Patent ID: 7324493
Filing Date: 2008-01-29
Classification: H01P,H04B

Abstract:
1. A 3-frequency branching circuit having a filter function of passing a transmitting frequency band and a receiving frequency band in each of first, second and third frequency bands, comprising: first, second and third internal terminals; an antenna terminal of connecting to an antenna; branching means having a first filter of passing the third frequency band between said first internal terminal and said antenna terminal and a second filter of passing said first and second frequency bands between said second internal terminal and said antenna terminal; a first switching circuit, connected to said first internal terminal, of switching between a first transmitting terminal used to transmit said third frequency band and a first receiving terminal used to receive said third frequency band; a second switching circuit, connected to said second internal terminal, of switching among a second transmitting terminal used to transmit a transmitting frequency band of said second frequency band, a second receiving terminal used to receive a receiving frequency band of said second frequency band, and the third internal terminal used to transmit and receive said first frequency band; and a duplexer, connected to said third internal terminal, of branching the transmitting frequency band and the receiving frequency band of said first frequency band.