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I have this Matlab code :

function PH = testing

close all;

x = [0:1e-3:10-1e-3];

ph = -(x-5).^2;

y = exp(-(x-5).^2./(0.2^2)).*exp(i*2*pi*ph);

Y = fft(y);

Y = fftshift(Y);

PH = angle(Y);

X = (x(2) - x(1))^-1*linspace(0,1,length(x));

figure

plot(x,ph);

figure

plot(X,PH);

end

I build a gaussian curve with quadratic phase and Fourier Transform it. I expect to have a quadratic phase (with opposite sign) in the spectral domain, but I cannot have it correctly. The plot of PH shows jumps between adjacent points. Even using unwrap.m I cannot plot it well.

Thanks in advance for any help

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# Plot spectral phase in Mtlab

Can you offer guidance or do you also need help?

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