Accession Number : ADA133209

Title :   Performance Characteristics of Passive Coherence Estimators.

Descriptive Note : Interim rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC

Personal Author(s) : Gerlach,A A

PDF Url : ADA133209

Report Date : 31 Aug 1983

Pagination or Media Count : 25

Abstract : Two dimensional coherence processing is commonly used for passive detection in acoustic sensor systems. Modern coherence processors, well suited for this purpose, include the magnitude squared coherence (MSC) estimator and the normalized correlation envelope (NCE) estimator. These are biased estimators, whose performance characteristics are not well understood and are exceptionally difficult to analyze. However, by developing a rather unique bias correcting function, the detection performance of biased estimators is derived as a function of both the input signal and the processor parameters, Design parameters, which optimize detection, are determined for both the MSC and the NCE estimators. In applications where the number of degrees of freedom (or time bandwidth product) of a target signal is severely limited, detection performance can be enhanced by signal overcontainment within the processor bandwidth. Performance data are presented in formats appropriate for selecting processor parameters which are optimum for a given application. Practical guidelines are given to avoid misapplying the theoretical results in cases where there are many narrowband interfering signals in the spectral region of a target signal.

Descriptors :   *Information theory, *Passive systems, *Coherence, False alarms, Bandwidth, Signal processing, Estimates, Signal to noise ratio

Subject Categories : Cybernetics
      Non-radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE