DEng 604

Unit Description and General Aims

This unit covers concepts related to data acquisition, enabling students to understand the issues required to achieve high-quality measurements. Students will better understand issues such as accuracy, precision, repeatability, calibration, uncertainty and noise. Measurements from a range of sensors (mechanical, optical, electrical) are introduced and subsequent signal conditioning (operational amplifiers, instrumentation amplifiers) are addressed with the aim of maximising signal quality. Statistical methods are discussed to better understand noise processes and how noise can be minimised. Methods to improve signal quality (signal to noise ratio) are discussed. Measurement signal and noise are analysed in both the time and frequency domain to better understand the connection between two domains and the importance of measurement bandwidth. Sampling is reviewed to understand the impact of moving from continuous-time (CT) to discrete-time (DT), including discussion of the Nyquist rate and aliasing. The conversion between the analogue and digital domains including CT-DT, system transfer functions, spectral analysis and the construction of finite and infinite impulse response filters to reduce noise are discussed

Learning Outcome

On successful completion of this Unit, students are expected to be able to:

1. Evaluate measurement concepts obtained through team-based learning.

Bloom’s Level 5

2. Generate and analyse data (numerically and in graphical form) in a manner that includes the uncertainty associated with the measurement.

Bloom’s Level 6

3. Produce measurements with minimised noise by moving between the time and frequency domains.

Bloom’s Level 6

4. Critically analyse and judge instrumentation characteristics that affect data collection in achieving high-quality measurements.

Bloom’s Level 5

5. Construct high quality experimental design.

Bloom’s Level 6

Bloom’s Taxonomy

The cognitive domain levels of Bloom’s Taxonomy:

Student assessment

Prescribed and Recommended Readings

Required Textbook(s)

The required text book provides important references in each chapter which are relevant to the subject matter. These references and those provided by the instructor will form the basis of the study material. The following textbook provides a study guide, and a student’s future reference book for statistical theory, numerous research methods, calculations and visuals.

• Suggested textbook: Measurement and Data Analysis for Engineering and Science, Fourth Edition, By Patrick F Dunn, Michael P. Davis.

Reference Materials

In addition to the above textbook, there are several useful reference material may be obtained on-line from published journals, and websites. Some recommendations are:

• High Frequency Measurements and Noise in Electronic Circuits by Douglas C. Smith
• Electrical Measurement, Signal Processing, and Displays edited by John G. Webster
• Measurement Systems and Sensors, Second Edition by Waldemar Nawrocki
• Digital Signal Processing for Measurement Systems: Theory and Applications by Gabriele D'Antona, Alessandro Ferrero

Software Reference Material

Software can be applied in the processing of data and the professional presentation of computed results. There are numerous software packages which can be applied. In this unit, Python and R environments are recommended. Other software such as MATLAB and Octave may be applied.

Unit Content

Topic 1 

Measurement terminology

This topic reviews measurement terminology associated with static and dynamic instrument characteristics.

1. Commonly used measurement terminology

2. Static Characteristics

3. Dynamic characteristics

4. Datasheet specifications

5. Static and dynamics systems and their response

Topic 2

Sensors

This topic reviews sensors including accelerometers, pressure sensors, flow meters and temperature sensors. The output quantity of sensors reviewed includes voltage, current, resistance, mechanical force and capacitance. Linear and non-linear (including logarithmic) sensor outputs are considered.

1. Sensor physical mechanisms

2. Classification of sensors

3. Sensor characteristics

4. Types of Sensors and applications

Topic 3

Signal conditioning

This topic introduces the basics of detecting a signal, amplifying it and transforming it into an appropriate form. This process is known as signal conditioning.

1. Amplifiers

2. Analogue signal processing

3. Signal conditioning

4. Noise and interference

Topic 4

Probability and Statistics

This topic introduces cumulative and probability density functions, (specifically the Gaussian distribution) as well as random variables. Means and variances of samples and populations are explored. The transformations of distributions is analysed using several different tool sets.

1. Statistical analysis

2. Probability distributions

3. Normal distributions

4. Identification of outliers

5. Convolution of probability distributions

6. Generate random variables with any desired probability density functions

Topic 5

Data presentation

This topic reviews how to take the data that has been analysed and present it in a rigorous manner, suitable for engineering technical reports and publications.

1. Data visualisation

2. Plotting data

3. Python for data visualisation

Topic 6 

The guide to the expression of uncertainty in measurement (The GUM)

This topic reviews and uses the ISO Guide 98-3 “Uncertainty of measurement – Part 3: Guide to the expression of uncertainty in measurement (GUM:1995)” and the corresponding “Australian National Measurement institute Monography 1: Uncertainty in Measurement: The ISO guide.”

1. Errors and uncertainty

2. Modelling the measurement

3. Evaluating standard uncertainty: Type A and Type B

4. Combined standard uncertainty

5. Determining expanded uncertainty

Reporting uncertainty

Topic 7

Least squares data analysis

This topic presents the fitting of data to a model using least squares data analysis. The consideration will be on how uncertainties can be determined from the fits to the data, which would be subsequently used for specifying measurement uncertainty. Linear and non-linear least squares is considered.

1. Model fitting

2. Regression analysis

3. The correlation coefficient

4. Graph format

5. Multivariable regression

6. Variable selection techniques

7. Student t test

Topic 8

Time and frequency analysis of random variables (Random processes)

This topic reviews signals that are deterministic and random. It looks at the tools to analyse deterministic signals in the time and frequency domain and under what conditions these tools can be used to analyse random signals.

1. Time and frequency spectrum – typical transforms

2. Power and energy in the time and frequency domains

3. Periodic, aperiodic and random signals and their analysis

4. Relevance of the Bandwidth-Time product and application

5. Random processes

Topic 9

Digitization

This topic reviews the concepts and mathematics associated with the conversion of a continuous time (CT) signal into a discrete time (DT) signal.

1. Digital Signal Processing

2. Discrete-time signals and systems

3. Sampling and quantization

4. ADC and DAC issues

5. Aliasing

Topic 10

Correlation and convolution

This topic reviews correlation of time series and looks at the links between convolution and filters.

1. Correlation forms and uses

2. Convolution and Linear Time Invariant (LTI) systems

3. Convolution and multiplication in the time and frequency domains

4. Filters

Topic 11

Sampled data analysis

This topic focuses on analysis of sampled data. All data dealt with computationally is in the form of x[n]. Key functions which can be performed are filtering and analysis in the time and frequency domain.

1. Discrete Fourier Transform (DFT)
2. Discrete time integration and differentiation
3. Difference equations and z transforms
4. Smoothing and averaging
5. Digital filters (FIR and IIR)

Topic 12

Unit review

In the final week, students will have an opportunity to review the contents covered so far. Opportunity will be provided for a review of student work and to clarify any outstanding issues. Instructors/facilitators may choose to cover a specialized topic if applicable to that cohort.

Software/Hardware Used

Software

• Software: N/A
• Version: N/A
• Instructions: N/A 
• Additional resources or files: N/A

Hardware

• N/A

Unit Changes Based on Student Feedback