Digital signal hardware protection switching
US5311551A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 24, 1992 |
| Grant date | May 10, 1994 |
| Priority date | — |
| Expiry date | Jan 24, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L1/22
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Protection switching of digital signal transmitting and receiving hardware is realized in a "hitless" manner. The hitless switch is obtained by employing hardware switching units which can individually determine the instant to switch from an active state to a standby state and vice versa. A switch is initialized by supplying a switch request signal from a control unit to a hardware switching unit in the active state. The active hardware switching unit, upon detecting a prescribed bit condition, for example, a predetermined bit state, of the digital signal being supplied as an output therefrom, supplies a predetermined synchronization pulse to the standby hardware switching unit. In response to the synchronization pulse, the standby hardware switching unit forces the bit condition of a bit of the digital signal to be supplied as an output therefrom resulting from a current input bit to be in the same bit condition as that detected in the active hardware unit. Output circuits in both the active hardware switching unit and standby hardware switching unit are simultaneously turned OFF and ON, respectively, in the individual units by observing the digital signal being supplied as an inp…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.