- Year not given · 4 marks
Analog versus digital measurement system
Short answer
Analog systems represent the measurand as a continuous signal with a pointer on a scale, subject to parallax and limited accuracy. Digital systems use discrete numeric display, offer higher accuracy, better noise immunity, and easy data processing but require more complex circuits.
Differentiate between analog and digital measurement system.
An analog measurement system represents the quantity by a continuously varying signal (pointer position or voltage). A digital system represents it as discrete numbers (binary codes) and shows it as digits.
| Point | Analog system | Digital system |
|---|---|---|
| Signal | Continuous in amplitude and time | Discrete (quantised, sampled) |
| Display | Pointer on a scale | Numeric digits (LED/LCD) |
| Resolution | Limited by scale and reading skill | Fixed by number of bits/digits |
| Reading error | Parallax and interpolation errors | No parallax; direct reading |
| Accuracy | Lower (about 0.5 to 2 %) | Higher (0.01 % or better possible) |
| Noise immunity | Poor; noise adds to the signal | Good; only levels 0/1 matter |
| Data storage and processing | Difficult | Easy; interface to computers |
| Speed | Slow (mechanical movement) | Fast |
| Cost and complexity | Simple, cheap | More complex circuits (ADC, logic) |
| Example | PMMC voltmeter, moving-coil ammeter | Digital multimeter, digital frequency counter |
Digital systems also have a quantisation error of ±½ LSB, which analog systems do not have.
✓ Answer checked by Claude Opus 5.5 (high effort)
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