I'm currently working on an article for ECG classification which it says that it has used elliptic bandpass filter with 0.5Hz and 50Hz critical frequencies to eliminate base-line and interference etc. First problem is that I think it should be stopband instead of bandpass, am I wrong?
the sampling rate of the signal is 300Hz.
[b, a] = ellip(10, 1, 100,[0.5 50]/150, 'bandpass') fvtool(b, a, 'Fs',300)
using this line, I apply the filter to my signal:
s_filtered = filtfilt(b, a, s)
and what it returns is all NaN! Am I doing something wrong?