Method and apparatus for multiplexing television signals
US4807030A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 13, 1986 |
| Grant date | Feb 21, 1989 |
| Priority date | — |
| Expiry date | Jun 13, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/0806
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A decoder for use in a multiplexing system wherein the adjacent frame lines of a first program are summed and differenced, and the sum signal and time-compressed difference signal of each line pair is transmitted during the period allotted for transmission of a single line, thereby transmitting data for two lines in the time allotted for a single line. The decoder avoids a need for complex digital wall filters at the input by sampling the timed-compressed difference signals at a non-unity multiple of the rate used for sampling the sum signals. The multiple is sufficiently fast to enable the standard "front-end" low pass filter of the decoder to function as an interpolation filter, eliminating the artifacts which would otherwise require the use of the complex filter. The disclosed decoder additionally includes a first memory-sharing arrangement wherein memory addresses are accessed during each operating cycle in a manner which permits data to be written into memory prior to the complete reading out of data from the previous operating cycle. A second memory-sharing arrangement is included wherein memory addresses are accessed during each operating cycle in a manner which permits data…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.