| 摘要 |
PURPOSE:To remarkably reduce a malfunction due to a disturbance or a radio interference by setting the limit level of a limiter to two stages by two limiter setting parts. CONSTITUTION:The serial connector of resistances 23, 24 is connected to the emitter of an emitter follower transistor 20, the serial connecting point is connected to the second base of the second emitter follower transistor 25 and the emitter of the second emitter follower transistor 25 is defined to be an output terminal 10. When a resistance value R22 is set to 30KOMEGA, and a resistance value R24 to 5KOMEGA, the limit level of the limiter amplifier 22 goes to 0.1Vp-p. When the limit level of the limiter amplifier 22 goes to 0.1Vp-p, if the detection sensitivity of a detection circuit is 200mV, the detection circuit 6 responds only to a signal of a frequency range above 200/100 in the gain of a band pass filter 5. Thereby, the malfunction due to the disturbance or the radio interference or the like. |
