function e_vec=exp_vector(N,m,Fs)
e_vec(1:N+1)=ones; % vector with the exponential factors,
% when we sample the frequency characteristics
% of a discrete linear filter of order N with
% a rational transfer function at frequency m
% Fs is the sampling frequency used with the filter
% Usage in computing samples of the frequency
% characteristics of the filter as needed
% for plotting amplitude or phase distortions
for k=2:N+1;
e_vec(k)=exp(-2*(k-1)*1i*pi/Fs*m);
end;