Raster correction circuit
US4719392A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 18, 1986 |
| Grant date | Jan 12, 1988 |
| Priority date | — |
| Expiry date | Jun 18, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N3/233
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a deflection apparatus which corrects for inside pincushion distortion, a deflection winding and a retrace capacitance form a retrace resonance circuit during a retrace interval. A trace capacitance forms a trace resonant circuit with the deflection winding during the trace interval. A circuit branch, that includes a second capacitance and an inductance, is coupled to the trace capacitance during the trace interval to form a second resonant circuit with the trace capacitance having a resonance frequency that is substantially higher during the trace interval than that of the trace resonant circuit. A current in the circuit branch, that is modulated in accordance with the modulated voltage, modulates the trace parabolic voltage across the trace capacitance in a manner to reduce inside pincushion distortion. The trace capacitance acts as a bypass capacitor around the inductance during retrace to prevent the inductance from affecting the retrace voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.