DipIETE – ET/CS (NEW SCHEME) – Code: DE58 / DC58
Subject: LOGIC DESIGN
Time: 3 Hours
Max. Marks: 100
NOTE: There are 9 Questions in all.
· Question 1 is compulsory and
carries 20 marks. Answer to Q.1 must be written in the space provided for it in
the answer book supplied and nowhere else.
· Out of the remaining EIGHT
Questions answer any FIVE Questions. Each question carries 16 marks.
· Any required data not
explicitly given, may be suitably assumed and stated.
Q.1 Choose
the correct or the best alternative in the following: (2
10)
a. When two n-bit binary numbers are added, the
sum will contain at the most
(A) n-bits (B) n+1 bits
(C) n+2 bits (D) n+n bits
b. The most suitable gate to check whether the number of
ones in a digital word is even or odd is
(A) EX-OR (B) NAND
(C) NOR (D) AND, OR & NOT
c. The output of a
gate is high if and only if all of its inputs are low. It is true for
(A) NAND (B) NOR
(C) EX-OR (D) EX-NOR
d. A multiplexer
can be used as a
(A) Logic element (B) Flip-flop
(C) Counter (D) 7-Segment LED driver
e. In a
combinational circuit the output at any instant of time depend
(A) Only on inputs present at that
instant of time
(B) Only on past inputs
(C) Only on past outputs
(D) On past inputs as well
present inputs
f. Shifting
binary data to the left by one bit position using shift registers amounts to
(A) Division by 2 (B) Subtraction of 2
(C) Addition of 2 (D) Multiplications by 2
g. The maximum modulo number
that can be obtained by a ripple counter using
Five flip-flops is
(A) 32 (B) 16
(C) 15 (D) 5
h. Which of the following memories can be
programmed by the user and then cannot be erased & reprogrammed?
(A) ROM (B) PROM
(C) EPROM (D) EEPROM
i. The binary equivalent of decimal number
0.0625 is
(A) 10011 (B) 0.10011
(C) 0.01101 (D) 0.0001
j. A switching function f(A B C D) = 
can
also be written as
(A) 
(B) 
(C) 
(D) 
Answer any FIVE Questions out
of EIGHT Questions.
Each question carries 16
marks.
Q.2 a. What are the advantages of digital
techniques? Mention two limitations of digital technique. (8)
b. Perform the
following conversions:
(i) (0.3125)10 to Octal (ii) (2374)8 to Decimal
(iii) (B2F8)16
to Octal (iv) (1011110101)2 to Hexadecimal (8)
Q.3 a. Realize
AND, OR & INVERTER operations using universal gates. Also write the
expressions at each gate outputs. (8)
b. Simplify the following equations using K-map and realize
using gates. (8)
(i)
(ii)
Q.4 a. Define
the following:
(i)
Propagation delay time (ii) Maximum clock frequency
(iii) Set-up time (iv) Hold time (8)
b. With the help
of block diagram and waveforms explain how JK flip-flop can be used in
frequency division and counting. (8)
Q.5 a. Explain parallel binary adder with the help
of block diagram. (8)
b. What
are the functions of an ALU? State the sequence of operations that occur in the
ALU while performing arithmetic operations.
(5)
c. Subtract (3A8)16 from (594)16. (3)
Q.6 a. Design
a Mod-10 ripple counter that count from 0000 through 1001. (8)
b. Design a
counter using JK flip-flop with the irregular binary count sequence shown in
the state diagram (8)
Q.7 a. What is encoder? Design a decimal to BCD
encoder using gates. (8)
b. Convert Gray
code 1011 to Binary and show the realization for the same using EX-OR gates. (5)
c. Differentiate between Multiplexer and De-Multiplexer.
Mention any two applications of Multiplexer. (3)
Q.8 a. With
the help of block diagram and waveforms explain four bit ring counter. (8)
b. What is the
difference between a counter and a shift register? Show the basic data movement
in shift registers for the following operations:
(i) Serial
in serial out (ii) Serial in parallel out
(iii) Parallel in serial out (iv) Parallel in parallel out
(v) Rotate
left (8)
Q.9 a. Define the following:
(i) Static memory device (ii)
Dynamic memory device
(iii) Volatile memory (iv) Auxiliary memory (8)
b. Explain memory
operation with the help of 
memory. (8)