Correct Answer: It is the comparison between the actual output of the converter and its expected output.
4. 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.
Correct Answer: 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.
5. What is the current in the feedback resistor for the circuit given below?
7. 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.
Correct Answer: error in the slope of the output staircase waveform
9. 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.
Correct Answer: 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.
10. A 4-bit R/2R D/A converter has a reference of 5 V. What is the analog output for the input code 0101?