PPTs on magnitude comarator

1. SYED HASAN SAEED
hasansaeedcontrol@gmail.com
https://shasansaeed.yolasite.com
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Syed Hasan Saeed, Integral University,
Lucknow

2. MAGNITUDE COMPARATOR
Syed Hasan Saeed, Integral University,
Lucknow
2

3. MAGNITUDE COMPARATOR: DIGITAL COMPARATOR
• It is a combinational logic circuit.
• Digital Comparator is used to compare the value of two binary
digits.
• There are two types of digital comparator (i) Identity Comparator
(ii) Magnitude Comparator.
• IDENTITY COMPARATOR: This comparator has only one output
terminal for when A=B, either A=B=1 (High) or A=B=0 (Low)
• MAGNITUDE COMPARATOR: This Comparator has three output
terminals namely A>B, A=B, A<B. Depending on the result of
comparison, one of these output will be high (1)
• Block Diagram of Magnitude Comparator is shown in Fig. 1
Syed Hasan Saeed, Integral University,
Lucknow
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4. BLOCK DIAGRAM OF MAGNITUDE COMPARATOR
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Lucknow
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n- Bit Digital Comparator
A
n-Bit
B
n-Bit
A<B A=B A>B
Fig. 1

5. 1- Bit Magnitude Comparator:
• This magnitude comparator has two inputs A and B and three
outputs A<B, A=B and A>B.
• This magnitude comparator compares the two numbers of single
bits.
• Truth Table of 1-Bit Comparator
Syed Hasan Saeed, Integral University,
Lucknow
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INPUTS OUTPUTS
A B Y1 (A<B) Y2 (A=B) Y3 (A>B)
0 0 0 1 0
0 1 1 0 0
1 0 0 0 1
1 1 0 1 0

6. K-Maps For All Three Outputs :
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Lucknow
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A
B
0 1
0
1
0
0 0
1
B B
A
A
BAY1 
K-Map for Y1 : A<B

7. K-Maps For All Three Outputs :
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Lucknow
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A
B
0 1
0
1
0
0 0
1
B B
A
A
BAY1 
K-Map for Y1 : A<B
A
B
0 1
0
1
1
0 1
0
B B
A
A
ABBAY2 
K-Map for Y2 : A=B

8. K-Maps For All Three Outputs :
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Lucknow
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A
B
0 1
0
1
0
0 0
1
B B
A
A
BAY1 
K-Map for Y1 : A<B
A
B
0 1
0
1
1
0 1
0
B B
A
A
ABBAY2 
K-Map for Y2 : A=B
A 0 1
0
1
0
1
0
BB
A
A
B
0
BAY3 
K-Map for Y2 : A>B

9. Realization of One Bit Comparator
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Lucknow
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BA
BAY1 
A
B
AB
BA
ABBAY2 
BAY3 
BA 
BA 
BAY1 
ABBAY2 
BAY3 

10. Realization of by Using AND , EX-NOR gates
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Lucknow
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BA
BAY1 
BA
BAY2


BAY3 
BA 
A
B

11. 2-Bit Comparator:
• A comparator which is used to compare two binary numbers each of two
bits is called a 2-bit magnitude comparator.
• Fig. 2 shows the block diagram of 2-Bit magnitude comparator.
• It has four inputs and three outputs.
• Inputs are A0 ,A1,B0 and B1 and Outputs are Y1, Y2 and Y3
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Lucknow
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A0
A1
B1
B0
Y1
Y2
Y3
2-Bit Comparator
Fig. 2
A
B
Input Output

12. GREATER THAN (A>B)
LESS THAN (A<B)
Similarly,
1. If A1= B1=1 and A0= 0, B0=1, then A<B
2. If A1= B1= 0 and A0= 0, B0=1 then A<B
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Lucknow
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A1 A0 B1 B0
1 0 0 1
1 1 1 0
0 1 0 0
1. If A1= 1 and B1= 0 then A>B
2. If A1 and B1 are same, i.e A1=B1=1 or A1=B1=0 and A0=1, B0=0
then A>B

13. INPUT OUTPUT
A1 A0 B1 B0 Y1=A<B Y2=(A=B) Y3=A>B
0 0 0 0 0 1 0
0 0 0 1 1 0 0
0 0 1 0 1 0 0
0 0 1 1 1 0 0
0 1 0 0 0 0 1
0 1 0 1 0 1 0
0 1 1 0 1 0 0
0 1 1 1 1 0 0
1 0 0 0 0 0 1
1 0 0 1 0 0 1
1 0 1 0 0 1 0
1 0 1 1 1 0 0
1 1 0 0 0 0 1
1 1 0 1 0 0 1
1 1 1 0 0 0 1
1 1 1 1 0 1 0
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Lucknow
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TRUTH TABLE

14. K-Map for A<B: K-Map for A=B:
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Lucknow
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0 1 1 1
0 0 1 1
0 0 0 0
0 0 1 0
1 0 0 0
0 1 0 0
0 0 1 0
0 0 0 1
00 01
00
01
11
10
11 10 00 01 11 10
00
01
11
10
A1A0
A1A0B1B0
B1B0
For A<B
For A=B
010110011 BBABABAAY 
01010101010101012 BBAABBAABBAABBAAY 

15. K-Map For A>B
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Lucknow
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0 0 0 0
1 0 0 0
1 1 0 1
1 1 0 0
00 01 11 10
00
01
11
10
A1A0
B1B0
001110103 BAABABBAY 

16. For A=B From K-Map
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Lucknow
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01010101010101012 BBAABBAABBAABBAAY 
)B(A)BA(Y
)BABA()BABA(Y
)BABA(BA)BABA(BAY
00112
000011112
1111001111002




17. LOGIC DIAGRAM OF 2-BIT COMPARATOR:
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Lucknow
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A1 A0 B1 B0
A< B
A=B
A > B
001 BAA
11 BA
010 BBA
11 BA
001 BAA
010 BBA
11 BA 
00 BA 

18. THANK YOU
Syed Hasan Saeed, Integral University,
Lucknow
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