Patent ID: 7142884
Filing Date: 2006-11-28
Classification: H04B

Abstract:
1. A front-end circuit for a multi-mode communication terminal device, comprising: at least one switch element selected from the group consisting of RF switches, duplexers and diplexers; a common antenna; a first transmission system being a pure mode transmission system configured to operate in a pure TDD mode; a second transmission system being a pure mode transmission system configured to operate in a pure FDD mode; filters provided for said first and second transmission systems; a connecting circuit via which individual filters of said filters are connected to said common antenna, said connecting circuit comprising said at least one switch element; said filters comprising a first filter, a second filter, and a third filter, said first filter being a transmit filter of said FDD system, said second filter being a common receive filter for said TDD system and said FDD system, and said third filter being a transmit filter for said TDD system; a duplexer formed by said first filter and said second filter; and a switch element comprising an RE switch to connect said common antenna with one of said duplexer and said third filter.