%
% Written by:
% --
% John L. Weatherwax                2009-04-21
%
% email: wax@alum.mit.edu
%
% Please send comments and especially bug reports to the
% above email address.
%
%-----

close all; clc; clear; 

% EPage 137

dt = 0.1;

y = [ 2, -0.404, 0.2346, 2.6687, -1.4142, -1.0973, 0.8478, -2.37, 0, ...
    2.37, -0.8478, 1.0973, 1.4142, -2.6687, -0.2346, 0.404, -2, ...
    1.8182, 1.7654, -1.2545, 1.4142, -0.3169, -2.8478, 0.9558, ...
    0, -0.9558, 2.8478, 0.3169, -1.4142, 1.2545, -1.7654, -1.8182 ];

nt = length(y);
T = dt * nt; 
t = 0:dt:(T-dt);
df = 1/T;
fmax = nt/(2*T);
f = 0:df:df*(nt/2-1);

Y = fft(y);
Ys = zeros(1,nt/2);
Ys(1:nt/2) = (2/nt)*Y(1:nt/2);
plot( f, abs(Ys) );
xlabel('frequency Hz'); ylabel('abs(DFT)'); 
grid('on');

%saveas( gcf, '../../WriteUp/Graphics/Chapter7/c_7_p_12_plot.eps', 'epsc' );