filtfilt function doesnt work

i have designed a 4th 0rder IIR elliptical filter, I wanted to remove the phase delay in it. i used filtfilt(d.sosMatrix,d.ScaleValues,input). The result gives NaN values?

please help...

Answer 1

[Cameron]

Not the only one with this problem. see the link below

http://www.mathworks.com/matlabcentral/answers/62553