Methods and apparatus for retiming and realignment of STS-1 signals into STS-3 type signal
US5331641A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 9, 1992 |
| Grant date | Jul 19, 1994 |
| Priority date | — |
| Expiry date | Mar 9, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2205/123
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Apparatus and methods for retiming an STS-3 type signal are provided. The SPE of an incoming STS-3 type signal is demultiplexed into three STS-1 payloads and fed to three FIFOs, and a byte which is synchronous with the TOH is tracked through the three FIFOs to provide an indication of the FIFO depth. A frame count is also kept to track the number of frames since a last pointer movement. Stuffs or destuffs are generated based on the FIFO depth as well as based on the frame count, with a stuff or destuff generated as quickly as four frames from a previous pointer movement if the FIFO is close to full or close to empty, and less quickly (e.g., at thirty-two frames from a previous pointer movement) if the FIFO is only starting to empty or to fill. Where the STS-3 type signal is a STS-3C signal, the decision on whether to stuff or destuff is made with reference to all three depth measurement circuits as all the STS-1 payloads must be stuffed or destuffed together. Also, to realign the STS-1 components of the STS-3C signal, the J1 bytes of the signal are tracked through the FIFOs, and a logic circuit is provided having phase 3 of the outgoing STS-3 clock, and the three J1 byte control si…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.