Picture-in-picture television receiver
US4249213A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1979 |
| Grant date | Feb 3, 1981 |
| Priority date | — |
| Expiry date | Sep 11, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/45
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A picture-in-picture television receiver is disclosed in which a television picture to be inset is compressed at a compression rate of 1/n and inset as a small-picture in part of a main television picture or large picture, and a single field memory for small-picture reproduction is provided therein in or from which a video signal can be randomly read and written line by line as a unit. In the single field memory is stored the small-picture video signal line by line by the application of a writing clock in which case the time taken in the writing is less than 1/(n+1) of a horizontal period. Then, from the memory is read the stored small-picture information by the application of a reading clock of n times the frequency of the writing clock during the time that writing is not performed, and supplied to be inset in the main television picture. A small-capacity buffer memory is provided at the prestage or following stage of the field memory to prevent the read/write timing overlap in the field memory irrespective of whether the small-picture and the main television picture are synchronized or not in the transmission systems. Thus, the capacity of the field memory essential for the small…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.