filtfilt

(/tools/hpmatlab/toolbox/signal/filtfilt.m)

Function Synopsis

y = filtfilt(b,a,x)

Help text

FILTFILT Zero-phase forward and reverse digital filtering.
	Y = FILTFILT(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 described by the 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)

	After filtering in the forward direction, the filtered
	sequence is then reversed and run back through the filter.
	The resulting sequence has precisely zero-phase distortion
	and double the filter order.  Care is taken to minimize
	startup and ending transients by matching initial conditions.

	The length of the input x must be more than three times
	the filter order, defined as max(length(b)-1,length(a)-1).

	See also FILTER.

Cross-Reference Information

end            /tools/hpmatlab/toolbox/matlab/lang/end.m
error          /tools/hpmatlab/toolbox/matlab/lang/error.m
filter         /tools/hpmatlab/toolbox/matlab/datafun/filter.m
for            /tools/hpmatlab/toolbox/matlab/lang/for.m
if             /tools/hpmatlab/toolbox/matlab/lang/if.m
input          /tools/hpmatlab/toolbox/matlab/lang/input.m
isempty        /tools/hpmatlab/toolbox/matlab/ops/isempty.m
length         /tools/hpmatlab/toolbox/matlab/general/length.m
max            /tools/hpmatlab/toolbox/matlab/datafun/max.m
more           /tools/hpmatlab/toolbox/matlab/general/more.m
nargchk        /tools/hpmatlab/toolbox/matlab/lang/nargchk.m
nargin         /tools/hpmatlab/toolbox/matlab/elmat/nargin.m
ones           /tools/hpmatlab/toolbox/matlab/elmat/ones.m
return         /tools/hpmatlab/toolbox/matlab/lang/return.m
size           /tools/hpmatlab/toolbox/matlab/general/size.m

decimate       /tools/hpmatlab/toolbox/signal/decimate.m
demod          /tools/hpmatlab/toolbox/signal/demod.m