On the analysis of sensitivity to parasitic effects

It is shown that the variation of a network function F(¿¿) due to the presence of a parasitic element ¿¿ is approximately equal to the sensitivity of that function with respect to ¿¿. Introducing the return difference with respect to e, a very simple expression for the variation of F(¿¿) is obtained in Appendix 7, namely the product of the null-return difference with respect to ¿¿ and the sensitivity of S¿¿F(¿¿) i.e. the null-return difference sensitivity, or n.r.s. product. If the numerator of F(¿¿) is independent of ¿¿, it is shown that the variation of F(¿¿) due to ¿¿ is equal to S¿¿F(¿¿) only. Various examples are given which demonstrate the usefulness of these results.