ladrfilt.m

DSP课程的Matlab程序

function [y] = ladrfilt(K,C,x)

% LATTICE/LADDER form realization of IIR filters

% ----------------------------------------------

% [y] = ladrfilt(K,C,x)

% y = output sequence

% K = LATTICE (reflection) coefficient array

% C = LADDER coefficient array

% x = input sequence

%

Nx = length(x); y = zeros(1,Nx);

N = length(C); f = zeros(N,Nx); g = zeros(N,Nx+1);

f(N,:) = x;

for n = 2:1:Nx+1

    for m = N:-1:2

        f(m-1,n-1) = f(m,n-1) - K(m-1)*g(m-1,n-1);

        g(m,n) = K(m-1)*f(m-1,n-1) + g(m-1,n-1);

    end

    g(1,n) = f(1,n-1);

end

y = C*g(:,2:Nx+1);