tired.m

用matlab设计FIR和IIR滤波器的设计函数与例程

%实时检测QRS复波，采样率1000HZ
%filename='D:\数据\刘新光.mat';
%实时检测QRS复波，采样率1000HZ
clear;
fs=1000;
filename='D:\硕士论文数据\北理工数据\BioSignal_mat\蔡刿.mat';
load(filename);
ecgdata=data(:,2);
ecg=ecgdata(1:2*fs);
%-------------------------------------
t=0.9;w=2*pi*50/fs;
b1=[1,-2*cos(w),1]; a1=[1,-2*t*cos(w),t*t];%50Hz窄带陷波器
ecgdata_denoise=filter(b1,a1,ecg);
figure(1);subplot(2,1,1);plot(ecg(1:2*fs));title('orignal');grid on;
subplot(2,1,2);
plot(ecgdata_denoise(1:2*fs));title('50Hz窄带陷波器');grid on;
 figure(2);
 freqz(b1,a1,512,fs);title('50Hz窄带陷波器');

M=fs/50;
%------------lp,截至频率11HZ，延迟5个采样点，增益36
b2=[1 zeros(1,M-1) -2 zeros(1,M-1) 1];
a2=[1 -2 1];
ecgdata_denoise1=filter(b2,a2,ecgdata_denoise);
 figure(3);subplot(2,1,1);plot(ecgdata_denoise(1:2*fs));title('50Hz窄带陷波器');grid on;
subplot(2,1,2);
plot(ecgdata_denoise1(1:2*fs));title('低通滤波');grid on;
 figure(4);
 freqz(b2,a2,512,fs);