Behavioural Modelling Of Instrumentation Delta-Sigma ADC

摘要

This paper examines the quantization error of a modulator for delta-sigma analog-to-digital converter (DSADC). In opposite to many papers, the analytical equations are found in time domain. This approach allows the authors to present the modulator as analog-to-digital converter (ADC) of input signal to code for given length of digital sequences at the modulator output. Such presentation is useful for investigation of quantization error for ordinary DSADC and can also be considered as the base for a new ADC type. Both analytical equations and results of simulations are used to find the sources of quantization errors: effect of the scale end, limited number of code transition levels, unequal length of code bin widths, non-ideal digital filters. Some suggestions are made to decrease influence of mentioned sources on quantization error including the new ADC type with conversion delay.