Dear Matlab Profession,
Please find the following code.
I have a code to generate a one side spectrum in frequency domain, I am not sure it is postive frequency or negative frequency.
But I do know the energetic portion of signal in time domain aftfter ifft must starts after 3.33 sec as either Figure (1) or (2).
The issue is based on Fourier transform theory, I should get a "real" signal, but I still get a complex signal in time domain.
May I ask how to fix it or use ifftshift? Thank you!
clear;clc;close all;
sig_end=7;
Fs=400;
dt=1/Fs;
L=Fs*sig_end;
t=(0:L-1)*dt;
df=Fs/L;
freq=0:df:Fs/2;
load('Sign_spectrum_one_side.mat','Pr')
Pr_other_side=conj(Pr);
Pr_two_sides_1=cat(1,Pr_other_side(2:end-1),flip(Pr));
Pr_two_sides_2=cat(1,Pr_other_side,flip(Pr(2:end-1)));
pr_two_sides_1=ifft(Pr_two_sides_1);
pr_two_sides_2=ifft(Pr_two_sides_2);
figure(1)
plot(t,pr_two_sides_1);
xlabel('Time (sec)');ylabel('Arbitrary magnitude')
figure(2)
plot(t,pr_two_sides_2)
xlabel('Time (sec)');ylabel('Arbitrary magnitude')
