| 摘要 |
PURPOSE:To attain desired characteristics for the entire circuit frequency characteristics and to obtain an excellent common mode rejection ratio (CMR) by constituting the titled circuit of the 1st-4th 2-terminal circuit networks having a capacitive element and a differential amplifier with a high gain. CONSTITUTION:External signal input terminals 1b, 1b are connected respectively to non-inverting and inverting input terminals 10a, 10b of a differential amplifier circuit 10 respectively via a capacitors (insulation capacitors) C1, C2 being the 1st and 2nd 2-terminal circuit networks. The differential amplifier 10 constitutes a feedback type differential amplifier circuit together with capacitors C1-C4. The production of a common mode voltage between the input terminals 10a and 10b of the differential amplifier 10 is prevented by making a potential of a connecting point (the non-inverting input terminal 10a of the differential amplifier 10) between the impedances Z1 and Z3 of a bridge circuit comprising the impedances Z1-Z4 identical to a potential 10 of a connecting point (the inverting input terminal 10b) between the impedances Z2 and Z4 to optimize the CMR of the differential amplifier 10. |
