生醫訊號處理概論
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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. 蔡哲霖 , 蔡政宏 , 林敬展 , 王沐凱 , 蕭景洲. 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

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生醫訊號處理概論 ECG

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Ecg

生醫訊號處理概論ECG

Electrocardiogram

蔡哲霖, 蔡政宏, 林敬展, 王沐凱, 蕭景洲


Ecg

ECG訊號之窗型函數(修改)

Window of ECG signals


Ecg l 512

ECG 補零點 ,強度、相位頻譜(L=512)


Ecg l 5121

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 l 1024

ECG 補零點 ,強度、相位頻譜(L=1024)

程式同上


Ecg l 2048

ECG 補零點 ,強度、相位頻譜(L=2048)

程式同上


Hamming window

原始訊號+Hamming window的頻譜


Hamming window1

切訊號+Hamming window的頻譜


Hamming window2

切訊號+Hamming window的頻譜

n1=length(cut_singal);

tc=(1:n1)/fs;

window1=hamming(n1); % Hamming window

addwindow1=(cut_singal).*hamming(n1); % 原始訊號乘上 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);

plot(tc,addwindow1);

title('原始訊號乘上 Hamming window');

axis tight;

xlim('auto');

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


Rectangular window

原始訊號+ Rectangular window的頻譜


Rectangular window1

切訊號+ Rectangular window的頻譜


Rectangular window2

切訊號+ Rectangular window的頻譜

window2=rectwin(n1); % Rectangular window

addwindow2=(cut_singal).*rectwin(n1); % 原始訊號乘上 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)

plot(tc,addwindow2);

title('原始訊號乘上 Rectangular window')

axis tight

xlim('auto');

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


Hann window

原始訊號+ Hann window的頻譜


Hann window1

切訊號+ Hann window的頻譜


Hann window2

切訊號+ Hann window的頻譜

window3=hann(n1); % Hann window

addwindow3=(cut_singal).*hann(n1); % 原始訊號乘上 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);

plot(tc,addwindow3);

title('原始訊號乘上 Hann window');

axis tight;

xlim('auto');

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


Blackman window

原始訊號+ Blackman window的頻譜


Blackman window1

切訊號+ Blackman window的頻譜


Blackman window2

切訊號+ Blackman window的頻譜

window4=blackmanharris(n1); % Blackman window

addwindow4=(cut_singal).*blackmanharris(n1); % 原始訊號乘上 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)

plot(tc,addwindow4);

title('原始訊號乘上 Blackman window')

axis tight

xlim('auto');

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


Triangular window

原始訊號+ Triangular window的頻譜


Triangular window1

切訊號+ Triangular window的頻譜


Triangular window2

切訊號+ Triangular window的頻譜

window5=triang(n1); % Triangular window

addwindow5=(cut_singal).*triang(n1); % 原始訊號乘上 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)

plot(tc,addwindow5);

title('原始訊號乘上 Triangular window')

axis tight

xlim('auto');

print('-f14', '-djpeg', '-r300', 'figure14');


Ecg

移動平均濾波器


M 5 10 20 50

M點比較5、10、20、50


Ecg

功率頻譜密度


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