Circuit for echo-cancellation in an asymmetric, two-way time-and frequency-shared communication medium
US6804348B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 8, 2000 |
| Grant date | Oct 12, 2004 |
| Priority date | — |
| Expiry date | Jun 19, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L5/1461
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A hybrid circuit models a plurality of attributes of a communication system including a subscriber line coupled to a line interface circuit. The plurality of attributes includes subscriber line impedance, and impedance of a coupling transformer. The attributes are based on other factors, such as whether or not bridge taps exist at or near the line interface circuit on the subscriber line. The plurality of attributes are modeled by a specific arrangement of resistive and capacitive elements to substantially duplicate the collective transforming effects of the attributes on a transmission signal being sent out on the subscriber line. The transmission signal is transformed and provided to an output, where it is subtracted from a composite signal representing a combination of the actual transformed transmission signal and a receive signal. The subtraction yields an isolated receive signal, which is later processed to recover the full receive signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.