# Education In Pakistan

## VU CS302- Digital Logic Design MIDTERM EXAMINATION 2010

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Question No: 1

( Marks: 10 )

(a) Convert the decimal number 6789.8 to octal correct to 3 decimal places

(b) Draw the truth table for the following expression F = xy + x’z

Marks = 4

Marks = 6

Question No: 2

( Marks: 15 )

Use Quine-McCluskey method to find all prime implicants for the given expression

f (a, b, c, d) = Σm(3,7,9,14) +Σd(1,4,6,11

Question No: 3

( Marks: 8 )

Implement f (A, B, C, D) = AC’D’ + B’D using a 4-to-1 multiplexer. Choose the appropriate

control inputs

Question No: 4 ( Marks: 3 ) – Please choose one

2’s complement of hexadecimal number B70A is

B70B

B709

48F6

48F5

Question No: 5 ( Marks: 3 ) – Please choose one

The minterm expansion for F(A,B,C) = (A + B + C)(A + B’ + C’)(A’ + B + C’)(A’ + B’ + C) is

F(A,B,C) = ΠM(0,3,5,6)

F(A,B,C) = Σm(0,3,5,6)

F(A,B,C) = ΠM(1,2,4,7)

F(A,B,C) = Σm(1,2,4,7)

Question No: 6 ( Marks: 3 ) – Please choose one

The minimum expression of the logic diagram shown below is:

(A’D + B)

((D +(A’B)’)(B + C)’ )’

(AB’D) +B’ +C’

B +C

Question No: 7 ( Marks: 3 ) – Please choose one

An 8-line to 1-line multiplexer is connected as shown in the following figure

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where output Y = F(x, y, z) and z is the least significant input. Which of the following functions

does Y generate?

F(x, y, z) = z

F(x, y, z) = y

F(x, y, z) = z’

F(x, y, z) = x