# Digital Logic and Computer Design 2013 – BSc Computer Science Part 1

#### Paper Code: 1305 1505 B.sc. (Computer Science) (Part 1) Examination, 2013 Paper No. 2.2 DIGITAL LOGIC AND COMPUTER DESIGN

##### Time: Three Hours] [Maximum Marks: 33

Note: Attempt any five questions. All questions carry equal marks.

1. (a) Convert the decimal number to the base indicated:

1. 175 to octal
2. 2479 to hexadecimal
3. 255 to binary

(b) Explain the open of clocked RS flip-flop.

2. (a) Draw the logic diagram and its truth table of half adder.

(b) Describe the PLA control method of designing a control unit.

3. (a) Write a short note about the various digital logic families.

(b) Obtain the complement of the following Boolean expressions:

1. latex]AB+A(B+C)+B^{‘}(B+D)[/latex]
2. latex]A+B+A^{‘}B^{‘}C[/latex]

4. (a) Explain the following:

1. Explain the difference between asynchronous and synchronous sequential circuit.
2. Define fundamental-mode operation.
3. Explain the difference between stable and unstable states.
4. What is the difference between an internal state and a total state.

(b) Explain the critical and non-critical races with the help of examples.

5. (a) Implement half adder using 4 NAND gates.

(b) Implement full sub tractor using NAND gates only.

6. Explain about analysis of clocked sequential circuits in details.

7. (a) Design a serial adder in shift registers.

(b) Write a HDL behavioural description of shift register.

8. (a) Convert the following number with indicated bases to decimal:

1. $(101111)_{2}$
2. $(A3B)_{16}$
3. $(237)_{8}$
4. $(43)_{5}$

(b) Obtains the 1’s and 2’s compliment of the following binary numbers:

1. 11101010=
2. 01111110=
3. 10000000=
4. 00000000=

9. (a) Implement the following Boolean algebra using AND, OR and Inverter gates:

(b) Using the rules of Boolean algebra, simplify the expressions that follow to the fewest total number of literals:

1. $F=AB+ABC+ACD$
2. $F=B+AD+BC+[B+A(C+D)]$

10. (a) Explain the working of 4-bit asynchronous counter.

(b) Explain the design of Arithmetic Logic unit.

………………End……………..

#### Lokesh Kumar

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