rdf-syntax-grammar
mods:
  schema location: http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
  title info:
    title: Variable rate speech coding based on subband measures of spectral flatness
  name:
    name part: McClellan, Stan.
    role:
      role term: creator
  type of resource: text
  genre: bibliography
  origin info:
    place:
      place term: xx
    date issued: 1995
    issuance: monographic
  language:
    language term: eng
  physical description:
    form: print
    extent: xii, 137 leaves : illustrations ; 28 cm.
  abstract: The development of digital multiple-access schemes for telephony and personal communications networks, in addition to the rapid standardization of digital audio-video delivery techniques, has placed a renewed emphasis on efficient compression of speech. Code-excited linear prediction (CELP) is the predominant coding methodology for medium-rate speech coding due to the adoption of several international and U.S. fixed-rate standards. With the standardization of a CELP- based variable-rate coder for digital spread-spectrum telephony, many variable-rate techniques which had not been previously studied have become an area of significant research interest. Variable-rate coding of speech is composed of two distinct components: voice-activity detection (VAD) and coding of active speech. In this research, we focus on new techniques to perform VAD and to efficiently encode time- varying parameters of active speech. These techniques are based on subband measures of spectral shape. This approach produces a departure from the usual methods used for rate allocation which are based on (subband) energy. Here, we use the concept of spectral flatness to modulate the allocation of rate and to determine coding procedures. We also make use of some highly speech-specific redundancy (previously untested in standard approaches) to efficiently encode spectral parameters. We test these techniques in the context of a multi-mode, variable-rate CELP coder and demonstrate that with appropriate assumptions regarding voice-activity, our CELP coder can maintain communications quality in the encoded speech at an average rate below 2000 bits/sec.
  note: by Stan McClellan.
  note: Vita.
  note: "Major Subject: Electrical Engineering".
  note: Issued also on microfiche from University Microfilms Inc.
  note: Includes bibliographical references.
  note: Ph. D. Texas A&M University 1995.
  subject:
    topic: Major electrical engineering
  identifier: 95-39263 UMI
  identifier: http://proxy.library.tamu.edu/login
  related item:
    location:
      url: http://proxy.library.tamu.edu/login
  record info:
    record content source: TXA
    record creation date: 960716
    record change date: 20190325093150.0
    record identifier: in00001314245