Variability analysis of electronic systems: classical and interval methods

Variability analysis or error analysis is a technique by which one can determine, with good approximation, whether a system will work within the specification limits when the part parameters vary between their limits. Classical methods of variability analysis include: worst-cast, probabilistic transformation of variables, method of moments and Monte Carlo. This paper shows the use of interval arithmetic as an alternative and valid technique to calculate how system accuracy varies as parameters vary. Comparisons with the classical techniques are presented. An applications to an electronic filter shows that interval arithmetic is able: to consider simultaneously the effects of uncertainty of all of the parameters on a system accuracy; to provide strict bounds (the minimum and maximum values) with only one evaluation; and to perform sensitivity analysis.