Apparatus and method for locating nonlinear impairments in a communication channel by use of nonlinear time domain reflectometry
US7230970B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 2, 2003 |
| Grant date | Jun 12, 2007 |
| Priority date | — |
| Expiry date | Nov 20, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B3/46
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A series of time domain reflectometry (tdr) measurements are made on a channel having nonlinear impairments as well as linear impairments. In a given measurement, the reflected signals from the impairments are digitized and sequentially stored in memory. The parameters characterizing the channel are then changed, preferably by biasing the line by means of a dc current. The changed bias condition modifies the impedance of nonlinear impairments in a nonlinear manner, while the impedance of linear impairments are unchanged by the bias. A second tdr measurement is initiated, and the reflected signals digitized and sequentially stored. The two sets of stored reflected signals are then sequentially compared, and corresponding signals having either the same amplitudes or linearly proportional amplitudes are identified as reflected from linear impairments, while those not the same, nor proportional, are identified as from nonlinear impairments.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.