Antenna switching circuit for a diversity receiving system and branching circuit with a signal attenuation operation
US4656364A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 10, 1985 |
| Grant date | Apr 7, 1987 |
| Priority date | — |
| Expiry date | Jul 10, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01Q3/24
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An antenna switching circuit which selectively transmits, to a receiver, RF signals from a plurality of antennas including RF signals of different frequency bands such as the VHF band and the MF band using a single output terminal. To prevent a level drop of RF signals of one of the frequency bands due to a common use of the output terminal, a unidirectional switching element is added to a switching circuit network by which the selection of RF signals from the different antennas is performed. A branching circuit for separating RF signals of different frequency bands is provided with an attenuation operation using a variable impedance characteristic of a semiconductor switching element which is basically on-off operated for the switching between the RF signals of the different frequency bands.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.