Alarm filter circuit
US6404347B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | May 4, 2001 |
| Grant date | Jun 11, 2002 |
| Priority date | — |
| Expiry date | May 4, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M11/04
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An alarm filter circuit used in telecommunication systems for interconnecting between incoming telephone lines and alarm unit located at a subscriber=s premises so as to block DSL data signals to and from the alarm unit for preventing interference is provided. In one preferred embodiment, the alarm filter circuit includes a first inductor, a second inductor and a third capacitor functioning as a second-order low-pass filter section so as to block the DSL data signals to and from the alarm unit. Second and third capacitors functioning as a first-order high-pass filter section is provided so as to bypass the DSL data signals on the incoming telephone lines to the house wiring. A third inductor and a fourth inductor functioning as a first-order low-pass filter is provided so as to block high-frequency signals between the house wiring and the alarm unit. In a second embodiment, a fourth-order elliptical low-pass filter section replaces the second-order low-pass filter section. In a third embodiment, a third-order high-pass filter section replaces also the first-order high-pass filter section.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.