Echo canceller
US5500892A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 14, 1994 |
| Grant date | Mar 19, 1996 |
| Priority date | — |
| Expiry date | Feb 14, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B3/237
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Analog signals representing individual digital values (+3, +1, -1, -3) of data pass through a telephone line to a receiver. These signals may first be provided in a pseudo random sequence. A linear echo canceller and a first adder at the receiver simultaneously eliminate, to some extent, echo signals resulting from second analog signals transmitted through the telephone line by the receiver. A non-linear echo canceller and a second adder further significantly reduce the echo signals and specifically reduce non-linear components in the echo signals. Adjustable signal delays achieve optimal performance of the linear and non-linear echo cancellers. In one inventive embodiment, each echo canceller includes a memory which stores, for each terminal in such echo canceller, data representing (a) the pseudo random sequence and (b) coefficients for adjusting the signals in such sequence. Such data for each terminal in such echo canceller is recorded in the memory for introduction to the next terminal in the memory. For each terminal in such echo canceller, the signals representing the data for the coefficient and the output from the associated adder are processed to determine an adjusted val…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.