A/D (Analog to Digital) and D/A (Digital to Analog) converters MCQs

Digital Electronics MCQs

1. The speed of conversion is maximum in_______.

a. Parallel-comparator A/D converter

b. Counter ramp A/D converter

c. Successive-approximation A/D converter

d. Dual-slope A/D converter

2. The A/D converter whose conversion time is independent of the number of bits is______.

a. Successive approximation type

b. Dual slope type

c. Flash type

d. Counter type

3. In successive-approximation A/D converter, offset voltage equal to 1/2 LSB is added to the D/A converter's output. This is done to_____.

a. Improve the speed of operation

b. Increase the range of input voltage that can be converted

c. Increase the number of bits at the voltage

d. Reduce the maximum quantization error

4. A weighted resistor digital to analog converter using n-bits required a total of_______.

a. n+1 precision resistors

b. n precision resistors

c. n-1 precision resistors

d. 2n precision resistors

5. The number of compensators required for 12-bit flash type ADC is_____.

a. 2512

b. 3095

c. 4095

d. 4000

6. A clock rate of one megahertz operating 12-stage counter of a counter-type ADC would need a maximum conversion time of approximately_______.

a. 3.2 ms

b, 7.1 ms

c. 8 ms

d. 4.1 ms

7. Which of the following is not true in the circuit for digital-to-analog voltage converter?

a. A resistor network

b. A resonant circuit

c. A reference voltage

d. Some logic circuitry

8. In a D/A converter made with binary weighted resistors, it is difficult to maintain high accuracy as the number of bits increases, because_____.

a. The finite gain of the opamp increases inaccuracies

b. The LSB resistance consume too much current, and power

c. Obtaining stable, precise resistors with a large spread in their values is very difficult

d. As the resistance values of the most significant bits become larger, the circuit takes a very long time to settle

9. An ADC has a total conversion time of 200 micro seconds. What is the highest frequency that its analog input should be allowed to contains?

a. 10 kHz

b. 7.5 kHz

c. 2.5 kHz

d. 5 kHz

10. Which of the following ADC do not use a DAC?

a. SAR type ADC

b. Ramp type ADC

c. Dual slope type ADC

d. Both (a) and (c)

 11. An ADC is used to convert signals in the range of 1 kHz to 50 kHz. The maximum conversion time would be equal to_____.

a. 10 μs

b. 20 μs

c. 5 μs

d. 15 μs

12. The full scale input voltage of an ADC is 10 V. The resolution required is 5 mV. The minimum number of bits required for ADC is______.

a. 6

b. 10

c. 11

d. 12

13. The output voltage range of a 12-bit DAC is 0 to 10 V. The integer number of 516 causes an analog output of______.

a. 1.26 V

b. 0.516 V

c. 4.17 V

d. 2.88 V