| 摘要 |
PURPOSE:To provide the multiplication circuit with correcting function which can remove influences caused by a secular change or temperature drift by using a D/A converter and an A/D converter for correction. CONSTITUTION:Amplifiers 3, 5 and 7, which enable offset control, are respectively provided behind a main D/A converter 2, D/A converter 4 for gain control and multiplier 6, and a control arithmetic circuit 13 is provided to compensate the DC error of this circuit by setting the combination of '0', '1' and '-1' when data to be applied to the main D/A converter 2 are defined as (x), data to be applied to the D/A converter 4 for gain control are defined as (y), the respective inputs of the multiplier 6 are expressed as ax+b and cy+d and the output value is expressed as e *(ax+b)*(cy+d)+f, to calculate the corrected values of (b), (d) and (f) based on respective output values on those respective conditions and to set these corrected values to respective D/A converters 9-11 for zero point control. |
