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Quine McCluskey Method is a tabular method of minimisation.
Here maxterms are given:
So, the rest of the numericals between 0 to 15 are minterms.
Use the minterms. Find the minimized function in Sum of products (SOP).
Apply De Morgan's Law to SOP to get product of sums(POS).
$f(A,B,C,D)= \sum m(0,1,3,4,5,6,11,13,15)$
Step 1: Input Grouping the minterms/don't care terms based on number of 1's.
Index | Minterm/Don't care terms | Binary Representation | |||
---|---|---|---|---|---|
0 | 0 | 0 | 0 | 0 | 0 |
1 | 1 | 0 | 0 | 0 | 1 |
4 | 0 | 1 | 0 | 0 | |
2 | 3 | 0 | 0 | 1 | 1 |
5 | 0 | 1 | 0 | 1 | |
6 | 0 | 1 | 1 | 0 | |
3 | 11 | 1 | 0 | 1 | 1 |
13 | 1 | 1 | 0 | 1 | |
14 | 1 | 1 | 1 | 0 | |
4 | 15 | 1 | 1 | 1 | 1 |
Step 2: First Comparison Group the terms in pairs:
Group | Pairs | Binary Representation | |||
---|---|---|---|---|---|
0 | (1,0) | 0 | 0 | 0 | - |
1 | (4,0) | 0 | - | 0 | 0 |
(3,1) | 0 | 0 | - | 1 | |
(5,1) | 0 | - | 0 | 1 | |
(5,4) | 0 | 1 | 0 | - | |
(6,4) | 0 | 1 | - | 0 | |
2 | (11,3) | - | 0 | 1 | 1 |
(13,5) | - | 1 | 0 | 1 | |
(14,6) | - | 1 | 1 | 0 | |
3 | (15,11) | 1 | - | 1 | 1 |
(15,13) | 1 | 1 | - | 1 | |
(15,14) | 1 | 1 | 1 | - |
Step 3: Second Comparison
Group | Pairs | Binary Representation | |||
---|---|---|---|---|---|
0 | (5,4,1,0) | 0 | - | 0 | - |
Step 4: Prime Implicants
(5,4,1,0) 0 - 0 -
(3,1) 0 0 - 1
(6,4) 0 1 - 0
(11,3) - 0 1 1
(13,5) - 1 0 1
(14,6) - 1 1 0
(15,11) 1 - 1 1
(15,13) 1 1 - 1
(15,14) 1 1 1 -
Step 4:Coverage Table
0-0- | 00-1 | 01-0 | -011 | -101 | -110 | 1-11 | 11-1 | 111- | |
---|---|---|---|---|---|---|---|---|---|
0 | x | ||||||||
1 | x | x | |||||||
3 | x | x | |||||||
4 | x | x | |||||||
5 | x | x | |||||||
6 | x | x | |||||||
11 | x | x | |||||||
13 | x | x | |||||||
14 | x | x | |||||||
15 | x | x | x |
$f=A'C'+ABD+B'CD+BCD'\\ \text{Applying De Morgan's law to find POS}\\ f'=(A'C')' . (ABD)'.(B'CD)'(BCD')'\\ f'=[(A')'+(C')'][A'+B'+D'][(B')'+C'+D'][B'+C'+(D')']\\ f'=[A+C][A'+B'+D'][B+C'+D'][B'+C'+D]$
Verify the output using this handy tool.