The Performance of a New Adaptive Filter for Digital Communications.

Abstract

The improvement in performance of a digital communications receiver preceded by an adaptive filter using the soft-constraint Least Mean Square algorithm is found. This algorithm has previously only been used in conjunction with adaptive antenna arrays. The fundamentals of adaptive filters and the spread spectrum technique are presented. A computer model is developed which simulated a 19 tap adaptive filter and spread spectrum receiver combination in the baseband region. The filter is shown to adapt well to hopping jammers and dual jammers. Plots of the filter's transfer function show notch depths ranging from -34 dB to -77 dB over iterations ranging from 15 to 5000 for the case of a 20 db sinusoid jammer. The improvement gained by adjusting the softness of the constraints is presented. The computer program and recommendation for further study are included as well as a 44 item bibliography. Originator-supplied keywords include: Soft-constraint LMS algorithm, LMS algorithm, Digital communication, Adaptive filters, and Spread spectrum.

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1984
Accession Number
ADA151890

Entities

People

  • J. R. Way Jr

Organizations

  • Air Force Institute of Technology

Tags

Communities of Interest

  • Electronic Warfare
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Adaptive Filters
  • Algorithms
  • Bandwidth
  • Code Division Multiple Access
  • Communication Channels
  • Communication Systems
  • Complex Variables
  • Computational Science
  • Computer Programming
  • Computer Programs
  • Computers
  • Digital Communications
  • Electrical Engineering
  • Filters
  • Frequency Agility
  • Modulation
  • Multiple Access

Fields of Study

  • Engineering

Readers

  • Acoustics.
  • Phased Array Antenna Design.