Browse Prior Art Database

Digital Voice Transmission System

IP.com Disclosure Number: IPCOM000039123D
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Galand, C: AUTHOR

Abstract

This system takes advantage of short-term non-varying or slightly varying condition and packet recovery procedure to avoid traffic jamming in a digital voice packet transmission network. The input speech signal is digitally encoded in a conventional Voice Excited Predictive Coder (VEPC) providing three types of information: Parcor coefficients (Ki), bloc energy information (Ei) and subband samples (Sb). Sb, Ei and Ki are digitally encoded (or re-encoded) in CODE using dynamic quantizing bit allocation methods. Re- encoded data Sb', Ei' and Ki' are then multiplexed in MPLX and transmitted over the digital channel L. On the receiving side, reverse operations are performed to regenerate the speech information. In addition, a variable rate control (VRC) device is provided.

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Digital Voice Transmission System

This system takes advantage of short-term non-varying or slightly varying condition and packet recovery procedure to avoid traffic jamming in a digital voice packet transmission network. The input speech signal is digitally encoded in a conventional Voice Excited Predictive Coder (VEPC) providing three types of information: Parcor coefficients (Ki), bloc energy information (Ei) and subband samples (Sb). Sb, Ei and Ki are digitally encoded (or re-encoded) in CODE using dynamic quantizing bit allocation methods. Re- encoded data Sb', Ei' and Ki' are then multiplexed in MPLX and transmitted over the digital channel L. On the receiving side, reverse operations are performed to regenerate the speech information. In addition, a variable rate control (VRC) device is provided. The VRC device computes the variations W information about each one of the three types of data, i.e., WSb, WEi and WKi. These W data are then compared with preset thresholds to enable identifying the considered speech block as stationary or non-stationary depending on whether the W data are below or above the thresholds. Only non-stationary blocks are transmitted over L. Transmission is made after assembling a fixed number of blocks of samples into a packet assigned with a sequence number. The transmission sequence counter is made to run even when a stationary block, which is kept from being transmitted, is detected at the transmitting side. Based on the sequence n...