"What do the ""real"" and ""imaginary"" parts of the Laplace and Z transform represent? I understand that the Fourier transform brings you from the time domain into frequency domain, and that the Fourier transform is just the Laplace transform but where sigma, the real valued portion of s = sigma + j omega, is set to 0. So if the imaginary portion, omega, is the frequency, what does the real sigma represent?

Sasha Hess

Sasha Hess

Answered question

2022-09-10

What do the "real" and "imaginary" parts of the Laplace and Z transform represent?
I understand that the Fourier transform brings you from the time domain into frequency domain, and that the Fourier transform is just the Laplace transform but where σ, the real valued portion of s = σ + j ω, is set to 0. So if the imaginary portion, ω, is the frequency, what does the real σ represent?
Furthermore, why is it not like this between the DTFT and the Z transform? The DTFT is a specialized case not where σ = 0, but where r in z = r e j ω is set to 0, i.e when | z | = 1. Do the real and imaginary parts of the signal change what they represent in continuous and discrete signals?

Answer & Explanation

shosautesseleol

shosautesseleol

Beginner2022-09-11Added 16 answers

After doing a chunk of analyzing, and looking videos, i have discovered the sigma is precisely what it appears, exponential boom and rot, essentially machine stability. you are looking on the response to an injection of a sinusoid whose amplitude increases or decreases exponentially.
So now not simply the reaction to a sure frequency, but the response to a sure frequency because the amplitude modifications exponentially through the years.

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