Method of signal alignment in television and device for implementing it
US5548343A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 5, 1994 |
| Grant date | Aug 20, 1996 |
| Priority date | — |
| Expiry date | Dec 5, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/72
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A television (TV) signal alignment method and device are disclosed which provide a clear TV picture. The alignment method provides reduced noise. Despite transmission noise, the alignment method reduces noise at frequencies lower than 15 kHz which is generated by the alignment device, to below the visual perception threshold. This improves signal-to-noise ratio. The alignment method and device reduce this noise while rejecting 50 Hz and 25 Hz frequencies of greater than 30 dB. At each line of an image, the alignment method and device use a feedback loop to successively align a plateau at a first start of the current line of a television signal, which has transmission noise superimposed thereon, on the plateau of the preceding line. This is performed to restore the DC component of the television signal. The low-frequency noise generated in the loop and superimposed on the plateau of the television is reduced by distributing a sampled television signal into two branches of a noise-reduction device at the input of the loop. The sampled television signal is preserved in the first branch, while it is filtered in the second branch. The filtered and preserved signals are subtracted. The l…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.