A Recursive Linear Predictive Vocoder.

Abstract

A non-real time 10 pole recursive autocorrelation linear predictive coding vocoder was created for use in studying effects of recursive autocorrelation on speech. The vocoder is composed of two interchangeable pitch detectors, a speech analyzer, and speech synthesizer. The time between updating filter coefficients is allowed to vary from .125 msec to 20 msec. The best quality was found using .125 msec between each update. The greatest change in quality was noted when changing from 20 msec/update to 10 msec/update. Pitch period plots for the center clipping autocorrelation pitch detector and simplified inverse filtering technique are provided. Plots of speech into and out of the vocoder are given. Formant versus time three dimensional plots are shown. Effects of noise on pitch detection and formants are shown. Noise effects the voiced/unvoiced decision process causing voiced speech to be re-constructed as unvoiced. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1983
Accession Number
ADA138008

Entities

People

  • W. A. Janssen

Organizations

  • Air Force Institute of Technology

Tags

Communities of Interest

  • C4I
  • Energy and Power Technologies
  • Weapons Technologies

DTIC Thesaurus Topics

  • Air Force
  • Algorithms
  • Analyzers
  • Authentication
  • Computer Programming
  • Detection
  • Detectors
  • Electrical Engineering
  • Equations
  • Filters
  • Filtration
  • Language
  • Larynx
  • Plastic Explosives
  • Signal Processing
  • Three Dimensional
  • Waveforms

Fields of Study

  • Engineering

Readers

  • Calculus or Mathematical Analysis
  • Speech Processing/Speech Recognition.