% ray2.m 
%
% Rayleigh fading simulator.
% Uses Jakes method of the summation of weighted quadrature sinusoids.
%
%
% Richard Wyrwas, 2 February 1995.
% plot labels added by Bill Cowley  4/97


disp('ray2: Jakes method: calculating weighted quadrature sinusoids  ....');
disp('      with Fs =1kHz ');

j=sqrt(-1);
fm=100.0; 	%Max Doppler frequency in Hz
fs=1000;	%Sample Frequency
ns=1024; 	%Number of samples
R=zeros(ns,1);
Mag=zeros(ns,1);
for x=1:ns
      tm=x/fs;
      I=0.0;
      I=1.848*cos(0.983*2*pi*fm*tm);
      I=I+1.414*cos(0.932*2*pi*fm*tm);
      I=I+0.765*cos(0.850*2*pi*fm*tm);
      I=I+0.0*cos(0.739*2*pi*fm*tm);  
      I=I-0.765*cos(0.603*2*pi*fm*tm);
      I=I-1.414*cos(0.446*2*pi*fm*tm);
      I=I-1.848*cos(0.247*2*pi*fm*tm);
      I=I-2.000*cos(0.092*2*pi*fm*tm);
      I=I+1.000*cos(1.000*2*pi*fm*tm);

      Q=0.0;
      Q=Q+0.765*cos(0.983*2*pi*fm*tm);
      Q=Q+1.414*cos(0.932*2*pi*fm*tm);
      Q=Q+1.848*cos(0.850*2*pi*fm*tm);
      Q=Q+2.000*cos(0.739*2*pi*fm*tm);
      Q=Q+1.848*cos(0.603*2*pi*fm*tm);
      Q=Q+1.414*cos(0.446*2*pi*fm*tm);
      Q=Q+0.765*cos(0.247*2*pi*fm*tm);
      Q=Q+0.000*cos(0.092*2*pi*fm*tm);
      Q=Q+1.000*cos(1.000*2*pi*fm*tm);
     
      
      R(x) = I+j*Q;
      Mag(x)=abs(R(x));

end;
hist(Mag,20);
title('Histogram of Simulated Signal Magnitudes');
pause;

plot(Mag);
title('Plot of Simulated Signal Magnitude versus sample number')
pause;
axis([100,300,0,10]);
pause;

[Pxx,f]=psd(R,[],fs);
% psd(R,[],fs);
plot(f-fs/2,fftshift(Pxx));
title('Spectral Estimate of simulated signal');
xlabel('Frequency (Hz) ');
pause;

%y=10*log10(max(Pxx));
%axis([0.0,1.1*fm,-40,y]);
%xlabel('Frequencies to 10% greater than max doppler');
%pause;

%plot(abs(fft(R)));
%plot(f-fs/2,fftshift(abs(fft(R))));