How to normalize and re-sample ECG signal?

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There is an ECG signal I want to normalize and re-sample at 200Hz. The signal is stored in first row of 16265m.mat
This recording is downloaded from website of PhysioNet . It's length is 10 seconds.

Accepted Answer

Star Strider
Star Strider on 20 Jan 2016
I have no idea what you mean by ‘normalize’. When I looked it up, it seemed relatively noise-free, and the baseline was smooth and not offset. The sampling frequency is 128 Hz, so the easiest way to resample it is to use the Signal Processing Toolbox resample function:
y = resample(x, 200, 128);
The resample function incorporates filtering of the resampled signal, so I prefer it for signal processing.
Star Strider
Star Strider on 24 Jan 2016
Edited: Star Strider on 25 Jan 2016
My pleasure.
I didn’t say that passband filtering is only appropriate for NSR. A 2-48 Hz passband is only appropriate to NSR (although you can use a 1-100 Hz passband). Quoting from my earlier Comment, ‘Irregular rhythms such as atrial fibrillation/flutter and ventricular tachyarrhythmias require a 1-100 Hz passband’
For bandpass filters, I usually define the passband and stopband as (using the current example):
Fs = 250; % Sampling Frequency
Fn = Fs/2; % Nyquist Frequency
Wp = [2 100]/Fn; % Filter Passband (Normalised)
Ws = Wp .* [0.5 1/0.5]; % Filter Stopband (Normalised)
Then follow the rest of the filter design procedure I linked to in my previous Comment. Either the Butterworth or Chebyshev Type II design will work. For EKGs, because the low frequency cutoff is close to 0, I prefer the Chebyshev with a 1 dB passband ripple and 10 dB stopband ripple. If you have problems getting a stable filter, increase the stopband ripple, perhaps to 25 dB or so.
I haven’t looked that the file you linked to. I only look at those attached to MATLAB Answers posts. Attach it using the ‘paperclip’ icon, and complete both the ‘Choose file’ and ‘Attach file’ steps.

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More Answers (1)

Image Analyst
Image Analyst on 20 Jan 2016
I haven't seen the signal, but how about using interp1()?

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