| 摘要 |
PURPOSE:To remove the influence of the internal impedance of a reference power source and a voltage drop across a diode which feeds the output of one amplifier back by connecting the reference power source to the operational amplifier and the diode to a signal line. CONSTITUTION:Signal-source elecromotive force ES is inputted to the inverted input terminal of an operational amplifier Z1. When this voltage is higher than that of a reference power source Vh, the diode D1 is biased forward to perform amplitude limiting operation. When the input voltage is lower, the diode D1 is biased reversely, so the signal is transmitted as it is. The trailing operational amplifier Z2 performs the same operation with the leading operational amplifier Z1 when the input voltage is minus. Therefore, almost no current from the reference power source is consumed, so the need to reduce the internal impedance of the reference power source is eliminated, a variable rsistor is usable, and the diode is in a negative feedback loop, so the influence of the voltage drop is eliminated. |
