Date: Sep 12, 2009 3:02 AM
Author: hans
Subject: zero phase low pass filter - filtfilt and IFIR

I'm looking for how to build a zero phase low pass filte. For example:
h = fdesign.lowpass(Fpass, Fstop, Apass, Astop, Fs);
Hd = design(h, 'ifir');
do a good job to easily create a filter operator, that works fine with filter. But there is a big offset when I use the "filter" command.
y = filter(Hd,time-series-data);

"filtfilt" ....
would avoid this offset, but doesn't like this filter operator.
So my question is how, create as easily such a low pass filter operator, accepted by "filtfilt" or how to create otherwise a zero phase low pass filter ?

hans