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162 CHAPTER 4/LOGIC FUNCTION REPRESENTATION AND MINIMIZATION

AB -^ /- ABCD /— AB
B
A\ oo \ 01 ' 11 /10 'BC D A\ 00/0 1 ' 11 10

0 1 T)

A 1 . D/4D
y
I r> ^-Tk. U 1 V 1 | , ^ V_
X
__ / I \ I x ~ / I I ' SOP
ACD - / _ \ C AC -> C
ABC—^
(a) (b)

01

1 1 ( ° DJ
0 1 3 2
A 1 ( o o) 1
h . , ^
4*
4 A f 5 l 7 7 fil
6
A,
POS
c
(C)
FIGURE 4.31
(a) First-order compression plot of the function X in Eq. (4.43) showing original p-terms. (b) Minimum
SOP cover, (c) Minimum POS cover.

4.6.1 Incompletely Specified Functions
The EV mapping method is further illustrated by compressing the incompletely specified
function

/(A, B, C, £>) = m(3, 6, 9, 10, 11) + 0(0, 1, 4, 7, 8) (4.45)

r AB
B v
°y / i 1 1 /-AD A\ 0 i 1 1 -A+B+D
\B
N<
0 ((j) D ) 0 1
(S^
b 1 0 1
,(e O (c O
L
£
3
^ 2 ~/ y A [^ f 2 3 / v
^^—/—
7 / A SOP / / *pos
A+C^
(a) (b)
FIGURE 4.32
Second-order compressions of the function X showing (a) minimum SOP cover and (b) minimum
POS cover.