Two-way digital communication system and method without carrier lock-on or ingress interference
US6393063B1 · kind B1 · utility
Inventors
Key dates
| Filing date | Jan 3, 1996 |
| Grant date | May 21, 2002 |
| Priority date | — |
| Expiry date | Jan 3, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N21/6168
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A communication system that provides two-way digital communication between a central site and a plurality of user terminals via standard cable television networks and facilities free from interference from “carrier lock-on” and “ingress” by transmitting an FSK signal over one frequency channel from the central site to the user sites and transmitting two spaced FSK subcarrier signals, on two other frequency channels, from the user terminals to the central site, and where the receiver at the central site has two channels matched in frequency to the subcarrier frequencies and having a decoder that will not pass received information unless it has been received for a prescribed duration at a prescribed level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.