TV and data cable system ingress noise blocker
US6094211A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 15, 1996 |
| Grant date | Jul 25, 2000 |
| Priority date | — |
| Expiry date | Aug 15, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N21/6168
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
This invention permits the upstream transmission of short packets of information in a cable TV system, and blocking upstream noise at all other times, and does so without interfering with image quality of normal TV viewing. A remotely operable ingress noise blocking filter is placed at the terminating junction between a subscriber's coaxial drop cable and a corresponding feeder tap in a cable TV system. The ingress noise blocking filter contains a high pass filter to pass the normal TV band. This high pass filter is bypassed by a section containing low pass filters and a switch operated when receiving a control signal from a cable modem during those short durations the cable modem is authorized to transmit an upstream signal. Low pass filters isolate the switching elements so that switching transients cannot occur in the downstream TV band. The level of the amplitude of the downstream signal is unaffected whether the switching elements are open or closed. Further, the switching arrangement provides a relatively constant impedance, both when the switching element is on and off to provide a high return loss and avoid signal reflections and maintain signal quality. In a diagnostic mod…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.