B.E. (Fourth semester) EXAMINATION,MAY,JUNE, 2006
(Common for EC/EE/EX Engg.)
(DIGITAL CIRCUIT AND SYSTEM)
Note: Attempt any five questions. All question carry equal marks. Assume any missing data.
1. (a) Convert the number (210.25)10 to base 2,8,16.
(b) Show 8-bit addition of these decimal number in 2’s complement the presentation:
(i) 52 and 67
(ii) 57 and -82
(c ) State dulity theorem .
(d) Write gray code and BDC code for (18)10 .
(e) At the following numbers :
(i) ABC + CDE (ii) (77)8 +(107)8
2. (a) Realize the following gates using minimum number of NAND gates :
AND, OR, NOT,NOR,EX-OR
(b) Express the following in some of minterms and product of maxterm from :
F (A,B,C) = (A+B) (BC)
F (x,y,z) =1
3. (a) Minimize the 04 variable logic function and release using NOR gate :
F (A,B,C,D) = ABCD+ ABCD+ ABCD + ABCD +ABCD
(B) Use De morgan’s theorem to convert the Boolean expression :
ABCD + ABCD = Y
To its max terms from and draw the logic diagram.
4. (a) Explain Serial adder and parallel adder .
(b) Implement a full adder using a multiplexer
5. (a) Explain the working of J-K flip-flop.
(b) Explain the operation of BCD counter.
6. (a) Design a mode -9 counter.
(b) Explain the working of a monostable multavibrator.
7. Write short notes on any two of the following:
(i) CMOS logic families
(ii) Asynchronous counter
(iii) Sample and hold circuit
(iv) D/A converter