Anzeige
Erschienen in:
2019 | OriginalPaper | Buchkapitel
2. Removal of Intersymbol Interference
verfasst von : Joachim Speidel
Erschienen in: Introduction to Digital Communications
Aktivieren Sie unsere intelligente Suche, um passende Fachinhalte oder Patente zu finden.
Wählen Sie Textabschnitte aus um mit Künstlicher Intelligenz passenden Patente zu finden. powered by
Markieren Sie Textabschnitte, um KI-gestützt weitere passende Inhalte zu finden. powered by
Abstract
To remove the intersymbol interference I(k) defined in (1.42), we may not impose any constraint on the symbol sequence a(k), because the system design should hold for any sequence given by the user at the transmitter. Therefore we can only touch upon the impulse response h(k). Looking at (1.38) the system is prepared already with two degrees of freedom, \(g_{I}(t)\) and \(g_{R}(t)\). Hence, for a given impulse response \(g_{C}(t)\) of the physical channel we can design the overall impulse response in such a way that (2.1) is called Nyquist’s first criterion in the time domain [1] and the corresponding impulse is referred to as Nyquist impulse. An example of a real-valued impulse response satisfying (2.1) is depicted in Fig. 2.1. Obviously, \(h_{e}(t)\) owns equidistant zeros except at \(t=t_{0}\).
$$\begin{aligned} h(k-m)=h_{e}\left( t_{0}+(k-m)T\right) ={\left\{ \begin{array}{ll} \begin{array}{ccc} 0 &{} ; &{} m\,\epsilon \,\mathbb {Z}\,\,;\,\,m\ne k\\ h(0)=h_{e}(t_{0})\ne 0 &{} ; &{} m=k \end{array}\end{array}\right. } \end{aligned}$$