Digital wipe generator
US4805022A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 19, 1988 |
| Grant date | Feb 14, 1989 |
| Priority date | — |
| Expiry date | Feb 19, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/265
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A digital wipe generator has a digital waveform generator to generate X and Y digital waveforms from a composite sync signal. A digital wipe solid generator processes the X and Y digital waveforms to produce a digital wipe solid waveform. The wipe solid generator has a circle generator using a square root function which preshifts the sum of the squares prior to access to a look-up table, and then post shifts the output of the look-up table by one-half the amount of the preshift to produce a desired curve pattern for the digital wipe solid waveform. The digital wipe solid waveform is input to mixer circuits where it is processed to produce an anti-aliased key signal for mixing external video signals, the anti-aliasing being based upon an interpolation/decimation scheme using fractional bits of the digital wipe solid waveform. The output of the mixer circuits is a desired wipe transition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.