iir1.m

用dsp解压mp3程序的算法

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%  iir1.m - First-order IIR filtering, alpha = 0.25
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

alpha = 0.25;                     % define parameter
b = [alpha]; a = [ 1 -(1-alpha)]; % coefficient vectors
load -ascii xn.dat;               % load xn.dat into vector xn
N = length(xn);                   % length of file
n = [0:N-1];                      % time index
yn = filter(b, a, xn);            % perform IIR filtering
plot(n,xn,'r-',n,yn,'b--');       % plot both input and output
axis([0 N-1 -inf inf]);
ylabel('amplitude'); xlabel('time index');
title('Input and output waveforms');