PHY3128 Electronics for Measurement Systems

2011-2012

Code: PHY3128
Level: 3
Title: Electronics for Measurement Systems
Instructors: Dr C.D.H. Williams
CATS Credit Value: 10
ECTS Credit Value: 5
Pre-requisites: Practical Electronics II (PHY2003)
Co-requisites: N/A
Duration: T2:01-11
Availability: unrestricted
Background Assumed: N/A
Directed Study Time: 22 lectures
Private Study Time: 78 hours
Assessment Tasks Time: -

Total Student Study Time

100 hours, to include: 22×1-hour lectures; 78 hours private study.

Aims

Physicists often need to build measurement and control systems, and there are many commercially available integrated circuits and modules which simplify the task. However, to use these successfully one needs not only to understand the detailed specifications of an individual device, but also to be aware of the subtle problems that can arise (for example as a result of non-ideal behaviour, or feedback) within the integrated system. This module is particularly appropriate for MPhys students undertaking experimental projects, and others with a particular interest in electronics.

Intended Learning Outcomes

Students will be able to:

Module Specific Skills:
1. describe and apply models of non-ideal op-amp behaviour;
2. analyse circuits involving op-amps;
3. quantify noise and signals in systems;
4. solve problems involving transmission lines;
5. explain how a range of phenomena can be exploited to measure basic physical quantities;
Discipline Specific Skills:
1. identify causes and cures for electrical interference;
2. describe electrical hazards and explain the protective purpose and function of insulation and grounding systems;
3. recognise the qualitative effect of feedback in AC systems and have a practical knowledge of PID control;
4. relate the behaviour of a system to features of its gain/phase response;
5. describe the operation of a lock-in amplifier;
6. judge what combination of analog or digital hardware, or software, would be an appropriate way to implement different parts of a new measurement system.
Personal Transferable Skills:
1. demonstrate widely applicable knowledge of electronics and systems,
2. recognise systems that are likely to exhibit complex behaviour.

Learning / Teaching Methods

Lectures, WWW resources and self-study documents, and problems classes.

Assessment and Assignments

Contribution (%)	Form of Assessment	Size (duration/length)
N/A	Solve self-study problems	20 hours work
100%	Final examination	90 minutes

Syllabus Plan and Content

Introduction
1. Build it or buy it?
Analogue Electronics
1. Revision of the ideal operational-amplifier model
2. Non-ideal operational-amplifier model, including: input bias and offsets, gain-bandwidth product, input and output impedance, differential and common-mode gains, and noise sources
Introduction to Sensors
1. Resistive - Temperature; Capacitive - Pressure; Inductive - Displacement; Electromagnetic - Flow; Thermoelectric - Heat Flux; Piezo-electric - Force; Photoelectric - Light Flux
Transmission of Signals
1. Transmission lines: time- and frequency-domain behaviour; n-mode systems.
2. Parallel and serial data exchange, handshaking, interrupts. Computer Interfaces for Instrumentation Systems: RS-232, IEEE 488 (GP-IB), etc.. Role of PC's and micro-controllers.
3. Case study: Ethernet
Feedback and stability
1. Transfer functions; Closed- and open-loop gain/phase; phase and gain margins; Bode diagrams
2. Case study: Proportional-integral-derivative (PID) temperature control
Detecting Small Signals
1. Noise sources
2. DC measurements, the instrumentation amplifier
3. Signal and noise transfer functions, definition of the responsivity, sensitivity and resolution of a measurement system
4. Phase-sensitive detection
5. Case study: Matched Photodiode Detectors for X-ray CT
Signal Integrity and Electromagnetic Compatibility
1. Interference, connections and grounding; how to avoid, recognise and cure problems
2. Case study: Electrocardiogram (ECG) Measurements
3. Analogue-to-digital and digital-to-analogue conversion, accuracy and sampling considerations
4. Non-idealities in passive components
Analogue signal processing
1. Linear Filters
2. Negative impedance conversion - gyrators
3. Modulation and Demodulation
4. Phase-Locked Loops
Nonlinear Circuits
1. Analysis by linearisation about an operating point
Electrical safety:
1. Physiological effects of electric current, Class I and Class II insulation, Residual Current Devices
Optional Topics
1. Nonlinear Circuits
  1. Case study: Voltage-to-Frequency and Frequency-to-Voltage conversion
  2. Logarithmic amplifiers
2. Extreme Techniques
  1. Resistance thermometry at low temperatures
  2. Coaxial AC-Bridge
  3. T-coils
  4. SQUIDS

Core Text

Not applicable

Supplementary Text(s)

Bentley J.P. (1988), Principles of Measurement Systems (2^nd edition), Longmans, ISBN 0-582-30543-8 (UL: 530.8 BEN)
Clayton G. and Winter S. (2003), Operational Amplifiers (5^th edition), Newnes, ISBN 0-7506-5914-9 (UL: 621.375 CLA)
Horowitz P. and Hill W., The Art of Electronics (2^nd edition), Cambridge (UL: 621.381 HOR/X)
Peatman J.B. (1998), Design with PIC Microcontrollers, Prentice Hall, ISBN 0-13-759259-0 (UL: 629.895 PEA)
Webster J.G., Clark Jr J.W. and Neuman M.R. (1997), Medical Instrumentation: Application and Design (3^rd edition), Wiley, ISBN 471-1536-80 (UL: 610.28 WEB)

Formative Mechanisms

Students monitor their own progress by attempting the problems set which will be discussed in class. Students who need additional guidance are encouraged to discuss the matter with the lecturer.

Evaluation Mechanisms

The module will be evaluated using information gathered via the student representation mechanisms, the staff peer appraisal scheme, and measures of student attainment based on summative assessment.