Propagation-delay-transparent video-signal interface
US5521625A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 19, 1993 |
| Grant date | May 28, 1996 |
| Priority date | — |
| Expiry date | Aug 19, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K2215/0077
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A propagation-delay-transparent, video-signal interface suitable for use in a laser printer to carry a video signal from a formatter to a laser driver with minimal distortion. The interface includes two transmission paths, one for carrying the video signal produced by the formatter and another for carrying an inverted video signal or complement of the video signal. A differential circuit is included in the interface to determine a difference between the signals transmitted by the two transmission paths so that common-mode noise introduced along the transmission paths is substantially eliminated. The transmission paths include buffers, which restore pulses in the video signal to appropriate digital levels. The differential circuit includes hysteresis circuitry that, in combination with the differential function of the differential circuit, eliminates pulse width distortion of the video signal caused by delays of the buffers. The buffers are formed in pairs on common substrates so that the two transmission paths have nearly identical propagation delays, to further minimize pulse width distortion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.