Apparatus and method for requiring proper synchronization of a digital data flow
US4433348A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 8, 1981 |
| Grant date | Feb 21, 1984 |
| Priority date | — |
| Expiry date | Sep 8, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/1803
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The synchronization circuitry can be described as operating in essentially four states and is particularly useful at startup, to locate synchronization codes and spacing there between in the data flows. In operation, the synchronization circuitry looks in a data flow at startup for any sync code and, when such sync code is found, counts ahead to where the next sync code should be. If a proper sync code is found, again the circuitry counts ahead to where the next sync code should be, continuing looking at points along the data flow until a certain number (n) of properly located sync codes are discovered whereat synchronization is declared and normal playback is ordered. However, if sync codes are not located where they should be in the data flow, then such failures are subtracted from success until either (n) successes are found or a total of successes less failures reaches zero whereat the circuitry returns to the first state of looking for any sync code.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.