adpcm.m

Adaptive Difference PCM code in matlab

function st = dpcm(s, bitsize, lpclen)
%[s,fs]=wavread('bye441');  %read .wav file
%lpc and encoder-decoder parameters
% lpclen=20;
% bitsize=input('bitsize=');
% fprintf('\nPlease wait... data length is %i\n',length(s))
%LPF parameters
% tap=100;
% cf=.15;
 
% DPCM with predictor
[Q,b, ai] = dpcm_encoder_linpredic(s, lpclen, bitsize);
[st]=dpcm_decoder_linpredic(b, ai, bitsize);
% Sa=LPF(tap,cf,st);
%[xa,ya]=stairs(tn,Sa);
 
figure
subplot(3,1,1):plot(s,'r');
ylabel('amplitude');
title('DPCM with predictor (red:input, green:decoder output, blue: LPF output)');
subplot(3,1,2):plot(st,'g');
ylabel('amplitude');
grid