Measurement styles: A continually variable, proportional indicator (for example, a smoothly varying needle or voltage) is an ________ representation.

Introduction / Context:
Signals and measurements can be represented as continuous values or discrete steps. This distinction defines analog versus digital approaches and affects sensor design, display technology, and signal processing methods.

Given Data / Assumptions:

• The indicator changes smoothly in proportion to the measured quantity.
• Examples include needles on a meter, continuous voltage levels, and varying light intensity.
• We need the correct classification term.

Concept / Approach:
An analog representation uses a continuously variable physical quantity to represent information. A digital representation instead uses discrete levels or symbols. A proportional, smoothly varying indicator therefore fits the analog definition precisely.

Step-by-Step Solution:

Verification / Alternative check:
Classic moving-coil meters provide analog readouts; modern digital multimeters convert to digital for display but may also present bar graphs that emulate analog style.

Why Other Options Are Wrong:
decimal: a base for numbers, not a representation style of continuity.

digital: discrete steps rather than continuous variation.

unconstitutional: irrelevant to engineering terminology.

Common Pitfalls:
Confusing “analog” with “old” or “less accurate.” Analog can be highly accurate; the distinction concerns continuity versus discreteness, not quality.

Final Answer:
analog