DIGITAL ELECTRONICS (B.Tech. 3rd Semester)

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Note:- This paper consist of three Serctions Section A is compulsory. Do any Four questions from Secion B and any two questions from Section C.
Section-A Marks:20

1.(a) Application of ASCII ,Excess-3 and grey codes.
(b) Differntiate between combinational and sequential circuits.
(c) the advantages of edge triggered flip-flops
(d) How subtractionof 4-bit no. is performed by addition?
(e) If two inputs are to be used for a 4 input NAND gate, discuss the options avalable with the unused inputs.
(f) A/D accuracy and resolution
(g) Fan in, Fan out, propagatoin gelay terms related to logic gates.
(h) Special features of content addressable memories.
(i) Advantages and diaadvantages of synchrounous over asynchronous counters.
(j) Conversion of 100.55(10) into binary, octal codes.

Section-B Marks : 5 Each

2. Draw the circuit of a 3 to 8 decoder and explain its operation. How this can be used as a DEMUX.
3. Find the complement of the boolean function and reduce it to a minimum number of literals :
B'D+A'BC'+ACD+A'BC.
4. Draw the circuit of a negative edge triggered J-K flip flop with d.c. pre-set and d.c. clear options using S-R flip flops
and explin its truth table.
5. Draw and discuss the circuit of a dual scope A/D convertor.
6. Draw the circuit of a 3- input TTL totem pole NAND gate and explin its operation.

Section-C MArks:10 Each

7.(a) Mention the various A/D convertors. Discus sthe comparision of advantages and disadvantages of each of these.
(b) Simple using Q-M method:
X(A,B,C,D)= SIGMA(0,1,2,8,10,11,14,15).
8.(a) Draw the circuit of Ecl gate and explin its operation.
(b) Discuss the comparision of the important characteristics of the various IC logic families.
9.(a) Draw the circuit of a BJT RAM cell and explin its operation
(b) Draw the circuit of a 4-bit shift register and explin its operation.