shanks

代码说明：

  function [a,b,err] = shanks(x,p,q) SHANKS Model a signal using Shanks method ---- Usage: [a,b,err] = shanks(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.