COMPOSITE DUPLEXER

摘要

A composite duplexer comprises an antenna terminal, a first receiving terminal, a second receiving terminal, a transmitting terminal, a first switch, a duplexer and a second switch. The first switch has a first branch contact; a second branch contact connected to the transmitting terminal; a third branch contact connected to the second receiving terminal; and a common contact connected to the first antenna terminal. The common contact of the first switch is selectively connected to one of the first through third branch contacts. The duplexer, which has a transmitting filter and a receiving filter connected to the first receiving terminal, is connected to the first branch contact of the first switch. The second switch can selectively establish or interrupt the electrical connection between the first transmitting filter of the first duplexer and the transmitting terminal. Even if frequency bands are close to each other, the composite duplexer can branch the signals of those frequency bands.