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# 生醫訊號處理概論 ECG - PowerPoint PPT Presentation

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### 生醫訊號處理概論ECG

Electrocardiogram

### ECG訊號之窗型函數(修改)

Window of ECG signals

ECG 補零點 ，強度、相位頻譜(L=512)

ECG 補零點 ，強度、相位頻譜(L=512)

L=512; % 補零點，EX:訊號切100~200 =>總點數為100，故補比100大的數，須為2的次方

fs=1024; % 取樣頻率

t=1/fs; % 取樣週期

m=0:L-1; % 頻率點數

fd=1/(L*t); % 頻率間隔

fy=m.*fd;

fft_cut_singal=fft(cut_singal,L);

figure(2)

subplot(411)

plot(cut_singal);

axis tight;

title('切訊號');

subplot(412)

plot(fy,fft_cut_singal);

axis tight;

title('切訊號 補零點 L=512 FFT ');

subplot(413)

plot(fy,abs(fft_cut_singal))

axis tight

title('強度頻譜')

subplot(414)

plot(fy,angle(fft_cut_singal))

axis tight%貼緊視窗

title('相位頻譜')

print('-f2', '-djpeg', '-r300', 'figure2');

ECG 補零點 ，強度、相位頻譜(L=1024)

ECG 補零點 ，強度、相位頻譜(L=2048)

n1=length(cut_singal);

tc=(1:n1)/fs;

window1=hamming(n1); % Hamming window

figure(10);

subplot(121);

plot(window1); % Hamming window的頻譜圖

title('Hamming window的頻譜圖');

axis tight;

subplot(122);

title('原始訊號乘上 Hamming window');

axis tight;

xlim('auto');

print('-f10', '-djpeg', '-r300', 'figure10');

window2=rectwin(n1); % Rectangular window

figure(11)

subplot(121)

plot(window2); % Rectangular window的頻譜圖

title('Rectangular window的頻譜圖')

axis tight

subplot(122)

title('原始訊號乘上 Rectangular window')

axis tight

xlim('auto');

print('-f11', '-djpeg', '-r300', 'figure11');

window3=hann(n1); % Hann window

figure(12);

subplot(121);

plot(window3); % Hann window的頻譜圖

title('Hann window的頻譜圖');

axis tight;

subplot(122);

title('原始訊號乘上 Hann window');

axis tight;

xlim('auto');

print('-f12', '-djpeg', '-r300', 'figure12');

window4=blackmanharris(n1); % Blackman window

figure(13)

subplot(1,2,1)

plot(window4); % Blackman window的頻譜圖

title('Blackman window的頻譜圖')

axis tight

subplot(1,2,2)

title('原始訊號乘上 Blackman window')

axis tight

xlim('auto');

print('-f13', '-djpeg', '-r300', 'figure13');

window5=triang(n1); % Triangular window

figure(14)

subplot(1,2,1)

plot(window5); % Triangular window的頻譜圖

title('Triangular window的頻譜圖')

axis tight

subplot(1,2,2)