STLD I MID IMPORTANT QUESTIONS

STLD  I MID IMPORTANT QUESTIONS

II ECE-A

1. a) Represent the decimal number 7258 in

            i) BCD code    ii) excess-3 code        iii)2421 code    iv) 6311 code

    b) What is a self complementary code? Explain with two examples.

2. a) Perform the following operations using 2’s complement arithmetic:

            i) (+43)10 − (−53)10.              ii) (3E91)16 − (1F93)16

    b) Represent the unsigned decimal numbers 351 and 986 in BCD, and then show the 

         steps necessary to form their sum.

3. a) Explain different methods used to represent negative numbers in binary system.

    b) In a new number system X and Y are successive digits such that (XY)r = (25)10 and

         (YX)r = (31)10 . Find X,Y,r

4. a) What do you understand by canonical and expanded forms of Boolean expressions?

        Illustrate with examples.

    b) Design a logic circuit having three inputs A, B, C such that output is 1 when A = 0 or

        whenever B = C = 1. Also obtain logic circuit using NAND gates.

5. a) It is proposed to construct an eight-input NAND gate using only two-input AND gates

        and two-input NAND gates. Draw the logic arrangement that uses the minimum   

        number of logic gates.

    b) What is a parity bit? Define even and odd parity. What is the limitation of the parity  

         code when it comes to detection and correction of bit errors?

6. a) Explain error correction and error detection codes with examples.

    b) Implement the following Boolean function F using the two-level form

         i) NAND-AND ii) AND-NOR where F (A,B,C,D) =∑(0,1,2,3,4,8,9,12)

7. a) Explain the fundamental postulates of Boolean algebra

    b) Obtain the compliment and dual for the following expressions

        i) AB + BC + AC  ii) A+B’C(A+B+C’)                  iii) AB+(AC)’+(AB+C)

8. Minimize the following function using tabular minimization and verify the same with

     K-map minimization F=π(0,2,4,5,6,7,8,10,14,17,18,21,29,31) . πd(11,20,22)

9. a) Write a simplified max-term Boolean expression for  π (0, 4, 5, 6, 7, 10, 14) using the

        Karnaugh mapping method.

    b) Minimizing a given Boolean expression using the Quine–McCluskey tabular method  

        yields the following prime implicants: −0−0, −1−1, 1−10 and 0−00. Draw the  

        corresponding Karnaugh map.

10.a) Write both sum-of-products and product-of-sums Boolean expressions for

        i) a two-input AND gate,    ii) a two-input NAND-gate,    iii) a two-input EX-OR gate and

        iv) a two-input NOR gate from their respective truth tables.

     b) Write the procedure of design of Combinational Circuits.