Error with Filtfilt line 124 and 67.

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Ambra
Ambra on 27 Aug 2014
Commented: Geoff Hayes on 28 Aug 2014
Hi everybody, I'm analyzing an EEG but I've encountered some problems. I apply this part of a script:
CR1 = readCRTsd('CSC10.ncs');
dataEEG = resample(Data(CR1), 1, 16);
timeEEG = linspace(StartTime(CR1), EndTime(CR1), length(dataEEG))';
EEG6=tsd (timeEEG,dataEEG);
filelist = dir('CSC*.ncs');
filenames = {filelist.name};
xl=xlim;
EEG6S2 = Restrict(EEG6, xl(1)*10000, xl(2)*10000);
plot(Range(EEG6, 'sec')-StartTime(EEG6, 's'),Data (EEG6)* 3.05185e-005); % plot in mV% ;
Fs = 1 / median(diff(Range(EEG6, 'sec')));
d = fdesign.bandpass('N,F3dB1,F3dB2', 10, 100, 300, Fs);
H = design(d, 'butter');
EslRipples = filtfilt(H.sosMatrix, H.ScaleValues, Data(EEG6S2));
  • * But when I arrive to EslRipples I get this error:
*Error using filtfilt>getCoeffsAndInitialConditions (line 124)
Data must have more than 6 samples.
_ * _ *Error in filtfilt (line 67)
[b,a,zi,nfact,L] = getCoeffsAndInitialConditions(b,a,Npts);
Error in loopcorrelogramandCo (line 13)
EslRipples = filtfilt(H.sosMatrix, H.ScaleValues, Data(EEG6S2));* *
(loopcorrelogramandCo is my script)** _ * _
What does it mean concretely and how may I solve it? Thanks in advance!
  3 Comments
Ambra
Ambra on 28 Aug 2014
Edited: Ambra on 28 Aug 2014
size(Data(EEG6S2))
ans =
1 1
I've tried also to check xl(1) and xl(2):
xl(1)
ans =
0
xl(2)
ans =
1
But xl derives frome xlim... Is this a problem of the resampling?
Geoff Hayes
Geoff Hayes on 28 Aug 2014
Ambra - presumably the above code is within a function or script, so you should put a breakpoint at the first line, and step through the code and check the variables. What is the size of CR1, and of the others? Try to figure out whether you have enough samples to begin with, and at what point they are reduced to 1.

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