Quiznetik

Digital Electronics | Set 1

1. Any number with an exponent of zero is equal to:

Correct : B. one

2. In the decimal numbering system, what is the MSD?

Correct : D. the digit with the most weight

3. Which of the following statements does NOT describe an advantage of digital technology?

Correct : A. the values may vary over a continuous range.

4. The generic array logic (GAL) device is ________.

Correct : B. reprogrammable

5. The range of voltages between VL(max) and VH(min) are ________.

Correct : C. unacceptable

6. What is a digital-to-analog converter?

Correct : A. it takes the digital information from an audio cd and converts it to a usable form.

7. What are the symbols used to represent digits in the binary number system?

Correct : A. 0,1

8. A full subtracter circuit requires ________.

Correct : D. three inputs and two outputs

9. The output of an AND gate is LOW ________.

Correct : B. when any input is low

10. Give the decimal value of binary 10010.

Correct : C. 1810

11. Parallel format means that:

Correct : A. each digital signal has its own conductor.

12. A decoder converts ________.

Correct : B. coded information into noncoded form

13. A DAC changes ________.

Correct : B. digital data into an analog signal

14. The output of a NOT gate is HIGH when ________.

Correct : A. the input is low

15. The output of an OR gate is LOW when ________.

Correct : A. all inputs are low

16. Which of the following is not an analog device?

Correct : C. light switch

17. A demultiplexer has ________.

Correct : A. one data input and a number of selection inputs, and they have several outputs

18. A flip-flop has ________.

Correct : C. two stable states

19. Digital signals transmitted on a single conductor (and a ground) must be transmitted in:

Correct : D. serial.

20. In a certain digital waveform, the period is four times the pulse width. The duty cycle is ________.

Correct : B. 25%

21. Select the statement that best describes the parity method of error detection:

Correct : C. parity checking is best suited for detecting single-bit errors in transmitted codes.

22. A logic circuit that provides a HIGH output for both inputs HIGH or both inputs LOW is a(n):

Correct : A. ex-nor gate

23. A logic circuit that provides a HIGH output if one input or the other input, but not both, is HIGH, is a(n):

Correct : C. ex-or gate

24. Identify the type of gate below from the equation

Correct : C. ex-or gate

25. Parity systems are defined as either________ or ________ and will add an extra ________ tothe digital information being transmitted.

Correct : B. odd, even, bit

26. Which type of gate can be used to add two bits?

Correct : A. ex-or

27. Show from the truth table how an exclusive-OR gate can be used to invert the data on one input if the other input is a special control function.

Correct : B. using a as the control, when a = 0, x is the same as b. when a = 1, x is the inverse of b.

28. In a flash analog-to-digital converter, the output of each comparator is connected to an input of a ________.

Correct : B. priority encoder

29. Which term applies to the maintaining of a given signal level until the next sampling?

Correct : A. holding

30. An op-amp has very ________.

Correct : D. all of the above

31. The dual-slope analog-to-digital converter finds extensive use in ________.

Correct : D. all of the above

32. The ADC0804 is an example of a ________.

Correct : D. successive-approximation analog-to-digital converter

33. In a digital representation of voltages using an 8-bit binary code, how many values can be defined?

Correct : D. 256

34. A 4-bit R/2R ladder digital-to-analog converter uses ________.

Correct : B. two resistor values

35. A binary-weighted-input digital-to-analog converter has a feedback resistor, Rf, of 12 k. If 50 A of current is through the resistor, voltage out of the circuit is ________.

Correct : B. –0.6 v

36. The resolution of a 6-bit DAC is ________.

Correct : D. 1.59%

37. How are unwanted frequencies removed prior to digital conversion?

Correct : A. pre-filters

38. Which type of programming is typically used for digital signal processors?

Correct : A. assembly language

39. Which of the following best defines Nyquist frequency?

Correct : D. the highest frequency component of a given analog signal

40. Which is not an A/D conversion error?

Correct : A. differential nonlinearity

41. Settling time is normally defined as the time it takes a DAC to settle within ________.

Correct : C. 1/2 lsb of its final value when a change occurs in the input code

42. Determine the output frequency for a frequency division circuit that contains 12 flip-flops with an input clock frequency of 20.48 MHz.

Correct : B. 5 khz

43. Which statement BEST describes the operation of a negative-edge-triggered D flip-flop?

Correct : A. the logic level at the d input is transferred to q on ngt of clk.

44. Propagation delay time, tPLH, is measured from the ________.

Correct : A. triggering edge of the clock pulse to the low-to-high transition of the output

45. How is a J-K flip-flop made to toggle?

Correct : D. j = 1, k = 1

46. How many flip-flops are in the 7475 IC?

Correct : C. 4

47. How many flip-flops are required to produce a divide-by-128 device?

Correct : D. 7

48. The ________ circuit overcomes the problem of switching caused by jitter on the inputs.

Correct : D. schmitt trigger

49. Why would a delay gate be needed for a digital circuit?

Correct : D. to provide for setup times and hold times

50. A Schmitt trigger has VT+ = 2.0 V and VT– = 1.2 V. What is the hysteresis voltage of the Schmitt trigger?

Correct : C. 0.8 volt

51. Which of the following circuit parameters would be most likely to limit the maximum operating frequency of a flip-flop?

Correct : C. propagation delay time

52. What is the result of taking more samples during the quantization process?

Correct : D. more bit requirements and more accurate signal representation

53. Which A/D conversion method has a fixed conversion time?

Correct : D. successive-approximation analog-to-digital converter

54. Which is a typical application of digital signal processing?

Correct : D. all of the above

55. If a DAC has a full-scale, or maximum, output of 12 V and accuracy of 0.1%, then the maximum error for any output voltage is ________.

Correct : C. 12 mv

56. What do we call the manipulation of an analog signal in a digital domain?

Correct : B. digital-to-analog conversion

57. How many address bits are needed to select all memory locations in the 2118 16K × 1 RAM?

Correct : C. 14

58. The check sum method of testing a ROM:

Correct : D. simply indicates that the contents of the rom are incorrect.

59. Refer to the given figures (a) and (b). A logic analyzer is used to check the circuit in figure (a) and displays the waveforms shown in figure (b). The actual analyzer display shows all four data outputs, Q0-Q3. The analyzer's cursor is placed at position X and all four of the data output lines show a LOW level output. What is wrong, if anything, with the circuit?

Correct : D. the q0–q3 lines can be either low or high, since the chip is in the tristate mode in which case their level is unpredictable.

60. What is the meaning of RAM, and what is its primary role?

Correct : C. random access memory; it is the memory used for short-term temporary data storage within the computer.

61. The storage element for a static RAM is the ________.

Correct : D. flip-flop

62. In a DRAM, what is the state of R/W during a read operation?

Correct : B. high

63. The condition occurring when two or more devices try to write data to a bus simultaneously is called ________.

Correct : B. bus contention

64. The difference between a PLA and a PAL is:

Correct : A. the pla has a programmable or plane and a programmable and plane, while the pal only has a programmable and plane.

65. ALM is the acronym for ________.

Correct : D. adaptive logic module

66. The GAL16V8 has:

Correct : C. 8 pins that are used as inputs or outputs.

67. PALs tend to execute ________ logic.

Correct : B. sop

68. How many pins are in an EDF10K70 package?

Correct : C. 240

69. Convert hexadecimal value 16 to decimal.

Correct : A. 2210

70. Convert the following decimal number to 8-bit binary.

Correct : A. 101110112

71. Convert binary 111111110010 to hexadecimal.

Correct : B. ff216

72. Convert the binary number 1001.00102 to decimal.

Correct : B. 9.125

73. One hex digit is sometimes referred to as a(n):

Correct : B. nibble

74. Which of the following is the most widely used alphanumeric code for computer input and output?

Correct : B. ascii

75. If a typical PC uses a 20-bit address code, how much memory can the CPU address?

Correct : C. 1 mb

76. Convert 59.7210 to BCD.

Correct : B. 01011001.01110010

77. Convert 8B3F16 to binary.

Correct : D. 1000101100111111

78. Which is typically the longest: bit, byte, nibble, word?

Correct : D. word

79. Assign the proper odd parity bit to the code 111001.

Correct : B. 1111001

80. Convert decimal 64 to binary.

Correct : B. 01000000

81. Convert hexadecimal value C1 to binary.

Correct : A. 11000001

82. The given hexadecimal number (1E.53)16 is equivalent to

Correct : B. (36.246)8

83. The octal number (651.124)8 is equivalent to

Correct : A. 16

84. The octal equivalent of the decimal number (417)10 is

Correct : A. (641)8

85. Convert the hexadecimal number (1E2)16 to decimal:

Correct : C. 482

86. (170)10 is equivalent to

Correct : C. (aa)16

87. Convert the binary number (01011.1011)2 into decimal:

Correct : A. (11.6875)10

88. 1011)2 = (11.6875)10

Correct : B. (010100)2

89. On addition of +38 and -20 using 2’s complement, we get

Correct : C. 010010

90. On addition of -46 and +28 using 2’s complement, we get

Correct : B. 0101110

91. On subtracting +28 from +29 using 2’s complement, we get

Correct : D. 1

92. The decimal number 10 is represented in its BCD form as

Correct : C. 00010000

93. When numbers, letters or words are represented by a special group of symbols, this process is called

Correct : B. encoding

94. Carry out BCD subtraction for (68) – (61) using 10’s complement method.

Correct : A. 00000111

95. How many bits would be required to encode decimal numbers 0 to 9999 in straight binary codes?

Correct : B. 14

96. The decimal equivalent of the excess-3 number 110010100011.01110101 is

Correct : A. 970.42

97. In boolean algebra, the OR operation is performed by which properties?

Correct : D. all of the mentioned

98. The expression for Absorption law is given by

Correct : A. a + ab = a

99. According to boolean law: A + 1 = ?

Correct : A. 1

100. The involution of A is equal to

Correct : A. a