| 摘要 |
PROBLEM TO BE SOLVED: To prevent the occurrence of cross modulation distortion in a speech state and to enhance standby time performance by reducing an operating current in a standby state. SOLUTION: A high frequency amplifier 3a consists of an amplifier 301 provided between input and output terminals t1 and t2 and of a bias changeover circuit 302 that selects the bias for this amplifier 301, and the bias changeover circuit 302 receives a transmission control signal Tc sent from a control section 40 to a control terminal t3. Moreover, a power supply voltage is applied to a power terminal t4. The bias changeover circuit 302 detects the operating state of a transmission circuit 5 by the transmission control signal Tc and increases an operating current of the amplifier 301 so as to obtain excellent distortion characteristics when the circuit 5 is in a transmission state and decreases the operating current of the amplifier 301 to improve the standby time performance when the circuit 5 is in a standby state. |
