Echo cancelling device for data transmission over two-wire lines
US4887257A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 1988 |
| Grant date | Dec 12, 1989 |
| Priority date | — |
| Expiry date | Mar 7, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B3/238
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Echo cancelling device for cancelling echoes affecting the incoming signal received over a two-wire telephone line, comprising near echo canceller 20, far echo canceller 22 and an adder 26 providing the estimated echo signal. A circuit path including a digital-to-analog converter 48 for converting the digital estimated echo signal into analog form and a subtracter 52 for subtracting the resulting analog signal from the analog incoming signal, is separated from a circuit path including an analog-to-digital converter 42 for converting the analog incoming signal into digital form and a subtracter 44 for subtracting the digital estimated echo signal from the resulting digital incoming signal thereby providing a digital signal used as a control signal for adjusting the echo cancellers 20 and 22.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.