Computer-monitor extended range communications link for attenuating and subsequently restoring high frequency components of transmitted video signals
US5193200A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 5, 1989 |
| Grant date | Mar 9, 1993 |
| Priority date | — |
| Expiry date | Dec 5, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/08
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A communications extension link for use between a computer and display unit (K.D.U.) has at the computer site a first interface circuit connected to it and adjacent to the keyboard and display unit a second interface circuit connected to it. The two interface circuits may then be spaced up to 300 feet for a monochrome K.D.U. and up to 150 feet for a color K.D.U. by an extension cable. The first interface circuit includes capacitors connected between keyboard data and clock lines and a positive supply terminal, and TTL buffer amplifiers coupled in single ended configuration are placed in the signal lines relating to video information transmission. The video signals (VS, HS, primary RGB and second rgb) are then each attenuated prior to being passed over the longest cable run, after which they are received by a second interface circuit. The second interface circuit employs discrete resistors between clock and data lines and the positive supply terminal with the attenuated video signals received by discrete buffer amplifiers which amplify the signal and make it compatible with TTL inputs of the monitor. In addition, capacitance is added between the positive supply terminal and logic gr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.