Compensated hybrid
US5541990A · kind A · utility
10Cited by
3References
12Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jul 5, 1994 |
| Grant date | Jul 30, 1996 |
| Priority date | — |
| Expiry date | Jul 5, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/0002
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A hybrid circuit for coupling a modem to an external telephone line substantially compensates for and thereby cancels reflected echo. The hybrid includes a transformer coupled between the telephone line and the modem transceiver, which includes a transmitter and a receiver. A matching resistor connected between the transceiver transmitter and the transformer at a hybrid point presents a matching impedance to the telephone line impedance. A feedback network is implemented between the transceiver receiver and transmitter to feed back sufficient voltage into the receive line to cancel echo produced at the hybrid point.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.