testspectrum.m

Matlab code for UWB communication

clear;
N = 1000;

b = fir1(120,0.5/50);

x = cos(2*pi*4.1*[0:99]/100);
w = [(x .* transpose(window(@blackmanharris,100)))  zeros(1, 400)];

x_rx = [w -w -w w -w -w];

% for k = 0 : 2 : 10
%    x_rx(1, k*length(w)+1:(k+1)*length(w)) = w; 
%    x_rx(1, k*length(w)+length(w)+1:(k+1)*length(w)+length(w)) = -w; 
% end
osc = exp(-j*(2*pi*3.9*[0:length(x_rx)-1]/100));

y_rx = x_rx .* real(osc) + j*x_rx .* imag(osc);

y_filtered = filter(b, 1, y_rx);

y_1 = [zeros(1,500) (y_filtered(1:length(y_filtered)-500) .* y_filtered(501:length(y_filtered)))];
y_2 = real(y_1) + imag(y_1);

% subplot(8,1,1);plot(real(x_rx)); grid
% subplot(8,1,2);plot(imag(x_rx)); grid
% subplot(8,1,3);plot(real(y_rx)); grid
% subplot(8,1,4);plot(imag(y_rx)); grid
% subplot(8,1,5);plot(real(y_filtered)); grid
% subplot(8,1,6);plot(imag(y_filtered)); grid
% subplot(8,1,7);plot(real(y_2)); grid
% subplot(8,1,8);plot(imag(y_2)); grid

z1 = abs(fft(real(x_rx))).^2;
z2 = abs(fft(real(osc))).^2;
z3 = abs(fft(real(y_rx))).^2;

diz1 = [z1((length(z1)/2)+1:length(z1)) z1(1:length(z1)/2)];
diz2 = [z2((length(z2)/2)+1:length(z2)) z2(1:length(z2)/2)];
diz3 = [z3((length(z3)/2)+1:length(z3)) z3(1:length(z3)/2)];

subplot(3,1,1); plot(diz1);
subplot(3,1,2); plot(diz2);
subplot(3,1,3); plot(diz3);