noise reduction of ecg signals matlab code

[ashwiniashok]

% Create one period of ECG signal
x = ecg(500).';
y = sgolayfilt(x,0,5);
Fs = 1000;
[M,N] = size(y);

% Initialize scopes
TS = dsp.TimeScope('SampleRate',Fs,...
'TimeSpan',1.5,...
'YLimits',[-1 1],...
'ShowGrid',true,...
'NumInputPorts',2,...
'LayoutDimensions',[2 1],...
'Title','Noisy and Filtered Signals');

% Design lowpass filter
Fpass = 200;
Fstop = 400;
Dpass = 0.05;
Dstop = 0.0001;
F = [0 Fpass Fstop Fs/2]/(Fs/2);
A = [1 1 0 0];
D = [Dpass Dstop];
b = firgr('minorder', F, A, D);
LP = dsp.FIRFilter('Numerator',b);

% Design Highpass Filter
Fstop = 200;
Fpass = 400;
Dstop = 0.0001;
Dpass = 0.05;
F = [0 Fstop Fpass Fs/2]/(Fs/2); % Frequency vector
A = [0 0 1 1]; % Amplitude vector
D = [Dstop Dpass]; % Deviation (ripple) vector
b = firgr('minord', F, A, D);
HP = dsp.FIRFilter('Numerator', b);

% Stream
tic;
while toc < 30
x = .1 * randn(M,N);
highFreqNoise = step(HP,x);
noisySignal = y + highFreqNoise;
filteredSignal = step(LP,noisySignal);
step(TS,noisySignal,filteredSignal);
end

% Finalize
release(TS)