Circular raster sweep generator
US4327312A · kind A · utility
Inventors
Key dates
| Filing date | Jun 16, 1980 |
| Grant date | Apr 27, 1982 |
| Priority date | — |
| Expiry date | Jun 16, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N3/30
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A sweep generator for producing a circular raster of curved scanning lines on the target surface of a video camera is disclosed. Each curved trace follows a substantially circular path through a scanning angle of 360.degree.. The circular raster is generated by horizontal and vertical scanning signals which are synchronized with the horizontal line frequency of a video receiver. The horizontal scanning signal is characterized by a constant amplitude component followed by a sine wave component, and the vertical scanning signal is characterized by a composite waveform including a constant amplitude component followed by a sine wave component which is shifted 90.degree. in phase with respect to the sine wave of the horizontal scanning signal. The constant amplitude components of each composite waveform are synchronized with the horizontal blanking pulse which occurs during horizontal retrace of the scanning beam in the receiver, and the phase shifted sine waves are synchronized with the forward trace of each horizontal line in the receiver. This produces a one-to-one correspondence of each circular trace in the video camera with each horizontal forward trace in the receiver. The compo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.