Learning objectives
To introduce students with the fundamentals of modern metrology, with particular reference to the electronic measurements. Topics include an introduction to metrology (International System of measurement units, electrical standards, and evaluation of measurement uncertainty) and the description of some basic instruments. Techniques, precautions for each measurement type, and required instrumentation configurations are stressed.
Prerequisites
It is expected that students will know operational amplifiers
Course unit content
Measurements for monitoring physical phenomena. Errors and uncertainty. Physical quantity, measurement units and standards. The International System of measurement units.
Modelling the measurement process: identifying sources of error, understanding and quantifying errors, codifying error effects on a specific reported value in a statement of uncertainty. Uncertainty propagation, type A and type B evaluations, composite and extended uncertainty, degrees of freedom.
Non-ideality in op-amps: offset, bias currents, noise (circuital modeling)
Analogue-to-Digital conversion. Sampling and quantisation effects on signals. Non-ideal behaviour of real converters. Dithering. Number of effective bits. Architectures of ADCs:
integrating voltmeter (dual slope and multiple slopes, Voltage-to-Frequency; normal mode rejection). Feedback converters (successive approximation, sigma-delta). Parallel converters (flash, interleaved). Analisys of the spectrum of a sampled signal (folding, noise level, leakage and windowing).
Some elements on the Digital-to-Analog converters.
Digital multimeter: block diagram. DC and AC measurements of voltage and current. Resistance measurements. Data acquisition systems.
Time-domain signal analysis. The analogue oscilloscope (block diagram, CRT, vertical amplifier, trigger, main and delayed time bases, controls). Real-time digital scope and equivalent-time sampling scopes (block diagrams, aliasing, interpolation, accuracy). Passive and active probes.
Time, period, and frequency measurements: conventional and reciprocal electronic counter, frequency and time-interval analyser. Analogue and digital interpolation techniques for measuring time-intervals with picosecond resolution. Measurement uncertainty.
Bibliography
J.R. Taylor, Introduction to Error Analysis: The Study of Uncertainties in Physical Measurements, Univ Science Books, 2nd edition
Assessment methods and criteria
Oral examination with a written exercise.
