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Institute for Telecommunication Sciences
the research laboratory of the National Telecommunications and Information Administration

Institute for Telecommunication Sciences / Resources / Audio Quality Research / Audio Home

ITS Audio Quality Research Program

The ITS Audio Quality Research Program seeks to identify and respond to selected open questions that arise in digital speech and audio compression, transmission, and quality assessment. The quality of speech sent over a telecommunication system depends on a variety of factors, such as the background noise in the environment, the algorithms used to digitally code the speech signal, the bandwidth used in transmitting the speech signal, as well as others.  For any set of factors, the user is concerned with the overall experience—the quality and intelligibility of the speech. The user experience can be enhanced through algorithms that robustly adapt to variations in the environmental factors listed above. Such adaptability allows telecommunications speech transmission to be well-matched to channel conditions even though those conditions are continually evolving, thereby enhancing the user experience.

The ITS Audio Quality Research Program supports community-wide efforts towards robust and adaptable telecommunication speech services. The program identifies, develops, and characterizes algorithm innovations in these areas, seeking to enhance the user experience through higher, more consistent speech quality, better intelligibility, or combinations of these two. The program also seeks to improve tools and techniques for quantitatively characterizing the user experience of speech quality and speech intelligibility, both through subjective testing and by means of signal processing algorithms.

The objectives of this work are:

  • Improved speech quality in wireless voice services
  • Enhanced speech intelligibility when wireless voice services are used in noisy environments
  • More consistent performance of voice services through greater robustness to transmission channel impairments

Program results are described in detail in the technical publications, all of which are available on this site.