The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 16, 1999
Filed:
Mar. 26, 1997
Hisashi Yajima, Tokyo, JP;
Noriaki Kawano, Tokyo, JP;
Yushi Naito, Tokyo, JP;
Shigeaki Suzuki, Tokyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
In a voice coding-and-transmission system using a differential coding, a degradation of voice quality caused by a silent period transmission network and an ATM network is prevented without improving a silent-period elimination transmission network and existing transmission networks such as a STM network. In a relay node 104, an encoder 114 codes a voice signal from a decoder 108 again for a transient period immediately after a voice is started, and a transmission node 100 and a reception node 102 are tandem-connected. The encoder 114 and a decoder 122 at a reception node 102 are given respectively same reference values of a differential processing by memories 118, 128 when the voice is started, thereby preventing an abnormal sound generation due to a mismatch of inner statuses thereof when the voice is started. During the transient period, the internal statuses of an encoder 106 at a reception node 100 and the decoder 122 are closed each other. After the transient period is elapsed, switching a switch in a silent-period eliminator 112 to a digital-one-link, thereby preventing the degradation of the voice quality caused by quantization errors.