Implementing a butterworth filter for ECG

I need Two filters of 10th order bandpass Butterworth filters with cut-off frequencies of 5Hz and 45Hz (narrow band) and 1Hz to 100 Hz (wide band) .

I tried this approach: https://in.mathworks.com/matlabcentral/answers/183972-implementation-of-narrow-band-pass-filter-butterworth

I am not really sure about how to do it for the ECG file : https://drive.google.com/file/d/1vXb3zY1hlKdXbn6cSvrm7O7OfL1Nx_qe/view?usp=share_link

This is a part of my project. Could someone help me understand how to do it.

Also attaching the expected outcome:

[Jan]

What about using the butter command? What is the frequency of the recorde signal?

Answer 1

[Santosh Fatale]

Hi Neha,

I understand that you want to create a filter with a tailored bandwidth for an ECG signal

There are several ways to do this, but it's important to remember that every filtering design function requires the sampling frequency at which the ECG signal is captured.

Refer to the bandpass and butter documentations for more details and illustrated examples.

Additionally, you can check out the "Signal Processing Onramp" course at the following URL.

https://matlabacademy.mathworks.com/details/signal-processing-onramp/signalprocessing

Answer 2

[Star Strider]

The approach you tried using that design procedure (thank you for referring to it) will work, and should work regardless of the MATLAB version/release you are using. I would use the procedure in the Comment that uses the zp2sos function, since that will produce a better and more stable result. It will work with either the Butterworth or elliptic design functions.

Use the filtfilt function to do the actual filtering of the ECG signal using the filter that you designed.

.