function cfoml_eval(x)

N = 1024;       % number of subcarriers
M = 103;        % number of subcarriers that carry information
omega = 2*pi/N; % carrier spacing

fa = 48000;
fo = 0.0;

x = 0.5*exp(i*2*pi.*(0:length(x)-1)'*fo/fa) .* x;

U = exp(i*omega*(0:N-1)'*(0:N-1));

W = U(:, 1:M);
V = U(:, (M+1):N);

phi = 0;
dphi = pi/100;

for j=1:100,
phik(j) = phi;
P = calcP(phi, N);
phi = phi + dphi;

S(j) = sum(abs(x'*P*U(:, M+1:N)).^2);
end

close all;

plot(phik, real(S)); grid

function P = calcP(phi, N)
P = diag(exp(i*(0:N-1)*phi));