| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a circuit shared for transmission and reception capable of simplifying/downsizing/saving power of the circuit by using one amplifier circuit for a transmission amplifier circuit and a reception amplifier circuit in common. <P>SOLUTION: A single amplifier circuit 12 is provided in a way of interconnecting between a speech transmission switch 4 and a speech reception switch 5 of a speech transmission section 7 and between a speech transmission switch 9 and a speech reception switch 8 of a speech reception section 10, and one microphone or speaker element 13 having a microphone function and a speaker function is provided in a way of interconnecting the speech reception switch 5 of the speech transmission section 7 and the speech transmission switch 9 of the speech reception section 10. The transmission reception combination circuit is provided with a control circuit 20 which controls the switches so that the speech transmission switches 4, 9 of the speech transmission section 7 and the speech reception section 10 are closed and the speech reception switches 5, 8 are opened at speech transmission, and the speech transmission switches 4, 9 of the speech transmission section 7 and the speech reception section 10 are opened and the speech reception switches 5, 8 are closed at speech reception. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
