Exponentials as eigenfunctions in LTI Systems

AI Thread Summary
The discussion focuses on the concept of eigenvalues in linear time-invariant (LTI) systems, specifically regarding the expression e^{s t} as an eigenvalue. The user questions the validity of the eigenvalue equation involving integrals of the system's impulse response function h(t) and its Laplace transform H(s). There is a belief that the integrals H(s) and the integral of h(τ) should be unique, suggesting that there is only one solution for the relationship H(s) = ∫_{-\infty}^{\infty} h(τ) e^{-s τ} dτ. The conversation also references the fundamental theorem of calculus to support the uniqueness of the integral. Overall, the thread seeks clarity on the uniqueness of solutions in the context of eigenvalue equations for LTI systems.
Tanja
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I hope I catched the correct forum.

Under http://en.wikipedia.org/wiki/LTI_system_theory
e^{s t} is an eigenvalue.
I don't really understand that the following is an eigenvalue equation:
\quad = e^{s t} \int_{-\infty}^{\infty} h(\tau) \, e^{-s \tau} \, d \tau
\quad = e^{s t} H(s),

where

H(s) = \int_{-\infty}^\infty h(t) e^{-s t} d t .

The integrals H(s) and \int_{-\infty}^{\infty} h(\tau) \, e^{-s \tau} \, d \tau should be unique, isn't it? So there is only one solution for H(s) = \int_{-\infty}^{\infty} h(\tau) \, e^{-s \tau} \, d \tau with one e^{s t}, isn't it?

Thanks
Tanja
 
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e^{s t} is an eigenvalue.
I don't really understand that the following is an eigenvalue equation:
\quad = e^{s t} \int_{-\infty}^{\infty} h(\tau) \, e^{-s \tau} \, d \tau
\quad = e^{s t} H(s),

where

H(s) = \int_{-\infty}^\infty h(t) e^{-s t} d t.

The integrals H(s) and \int_{-\infty}^{\infty} h(\tau) \, e^{-s \tau} \, d \tau should be unique, isn't it? So there is only one solution for H(s) = \int_{-\infty}^{\infty} h(\tau) \, e^{-s \tau} \, d \tau with one e^{s t}, isn't it?
F(x) = \int_a^xf(t)dt is unique by the fundamental theorem of calculus.
 
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