RGPV Exams Questions Papers Digital Circuit & Systems Dec 2005
B.E. (Fourth semester) EXAMINATION,DEC. 2005
(Common for EC/EE/EX Engg.)
(DIGITAL CIRCUIT AND SYSTEM – EE/EC/EX-402)
Note: Attempt any five questions. All question carry equal marks. Assume any missing data.
1. (a) Convert the number ( 350.25)10 to base 4,8 and 16.
(b) What is BCD? Write BCD representation of decimal number 257.
(c ) Show 8-bit addition of the following decimal number in 2’ complement representation:
45 and 48
68 and 37.
(d) Write gray code for (18)10 and (67)10.
2. (a) Minimize the four variable logic function and release using NAND gate :
F(A,B,C,D) = ABCD + ABCD + ABCD + ABCD + ABCD + ABCD
(b) For a full adder first make a truth table and than using Quine and McCluskey’s method simplify the
expression for some and carry. Also draw the circuit fir NAND-NAND reliasation
3. (a) What is racing in a flip-flop? How it can be avoided? Explain.
(b) Describe the procedure to design MOD X counter . Take any number of X between 0 and 15.
4. (a) Explain serial-in serial-out parallel-in-parallel-out type of registers with the help of circuit diagram.
(b) Explain the working of a bistable multavibrator .
5. (a) Explain TTL and CMOS in detail with circuit diagram.
(b) Explain the operation of a Schmitt trigger
6.(a) Simplify the Boolean function F using the don’t care condition X in product of sum form:
F = A B D + ACD + ABC
X = ABCD + ACD + ABD
(b) Draw and explain an operation of a full subtractor.
7. (a) Explain and discuss any one method of D to A converter.
(b) What do you mean by PLA ? Explain .
8. Write short note on any two of the following:
(a) V-F converter
(b) Look-ahead carry generater
(c ) Interfacing between TTL to MOS.
(d ) Semiconductor memories.