Low pass filter returns NAN

hi, I'm trying to use a Low pass filter for my signal data. I have following code for the same

CutF = 25
  step = 0.001  
  fNorm=CutF/(1/(2*step));    
      [b,a]=butter(10,fNorm,'low');
      C1=filtfilt(b,a,Data(:,(i-1)*6+1));

Now this works for some of my data set but for some it returns NAN. I cant figure out why it works in some case and not in others.

thanks in advance

[Honglei Chen]

Did you check if your input contains NaN?

[the cyclist]

Would it be possible for you to include a very small example of "Data" that will allow us to run your code, and exhibits the problem?

Answer 1

[Jan]

The algorithms of filter and filtfilt do not contain magic sources of NaNs. I'd be very surprised, if the NaNs do not exist in the inputs already, or at least Infs. Test this:

all(isfinite(Data(:))

[Cameron]

You are not the only one with this problem see link below

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