Signal separator for separating teletext bit sequences from a broadcast television signal
US5218437A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 26, 1991 |
| Grant date | Jun 8, 1993 |
| Priority date | — |
| Expiry date | Aug 26, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/035
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A signal separator, particularly a teletext-signal separator, includes an integrating unit which delivers a center-of-bit-indicating (i.e., center-crossing) signal and a residual-value signal. A residual-value-signal-evaluating device evaluates the respective residual value and uses a selection control signal to determine how the value of the current signal bit is to be estimated. This is accomplished by using a selection facility which derives from the current sample value and the preceding and subsequent sample values the respective preaverage value and postaverage value and selects the value best suited for the estimation using the selection control signal. A phase corrector evaluates a signal pattern from an edge logic which indicates whether the current sample value is approaching an edge of the signal, and controls a change of the integration period if the residual-value signal lies within a predetermined residual value signal range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.