AD/DA conversion

When a microcontroller produces an analog voltage by passing a PWM signal through a low-pass filter, what determines the output voltage?

  1. AThe duty cycle of the pulses (the fraction of each period that is on)
  2. BThe color of the pulses
  3. CThe memory capacity of the microcontroller
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Answer: A. The duty cycle of the pulses (the fraction of each period that is on)

When a PWM signal is averaged by a low-pass filter, the output voltage is amplitude × duty cycle. For example, 5 V pulses with a 40% duty cycle give about 2 V. Analog voltages can be produced easily without a dedicated DAC, but ripple remains, so accuracy and speed are limited.

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More AD/DA conversion questions

  1. What does 'MS/s (MSPS)', used to express the conversion speed of an AD converter, mean?
  2. In the transfer characteristic of an AD converter, what is the error called when the output deviates from 0 at zero input?
  3. What is an advantage of using a differential input for an AD converter?
  4. In a delta-sigma AD converter, which digital circuit converts the fast, coarse quantized output into high-resolution data at a lower sampling rate?
  5. What is the brief spike-like error that appears at the output of a DA converter at the moment the input code changes?