Improvement in the linearity of fast digital oscilloscopes used in averaging mode

Accurate measurement of signals with very fast variations between values separated by several orders of magnitude is difficult. When signals are periodic, a fast digital oscilloscope can be used in an averaging mode but the measurement accuracy is mainly limited by analog to digital conversion (ADC) linearity. Several methods for improving the conversion linearity are proposed. These methods are theoretically justified and experimentally validated. Several of these methods can be used simultaneously by a digital oscilloscope to provide, in an averaging mode, with a 8-b ADC, the linearity of a 11-b or 12-b ADC. Residual errors are caused mainly by drifts of ADC characteristics. The compatibility of the proposed methods is discussed. >