E C192056 Pages:3

Reg No.:_. Name:

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
THIRD SEMESTER B.TECH DEGREE EXAMINATION(R&S), DECEMBER 2019
Course Code: EC207
Course Name: LOGIC CIRCUIT DESIGN

Max. Marks: 100 Duration: 3 Hours
PARTA
Answer any two full questions, each carries 15 marks. Marks
1 a) Twonumbers A & B in Hex are given A= 850۸ B= 6 (10)
i. Find the Decimal equivalent of A & B

ii. Find the binary of A & B
111, What is the sum of A& B in HEX

b) Write down the algorithm for BCD Addition. Find the sum of numbers 74998 and (5)
38976 by BCD addition. Show the steps clearly.

2 ௨ Express f=AB + ^^ + (~ + ^ + ABC + ABC in standard SOP form. (7)

b Using K map simplify the SOP function, and realize it using logic gates. (8)
f(a,b,c,d) = Xm (0,1,2,4,5,6) , 0> (3,7,14,15)

3 2) Realize a XNOR circuit using NAND gate only. (6)

b) A logic circuit has our inputs A,B,C and D. A four bit input is fed with A as MSB (9)
and D as LSB. Design and implement a circuit such that the output is one when
the input is more than or equal to decimal 6.

PART 13
Answer any two full questions, each carries 15 marks.

4 a) Realize a 3 bit gray to binary decoder using PROM. Give all details. (7)
b) What is meant by race around condition? How it is eliminated. Illustrate with the (8)

help of necessary sketches.

5 ൭ Converta JK flipflop into a D flipflop, (7)

b) Design and implement a circuit for generating the sequence 2-5-7-3-0 (8)

6 a) Define the following (4)
(i) Fan out

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