# DIGITAL ELECTRONICS PREVIEW YEAR QUESTION PAPER 2014-15

### DIGITAL ELECTRONICS PREVIEW YEAR QUESTION PAPER 2014-15

Introductions of Digital Electronics :

Digital Electronic is represent a analog levels. The Digital Electronic .Can be used to made large assemblies of logic gates and digital circuit. Digital circuits are made analog Components that’s deigned Digitally system. The Digitally circuits calculate more slowly than low-precision analog circuits. Digital circuit are often form small electronic circuit called logic gates and that can be used Boolean logic . basically the Digital Electronic are study in more details of hardware work and deigned.

DIGITAL ELECTRONICS

Q1. Attempt any Four Question

1. State De Morgan’s Theorem .Write the Logic Expressions for the Differences and borrow of a half subtraction?.
2. Draw a Logic diagram of a 2-bit by 2-bit binary multiplier and explain its operations .Explain the operation of a BCD Adder?.
3. Write the Characteristics equation of a JK Flip flop. Design a full adder using two half adders and an OR gate?.
4. [i] How many 32k*4 RAM chips are needed to provide a memory capacity of 256k Bytes?.

[ii] Simplify the Boolean expression:

F=A’B+A.B’+A.B+A

1.    [i] Implement the following Function using a suitable multiplexer

F(A,B,C,D)-(1,3,11,12,13,14,15)

[ii] Convert D flip flop to T flip flop

Q2.Attemt any Three Question

•    [i] Describe the Mechanism of an instructions fetching , decoding and execution using flow chart?.

[ii] Implement exclusive – or function using ROM.

• [i] What are the Function performed by an I/O interface ?Explain with an example.

[ii] Compare and Contrast isolated I/O and memory mapped I/O.

• [i] Explain the need of the memory hierarchy ?

[ii] What is associated memory and what king of operation it is more suitable ?.

• [i] why does I/O interrupt make more efficient use of the CPU?

[ii] Simplify the following expression using K-Map Method .

Y=<m (7,9,10,11,12,13,14,15)

Q3.          Define any Four question

• Synchronous and Asynchronous data transfer
• Cache memory and virtual memory
• Difference between magnetic disk and magnetic tape