Analytical Study On P Wave Of ECG Signal Based On Wavelet Transform And Its FPGA Implementation

Heart disease has a high incidence rate, sudden,strong and hidden illness, the mortalityrate has been high, and it has become an important disease to harm people’s health.Currently treatment for heart disease generally means the initial diagnosis, active prevention,timely treatment, so the ECG signal analysis research has the very high clinical value. ECGis a nonlinear weak signals highly affected by the environment, and often mixed with allkinds of noise, increasing the difficulty of analysis and diagnosis, and thus to improve theprecision and accuracy of the ECG analysis and detection system is very necessary.This paper studies the extraction of ECG P wave signal and the implementation ofdetection system on FPGA.For the extraction of P wave, i adopt double orthogonal quadratic B-spline wavelet asbasis function,4layer decomposition for ecg signal, the detection threshold MAX of Rwave and detection threshold MIN of P wave is determined based on the fourth layerwavelet coefficient, the detection of modulus maxima in the range of greater than MIN andless than MAX, so the positive and negative modulus maxima correspond to thezero-crossing point is the P wave peak.Since FPGA can be repeatedly programmed, high integration, and low powerconsumption, based on Altera’s Cyclone II family EP2C35F672C8core chip, Matlab,QuatusII software and VHDL, Verilog programming language is used to design P wavedetection module. Then referring to the R wave threshold method detection system, Pwave detection system is designed. P wave detection system is divided into two parts,including wavelet transform module and detection module, wavelet transform module is4layer decomposition of ECG signal, the low frequency coefficients of each layer is theinput of the next layer, resulting the wavelet coefficients on the4th layer; detection moduleusing the R wave detection threshold MAX and P wave detection threshold MIN, detected apositive and negative modulus maxima of P wave in the range of greater than MIN and lessthan MAX, according to the principle of wavelet singularity, zero-crossing point of thepositive and negative modulus maxima is the peak of P wave. In this paper, the simulationverification were carried on the48groups of ECG data, the analysis of experimental resultsby Matlab and QuatusII shows that this detection method can detect the P wave,and power consumption is lower, can run in real time.