Method and apparatus for controlling signal coherency in simulcast systems
US4972410A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 20, 1989 |
| Grant date | Nov 20, 1990 |
| Priority date | — |
| Expiry date | Jul 20, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B7/2625
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A simultaneous broadcast (simulcast) system transmits from a control site to two or more remote sites the same data information along with a synchronous digital signal via a synchronous digital transmission network. At the remote sites, a clock signal is derived from the digital signal for timing the broadcast of the data information on an RF carrier. The clock signal phase is periodically reset to a known phase using a predetermined pattern of data bits in the digital signal. A time delay circuit at the control site delays the synchronous digital signal such that, where RF carrier signals from the remote sites overlap, there is time coherency between the data information. The time delay circuit is constructed so as to preserve the synchronization of the digital signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.