Ultralow distortion and low noise high performance signal generators are required to test precise instruments. New concepts are required to ensure a characterization at a high performance level. Reference designs like the ADMX1002 simplify this task by taking advantage of high performance precision digital-to-analog converters (DACs), which have reached unprecedented levels of accuracy and resolution. Moreover, the addition of a novel digital predistortion algorithm can further enhance the test signal fidelity, enabling unprecedented low distortion signals in a small, low cost form factor.