# Andhra University BE/B.Tech Digital Logic Design Previous Paper 2010

First question is compulsory

Answer any four questions from the remaining questions

All questions carry equal marks

1. (a) List different types of ROMS

(b)Differentiate static and dynamic RAMS

©give the truth table foot 3-bit serial in serial out shift register

(d)List any two applications of counters

(e)Differentiate between encoder and decoder

(f)Implement AND logic using NAND gates only

(g)Write HDL code for NAND logic

2. (a) Convert the following numbers with the indicated bases to decimal (12121)_{3}(4310)_{5};(50)_{7} and(198)_{12}

(b)noting in that 3^{2}=9,formulate a simple procedure for converting base -3 numbers directory to base-9 use the procedure to convert (2110201102220112)_{3}to base-9

3. (a)using a demorgans theorem, convert the following Boolean expressions to equivalent expression so that have only OR and complement operations. Show that the functions can be implement with logic diagrams that have only OR gates and inverters

(i)f= x’y+x’z+y’z

(ii)f=(y+z’)(x+y)(y’+z)

(b)The sum of all the minterms of a Boolean function on variables is equal to 1

(i)prove the above statement for n=3

(ii) Suggest a procedure for a general proof

4. (a)a logic circuit implements the following Boolean functions :F=A’C+AC’B. It is found that the circuit input combination A=C=1 can never occur find a simpler expression for ‘F’ using the don’t care conditions

(b)Simplify the following Boolean function by means of the tabulation method

P(A,B,C,D,E,F,G)=∑(20,28,52,60)

5. (a)design a combinational circuits that adds 1 to a 4-bit binary number A_{3}A_{2}A_{1}A_{0} for example if the input of the circuit is A_{3}A_{2}A_{1}A_{0 }=1101 ,the output is 1110

(b)Write HDL code for full adder.

6.(a)Construct a mod 6 counter using three different ways.

(b)Explain with the help of state diagram decimal BCD triple counter. Draw the timing Diagrams .

7.(a) What is the difference between a serial and parallel transfer? Explain how to convert serial data to parallel and parallel data to serial. What type of register is needed?

(b)Construct D-flip flop from a J-KFF. Give the truth table.

8.(a)Write short notes on the following

(a) Different types of ROMS

(b)Compare DRAM and SRAM

©programmable array logic

http://www.stepinau.com/2013/09/26/andhra-university-beb-tech-digital-logic-design-previous-paper-2010/IT 2.1 Previous PapersCSE,CSE Previous Papers,Digital Logic Design Previous Papers,IT,IT Previous Papers
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