Patent ID: 8378865

Claim:
A method of testing a converter for converting between a digital signal and an analog signal one of which is an input signal and the other of which is an output signal, the converter including a coarse voltage divider comprising a set of repetitive coarse resistor elements and a fine voltage divider comprising a set of repetitive fine resistor elements, taps connected to respective positions in said sets of repetitive resistor elements, and a digital tap selector for coupling a selection of said coarse resistor elements with a selection of said fine resistor elements corresponding respectively to more significant and less significant bits of said digital signal, said method of testing comprising: providing reference input signals corresponding to a first selection of said fine resistor elements with each of said selections of said coarse resistor elements in succession, measuring corresponding output signals of said converter, and using said reference input signals and said output signals to provide calculated differential non-linearity values and integral non-linearity values for said first selection of said fine resistor elements with each of said selections of said coarse resistor elements; providing reference input signals corresponding to a first selection of said coarse resistor elements with each of said selections of said fine resistor elements in succession, measuring corresponding output signals of said converter, and using said reference input signals and said analog output signals to provide calculated differential non-linearity values and integral non-linearity values for said first selection of said coarse resistor elements with each of said selections of said fine resistor elements; and calculating differential non-linearity values and integral non-linearity values for other combinations of said coarse resistor elements with said fine resistor elements using combinations of said calculated differential non-linearity values and said calculated integral non-linearity values.