13 Nov 2012
This is a code to demonstrate CELP codecs of bitrate 9.6kbps and 16kbps.
function ac = lpcweight(ar,c)
% lpcweight --> LPC based perceptual weighting filter.
% ac = lpcweight(ar,c)
% The function takes the LP coefficients, ar = [1 -a(1) ... -a(M)],
% and the parameter, c, as inputs, and returns the coefficients of
% the filter function A(z/c) in the vector ac.
% Linear predictor order.
M = length(ar);
% The i'th coefficient of A(z/c) is given by ar(i)*c^(i-1).
ac = ar;
ci = c;
ac(i) = ar(i)*ci;
ci = ci*c;