Ingress noise control system and ingress noise blocking device
US6868552B1 · kind B1 · utility
Assignees
Inventors
Key dates
| Filing date | Jun 7, 2000 |
| Grant date | Mar 15, 2005 |
| Priority date | — |
| Expiry date | Jan 9, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/17309
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention concerns an ingress noise control system and an ingress noise blocking device which are used in a cable system to suppress ingress noise. In the cable system providing two-way communication using different frequency bands for transmission of upstream and downstream signals, the ingress noise control system includes, within a distribution unit, a two-way amplification unit, etc. provided in an upstream signal transmission path, a synchronous detection controller 6 for synchronously detecting the upstream signal transmitted from terminal equipment and separated by a low-pass filter 4 in a second separation filter 2, a gate switch circuit 5 which is turned on by the synchronous detection controller 6 to pass the upstream signal only when the upstream signal is synchronously detected, and an indicator 7 for indicating the on/off state of the gate switch circuit 5.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.