# Andhra University BE/B.Tech Digital Logic Design Previous Paper 2007

First question is compulsory

Answer any four questions from the remaining questions

All questions carry equal marks

1.(a)Convert the following in to decimal and then to binary (7766)_{8}

(b)Reduce the following between Boolean expressions (AB’+AC’) (BC+BC’)(ABC)

©obtain the dual of the following Boolean expressionABC+A’B+ABC’

(D)Define standard (or canonical) Spoors POS

(e)Difference between the serial and parallel adders

(f)What is the difference between the PLA and ROM?

(g)In any logic design what are the essential requirements that are to be met for designing a product

2.(a)Represent the unsigned decimal numbers 842 and 537 in BCD, and then show that steps necessary to form their sum

(b)Represent the decimal number 5137 is

(i)BCD

(ii) Excess – 3 Code

(iii) 2421 code and

(iv) A 6311 code

3. (a) Show that the dual of the exclusive- OX is equal to it’ s compliment

(b)Express the compliment of following functions in sum of minters form

(i)F(x, y, z)= xy + xz

(ii)f(A,B,C)=π(2,4,5,7)

4. Simplifying the following Boolean function f together with the don’t care condition d, then express the simplified Boolean function in sum of minterms

(a)f(x,y,z)=∑(0,1,2,4,5)

(b)d(x,y,z)=∑(3,6,7)

5. Implement the following functions with multiplexer with an 8×1 multiplexer

F(A,B,C,D)=∑(0,3,5,6,8,9,14,15)

6. Realize the given function using a PLA with 6 inputs,4 outputs and ten AND gates

F1(A,B,C,D,E,F)=∑m(0,1,2,3,7,8,9,10,11,15,32,33,34,35,39,40,40,42,43,45,47)

F2(A,B,C,D,E,F)=∑m(8,9,10,11,12,14,21,25,27,40,41,42,43,44,46,57,59)

7. (a) design a mod6 synchronous counter using j-k flip flops

(b)Compare the combinational and sequential circuits

8. Determine the ROM size to realize the following logic functions

(a)BCC to excess 3code converter

(b) 5-32 line decoder

http://www.stepinau.com/2013/09/26/andhra-university-beb-tech-digital-logic-design-previous-paper-2007/IT 2.1 Previous PapersCSE,CSE Previous Papers,Digital Logic Design Previous Papers,IT,IT Previous Papers
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