Calculation of analytical signal data in Matlab

%% Calculation of the theoretical values
h = [2, -0.5, 4, -2, -1, 2.5].';
Nh = length(h);
Nc  = Nh;

theta = pi/2;
sigma2_u = 3.5; % Noise characteristics
rxx_analytical = 1/2*cos(theta*(0:Nh-1));
rxx_analytical(1) = rxx_analytical(1) + sigma2_u;
Rxx_analytixal = toeplitz(rxx_analytical);
p_analytical = Rxx*h;