Measurement Techniques and Instrumentation

Code:

F4042

Acronym:

F4042

Level:

400

Keywords
Classification	Keyword
OFICIAL	Physics

Instance: 2024/2025 - 1S

Active?	Yes
Responsible unit:	Department of Physics and Astronomy
Course/CS Responsible:	Master in Physics

Cycles of Study/Courses

Acronym	No. of Students	Study Plan	Curricular Years	Credits UCN	Credits ECTS	Contact hours	Total Time
M:A_ASTR	1	Study plan since academic year 2024/2025	1	-	6	42	162
			2
M:F	5	Official Study Plan	1	-	6	42	162

Teaching language

Suitable for English-speaking students

Objectives

This course seeks the development of the student’s ability to design and implement measurement systems and instrumentation, enabling the acquisition of skills for professional activity in scientific or industrial environment, or even pursuing more advanced studies. To achieve these, the student will learn: the general concepts and structures of the measurement process, as well as fundamental techniques and instrumentation; the operating principles and characteristics of major types of sensing elements (transducers) and on signal conditioning elements; gain knowledge on signal conditioning and instrumentation; study the origin and characteristics of the noise sources affecting measurement systems and instrumentation, and techniques used to minimize their effects;  assess the factors that determine the integration of the various blocks that constitute a measurement system; working principles of advanced instrumentation and measuring principles.

Learning outcomes and competences

 

• Knowledge of factors conditioning the process of measurement.
• Ability to design and implement measurement systems and instrumentation;
• Skills to work in a science experiment or an industrial environment.
• Knowledge in the area of structural instrumentation targeting measurement processes, enabling the acquisition of skills for professional activity in the area, or proceeding to more advanced studies.

 

Working method

Presencial

Program

The Course Unit is divided into 3 modules. In the first module is made an introduction to several important topics for instrumentation. In the second module a formal treatment is made of some of the topics considered most important. In the third module applications of knowledge are made using some specific systems.

Module 1

General Elements of a Measurement System. Static Characteristics of Measurement Systems; error measurement and generic techniques for its reduction.  Dynamic characteristics of 1st and 2nd order measurement systems: dynamic error and techniques for its minimization. 

Introduction to electronic noise. Signal-to-noise ratio. Noise factor of an amplifier. Noise temperature. Thermal, quantum and flicker noise (1 / f). Environmental or extrinsic noise

Theory of feedback. Positive and negative feedback. Importance of negative feedback in gain stabilization. Output stabilization time and self-oscillation problems. Operational amplifier in the non-inverting assembly. Operational amplifier in the inverter assembly (transresistance amplifier). Add-on circuit. Integrator and differentiator circuits. Influence of negative feedback on the input impedance of voltage amplifiers. Influence of negative feedback on the output impedance of voltage amplifiers. Positive feedback circuits. Importance of hysteresis in instrumentation. Timing circuits and their importance in instrumentation.

Transducers and Sensors. The sensor in a measurement chain. Classification and static characterization of sensors. Dynamic sensor characteristics. Sensor noise

Digital-to-analog conversion. Main Types of Converters. Characteristics of DACs. Analog-to-digital conversion. Converters of the type flash and half-flash. Converters in ladder. Converters of successive approximation. Ramp converters. Double ramp converters. Voltage-frequency converters. Use of sample and hold and multiplexing.

Simple passive filters (RC and RLC). Types of filters (high pass, low pass, bandpass and band reject). Frequency response and phase response. Concatenation of filters. Main features of filters. Filters of Butterworth, Chebyshev and Bessel. Active filters, differences for passive filters. Filter selection factors.

Principles of control. System in open-loop, impossibility to correct small changes. System with feedback. Proportional control systems. On-Off Control. Proportional control. Problems associated with the response times of the components of a closed-loop control system. Proportional systems that incorporate integral and differential response. PID systems. Other control systems. Bases of digital control.

Analysis of some instruments. Counters. Functional blocks. Operation as frequency meter, time interval measure, and counter. Origin of the main errors associated with measurements with counters. Importance of the trigger. Operation of sampling oscilloscopes Spectrum analyzers, operating model and specifications. Lock-In. Correlation function between two signals. Autocorrelation of electrical signals. Autocorrelation of noise. Autocorrelation of a periodic signal. Principle of operation of the "Phase Sensitive Detector". Lock-In operating modes and importance of the integration time (time constant) of the output filter. Operation of the "Box-Car Averager". Importance of time delay control and gate duration. Complementarity of the "Lock-In" and "Box-Car Averager"

 

Module 2.

Characterization of signals and systems. Properties of discrete and continuous functions of time. Complex exponential functions, Dirac and Heaviside step and their derivatives.

The operation of correlation between continuous and discrete functions. How to operate. Properties and applications.

For discrete and continuous functions, study of the Fourier series, Fourier transform, its properties and applications.

Transfer functions associated with differential equations and finite differences. Impulse response of a system. Response to Heaviside's step and their relations. Response to arbitrary input.

Filters and Filters Association. Bode diagrams (module and phase).

Modulation in Amplitude and frequency. Sampling of signs and ways to sample.

 

Module 3.

Analysis of some measurement systems with emphasis on optical and magnetic properties measurement systems.

Mandatory literature

Alan V. Oppenheim; Signals & systems. ISBN: 0-13-651175-9

Complementary Bibliography

Fraden Jacob; Handbook of modern sensors. ISBN: 1-56396-538-0
Davies E. R.; Electronics, noise and signal recovery. ISBN: 0-12-206131-4
Connor F. R.; Noise. ISBN: 0-7131-3306-6
Bentley John P.; Principles of measurement systems. ISBN: 0-582-30543-8

Teaching methods and learning activities

Theorectical lectures, and supervised problem solving tasks / discussion in context
The course proposes the study of a broad set of signal transduction devices that should be part of the base knowledge of future specialists developing their work with a strong instrumentation component, such as in industrial environments, or scientific research. Fundamental topics on noise in electronic systems that are absent in previous electronics UC are addressed in a consistent and contextualized approach. The programatic contents also review the knowledge previously acquired in electronics, signals and systems, statistics UCs, using an integrating approach, directed to the development, characterization and optimization of measuring systems solutions and electronic instrumentation. Measuring systems are studied from the base signal transduction  up to the generation of a final response, including errors estimation derived from either interference processes, and/or from system intrinsic  noise sources.

Software

Matlab
Scilab

keywords

Physical sciences > Physics > Applied physics > Experimental physics
Physical sciences > Physics > Electronics > Applied electronics
Physical sciences > Physics > Metrology

Evaluation Type

Evaluation with final exam

Assessment Components

designation	Weight (%)
Exame	100,00
Total:	100,00

Amount of time allocated to each course unit

designation	Time (hours)
Estudo autónomo	120,00
Frequência das aulas	42,00
Total:	162,00

Eligibility for exams

Frequency of at least 2/3 of the class hours.

Calculation formula of final grade

Final grade equal to exam grade