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Digital Electronics
Solution
• Let the Boolean function be ffAA BB CC =
1 2 5.
• The equivalent sum-of-products expression can be written as ffAA BB CC =
0 3 4 6 7.
The truth table for the given Boolean function is given in Table 8.5. The given function can be
implemented with a 4-to-1 multiplexer with two selection lines. Variables A and B are chosen for the
selection lines. The implementation table as drawn with the help of the truth table is given in Table 8.6.
Figure 8.12 shows the hardware implementation.
Table 8.5 Truth table.
C
B
A
f(A,B,C)
0
0
0
1
0
0
1
0
0
1
0
0
0
1
1
1
1
0
0
1
1
0
1
0
1
1
0
1
1
1
1
1
Table 8.6 Implementation table.
I 0
I 1
I 2
I 3
C
0
1
2
3
C
4
5
6
7
1
0
C
1
4-to-1
MUX
F
A
B
I 0
I 1
I 2
I 3
S 1 S 0
C
Y
'0’
'1’
Figure 8.12 Example 8.1.