Having troubles getting a rect function ussing fft and the sinc function

As the title says I am unable to get the rect function when I fft my sinc function

Heres my code to begin with:

x = linspace(-10, 10, 10000);

y = sinc(x);

Pretty simple stuff imo.

when I do:

plot(x, y)

I get

but then when I do:

plot(x, fft(y))

I get

any help would be apprecaited

Answer 1

[Star Strider]

You are not plotting your Fourier transform correctly.

Try this:

x = linspace(-10, 10, 10000);
y = sinc(x);

Fs = 1/mean(diff(x));                               % Sampling Frequency
Fn = Fs/2;                                          % Nyquist Frequency

Y = fft(y)/numel(y);
Ys = fftshift(Y);
Fv = linspace(-1, 1, fix(numel(Y)))*Fn;

figure
plot(Fv, abs(Ys)*2)
grid
xlim([-5  5])

EDIT — (2 Apr 2019 at 20:09)

Added plot figure: