Postfiltering techniques in low bit-rate speech coders

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1999.Includes bibliographical references (leaves 78-80).by Azhar K. Mustapha.M.Eng

Erhöhung der Sprachqualität von CASA separierten Sprachsignalen

Ziel dieser Arbeit war es unter Einsatz einer Auswahl an Algorithmen die Sprachqualität von CASA separierten Sprachsignalen zu verbessern. Der Ursprung dieses Problems liegt in der von CASA verwendeten Zeit-Frequenz-Maskierung. Diese kann zu einer fehlerbehafteten Ausgabe führen, wenn zur gleichen Zeit zwei Sprecher den selben Frequenzbereich mit ihren Stimmen abdecken. Der beschriebene Bereich kann folglich nur als Ganzes einem Sprecher zugeordnet werden, sodass fehlerbehaftete Signale entstehen. Zur Verbesserung dieser wurde der Einsatz eines LPC-Vocoders, die Reduktion der Abtastrate der Signale sowie eine Kombination beider als Reparaturverfahren eingesetzt und überprüft

Perceptual models in speech quality assessment and coding

The ever-increasing demand for good communications/toll quality speech has created a renewed interest into the perceptual impact of rate compression. Two general areas are investigated in this work, namely speech quality assessment and speech coding. In the field of speech quality assessment, a model is developed which simulates the processing stages of the peripheral auditory system. At the output of the model a "running" auditory spectrum is obtained. This represents the auditory (spectral) equivalent of any acoustic sound such as speech. Auditory spectra from coded speech segments serve as inputs to a second model. This model simulates the information centre in the brain which performs the speech quality assessment. [Continues.

Models and analysis of vocal emissions for biomedical applications

This book of Proceedings collects the papers presented at the 3rd International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications, MAVEBA 2003, held 10-12 December 2003, Firenze, Italy. The workshop is organised every two years, and aims to stimulate contacts between specialists active in research and industrial developments, in the area of voice analysis for biomedical applications. The scope of the Workshop includes all aspects of voice modelling and analysis, ranging from fundamental research to all kinds of biomedical applications and related established and advanced technologies

Proceedings of the Mobile Satellite Conference

A satellite-based mobile communications system provides voice and data communications to mobile users over a vast geographic area. The technical and service characteristics of mobile satellite systems (MSSs) are presented and form an in-depth view of the current MSS status at the system and subsystem levels. Major emphasis is placed on developments, current and future, in the following critical MSS technology areas: vehicle antennas, networking, modulation and coding, speech compression, channel characterization, space segment technology and MSS experiments. Also, the mobile satellite communications needs of government agencies are addressed, as is the MSS potential to fulfill them