An error in filtfilt

load P01EC1
sig= P01EC1(:,:)';

sig is 4x30800 double

When I did like this:

subs_cd1_alpha=filtfilt(b,a,sig);
I’ve got this error:
Error using filtfilt>getCoeffsAndInitialConditions (line 228)
Data length must be larger than 18 samples.

Error in filtfilt>efiltfilt (line 129)
[b2,a2,zi,nfact,L] = getCoeffsAndInitialConditions(b,a,Npts);

Error in filtfilt (line 89)
y=efiltfilt(b,a,x);

Error in subject_01_EC1Ac (line 287)
subs_cd1_alpha=filtfilt(b,a,sig);

And

In this case:

for i=1:4
    subs_cd1_alpha=filtfilt(b,a,sig(:,i));
end

This error happened:
Error using filtfilt>getCoeffsAndInitialConditions (line 228)
Data length must be larger than 18 samples.

Error in filtfilt>efiltfilt (line 129)
[b2,a2,zi,nfact,L] = getCoeffsAndInitialConditions(b,a,Npts);

Error in filtfilt (line 89)
y=efiltfilt(b,a,x);

Error in subject_01_EC1Ac (line 285)
subs_cd1_alpha=filtfilt(b,a,sig(:,i));

Answer 1

[Bruno Luong]

Don't tranpose your date if you want to filter along the long dimension

sig= P01EC1(:,:);