Sreyas Institute of Engineering & Technology Nagole, Hyderabad - 500 068.

Department of ECE

Course :II-B.Tech Subject:STLDImportant Questions Unitwise

QUESTION BANKUnit-1

1. (a) Convert the following numbers:i. (6753)8 to base 10 ii. (00111101.0101)2 to base 8 and base 4 iii. (95.75)10 to base 2.(b) Represent +65 and -65 in sign-magnitude, sign-1’s complement and sign-2’sComplement representation.

2. Given a = 10101001 and b = 1101 find:i. a + b ii. a – b iii. a . b iv. a / b.

3. What is the Gray code? What are the rules to construct Gray code? Developthe 4 bit Gray code for the decimal 0 to 15.

4. What are the rules for XS3 addition? Add the two decimal numbers 123 and658 XS3 code.

5. Define a single error correcting code for a 11 bit group 01101110101

Unit-2 1. State and prove the following Boolean laws:

i. Commutative ii. Associative iii. Distributive.2. Simplify the following Boolean functions to minimum number of literals:

i. ( a + b )’ ( a’ + b’ )’ ii. y(wz’ + wz) + xy 3. State Duality theorem. List Boolean laws and their Duals. 4. Prove that OR-AND network is equivalent to NOR-NOR network and AND-OR network is equivalent to NAND-NAND network.

5. For the given Boolean function F=xy’z+x’y’z+w’xy+wx’y+wxy

i. Draw the logic diagram ii. Simplify the function to minimal literals using Boolean algebra.

Unit-31. Simplify the following Boolean expressions using K-map and implement them using NOR gates:

F (A, B, C, D) = AB’C’ + AC + A’CD’

2. List the Boolean function simplification rules using Tabulation method.3. Simplify the Boolean function using K-map and implement using NAND gates

F=Σm(0,2,3,4,5,6)4. Reduce the given function using tabular minimization method

F(A,B,C,D)=П(0,1,3,4,5,6,7,8,9)+d(10,11,12,13,14,15)

5. Simplify the Boolean expression using K-map F=A1+AB+ABD1+AB1D1+C

Unit-41. Implement the following Boolean functions using decoder and OR gates:

F1(A,B,C,D) = ∑(2,4,7,9), F2(A,B,C,D) = ∑(10,13,14,15)2. What is Hazard in switching circuits? Explain the design of Hazard free

Switching circuit with an example.3. What is Encoder? Design Octal to Binary Encoder.

4. Design a combinational circuit that converts a decimal digit from 8, 4,-2,-1 code to 8,4,2,1 BCD code.

5. Design a combinational circuit that accepts a 3 bit number and generates an output binary number equal to the square of the input number.

Unit-5

1. Implement the following boolean functions using PLA.

f1(w,x,y,z) = P(0,1,3,5,9,13) , f2 (w,x,y,z) = P(0,2,4,5,7,9,11,15).2. The following memory units are specified by the no of words times the number of bits per word.

How many address lines and input-output data lines are needed in each case?

i. 4K × 16 ii. 2G × 8 iii. 16M × 32 iv. 256K × 64. Give the number of bytes stored in the memories listed above.

3. (a) Draw the basic macro cell logic diagram and explain.

(b) Explain the general CPLD configuration with suitable block diagram.4. For a given 3-input, 4-output truth table of a combinations ckt, tabulate the PAL programming

table for the ckt.

Inputs Outputx y z A B C D0 0 0 0 1 0 00 0 1 1 1 1 10 1 0 1 0 1 10 1 1 0 1 0 1

10 0 1 0 1 010 1 0 0 0 111 0 1 1 1 0

11 1 0 1 1 15. Write a brief notes on a) Architecture of PLD’s. b)Capabilities and limitations of threshold gates.

UNIT-6

1. Design Mod-6 synchronous counter using JKFF’s.2. Explain the following

a. Race around condition in FF’s.b) JK master slave FF. c)Excitation table for FF’s.

3. Draw the logic diagram of a SR latch using NOR gates. Explain its operation using excitation table.

4. (a) Draw the logic diagram of a 4 bit binary ripple counter using positive edge triggering.

(b) Draw the block diagram of a 4 - bit serial adder and explain its operation.5. a) Show that the characteristic equation for the complement out put of a JK flipflop is

Q′ (t + 1) = J ‘Q′ + kQ.

b)Discuss about mod-6 synchronous counter using JK FF’S.

Unit-7

1. Find the state table for the following state diagram

2. Draw the diagram of mealy-type FSM for serial adder.

3. (a) Draw the ckt for the moore type FSM.

x1(P,Q,R) =Σ(0,1,2,7), x2(P,Q,R) = Σ(1,4,5,6).

(b) Explain merger chart methods of minimal cover table.

4. Design a sequence detector which detects 110010 Implement the sequence detector by using D - type flipflops.

5. . A clocked sequential circuit is provided with a single input x and single output Z.Whenever the input produce a string of pulses 1 1 1 or 0 0 0 and at the end of the sequence it produce an output Z = 1 and overlapping is also allowed. (a) Obtain State - Diagram. (b) Also obtain state - Table. (c) Find equivalence classes using partition method & design the circuit using D- flip-flops.

Unit-8

1. For the given state diagram, as shown in figure obtain its ASM chart and Design the above circuit using one flip flop per each state.

2. For the given control state diagram, draw the equivalent ASM chart and Design the control circuit using multiplexers

3. For the ASM chart given below, draw the state diagram and Design the control unit using D-flip flops and a decoder.

4. state diagram of a control unit iS

(a) Draw the equivalent ASM chart(b) Design the control unit using D flip-flops and a decoder.

5.Draw the ASM chart for the following state transistion, start from the initialstate T1, then if xy=00 go to T2, if xy=01 go to T3, if xy=10 go to T1, otherwise go to T3.