Adaptive multiple sub-band common-mode RFI suppression
US6052420A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | May 14, 1998 |
| Grant date | Apr 18, 2000 |
| Priority date | — |
| Expiry date | May 14, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/126
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A noise suppression circuit for a two-wire communications channel comprises a hybrid device, for example a hybrid transformer or circuit, for providing a differential mode signal corresponding to a differential signal received from the two-wire channel. A summing device extracts from the two-wires of the channel a common mode signal and supplies it to a noise estimation unit which derives from the common mode signal an estimate of a noise level in at least one frequency band having a bandwidth considerably narrower than an operating bandwidth for the channel. The noise estimation unit adjusts the amplitude of the noise estimate to correspond to the residual noise in the differential mode signal and subtracts it from the differential mode signal to produce a noise-suppressed output signal. A noise detection and control unit scans the operating band, identifies a frequency band having an instant highest noise level, and sets the noise estimation unit to the detected noisy band. The noise estimation unit suppresses the noise in that band. In preferred embodiments, the noise estimation unit comprises several channels, each comprising a tunable filter, a phase shifter and an amplifier, …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.