| 摘要 |
<p>PROBLEM TO BE SOLVED: To dispense with a diode and detect a peak value of good characteristic up to a high frequency territory by separating a peak detecting means into the positive side and the negative side, and individually detecting the peak value. SOLUTION: In the case of no signal, the voltage V0 of an output terminal 12 becomes reference bias voltage Vcc/2. When a positive side signal (a voltage signal higher than the reference bias voltage Vcc/2) is input to an input terminal 11, an operational amplifier 1 becomes in the condition of inversion input terminal voltage > non-inversion input terminal voltage Vcc/2 so as to make transistor 3 conductive, and a capacitor 10 is charged by current passed through resistance 5, 7. When the voltage V0 of the output terminal 12 rises equal to the input voltage of the input terminal 11, the transistor 3 is intercepted, and the capacitor 10 outputs the voltage V0 corresponding to the peak value of the positive side voltage held therewith from the output terminal 12. Next when the input negative side signal is lower than the peak detecting voltage V0 of the output terminal 12 inverted by an inversion amplifier 8, the output voltage of an operational amplifier 2 lowers so as to make a transistor 4 conductive, and the capacitor 10 is further charged.</p> |
