| 摘要 |
PURPOSE:To make circuit integration easy, by interposing a switching means in a negative feedback loop of an operational amplifier and controlling this switch means so that it is closed at an opened section of a switch provided to the noninverting terminal and the inverting terminal of the operational amplifier. CONSTITUTION:Normal mode signal voltages Va, Vb, and a common mode noise voltage Vc are sampled with the switching of a timing pulse signal Sig1 of switching means S1, S2, and the sampled noise is smoothed through pulse filters LPF1, LPF2 and fed to the noninverting terminal and the inverting terminal of an operational amplifier 14. On the other hand, an output signal Vo of the operational amplifier 14 is sampled at a negative feedback loop with the switching of a timing pulse signal Sig2 of a switching means S3, and the sampled noise is smoothed through the low pass filter LPF2 and fed to the inverting terminal of the operational amplifier 14. |
