Echo and crosstalk cancellation
US7020068B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 30, 2001 |
| Grant date | Mar 28, 2006 |
| Priority date | — |
| Expiry date | Jan 17, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B3/23
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A cancellation system comprises a channel circuit (11) for each noise source, such as echo in a particular cable pair. There are only eighty taps per channel, in two blocks (n_echo_a, f_echo_a). Each block is preceded by a variable delay line comprising blocks of registers cascaded so that a delay value of 0 to 40 clock cycles can be chosen. The delay value is determined by determining an optimum position for each tap block. This is achieved by determining a maximum coefficient sum for a number of windows. Taps from other channels are used during training, so that there is a total of 160 taps for each channel during training to enable the optimum positions to be determined.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.