D/A converter fundamentals — definition of resolution Which statement correctly defines the resolution of a digital-to-analog (D/A) converter?

Difficulty: Easy

Correct Answer: It is the reciprocal of the number of discrete steps in the D/A output.

Explanation:


Introduction / Context:
Resolution indicates the smallest analog change a D/A converter can produce for a one-LSB digital change. It is fundamental when matching a converter to sensor accuracy and control requirements.


Given Data / Assumptions:

  • N-bit DAC has 2^N discrete output steps across full-scale range.
  • Resolution is typically expressed as a fraction (1/2^N of full scale) or as a percentage.


Concept / Approach:
For an ideal N-bit DAC, the minimum output increment (1 LSB) equals full_scale / 2^N. As a fraction of full scale, resolution = 1 / 2^N, which is the reciprocal of the number of steps. (Sometimes expressed in volts: V_LSB = V_FS / 2^N.)


Step-by-Step Solution:
Number of steps = 2^N.Resolution (fraction of full scale) = 1 / 2^N.Hence, it is the reciprocal of the number of discrete steps.


Verification / Alternative check:
Example: 10-bit DAC → 1024 steps → resolution ≈ 0.0977% of full scale per LSB, matching the reciprocal definition.


Why Other Options Are Wrong:

  • Comparison between actual and expected output defines accuracy.
  • Deviation from ideal straight line defines linearity error.
  • Forward/reverse step resolving addresses monotonicity/hysteresis, not resolution.


Common Pitfalls:

  • Confusing resolution with accuracy or linearity.
  • Forgetting that resolution sets granularity; accuracy tells how close outputs are to ideal.


Final Answer:
It is the reciprocal of the number of discrete steps in the D/A output.

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