Is There Life Beyond 14-Bits in A/D and D/A Conversion ?

Several high-resolution A/D and D/A converters such as "dual" slope conversion, delta modulation, R/2R ladder networks with trimming or adaptive adjustment procedures and "dynamic element matching" are discussed. Special attention is paid to dynamic characteristics like signal-to-noise ratio, linearity, distortion and "glitch"-free operation. In complete A/D and D/A conversion systems the anti-aliasing filters must not be forgotten and form part of the total system. Partitioning of the conversion problem into a digital signal processing part, including oversampling and digital filtering, and a converter part improves the system performance. In D/A converters an increase in resolution of 18 to 20 bits can be realized with a linear phase characteristic, while in A/D converters this maximum is at the 16 to 18 bits level. Noise in the sample-and-hold function is the limiting factor in A/D converter systems.