Download GTU B.Tech 2020 Winter 4th Sem 2140910 Digital Electronics Question Paper

Download GTU (Gujarat Technological University Ahmedabad) B.Tech/BE (Bachelor of Technology/ Bachelor of Engineering) 2020 Winter 4th Sem 2140910 Digital Electronics Previous Question Paper

Seat No.: ________
Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE- SEMESTER?IV (NEW) EXAMINATION ? WINTER 2020
Subject Code:2140910 Date:11/02/2021
Subject Name:Digital Electronics
Time:02:30 PM TO 04:30 PM Total Marks:56
Instructions:
1. Attempt any FOUR questions out of EIGHT questions.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.


MARKS
Q.1 (a) Explain Octal to Binary encoder.
03

(b) Explain Minterm and Maxterm.
04

(c) State and prove De Morgan's theorems.
07


Q.2 (a) Define the following general characteristics of logic families.
03
(i) Propagation delay time (ii) Fan-in (iii) Fan - out

(b) Draw and explain with truth table Ex-OR and Ex-NOR gates.
04

(c) Prove that NAND and NOR gates are universal gates.
07
Q.3 (a) Explain full- subtractor in brief.
03

(b) Do as directed:-
04
I.
Add the following decimal numbers using 8421 BCD equivalent
codes 679.6 + 536.8
II.
Multiply the binary numbers (1011.01) X (10.1)

(c) Write a short note on XS-3 code.
07




Q.4 (a) Solve: (1) (105.15)10 = (_______)2
03
(2) (378.93)8 = (________)2
(3) (B9F.AE)16 = (________)8

(b) Explain Binary addition & subtraction with Example.
04

(c) Explain Hamming codes. A seven bit Hamming code is received as
07
1110101. What is the correct code for even parity?
Q.5 (a) Differentiate between sequential circuit and combinational circuit.
03

(b) Describe the operation of R-2R ladder D/A converter in brief
04

(c) Minimize using K-map f(A,B,C,D) = (1,2,7,8,10,12,15) +d(0,5,6)
07
also draw MSI circuit for the output.



Q.6 (a) What are Preset and Clear inputs with flipflop? Why are they provided
03
with flipflop?

(b) Explain operation of clocked S-R Flip-Flop.
04

(c) Describe the working of look-ahead-carry adder.
07
Q.7 (a) Design a full adder circuit using decoder and multiplexer (4:1 MUX).
03

(b) Compare between various types of ROM.
04

(c) Explain working of Successive-Approximation-Register A/D
07
converter. Compare it with Flash A/D converter.



Q.8 (a) State the applications of A to D converters
03
(b) Explain concept of shift registers
04
(c) Explain the concept of RAM. Explain working of any one type of
07
RAM.
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