Method and apparatus for reducing systematic errors in a current steering digital-to-analog converter. An other-color-information eliminating unit eliminates information of other colors from a tone level of the specific color by correcting the tone level of the specific color based on tone levels of two colors other than the specific color out of the three primary colors in pigment or the three primary colors in light. 5, 0<n\u22662 and 0\u2266z<2. The resulting probe structure is intended to extend the frequency range of the well-developed epoxy probe card technology while retaining its ruggedness and low cost features.