart Sound Signal in Smart Clothing

Aimed at the heart sound signal acquired by new type FBG heart sound sensor in smart clothing, time-frequency algorithm is proposed to analyze the first heart sound (s1) and the second heart sound (s2). Firstly, db4 wavelet is used to decompose the signal which is reconstructed according to different signal contained in different layers of component after compulsory denoising. The reconstructed signal is then transformed into analytical signal by Hilbert transform, and negative frequency components are eliminated. Finally, analytical signal is analyzed by Wigner-Ville distribution, and the parameters of s1 and s2 are obtained. Analysis results show that the method can get the frequency range, duration time and amplitude of s1 and s2 accurately.