| 摘要 |
PROBLEM TO BE SOLVED: To linearly correct the non-linearity of A/D conversion output data at low cost regardless of temperature changes. SOLUTION: At first, prescribed reference voltages v0, v1, v2 are A/D converted respectively and corresponding digital data d0, d1, d2 are obtained. On the other hand, optional reference digital values y1, y2 satisfying y1/y2=(v1-v0)/(v2-v0)=1/2 are preliminarily set. Then x1 and x2 are obtained by the arithmetic operation of respective equations x1=d1-d0, x2=d2-d0. Then a quadratic curve (quadratic function y=f(x)) passing points D(x1, y1), E(x2, y2) and an origin in xy coordinates is set as a linearity correction expression. By correcting a shift value x obtained by subtracting d0 from data ds having non-linearity outputted from an A/D conversion circuit by using the obtained linearity correction expression, a linearity correction value y of the data ds can be obtained. COPYRIGHT: (C)2005,JPO&NCIPI
|
