A New Approach to the Characterization and Detection of Nonstationary Environments and Channels

Abstract

A new method to study nonstationary systems and channels that applies to both the time-variant and time-invariant case has been developed. It is shown that a significant simplification occurs when systems are formulated in phase space. The phase space can be time-frequency for the usual formulation of channels/systems, or position-wave number for dispersive channels and pulses. In the standard textbook approach of input-output relations and system functions, the relations are formulated in time or frequency. We have derived input-output relations for time-varying channels. The method has led to practical solutions to a number of problems, both deterministic and random. Among them are defining the concept of quasi-stationarity, formulating features that are dispersion invariant, obtaining simple characterizations of pulses that propagate in dispersive channels with attenuation.

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Document Details

Document Type
Technical Report
Publication Date
Feb 20, 2009
Accession Number
ADA495431

Entities

People

  • Leon Cohen

Organizations

  • Hunter College

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Attenuation
  • Classification
  • Complex Variables
  • Detection
  • Differential Equations
  • Dispersion Relations
  • Dispersions
  • Equations
  • Frequency
  • Frequency Domain
  • Group Velocity
  • Multiple Input Multiple Output
  • New York
  • Partial Differential Equations
  • Standards
  • Target Recognition
  • Wave Equations

Fields of Study

  • Engineering
  • Physics

Readers

  • Adaptive Control and Estimation with Uncertainty in Dynamic Systems.
  • Wave Propagation and Nonlinear Chaotic Dynamics.

Technology Areas

  • Space