RFI canceller using narrowband and wideband noise estimators
US6959056B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 5, 2001 |
| Grant date | Oct 25, 2005 |
| Priority date | — |
| Expiry date | Apr 16, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L21/0216
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In an adaptive filter for cancelling common-mode noise in digital subscriber loops, a narrowband noise estimator is used to detect one or more noisy frequency bands of the common mode signal and derive therefrom a first noise estimation signal. A wideband noise estimator derives from the remainder of the common mode signal a second noise estimation signal. The first and second noise estimation signals are subtracted from the differential signal, The wideband noise estimator comprises a bandstop filter for removing the frequencies detected by the narrowband noise estimator, an analog-to-digital converter for digitizing the bandstopped signal, and an adaptive filter for deriving the second noise estimation signal from the digitized bandstopped signal and, in the process, compensating for phase and gain differences, especially attributable to the interference being injected at different points along the length of the channel.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.