| 摘要 |
PURPOSE:To eliminate a DC offset portion, and to digitize exactly an analog signal by adding an offset detecting means and an offset eliminating means. CONSTITUTION:An analog signal A from an input terminal 11 is supplied to an S & H circuit 12 through a variable bias circuit 22. An output of this S & H circuit 12 is supplied to an offset detecting circuit 27 through an ADC circuit 20. Subsequently, offset data detected by the detecting circuit 27 is converted to an analog signal by a DAC circuit 37, and a DC offset voltage of an analog value is obtained. By applying this DC offset voltage to the bias circuit 22 through an inverting circuit 38, a DC offset portion is eliminated from an analog signal A and it is brought to digital conversion. In this way, the DC offset portion is eliminated and the analog signal can be digitized exactly. |
