Bandwidth compressed transmission system
US4692801A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 14, 1986 |
| Grant date | Sep 8, 1987 |
| Priority date | — |
| Expiry date | May 14, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/0152
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a bandwidth compressed transmission system in which a frequency band of a television signal of 2:1 interlace system is compressed, on an encoder side, by interfield offset subsampling at a first sampling frequency corresponding to a substantially upper limit frequency of the television signal and, after an output signal thus subsampled is applied to a LPF for passing a signal component having an aliased portion resulting from the interfield offset subsampling and having a cut-off frequency substantially equal to one half of the first sampling frequency, by interframe offset subsampling at a second sampling frequency lower than the first sampling frequency and higher than one half of the first sampling, so that a multiplexed subsampled transmission signal which does not include an aliased portion of reverse phase results from the interframe offset subsampling. When decoding, interframe interpolation processing of a multiplexed subsampled transmission signal is performed to obtain a signal for a still picture portion, while intrafield interpolation processing of the same transmission signal is performed to obtain a signal for a motion picture portion. An interframe difference of t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.