| 摘要 |
PROBLEM TO BE SOLVED: To provide a radio transmission reception circuit using no antenna switch module.SOLUTION: The radio transmission device includes: a first amplifier 31 that amplifies transmission signals; a transmission circuit 37 that processes the amplified transmission signals; an antenna 13; and a control section 10e that controls the first amplifier 31 to alternately repeat activation and inactivation. Defining the impedance when the control section 10e controls the first amplifier 31 to activate viewing the transmission circuit 37 from the antenna 13 as ZonT; the impedance when the control section 10e controls the first amplifier 31 to inactivate viewing the transmission circuit 37 from the antenna 13 as ZoffT, the transmission circuit 37 matches the impedance of the antenna 13 and ZonT, and for obtaining a large absolute value of voltage reflection coefficient &Ggr;, is provided with a first impedance matching circuit 32 that transits ZonT and the ZoffT, and a first phase adjustment circuit 33 that transits ZoffT to a high impedance state. |
