## Learning objectives

At the end of this course, students will be able to:

1. understand the principles on which the operation of quasi-sinusoidal oscillators is based,

2. know the basic elements of signal conditioning and noise sources in electronic instrumentation,

3. develop judgment of what response and architecture is appropriate in the filter design for different applications,

4. analyze noise in electronic circuits and make a noise and static error budget

5. know and understand the physical principles of sensors and select the right sensor for a given application

6. represent by mathematical models some sensors and actuators which transduce energy between different domains

## Prerequisites

Familiarity with analog circuit analysis (transistor models, small signal circuit analysis, frequency compensation, etc.), building blocks (amplifiers, mirrors, etc.)

## Course unit content

To introduce students with the fundamentals of modern electronic instrumentation and sensor principles. 9 CFU will be dedicated to lessons (Madule I) and 3 CFU to laboratory projects (Module II).

Topics include:

1. ELECTRONIC INSTRUMENTS

1.1. signal conditioning components such as:

1.1.1. electronic amplifiers

1.1.2. active filters

1.1.3. non-linear circuits

1.2. oscillators

1.3. electronic noise

2. SENSORS

2.1. sensors and actuators: lumped models,

2.2. physical principles of sensing, modeling and applications

2.2.1 photodetectors

2.2.2. thermal sensors

2.2.3. strain sensors (with elements of elasticity, stress and strain tensors, stiffness and compliance matrices, and of mechanical structures)

2.2.4. capacitive sensors

2.2.5. magnetic sensors

2.2.6. piezoelectric sensors and actuators

2.3. energy-conserving transducers, linear and non-linear system dynamics

## Full programme

Lessons:

1. ELECTRONIC INSTRUMENTATION (38 h)

1.1. signal conditioning components such as: (Total: 18 h)

1.1.1. electronic amplifiers

- voltage feedback amplifiers (VFA): complements about compensation to handle capacitive loads, photo-sensor and charge amplifiers, PCB layout issues for ultra-low leakage amplifiers in electrometers

- current feedback amplifiers (CFA): behavioral model and simplified circuit diagram, bandwidth, slew-rate, stability issues, basic circuits (VCVS, VCCS, CCVS, CCCS, integrators)

- transconductance operational amplifiers (OTA): characteristics

- isolation amplifiers,

- differential amplifiers and instrumentation amplifiers (common solutions using VFAs, CFAs and OTAs)

1.1.2. active filters

- specifications

- synthesis of Butterworth and Chebyshev low-pass filters

- frequency transformations for the synthesis of high-pass and pass-band filters

- synthesis by Bi-Lin and Bi-Quad sections

- active RC synthesis

- sensitivity

1.1.3. non-linear circuits (logarithmic amplifiers, multipliers)

1.2. oscillators (10 h)

1.2.1. positive feedback and negative resistance oscillator concepts

1.2.2. oscillator start-up requirement and transient

1.2.3. amplitude limits, frequency control

1.2.4. RC, LC, crystal oscillators

1.3. Electronic noise (6 h)

1.3.1. noise analysis in passive circuits; diode, BJT and FET noise; 1/f noise;

1.3.2. two-port noise analysis, role of source resistance, equiv. input noise voltage

1.3.3. noise figure, total input noise for cascaded blocks

1.4. Conditioning circuits for resistive/capacitive/inductive sensors (4 h)

1.4.1 Lock-In

1.4.2 Sigma-Delta modulation

1.4.3 Resonant circuits, relaxing and sinusoidal oscillators

1.4.4 TDC e FDC

2. SENSORS (34 h)

2.1. sensors and actuators: introductions, lumped modeling; (2 h)

2.2. Physical principles of sensing, modeling and applications

2.2.1. Photodetectors (4 h)

2.2.2. Thermal sensors (thermal expansion, heat transfer, Seebeck and Peltier effects; thermocouples, pn junction sensors, RTD (conductor sensors such as PT100), Thermistors NTC and PTC; Hot-wire anemometer) (4 h)

2.4.3. Strain sensors (some elements of theory of elasticity, stress and strain tensors, stiffness and compliance matrices, and elements of mechanical structures; resistance and specific resistivity, strain sensitivity in conductors, piezoresistive effect; signal conditioning for resistive sensors (bridges, linearization)) (4 h).

2.4.4. capacitive sensors: applications and conditioning circuits (4 h)

2.4.5. magnetic sensors (magnetism: Faraday, Ampère, induction laws; induction sensors fluxgate, search-coil, LVDT; conditioning in search-coils and synchronous detector for fluxgates); Hall effect and magneto-resistors; non-contact position magnetostrictive sensors) (6 h)

2.4.6. piezoelectric sensors and actuators (4 h) (piezoelectric effect, models, signal conditioning at low-frequency and at resonance)

2.5. Analysis of energy-conserving transducers, linear and non-linear system dynamics: applications to electrostatic and magnetic transducers. (6 h)

## Bibliography

Recommended:

S. Franco, Design with operational amplifiers and analog integrated circuits, 3rd ed., McGrawHill, 2002 (ISBN: 0071207031)

M. Tartagni, Electronic sensor design principles, Cambridge University Press, 2021, 1st Ed. (ISBN 978-1-107-04066-3)

Suggested References:

A. S. Sedra, K. C. Smith, Circuiti per la microelettronica, EdiSES, 4a Ed. (sulla 6a in inglese), 2013

S.D. Senturia, Microsystem Design, Springer, 2001, (ISBN: 978-0-7923-7246-2) Cap.5-10

V. Kaajakari, Practical MEMS, Small Gear Pub., 2009, (ISBN: 978-0-9822991-0-4)

R. Pallas-Areny, J. G. Webster, Sensors and signal conditioning, 2nd ed., J. Wiley & Sons Inc., 2001 (ISBN: 0-471-33232-1)

Practical design techniques for sensor signal conditioning, Analog Devices, http://www.analog.com/

J. Fraden, Handbook of modern sensors, Springer, 3a Ed.

## Teaching methods

In the Module I there will be 36 Lectures of 2 hours each and, in the Module II, up to 5 laboratory assignments to be developed preferably in groups of 2 or 3 students during 12 weeks (3 consecutive hours per week).

Laboratory projects consist of

- design of an active filter by means of Matlab and Spice

- design of a sinusoidal oscillator with Spice

- design of a signal conditioning circuit for a NTC sensor

- analysis with Spice or Matlab of a self-balancing bridge or other circuit described in a scientific paper for a capacitive sensor

- analysis with Spice or Matlab of a conditioning circuit described in a scientific paper for magnetic or piezoelectric sensors/actuators

The due dates for laboratory assignments will be given on the web page.

Homework assignments must be submitted in a concise (4 page maximum) format that is organized, professional and legible (labeled axes, correct units, readable simulations, etc...)

Lesson handouts and assigned scientific articles will be periodically posted on Elly

In order to download handouts, homeworks, etc., students have to be registered by the Instructor.

Reading assignments include sections of the recommended textbook, distributed readings, and supplementary notes handed out in lecture.

More details will be available during the semester in the Course website.

It is highly suggested the use of Matlab and LTSpice (or TINA-TI, or PSpice for TI)

## Assessment methods and criteria

Grading:

Homework/Laboratory assignments 40% - Final oral examination 60%.

The final exam will be in oral form. The knowledge, understanding and ability will be valued by 3 short parts:

1. the presentation of a subject covered in the lessons (25%)

2. the analysis of an electronic circuit similar to those analysed during the course (20%)

3. the technical discussion of one of the assigned scientific papers, in order to verify criticism and autonomous capability to read an english paper facing a new technical problem (15%)

## Other information

See web site Elly