function [a,b,err] = prony(x,p,q)%PRONY	Model a signal using Prony's method%----%Usage: [a,b,err] = prony(x,p,q) %%	The sequence x is modeled as the unit sample response of%	a filter having a system function of the form%		H(z) = B(z)/A(z) %	The polynomials B(z) and A(z) are formed from the vectors%		b=[b(0), b(1), ... b(q)]%		a=[1   , a(1), ... a(p)]%	The input q defines the number of zeros in the model%	and p defines the number of poles.  The modeling error%	is returned in err.%%  see also ACM, COVM, PADE, SHANKS%%---------------------------------------------------------------% copyright 1996, by M.H. Hayes.  For use with the book % "Statistical Digital Signal Processing and Modeling"% (John Wiley & Sons, 1996).%---------------------------------------------------------------x   = x(:);N   = length(x);if p+q>=length(x), error('Model order too large'), endX   = convm(x,p+1);Xq  = X(q+1:N+p-1,1:p);a   = [1;-Xq\X(q+2:N+p,1)];b   = X(1:q+1,1:p+1)*a;err = x(q+2:N)'*X(q+2:N,1:p+1)*a;end;