Hi all,
I'm trying to band pass filter (9Hz to 70Hz) an ECG signal which is sampled at 256 Hz using MATLAB's 'butter' followed by 'filter'. I'm using an order of 10, just being greedy about making the pass band near perfect. Filtering happens alright but the time domain filtered signal has sort of ringing effect.
I then reduce the order to 2 and perform the filtering and now the ringing is not there. What's this theoretically? Is this a manifestation of Gibb's phenomenon?
Any help would be greatly appreciated.
King regards, Pooja Narayan
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