| 摘要 |
PURPOSE:To adjust automatically an offset amount generated at an output of an operational amplfier having a nonlinear feedback circuit by digitizing an offset to form a correcting analog signal. CONSTITUTION:When an output of a DA converter 20 is zero, an output of a voltage comparator 12 goes to a high level by a current flowing to a resistor 8. A clock signal 15 passes through an AND gate 16, is fed to a binary counter 19, and when the counter counts up, an output of the DA conerter 20 increases gradually, an output of an operational amplifier 9 also increases and the polarity of the output is changed. The output of the voltage comparator 12 changes from a high level to a low level, the gate 16 is closed and an output of the DA converter 20 is obtained according to a value stored in the binary counter to complete the offset adjustment operation. |
