Digital Electronics-Interfacing to the Analog World

Digital Electronics-Interfacing to the Analog World
41. Three characteristics of op amps make them almost ideal amplifiers: very high input impedance, very low impedance, and ________.
  • very high voltage gain
  • unlimited bandwidth
  • a low slew rate
  • very high current gain
Show Answer
42. Sample-and-hold circuits in A/D converters are designed to:
  • sample and hold the output of the binary counter during the conversion process
  • stabilize the comparator's threshold voltage during the conversion process
  • stabilize the input analog signal during the conversion process
  • sample and hold the D/A converter staircase waveform during the conversion process
Show Answer
43. What is the main disadvantage of the counter-ramp A/D converter?
  • It requires a counter.
  • The counter must count up from zero at the beginning of each conversion sequence, and the conversion time will vary depending on the input voltage.
  • It requires a precision clock in order for the conversion to be reliable.
  • The counter must count up from zero at the beginning of each conversion sequence, and the conversion time will vary depending on the input voltage. It requires a precision clock in order for the conversion to be reliable.
Show Answer
44. Why is a binary-weighted DAC usually limited to 4-bit binary conversion?
  • too many pins on the IC
  • too many op amps needed
  • too many different values of capacitors
  • too many different values of resistors
Show Answer
45. What is the resolution of a D/A converter?
  • It is the reciprocal of the number of discrete steps in the D/A output.
  • It is the comparison between the actual output of the converter and its expected output.
  • It is the deviation between the ideal straight-line output and the actual output of the converter.
  • It is the converter's ability to resolve between forward and reverse steps when sequenced over its entire range of inputs.
Show Answer
46. An actuator is usually a device that:
  • converts analog data to meaningful digital data.
  • controls a physical variable.
  • stores digital data and then processes that data according to a set of specified instructions.
  • converts a physical variable to an electrical variable.
Show Answer
47. The DAC0808 and the MC1408 are very popular and inexpensive 8-bit D/A converters.
  • TRUE
  • FALSE
Show Answer
48. The delay between a change on the digital input of a DAC and the appearance of the change on the output is called settling time.
  • TRUE
  • FALSE
Show Answer
49. The main advantage of the SAR ADC method is its high speed.
  • TRUE
  • FALSE
Show Answer
50. One way to determine the resolution of a DAC is to calculate the ratio of one step voltage to the maximum output voltage.
  • TRUE
  • FALSE
Show Answer
Electronics
Questions and Answers for Competitive Exams Various Entrance Test