NONLINEARITY CORRECTION METHOD AND NONLINEARITY CORRECTION APPARATUS FOR A/D CONVERTED OUTPUT DATA

摘要

PROBLEM TO BE SOLVED: To correct nonlinearity of A/D converted output characteristics into linearity at low cost without taking a temperature change into account.;SOLUTION: Input voltage ranges Vmin-Vmax to an A/D converter (TAD) are equally bisected into an area 1 and an area 2 with a central voltage VC as a boundary and for each area, a TAD output characteristic curve is approximated with an approximate straight line resulting from connecting both ends of the TAD output characteristic curve. In the area 1, the TAD output characteristic curve is approximated into an approximate straight line L11 and in the area 2, it is approximated into an approximate straight line L12. A conversion expression for converting points on the approximate straight lines L11, L12 into points on ideal A/D straight lines is calculated for each area. Output data from the TAD are converted by thus obtained conversion expression, thereby realizing linear correction of TAD output characteristics with nonlinearity. Further, the conversion expression is reflected with the ambient temperature when the approximate straight lines L11, L12 are set.;COPYRIGHT: (C)2004,JPO&NCIPI