FFT komutu kullanarak matlabda basit DFT

clear all;
for n =1:20,
    sign1(n)=0.5*cos(2*pi*n/10); % transfer edilecek sinyal
end

XK(1:20)=0;
for k =1:20
    for n=1:20
    XK(k)=XK(k)+sign1(n)*exp(-j*2*pi*n*k/20); %matrisle transfer et
    end
end

%using fft command
XK2=fft(sign1,20); %fft komutu kullanarak transfer et
XK2(1)=[];
stem(XK); %cizdir
plot();
stem(XK2) %cizdir

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Great Windows tools

http://rainmeter.net/cms/Final25
http://www.infoworld.com/d/applications/top-15-free-tools-every-windows-desktop-063?page=0,0
Microsoft synctoy 2.1

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Good practical source on antennas

http://wndw.net/pdf/wndw2-en/ch04-antennas.pdf

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Simple DFT using FFT command in matlab

clear all;
for n =1:20,
    sign1(n)=0.5*cos(2*pi*n/10); %sinal to convert, f=10 Hz
end

XK(1:20)=0;
for k =1:20
    for n=1:20
    XK(k)=XK(k)+sign1(n)*exp(-j*2*pi*n*k/20); %convert with math
    end
end

%using fft command
XK2=fft(sign1,20); %convert with command
XK2(1)=[];
stem(XK);
plot();
stem(XK2)

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Simple Fourier Transform with Matlab - More Accurate

% SimpFourierTransform2
clear Q, f;
f=14;
h = @(x,y) cos(2*pi*x*f).*exp(-2*pi*i*x.*y);
mintime=-10;
maxtime=10;


for f=1:20;
  Q(f) = quadgk(@(x)h(x,f),mintime,maxtime);
end

stem(round(abs(Q)));

%stem(abs(Q))

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Simple Fourier Transform with Matlab - With Plots

% SimpFourierTransform1
clear Q, f;
f=3;
h = @(x,y) sin(2*pi*x*f).*exp(-2*pi*i*x.*y);
mintime=-1;
maxtime=1;
tim1=linspace(mintime,maxtime,1000);


  figure()
  subplot(2,1,1), plot(tim1, real(h(tim1,f)));
  title('Real Part of Integrated Function')
  xlabel('Time (seconds)');
  ylabel('Magnitude or real part');
  subplot(2,1,2), plot(tim1, imag(h(tim1,f)));
  title('Imaginery Part of Integrated Function')
  xlabel('Time (seconds)');
  ylabel('Magnitude of imaginery part');


for f=1:20;
  Q(f) = quad(@(x)h(x,f),mintime,maxtime);
end
figure()
  subplot(2,1,1), stem(round(real(Q)));
  title('Real Part of the result of the integral')
  xlabel('F (1/seconds)');
  ylabel('Magnitude or real part');
  subplot(2,1,2), stem(round(imag(Q)));
  title('Imaginery Part of the result of the integral')
  xlabel('F (1/seconds)');
  ylabel('Magnitude of imaginery part');



%stem(abs(Q))

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Simple Fourier Transform With Matlab

% SimpFourierTransform1
% Simple sin function with a frequency of 10 Hz, sin(2*pi*t*10)
% Multiply the function with basis transformer and integrate for a time interval


h = @(x,y) sin(2*pi*x*10).*exp(-2*pi*i*x.*y);

for f=1:20;
  Q(f) = quad(@(x)h(x,f),0,2);
end

stem(abs(Q))

 

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Simple Integral With Matlab

%simple integral for notation

f = @(x) sin(x)./x
Q = quad(f,0,pi)

%another code to define a function and plot the result
f = @(x) sin(x)./x
t=linspace(-10*pi,10*pi,1000);
plot(t,f(t));

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