Signal-to-Noise Ratio for Operating Window Using Unified Methodology

Abstract

Operating window is a particular case of multi-variate system in which the objective is to make the system robust with respect to one particular factor in the presence of others. The signal-to-noise ratio of an operating window is the addition of the signal-to-noise ratios at the lower and upper thresholds of the window. Linear transformation on the lower threshold and reciprocal transformation on the upper threshold tend to render different weights at these thresholds, which results in an imbalanced optimization of a nondynamic operating window. In this article, a new signal-to-noise ratio for an operating window based on the unified methodology is proposed to reduce or eliminate this bias. Advantages of this methodology are discussed and an example is used to demonstrate the proposed methodology and compare with an existing methodology.