Modem with improved remote echo location and cancellation
US4970715A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 3, 1989 |
| Grant date | Nov 13, 1990 |
| Priority date | — |
| Expiry date | Apr 3, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B3/237
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A modem capable of simultaneously transmitting and receiving data signals over a single communication channel with a remote modem includes a transmitter for converting TX digital data into analog signals for transmission over the channel and a receiver for converting received analog signals into RX digital data. A mechanism identifies a remote echo returning to the modem corresponding to previously transmitted TX digital data. The identifiying mechanism is capable of identifiying a echo originating intermediate between the modem and the remote modem. Another mechanism substantially cancels the identified remote echo. The present invention also encompasses the method of identification and cancellation of remote echos. In addition, remote echo cancellation signals are not combined with received signals until local echo has been substantially cancelled.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.