An analog-to-digital converter has a four-bit output. How many analog values can

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Question
An analog-to-digital converter has a four-bit output. How many analog values can it represent?
Options
A. 4
B. 1/4
C. 16
D. 0.0625

Correct Answer

1. What is the major advantage of the R/2R ladder D/A converter as compared to a binary-weighted D/A converter?
Options
A. It has fewer parts for the same number of inputs.
B. It is much easier to analyze its operation.
C. It uses only two different resistor values.
D. The virtual ground is eliminated and the circuit is therefore easier to understand and troubleshoot.

2. What is the accuracy of a D/A converter?
Options
A. It is the reciprocal of the number of discrete steps in the D/A output.
B. It is the comparison between the actual output of the converter and its expected output.
C. It is the converter's ability to resolve between forward and reverse steps when sequenced over its entire range of inputs.
D. It is the deviation between the ideal straight-line output and the actual output of the converter.

3. What is the main disadvantage of the counter-ramp A/D converter?
Options
A. It requires a counter.
B. 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.
C. It requires a precision clock in order for the conversion to be reliable.
D. 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.

5. One disadvantage of the tracking A/D converter is:
Options
A. that it requires two counters?one for up and one for down.
B. that the binary output will oscillate between two binary states when the analog input is constant.
C. the need for an accurate clock reference for the counter.
D. the need for a latch and its associated control circuit.

8. A certain digital-to-analog converter has a step size of 0.25 V and a full-scale output of 7.75 V. Determine the percent of resolution and the number of input binary bits.
Options
A. 31%, 4 bits
B. 3.23%, 4 bits
C. 31%, 5 bits
D. 3.23%, 5 bits

9. What is gain error in a DAC?
Options
A. missing codes
B. error in the slope of the output staircase waveform
C. more or less input voltage is required for the first step than what is specified

10. Which of the following describes the basic operation of a single-slope A/D converter.
Options
A. The input voltage is used to set the frequency of a voltage-controlled oscillator (VCO). The VCO quits changing frequency when the input voltage stabilizes. The frequency of the VCO, which is proportional to the analog input voltage, is measured and is displayed on the digital display as a voltage reading.
B. A ramp generator is used to enable a counter through a comparator. When the ramp voltage equals the input voltage the counter is latched and then reset. The counter reading is proportional to the input voltage since the ramp is changing at a constant V/second rate.
C. A ramp voltage and analog input voltage are applied to a comparator. As the input voltage causes the integrating capacitor to charge, it will at some point equal the ramp voltage. The ramp voltage is measured and displayed on the digital panel meter.
D. Any of the above could be correct, depending on the specific type of A/D converter involved.

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