Introduction / Context:
Resolution specifies the smallest change in output that can be resolved by a DAC. It is a fundamental specification distinct from linearity or accuracy. This item asks for the clearest definition among common, sometimes-confused terms.
Given Data / Assumptions:
- A DAC maps N-bit codes to analog levels.
- LSB step size is related to full-scale range and the number of bits.
- Other parameters (DNL, INL, accuracy) are separate characteristics.
Concept / Approach:
Resolution can be expressed either as the number of bits (N) or as the size of one LSB step. Stating it as “number of bits that are converted to an analog output” is the common textbook definition. Minimum output voltage, deviation from a straight line (linearity), and error are different concepts.
Step-by-Step Solution:
Relate resolution to bits: higher N → more quantization levels → smaller LSB.Understand that “minimum output voltage” is not a standard metric for resolution.Recognize that “deviation from a straight line” is INL, not resolution.Recognize that “difference between expected and actual outputs” is accuracy or error, not resolution.
Verification / Alternative check:
Compute LSB: LSB = (Full-scale range) / (2^N - 1). This ties bits directly to output granularity.
Why Other Options Are Wrong:
minimum output voltage: Depends on offset and reference; not “resolution.”deviation from a straight line: That’s integral nonlinearity.difference between expected and actual outputs: That’s accuracy/total error.
Common Pitfalls:
Equating high resolution with high accuracy; noise and linearity can limit effective number of bits.Ignoring that effective resolution (ENOB) can be less than nominal N due to noise.
Final Answer:
number of bits that are converted to an analog output
Discussion & Comments