One-way addressable system
US4741048A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 17, 1986 |
| Grant date | Apr 26, 1988 |
| Priority date | — |
| Expiry date | Oct 17, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/163
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A one-way addressable system includes a broadcasting center from which pay television signals and time codes representing time are produced, and subscriber's television receivers. The receiver includes a detector which produces a failure signal upon detection of a failure of a power supply along a primary power line, and produces an establish signal upon detection of an establish of the power supply along the primary power line. A secondary power source is provided for supplying power to the receiver when the failure signal is produced. A buffer is provided for storing newly received time code while the establish signal is present and for holding the same time code, which is received immediately before the generation of the failure signal, while the failure signal is present. A memory is provided for storing the time code shifted from the buffer in response to the receipt of a new time code to the buffer. A microcomputer calculates a time difference between the time codes maintained in the buffer and in the memory, thereby enabling the time count during the failure signal is present.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.