** Digital filter. **

** Y = FILTER(B, A, X) filters the data in vector X with the **

** filter described by vectors A and B to create the filtered **

** data Y. The filter is a "Direct Form II Transposed" **

** implementation of the standard difference equation: **

** **

** **

** y(n) = b(1)*x(n) + b(2)*x(n-1) + ... + b(nb+1)*x(n-nb) **

** - a(2)*y(n-1) - ... - a(na+1)*y(n-na) **

** **

** **

** [Y,Zf] = FILTER(B,A,X,Zi) gives access to initial and final **

** conditions, Zi and Zf, of the delays. **

** **

** **

** See also FILTFILT in the Signal Processing Toolbox. **

** **