Computing and Ploting Fourier transform
How can i use the fft command to transform a rectangular pulse to sinc function and plot the sinc function, i'm using a very traditional way to compute the fourier transform and plot it, but this way is too slow, when i use the fft command and try to plot, the ploting of the magnitude is only the pins or a spike, i need the plot to be a sinc function as the picture that i attached here, also i'm using the same method to compute the inverse fourier transform so i also need to use the ifft command, can anyone help? if true p = heaviside(t+1)-heaviside(t-1); k = 0; F=zeros(1,8001); for f= -4:0.001:4 k=k+1; F(k) = trapz(t,p.*exp(-1i*2*pi*f*t)); end f = -4:0.001:4; figure(1); plot(f,F); grid end
Prashant Kumar answered .
2025-11-20
Fs = 8; dt = 1/Fs; N = 8000; t = dt*(-N/2:N/2-1)'; dF = Fs/N; f = -Fs/2:dF:Fs/2-dF; p = heaviside(t+1)-heaviside(t-1); P = dt*fftshift(fft(ifftshift(p))); figure; plot(f,real(P)); grid on;