function x = fmpoly(N, p)% fmpoly -- create a signal with a polynomial frequency modulation%%  Usage%    x = fmpoly(N, p)%%  Inputs%    N    length of the signal%    p    order of the polynomial phase (p=2 -> linear chirp)%%  Outputs%    x    signal% Copyright (C) -- see DiscreteTFDs/Copyrighterror(nargchk(2,2,nargin));if (p<2)  error('p must be at least 2')endif (rem(N,2)==0)  center = N/2+1;else  center = (N+1)/2;endn = (1:N)';x = exp(j*pi*(n-center).^p/(N/2)^(p-1)/p);