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ECE :: Digital Electronics

  1. A crystal is frequently used in digital circuits for timing purpose because of its

  2. A.
    low cost
    B.
    high frequency stability
    C.
    simple circuitry
    D.
    ability to set frequency at desired value

  3. The value of program counter of 6800 at power on are after reset is

  4. A.
    000
    B.
    FFFE
    C.
    User Programmable
    D.
    FFFF

  5. The Boolean expression for the sub-class (Q) of all electronic instruments which are measuring instruments or are non-digital instruments with battery supply is

  6. A.
    Q = X(Y + Z)
    B.
    Q = X + YZ
    C.
    Q = XY + Z
    D.
    Q = XY + Z

  7. Serial in-serial out shift register can be built using D flip flops.

  8. A.
    True
    B.
    False

  9. A binary ladder network D/A converter requires

  10. A.
    resistors of one value only
    B.
    resistors of many different values
    C.
    resistors of two different values
    D.
    none of the above

  11. Data from a satellite is received in serial form (1 bit after another). If this data is coming at a 5 MHz rate and if the clock frequency is 5 MHz how long will it take to serially load a word in a 32-bit shift register?

  12. A.
    1.6ms
    B.
    3.2ms
    C.
    6.4ms
    D.
    12.8ms

  13. Assuming accumulator contain A 64 and the carry is set (1). What will register A and (CY) contain after CMA?

  14. A.
    6 AH, 1
    B.
    6 AH, 0
    C.
    59 H, 0
    D.
    9 H, 0

  15. The minimum number of 2 input NAND gates required to implement Boolean function A B C is A, B, C are available is

  16. A.
    2
    B.
    3
    C.
    5
    D.
    6

  17. Single parity check is not reliable in case of

  18. A.
    paper tape
    B.
    magnetic tape
    C.
    magnetic drum
    D.
    cores

  19. A 0 to 6 counter consist of 3 flip-flop and a combinational circuit of 2 input gates. The combinational circuit consist of

  20. A.
    one AND gate
    B.
    one OR gate
    C.
    one AND and One OR
    D.
    two AND gate