Randomly Changing Time-Variant Systems

  • Joachim SpeidelEmail author
Part of the Signals and Communication Technology book series (SCT)


Hitherto, we have considered signals and characteristic functions of time-variant system, in particular, the delay spread function \(g(t,\tau )\), as deterministic. With the Fourier transform different spectra or transfer functions, such as the Doppler spread function \(G(f_{t},f_{\tau })\), have been defined. In many applications, e.g., wireless communications the time-variant channel can take on a fast of different characteristics depending on the environment, the speed of the transmitter or receiver, and other effects. Hence, there is a need for the introduction of a statistical description for the most important system parameters. The use of multivariate probability density functions could help in principle.


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© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Institute of TelecommunicationsUniversity of StuttgartStuttgart, Baden-WurttembergGermany

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