Bus transmission system
US4388725A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 26, 1980 |
| Grant date | Jun 14, 1983 |
| Priority date | — |
| Expiry date | Nov 26, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/4072
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A bus transmission system in which two or more drive circuits are connected to the same transmission line, wherein both ends of a transmission line are grounded via a terminal resistance where is nearly equal to the characteristic impedance of the line. The drive circuits have three states consisting of a low-level state in which the output impedance is small, a high-level state in which the output impedance is small and a high-impedance state in which the output impedance is very high. When data is not to be transmitted, the drive circuit is placed in the high-impedance state, when data is to be transmitted, the high-impedance state of one of the drive circuits is converted into the low-level state in which the output impedance is small so that data can be transmitted based upon the low-level state and the high-level state, and when the transmission of data is finished, the drive circuit is placed in the low-level state again and thereafter placed in the high-impedance state. The data to be transmitted is modulated by a pulse width modulation device that uses a return to zero amplitude method as part of the modulation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.