function [f,H]=lp_t1_o2_dft(fc,K,fmax,N)
%determine odd or even length
%to specify a specific discrete frequency let
%fc=kc and fmax= N/2 for N even and (N-1)/2 for N odd
temp=floor(N/2); temp=temp*2; % test for odd or even
evenodd=0; % guess odd
if temp==N,
   evenodd=1; % even
end;
% determine the frequency vector
if evenodd==1
   n0=-((N/2)-1);
else
   n0=-((N-1)/2);
end;
n1=n0+N-1;
na=n0:1:-1; % index vector
nb=0:1:n1;
n=[nb,na];
df=fmax/n1; % frequency increment
f=n*df; % frequency vector
w=2*pi*f;
wc=2*pi*fc;
coef=1/wc; % coef= R C
H=(K*wc^2)*(-w.*w + (i * wc*(3-K) * w)+wc^2).^(-1);