www.pudn.com > DHMM_MATLAB.rar > My_lpc.m

%	by lkk@mails.tsinghua.edu.cn 
 
function [lpc_number] = My_lpc(frames,rank); 
 
%   输入： 
%      frames       输入帧  
%      rank         lpc阶数  
%   输出： 
%       lpc_number  lpc系数矩阵，rank行n列向量 
[windowsize, numframes] = size(frames); 
 
 
lpc_number = []; 
 
 
% 用自相关法计算lpc系数 
for nFrame = 1:numframes 
    R = zeros(rank+1,1); 
    alpha = zeros(rank,rank); 
    E = zeros(rank+1,1); 
    k = zeros(rank,1); 
    for i = 1:rank+1 
        R(i) = sum(frames(i:windowsize,nFrame).*frames(1:windowsize-i+1,nFrame)); 
    end 
     
    E(1) = R(1); 
    for i = 1:rank 
        tmpSum = 0; 
        for j = 1:i-1 
            tmpSum = tmpSum + alpha(j,i-1)*R(i-j+1); 
        end 
        k(i) = (R(i+1) - tmpSum)/E(i); 
        alpha(i,i) = k(i); 
        for j = 1:i-1 
            alpha(j,i) = alpha(j,i-1) - k(i)*alpha(i-j,i-1); 
        end 
        E(i+1) = (1-k(i)*k(i))*E(i); 
    end 
     
    % lpc系数 
    lpc_number = [lpc_number,alpha(:,rank)]; 
 
end