Digital signal transmission
US4003020A · kind A · utility
Assignees
Inventor
Key dates
| Filing date | Jun 30, 1975 |
| Grant date | Jan 11, 1977 |
| Priority date | — |
| Expiry date | Jun 30, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L1/0045
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Digital words are transmitted together with associated parity or checking digits. The parity bits are each related to a group of bits of the same significance from several different words. At a receiving station, a parity bit is generated for the same group from the incoming words and compared with the corresponding received parity bit. When the generated and received parity bits differ, a value is estimated for each word containing a bit from the respective group, and the estimated and received values for the word are compared to detect any word containing an erroneous bit, which bit is then corrected. This invention relates to the transmission of digital signals. In digital television systems the video signal is commonly represented by a series of eight-digit binary numbers. If any of the bits are altered by errors, then the effect appears as a brightness error in the picture, the magnitude of which depends on the significance of the affected bit. Extra bits, known as parity bits, can be added to the signal to reduce the effect of errors. Each parity bit may typically describe the modulo-two sum of a group of bits in the signal; the rules of modulo-two addition, for which the sym…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.