With the increasing demand for wireless voice services and limited bandwidth resources, it is critical to develop and implement coding techniques which use spectrum efficiently. One approach to increasing system capacity is to lower the bit rate of telephone speech. A typical telephone conversation contains approximately 40% speech and 60% silence or background acoustic noise. A reduction of th...

A speech coding for a full-band speech analysis/synthesis system is described. In this work, full-band speech is defined as speech with a sampling frequency above 40 kHz, whose Nyquist frequency covers the audible frequency range. In prior works, speech coding has generally focused on the narrowband speech with a sampling frequency below 16 kHz. On the other hand, statistical parametric speech ...

Cortical oscillations are likely candidates for segmentation and coding of continuous speech. Here, we monitored continuous speech processing with magnetoencephalography (MEG) to unravel the principles of speech segmentation and coding. We demonstrate that speech entrains the phase of low-frequency (delta, theta) and the amplitude of high-frequency (gamma) oscillations in the auditory cortex. P...

An improved genetic programming is proposed in this paper to construct the nonlinear models of speech signals, and the speech coding is further accomplished. After the preprocessing of the speech signals, the improved GP is used to construct the corresponding model of each speech frame. Then by analyzing these models, a normalized model that has generalization ability is obtained. And finally t...

Distributed speech recognition (DSR) is motivated by the fact that codecs used in speech transmission usually reveal a degrading voice quality below some channel quality (carrier-to-interferer ratio C/I), which justifies efficient coding of features with an appropriate channel coding in the mobile terminal. The Adaptive MultiRate (AMR) speech codec standardized for GSM and UMTS however delivers...

An educational software tool on speech coding is presented. Portions of this program are used in our senior-level DSP class at Arizona State University to expose undergraduate students to speech coding and present speech analysis/synthesis as an application paradigm for many DSP fundamental concepts. The simulation software provides an interactive environment that allows students to investigate...

Problem statement: In spontaneous speech communication, speech coding is an important process that should be taken into account, since the quality of coded speech depends on the efficiency of the speech coding algorithm. As for tonal language which tone plays important role not only on the naturalness and also the intelligibility of the speech, tone must be treated appropriately. Approach: This...

Speech coding is the process of obtaining a compact representation of voice signals for efficient transmission over band-limited wired and wireless channels and/or storage. Today, speech coders have become essential components in telecommunications and in the multimedia infrastructure. Commercial systems that rely on efficient speech coding include cellular communication, voice over internet pr...

Problem statement: In modern speech communication at low bit rate, speech coding deteriorates the characteristics of the coded speech significantly. Considering the dialects in Thai, the coding quality of four main dialects spoken by Thai people residing in four core region including central, north, northeast and south regions has not been studied. Approach: This study presents a comparative st...

This paper presents a new unit selection process for Very Low Bit Rate speech encoding around 500 bits/sec. The encoding is based on speech recognition and speech synthesis technologies. The aim of this approach is to use at best the speech corpus of the speaker. The proposed solution uses HMM modelling for the recognition of elementary speech units. The HMM are first trained in an unsupervised...