Line interface and method for detecting and eliminating an impedance mismatch between a transceiver and a transmission line
US6400772B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 16, 1998 |
| Grant date | Jun 4, 2002 |
| Priority date | — |
| Expiry date | Jun 16, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/0278
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A line interface apparatus includes a line coupling transformer having first and second windings, and an impedance matching circuit connected to the first winding. The impedance matching circuit includes a first section characterized by a first impedance, a second section characterized by a second impedance, and a switch circuit, connected to the first and second sections and to the first winding of the line coupling transformer, for switching either the first or the second section in series with the first winding of the line coupling transformer. An echo of a transmitted signal is replicated and subtracted from a composite signal comprising a received signal and the echo of the transmitted signal. The result of the subtraction is compared to a threshold value to indicate whether a loop connected to the second winding of the line coupling transformer has an impedance about equal to a first impedance or about equal to a second impedance. If the result of the subtraction is at least as great as the threshold value, an arm of a switch is connected to the first inductive circuit, and if the result is less than the threshold value, the switch arm is connected to the second inductive. Th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.