fg_08_25.m

英文书《Digital Signal Processing with Examples in MATLAB》附带的MATLAB实例

% fg_08_25     Predictive compression - 
N=6; K=40000;
% Read the signal.
fid=fopen('signal_2.txt');
f=fscanf(fid,'%7d%8d%8d%8d%8d%8d%8d%8d%8d%8d\n',K+5000);
fclose(fid);
d=f(5001:K+5000);

% Generate the prediction error, e.
f=[0; d(1:K-1)];
Rff=autocovar_mat(f,N);
rfd=crosscovar(f,d,N);
b=Rff\rfd;
e=d-filter(b,1,f);
% Recovery - generate d hat.
dhat=filter(1,[1 -b'],e);

% Plot dhat and d-dhat.
sp_fig(1);
subplot(2,1,1);
set(gca,'fontname','times','fontsize',16);
dhat=dhat(1:K);
line([0:K-1]/20,dhat,'color','k'); grid on;
ylabel('Reconstructed signal');  title('T=.05 s');

subplot(2,1,2);
set(gca,'fontname','times','fontsize',16);
diff=d(1:K)-dhat;
line([0:K-1]/20,diff,'color','k'); grid on;
ylabel('Reconstruction error');
xlabel('t (s)');