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FFT of square pulse in MATLAB problem

  1. Feb 8, 2012 #1
    I am trying to compute the Fourier transform of a square pulse with MATLAB's FFT.
    Code:

    Fs=1000; %Sampling rate (Hz)
    T=1/Fs; %Sampling time interval
    P=10; %Period of pulse
    t=0:1/Fs:P/2; %Time axis
    N=length(t);
    x=rectpuls(t,P); %Pulse amplitude
    n=pow2(nextpow2(N)); %Number of frequency components
    Y=fft(x,n);
    freq=Fs/2*linspace(0,1,n/2+1);
    subplot(1,2,1)
    plot(t,x)
    subplot(1,2,2)
    plot(freq, 2/N *abs((Y(1 : n/2+1))));
    xlim([0 2])

    Magnitude at the first frequency component should be 10, but is giving a result of 2. Why is this occurring?
    Thanks
     
  2. jcsd
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