Composite video color signal generation from digital color signals
US4442428A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 12, 1981 |
| Grant date | Apr 10, 1984 |
| Priority date | — |
| Expiry date | Aug 12, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G1/285
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A 3.58 MHz subcarrier signal and a 14.318 MHz clock signal are applied to three flipflops (50, 52 and 54) in such a manner that there appears on the output terminals (Q and Q) of the latches individual phase-shifted subcarriers having relative phases of 0.degree., 180.degree., 90.degree., 270.degree., 135.degree. and 315.degree. , respectively, representing the colors yellow, blue, red, cyan, magenta and green, respectively. Computer-generated digital color signals (+BLUE, +GREEN, +RED) are applied to the switching inputs (A, B, C) of a multiplexer (56) in order selectively to switch to the output of the multiplexer individual ones of the phase-shifted subcarriers in accordance with the code represented by the digital color signals. The individual subcarriers are combined in a summing circuit (62, 64) with television synchronizing and blanking pulses to produce a composite video color signal which is directly compatible with a conventional composite monitor and, after R.F. modulation, with a conventional television receiver. Brighter versions of the colors are obtained by increasing the direct current level (+INTENSITY) at the summing circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.