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matlabmathsignal-processingsymbolic-math

Why i am getting blank graph?How can i solve this issue?

I am trying to plot symbolic variable in MATLAB, for which I have used the same strategy that is available in an answer to a similar question.

This is my code, which outputs a blank graph:

syms t w
x=exp(-t^2)
h=exp(-t)*heaviside(t)+exp(t)*heaviside(-t)
X=fourier(x,w);
H=fourier(h,w);
right=ifourier( rewrite(X*H, 'exp'),t)
fplot(right,[0 8])

How can I make the graph appear?

Solution

  • The problem is that MATLAB ifourier function cannot compute the inverse Fourier transform of the product X*H.

    Check that X*H returns:

    X*H

    enter image description here

    Rewriting the expression does not change it at all:

    rewrite(X*H, 'exp')

    enter image description here

    Either way, when computing the inverse Fourier transform:

    right=ifourier( X*H,t)

    enter image description here

    Documentation on the ifourier function states that:

    If ifourier cannot transform the input, then it returns an unevaluated call to fourier.

    Since it cannot evaluate explicitly the function, it cannot plot it.