System and method for voice Playout in an asynchronous packet network
US5790538A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 26, 1996 |
| Grant date | Aug 4, 1998 |
| Priority date | — |
| Expiry date | Jan 26, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q2213/13362
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A System for Voice Playout in an Unsynchronized Packet Network for use with isochronous and asynchronous data transmission over a communication network having at least one receiving unit and at least one transmitting unit each having independent clocks. A FIFO voice codeword storing device in the receiving unit removes timing jitter from incoming packets--and receives voice packets from a data network. A phase continuous packet clock thereafter removes packets from the FIFO voice codeword storing device which is synchronized to the incoming data rate using the fill status of the FIFO voice codeword storing device as a frequency control signal. A continuous phase resampler removes timing frequency offset without causing packet slips or loss of data. The transmitter inserts the contents of a free running packet counter into each transmitted packet, allowing the receiver to detect lost packets and to properly reproduce silence intervals during Playout. A receive sequence counter increments at the local packet rate to schedule Playouts for multiple voice segments. A clock frequency recovery is utilized where the receiver clock frequency differs from the transmitter clock frequency. Whe…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.