Past Issues

Studies in Informatics and Control
Vol. 5, No. 4, 1996

Comparative Study Of Some Sequential Detection Methods for Digital Signals

Theodor-Dan Popescu
Abstract

The paper deals with performance eval­ uation of some methods for sequential detection of changes in non-stationary digital signals. Methods are "exactly" valid under the assumption that the signal under study is an autoregressive process. However, they appear to be robust to this assumption and can, therefore, be applied to other signals as well. The detection algorithms herein consid­ered are based on the quadratic forms of Gaussian random variable, which are x2 distributed under the null hypothesis (no change); random variables used to construct the quadratic forms include AR parameters, estimated residual variance and sam­ple and partial residual correlations. The presented methods combine sequential and sliding block anal­yses. The considered methods performances are eval­uated by simulation. Also, the methods' robustness as to the assumption of autoregressive data and to the model structure, is investigated.

Keywords

Hypothesis testing, detection of changes, autoregressive modelling, non-stationary time series, quadratic forms, simulation.

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