S1 Teknik TelekomunikasiFakultas Teknik Elektro
2016/2017
Boole Algebra and Logic Series
CLO1-Week3-Simplify Boolean
Expression Using Algebra Axiom
• Understand the Axiom of Boolean Algebra
• Knowing the Boolean Algebra Theorem
• Understand the Concept of Duality in Boolean Algebra
• Understand how to solve Boolean Algebra Expression
by Thruth Table
• Understand how to simplify Boolean Expression by
Using Boolean Algebra
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Outline
Why should be “Simple”?
• Digital computers contain circuits that implement Boolean functions.
• The simpler that we can make a Boolean function, the smaller the circuit that will result.
– Simpler circuits are cheaper to build, consume less power, and run faster than complex circuits.
• With this in mind, we always want to reduce our Boolean functions to their simplest form.
• There are a number of Boolean identities that help us to do this.
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Axiom in Boolean Algebra
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1a. 0 0 = 01b. 1 + 1 = 1
2a. 1 1 = 12b. 0 + 0 = 0
3a. 0 1 = 1 0 = 03b. 1 + 0 = 0 + 1 = 1
4a. If x = 0, then = 14b. If x = 1, then = 0
x_
x_
Single Variable Theorem
• Null Law
• Identity Law
• Idempotent Law
• Inverse Law
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5a. x 0 = 05b. x + 1 = 1
6a. x 1 = x6b. x + 0 = x
7a. x x = x7b. x + x = x
8a. x = 08b. x + = 1
9. = x
x_
x_
x
__
Duality Concept
• Duality of Boolean Expression is obtained byreplacing the AND operator with the equivalentof an OR operator, and the operator OR byequivalent operators AND, bit '0' with theequivalent bit '1' and bit '1' to bits '0‘
• This principle will be useful in the manipulation ofBoolean algebra in a logic circuit simplification
• To simplify the Boolean Expression, you need touse Boolean Algebra Law and also itsCharacteristic
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Two or Three Variable-Characteristic in Algebra
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10a. x y = y x10b. x + y = y + x
11a. x (y z) = (x y) z11b. x + (y + z) = (x + y) + z
12a. x (y + z) = x y + x z12b. x + (y z) = (x + y) (x + z)
13a. x + x y = x13b. x (x + y) = x
Commutative}
}
}
}
Associative
Distributive
Absorptive
Two or Three Variable-Characteristic in Algebra
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14a. x y + x = x
14b. (x + y) . (x + ) = x
15a.
15b.
Combining
Theorem of DeMorgan}
}y
y
x . y x= + y
x + y x y= .
X = X'
X = (X')'} Symbol Equivalence
For Example
By Using Boolean Theorem, Proof that:
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1. X • Y + X • Y' = X
2. X + X • Y = X
Examples: Proof Theorem of Algebra Boole By Using Axiom and Single Variable Theorem:
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1. Proof Theorem : X • Y + X • Y' = XX • Y + X •Y' = X • (Y + Y')
X • (Y + Y') = X • (1)
X • (1) = X
2. Proof Theorem : X + X • Y = XX + X • Y = X • 1 + X • Y
X • 1 + X • Y = X • (1 + Y)
X • (1 + Y) = X • (1)
X • (1) = X
Distributive :
Complement :
Identity :
Identity
Distributive
Identity
Identity
THEOREM of DeMorgan
(X + Y)' = X' • Y'
(X • Y)' = X' + Y'
NOR Gate equivalent with
AND Gate with complemented input
NAND Gate equivalent withOR Gate with complemented input
Example:
Z = A' B' C + A' B C + A B' C + A B C'
Z' = (A + B + C') • (A + B' + C') • (A' + B + C') • (A' + B' + C)
DeMorgan theorem can be used to convertDeMorgan theorem can be used to convert
statement AND/OR be a statement OR/AND
X 0 0 1 1
Y 0 1 0 1
X 1 1 0 0
Y 1 0 1 0
X + Y 1 0 0 0
X•Y 1 0 0 0
X 0 0 1 1
Y 0 1 0 1
X 1 1 0 0
Y 1 0 1 0
X + Y 1 1 1 0
X•Y 1 1 1 0
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A Truth Table can be expressed as a Boolean function
A truth table can be expressed in two forms that are equivalent Boolean function
The functions of the equation obtained from a truth table called a canonical form.
Sum of Products Form
Also called disjunctive normal form, an expansionPart minterm truth table
F = A' B C + A B' C' + A B' C + A B C' + A B C
0 1 1 1 0 0 1 0 1 1 1 0 1 1 1
F' = A' B' C' + A' B' C + A' B C'
F 0 0 0 1 1 1 1 1
F 1 1 1 0 0 0 0 0
C 0 1 0 1 0 1 0 1
B 0 0 1 1 0 0 1 1
A 0 0 0 0 1 1 1 1
TABEL KEBENARAN (TRUTH TABLE)
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Sum of Products
F in form of SoP :
F(A,B,C) = Sm(3,4,5,6,7)
= m3
+ m4
+ m5
+ m6
+ m7= A' B C + A B' C' + A B' C
+ A B C' + A B C
Simplify by Using Boolean Algebra Theorem:
F = A B' (C + C') + A' B C + A B (C' + C)
= A B' + A' B C + A B
= A (B' + B) + A' B C
= A + A' B C
= A + B C
Realization Results SimplificationSoP expression
B
C
A
F
A B C = m 1 A B C = m 2 A B C = m 3 A B C = m 4 A B C = m 5 A B C = m 6 A B C = m 7
A
0 0 0 0 1 1 1 1
B
0 0 1 1 0 0 1 1
C
0 1 0 1 0 1 0 1
Minterms
A B C = m 0
CANONICAL SUM of PRODUCT (SoP)
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Product of Sums / Conjunctive Normal Form / Maxterm Expansion
Boolean function PoS readings based on the truth table:
Maxterm form :
Define rows in the truth tableWith F = 0.'0' in the input field is a notationPut without complement.'1' on the input field notationPut the complement.
F(A,B,C) = PM(0,1,2)
= (A + B + C) (A + B + C') (A + B' + C)
F’(A,B,C) = PM(3,4,5,6,7)
= (A + B' + C') (A' + B + C) (A' + B + C') (A' + B' + C) (A' + B' + C')
A 0 0 0 0 1 1 1 1
B 0 0 1 1 0 0 1 1
C 0 1 0 1 0 1 0 1
Maxterms A + B + C = M 0 A + B + C = M 1 A + B + C = M 2 A + B + C = M 3 A + B + C = M 4 A + B + C = M 5 A + B + C = M 6 A + B + C = M 7
PERNYATAAN CANONICAL PRODUCT of SUM (PoS)
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Canonical Sum of Products
Minimized Sum of Products
Canonical Products of Sums
A
B
F 2
F 3
F 1
C
COMPARISON OF IMPLEMENTATION
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End of Chapter 3
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