exponential function phase reversal

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STP
STP on 4 Apr 2019
I wish to know when using exponential function do i get a phase reversal of 180 degrees like -- exp(1i*0) to exp(1i*pi) or exp(1i*180)?

Answers (1)

Bjorn Gustavsson
Bjorn Gustavsson on 4 Apr 2019
Try:
phi = linspace(-5*pi,5*pi,5*360+1);
Phi = angle(exp(1i*phi));
plot(phi,Phi)
grid on
set(gca,'XTick',[-2.5*360:180:2.5*360])
HTH
  2 Comments
Bjorn Gustavsson
Bjorn Gustavsson on 4 Apr 2019
OK, so you will need to write a function that is zero for all times except for a brief period of time, in that time-period you'll have something that looks like a parabloically (exponentially, something with an increasing rate of phase-variation) and then back to zero. Preferably your function should return a vector of phases for a vector of times in. Something like:
function Phi = my_phase_variationing(t)
if t_start <= t && t < t_stop
Phi = t.^2;
else
Phi = 23;
end
end
Adapt after your own needs.
Bjorn Gustavsson
Bjorn Gustavsson on 4 Apr 2019
Yes. Have a look at the function-sketch I gave above. Read it think about what it does, and how it takes you halfway to what you want. Then have a think about how you can modify that sketch to make what you need for your homework. Ask yourself these questions:
  • Can I use something like elseif to split up a time-vector into multiple segments?
  • Can I use logical indexing to smoothly vectorize the code? Or do I perhaps need to loop over all elements in t?
  • How do I get real-complex values from given phase-values?
After you've asked and answered those questions you will see that you can solve this problem rather easily. I will not write what I start to think because I start to have opinions.
HTH

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