Convergence correction
US5747948A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 15, 1997 |
| Grant date | May 5, 1998 |
| Priority date | — |
| Expiry date | May 15, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/28
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A correction circuit for a cathode ray tube displaying images subject to distortions comprises: a multiplier for a first horizontal sine waveform and a vertical parabola waveform to define a correction signal, the vertical parabola having a zero value during vertical retrace; a summer for combining a second horizontal sine waveform with the correction waveform to define a composite correction signal, one of the second horizontal sine waveform and the correction signal being first inverted; and, a correction coil for the cathode ray tube receiving the composite correction signal and generating a dynamic magnetic field responsive to the composite correction signal for correcting a residual inner pincushion distortion and for correcting a horizontal linearity distortion imparted by the correction of the residual inner pincushion distortion. When the first and second horizontal rate sine waves are generated by the same waveform generator, the composite correction signal further corrects any distortion due to asymmetry of the horizontal rate sine waveform as generated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.