fft_view.m

cognitive radio model programme with MATLAB

function [sys, x0, str, ts] = fft_view(t, x, u, flag)

switch flag,
    case 0 
        [sys,x0, str, ts] = mdlInitializeSizes;
    case 3
        sys = mdlOutputs(t,x,u);
    case {1,2,4,9}
        sys = [];
    otherwise
        error(['Unhandled flag = ', num2str(flag)]);
                
end;

function [sys, x0, str, ts] = mdlInitializeSizes
sizes = simsizes;
sizes.NumContStates = 0;
sizes.NumDiscStates = 0;
sizes.NumOutputs = 1000;
sizes.NumInputs = 1000;
sizes.DirFeedthrough = 1;
sizes.NumSampleTimes = 1;
sys = simsizes(sizes);
x0=[];
str=[];
ts=[-1,0];
function sys = mdlOutputs(t,x,u)
ts = 0.001;
fs = 1/ts;
ws = 2*pi*fs;

f0=10;
w0=2*pi*f0;
x1=u;

BW = fs/2;

w = linspace(-BW, BW, length(x1));
dw = w(2)-w(1);

F = fftshift(fft(x1))/fs;
FT = abs(F);

FT2 = dw*FT;

fig1 = figure(3);
plot(w, FT2')
axis([180, 300, 0, 0.8])
xlabel('w [radian/sec]')
ylabel('|F(w)|')
sys = FT2';
set(fig1,'units','nor','pos',[0.01,0.5,0.5,0.3]);