GTU Last Year question papers Digital Logic Design

GTU previous question papers


B.E. Sem-III Examination December 2009

Subject code: 1301

Subject Name: Digital Logic Design



1. Attempt all questions.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.

Q.1 (a) Convert the following numbers to decimal          

(i) (10001.101)2 (ii) (101011.11101)2 (iii) (0.365)8

(iv) A3E5 (v) CDA4 (vi) (11101.001)2 (vii) B2D4

(b) Perform the operation of subtractions with the following binary numbers using 2′ complement

(i) 10010 – 10011 (ii) 100 -110000 (iii) 11010 -10000

Q.2 (a) Obtain the simplified expressions in sum of products for the

following Boolean functions:


(i) F(A,B,C,D,E) =Σ(0,1,4,5,16,17,21,25,29)

(ii) A′B′CE′ + A′B′C′D′ +B′D′E′ + B′C D′

(b) Demonstrate by means of truth tables the validity of the following Theorems of Boolean algebra

(i) De Morgan’s theorems for three variables

(ii) The Distributive law of + over-


(b) Implement the following Boolean functions          

(i) F= A (B +CD) +BC′ with NOR gates

(ii) F= (A + B′) (CD + E) with NAND gates

Q.3 (a) Design a combinational circuit that accepts a three bit binary

number and generates an output binary number equal to the square of the input number.

 (b) Discuss 4-bit magnitude comparator in detail          


Q.3 (a) With necessary sketch explain full adder in detail

(b) Design a combinational circuit that generates the 9′ complement of a BCD digit,

Q.4 (a) Discuss D-type edge- triggered flip-flop in detail          

(b) Design a counter with the following binary sequence:0,4,2,1,6and repeat (Use JK flip-flop)        


Q.4 (a) Design a counter with the following binary sequence:0,1,3,7,6,4,and repeat.(Use T flip-flop)

 (b) (i)With neat sketch explain the operation of clocked RS flip         

(ii)Show the logic diagram of clocked D

Q.5 (a) With necessary sketch explain Bidirectional Shift Register with parallel load.

(b) Draw the state diagram of BCD ripple counter, develop it’s logic diagram, and explain it’s operation.


Q.5 (a) Construct a Johnson counter with Ten timing signals.

(b) Discuss Interregister Transfer in detail          


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