| 摘要 |
PROBLEM TO BE SOLVED: To provide a AC/DC separation circuit which can separate an AC voltage from a DC voltage without using a large-scale inductor, and further has a high input impedance while improving the noise resistance without deteriorating the S/N ratio. SOLUTION: The AC/DC separating circuit 4 separates an input voltage in which an AC voltage Vac is superimposed on a DC voltage Vdc into a DC voltage and an AC voltage. The AC voltage Vac is inputted into a first differential amplifier A1 having a high input impedance through first and second capacitors C1, C2, and an AC voltage Vac1 is extracted. A circuit configuration is made a balanced type by providing the amplifier A1, and a common mode noise on a signal line 3 can be prevented from changing into a normal mode noise with the circuit 4. As the result, the AC/DC separating circuit is obtained with a high input impedance while improving the noise resistance without deteriorating an S/N ratio. COPYRIGHT: (C)2004,JPO
|
