Method and apparatus for multiplexing fixed length message data and variably coded speech
US5515375A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 30, 1993 |
| Grant date | May 7, 1996 |
| Priority date | — |
| Expiry date | Jul 30, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J3/1688
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Speech of an unknown amount and control message data (150) of known amount are multiplexed so that the coded voice data is transmitted before the elapse of a predetermined number of frames. A variable rate vocoder (110) receives and codes the speech of an unknown amount at one of full and less than full rates to produce the coded voice data. A multiplexer (120) receives the coded voice data from the variable rate vocoder (110) and sends frames containing the coded voice data when the variable rate vocoder operates at a full rate. When the variable rate vocoder (110) operates at a less than full rate, the multiplexer (120) sends frames containing portions of the message data together with the coded voice data. However, when the number of frames remaining before a predetermined number of flames has been sent is the minimum number of frames necessary to send remaining of the control message data (150) together with the coded voice data at less than full rate, the variable rate vocoder (110) is forced to a voice coding rate lower than full rate. The lower than full rate voice coding of the variable rate vocoder (110) reduces the amount of coded voice data to send in a frame and makes s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.