Method and apparatus for filtering asymmetric digital subscriber line (ADSL) signals
US6813343B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | May 12, 1999 |
| Grant date | Nov 2, 2004 |
| Priority date | — |
| Expiry date | May 12, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2601
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for selectively filtering signals on a digital subscriber line (DSL) so as to prevent interference resulting from a telephone instrument switching between its on-hook and off-hook states. One embodiment of the invention utilizes an off-hook detector controlling a variable attenuator element. Another embodiment of the invention uses a switch in parallel with a resistive element to implement the variable attenuator element. Yet another embodiment has an inductive element with a saturable core for providing attenuation to compensate for inconsistencies that result from the changing hookswitch status of a telephone instrument.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.