Adaptive television deghosting system
US4703357A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 24, 1985 |
| Grant date | Oct 27, 1987 |
| Priority date | — |
| Expiry date | Dec 24, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/211
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An adaptive television deghosting system operates on modulated video signals including a direct signal component and one or more ghost signal components. The system uses synchronously demodulated in-phase and quadrature-phase baseband video signals as the respective real and imaginary input signals to a complex IIR filter. The filter coefficients are developed adaptively from preset initial values using the signals provided by the filter during a training interval. The training interval includes the interval between the leading edge of the vertical sync pulse and the first serration pulse of each field. The filtered training signals are subtracted from a sync-tip reference value to develop a signal which is proportional to the error in the filter coefficient values. The error signal values corresponding to ghost signals are multiplied by the complex conjugate of the training signal values which represent the analogous sampling points of the direct signal. The values produced by this multiplication operation are scaled by an adaptation constant and accumulated to produce the filter coefficients which are used to cancel the ghost signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.