Some thoughts on the word error rate measurement of A/D converters

The word error rate (WER) of an A/D converter quantifies the probability that a wrong output code occurs because of metastability, intrinsic noise or aperture uncertainty. It can be measured in real-time, as it is customary for very low WER converters, or by post processing, when the WER is more relevant. In the paper the possible causes of inaccuracy are analyzed. First, the existing methods are reviewed, then the errors which may arise from the conventional analysis of experimental data are discussed, and it is shown that these errors can be removed in the case of post processing. Finally, the requirements on the test bench noise are discussed in connection with the qualified error level (i.e. 1, 2, 4, .., 16 LSB) and with the expected error rate