Full duplex transceiver comprising hybrid coil and automatic impedance adjustment means
US4246582A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 26, 1978 |
| Grant date | Jan 20, 1981 |
| Priority date | — |
| Expiry date | Dec 26, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/525
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Data signals are transmitted from a transmission unit (12) through a hybrid coil (16) and transmission line (18) to a remote transceiver. Data signals of a different frequency are received from the remote transceiver through the transmission line (18) and hybrid coil (16) in a full duplex mode and passed to a reception unit (26). A ratio of the signal levels of the received data signals passed through the hybrid coil (16) in a desired manner to transmitted data signals which leak through the hybrid coil (16) in an undesired manner is sensed at a reception signal output of the hybrid coil (16). The resistance of a variable resistance pad (17) provided in the transmission line (18) is varied in accordance with the sensed ratio so as to adjust the ratio to a predetermined optimum value. The sensed ratio is a predetermined function of the impedance of the transmission line (18) as viewed from the hybrid coil (16). The amplification factors of transmission and reception amplifiers (14), (22) are also varied to compensate for variations in attenuation of the transmitted and received signals by the resistance pad (17).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.