WSEAS TRANSACTIONS on MATHEMATICS Stevan Berber The Exponential, Gaussian and Uniform Truncated Discrete Density Functions for Discrete Time Systems Analysis STEVAN BERBER Electrical and Computer Engineering Department The University of Auckland Princes Street, 1010 Auckland Central NEW ZEALAND
[email protected] Abstract: - Continuous density functions and their truncated versions are widely used in engineering practice. However, limited work was dedicated to the theoretical analysis and presentation in closed forms of truncated density functions of discrete random variables. The derivations of exponential, uniform and Gaussian discrete and truncated density functions and related moments, as well as their applications in the theory of discrete time stochastic processes and for the modelling of communication systems, is presented in this paper. Some imprecise solutions and common mistakes in the existing books related to discrete time stochastic signals analysis are presented and rigorous mathematical solutions are offered. Key-Words: - truncated densities, Gaussian truncated discrete density, exponential truncated density, moments of truncated densities. 1 Introduction density function in the theory of discrete time stochastic processes can be found in published papers and books. For example, in book [1], page 78, example 3.3.1 and book [2], pages 71 and 72, 1.1 Motivation example 2.2.3, the mean and autocorrelation Digital technology is widely used in the function of a discrete time harmonic process, which development and design of electronic devices in is defined as X( m ) A sin( m ) with communication systems. Therefore, the theoretical analysis of these systems assumes representation of uniformly distributed phases in the interval (-π, π) having continuous density function =1/2π, are signals in discrete time domain.