function [b] = latc2dir(K)
% 全零格型到FIR的直接型式的型式轉換
% ---------------------------------------------------
% [b] = latc2dir(K)
%  b = 直接型式的多項式系數(脈沖響應)
%  K = 格形濾波器系數(反射系數) 
%
M = length(K);
J = 1; A = 1;
for m=2:1:M
	A = [A,0]+conv([0,K(m)],J);
	J = fliplr(A);
end
b=A*K(1);