C/N performance of broadband two-way transmission of RF signals over transmission mediums with limited bandwidth
US6353490B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 12, 1999 |
| Grant date | Mar 5, 2002 |
| Priority date | — |
| Expiry date | May 12, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N21/6168
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The bandwidth of a two-way broadband signal transmission system is expanded by frequency stacking shared band signals. The up conversion (stacking) and down conversion (destacking) systems utilize matched filters, preferably in a multiplexer configuration, which are directly connected, without a combiner, to output the stacked frequency signal in the case of the up conversion system, and without a splitter to separate the frequency stacked signals in the down conversion system. A single base local oscillator signal is used to generate all of the local oscillator signals needed in the system for up and down conversion. In a coax/HFC cable system in which shared band signals from multiple groups of subscribers are frequency stacked in service area nodes for transmission to a headend containing the down conversion system, the single base local oscillator signal is generated by a redundant high quality local oscillator in the headend and transmitted to all of the service area nodes in the broadband downstream signal. A comb generator in each service area node and in the headend generates the local oscillator signals needed for up/down conversion as harmonics of the base local oscillato…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.