Download PTU B.Tech 2020 March CSE-IT 3rd Sem BTCS 303 Digital Circuits & Logic Design Question Paper

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Roll No. Total No. of Pages : 02

Total No. of Questions : 18

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B.Tech.(CSE)/(IT) (2012 to 2017) (Sem.-3)

DIGITAL CIRCUITS & LOGIC DESIGN

Subject Code : BTCS-303

M.Code : 56593

Time : 3 Hrs. Max. Marks : 60

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INSTRUCTION TO CANDIDATES :

1. SECTION-A is COMPULSORY consisting of TEN questions carrying TWO marks each.
2. SECTION-B contains FIVE questions carrying FIVE marks each and students have to attempt any FOUR questions.
3. SECTION-C contains THREE questions carrying TEN marks each and students have to attempt any TWO questions.

SECTION-A

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Answer briefly :

1. Perform 2’s complement subtraction of (7)10— (11)10
2. What is race around condition? How it can be avoided?
3. How many states can an n-bit Ring counter and an n-bit Johnson’s counter have?
4. What is meant by the term edge triggered?

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5. How many flip-flops are required to design a mod-7 up down counter?
6. What is difference between static RAM and dynamic RAM?
7. What is EEPROM?
8. What are the advantages of ring counter?
9. Differentiate between A/D and D/A conversion techniques.

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10. Write a short note on : SOP and POS.

SECTION-B

1. Prove the following identities using Boolean algebra :
   (A+B)A+(AB))C+A'B+C)+AB+ABC=C(A+B)+A'B+C
2. A microprocessor uses RAM chips of 1024 x 1 capacity.
   

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   (a) How many chips will be required and how many address lines will be connected to provide capacity of 1024 bytes?
   (b) How many chips will be required to obtain a memory of capacity of 16 K bytes?
3. What are the characteristics of digital ICs used to compute their performance?
4. Design an FPLA circuit, programed to implement a 3- bit binary to Gray conversion.
5. Design a sequence detector to detect the sequence 1010 (overlapping of the sequence is permitted). Use D flip-flop to design the circuit. Show the intermediate design steps :
   

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   (a) State Diagram
   (b) Truth Table/ Excitation table
   (c) Logic Diagram of the circuit.

SECTION-C

1. A combinational circuit has 3 inputs A, B, C and output F. F is true for following input combinations
   

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   A is False, B is True
   A is False, C is True
   A, B, C are False
   A, B, C are True
   (a) Write the Truth table for F. Use the convention True = 1 and False = 0.
   

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   (b) Write the simplified expression for F in SOP form.
   (c) Write the simplified expression for F in POS form.
   Draw logic circuit using minimum number of 2-input NAND gates.
2. Design a 8 to 1 multiplexer by using four variable function given by
   F (A, B, C, D) = £m(0,1,3,4,8,9,15)

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3. What are synchronous counters? Design a 3-bit Gray code counter using T-Flip Flop.

NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any page of Answer Sheet will lead to UMC against the Student.

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