# Change input x observe output f see if output f

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Unformatted text preview: and only if each variable appears only primed or unprimed but not both Boolean Diﬀerence Cofactor •  For a func%on f(x1, x2,…, xn) deﬁne the posi0ve cofactor with respect to xi as: f+(x1, x2,…, xn) = f(x1, x2,…, xi = 1,…, xn) •  For a func%on f(x1, x2,…, xn) deﬁne the nega0ve cofactor with respect to xi as: f- (x1, x2,…, xn) = f(x1, x2,…, xi = 0,…, xn) Boolean Diﬀerence •  The Boolean diﬀerence of f with respect to xi, wriXen as df/dxi, is deﬁned as: df/dxi = f+(xi) XOR f- (xi) •  Useful for tes%ng circuit faults Boolean Diﬀerence: Example •  Consider f(w, x, y, z) = wx + w’z’ •  How is signal x tested for a fault? –  Change input x –  Observe output f –  See if output f changes when input x is changed •  What values of othe...
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## This note was uploaded on 11/07/2012 for the course ECE 462 taught by Professor Vasudevan,s during the Spring '08 term at University of Illinois, Urbana Champaign.

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