| 摘要 |
PURPOSE:To interrupt a reception tone during the sounding of a buzzer for the confirmation of key operation and prevent the generation of a click noise generated during mode switching and frequency band switching by providing a receiver circuit with a muting circuit. CONSTITUTION:A receive signal is detected by a detecting circuit 1, amplified by an amplifier 2, and passed through the muting circuit 3 to drive a speaker 5. When a key matrix 7 connected to a CPU6 is operated, a buzzer circuit 8 operates and the receive signal is muted by the muting circuit 3. Further, a click noise due to the mode switching and frequency band switching on the matrix 7 is also muted by the muting circuit 3, so it is not outputted from the speaker 5. |
