73738 - Laboratory of Electronic Measurement T

Learning outcomes

After successfully attending the Course, the student is capable of programming in the framework of commercial software the remote control both of single instruments and entire automated measurement set-ups.

Course contents

The cultural contents of the course unit, which are strictly connected and complementary to those of the unit Electronic Measurement T-1, are provided mainly through laboratory experimental activities carried out directly by the students, preceded in some cases by preparatory class lectures.

§ Fundamentals of Metrology and Measurement Science

Measurement scales. Coherent and non-coherent systems of units. Coordination equations. The International System of Units (SI): base and derived quantities. Unit standards and traceability. Standard of resistance: quantum Hall effect. Standard of electromotive force: Josephson effect. Unit writing and reporting standard rules. Measurand and measurement process. Resources and activities associated with the process. The model of a measurement process and the influence quantities. Uncertainty of measurement. Methodologies for the evaluation of standard uncertainty: type A and type B evaluation. Uncertainty propagation: combined standard uncertainty. Expanded uncertainty. Expression of the result of a measurement process. Application examples for the law of propagation of uncertainty.

§ Methods and Resources for the Implementation of Automated Measurement Set-Ups

Main architectures and standards for automated instrumentation set-ups. The IEEE-488 standard. Introduction to the LabVIEW environment: fundamentals, block diagram, front panel. Structures, sequences, timing elements. Graphs for the visualization of data and signals. Application examples for the remote control of a digital multimeter, a sampling oscilloscope, an arbitrary waveform generator, a spectrum analyzer. Automated evaluation of uncertainty of measurement.

§ Laboratory Activities

- Digital Multimeter (1): Main operation through the instrument front panel. Range, resolution digits, auto-zero. LabVIEW programming for the remote control of the multimeter. Acquired data storage and processing, graphic visualization of a repetition of readings and related statistical analysis.

- Digital Multimeter (2): Laboratory resources and components for the implementation of the measurement set-ups: cables, boards, DC supplies. Estimation of the DC attenuation factor of a resistive attenuator by means of i) a measurement model based on voltage direct observations and ii) a measurement model based on resistance direct observations. Evaluation and expression of the uncertainty of measurement. Compatibility comparison between the results obtained by means of the two different models.

- Operational Amplifiers (1): Estimation of the DC input/output characteristics of amplifiers implemented by means of Op Amps. Inverting and non-inverting topologies.

- Operational Amplifiers (2): Estimation of the static metrological parameters of Op Amps. Offset voltage. Offset compensation. Bias currents. Offset current.

- Sampling Oscilloscope: Operation of a sampling oscilloscope and an arbitrary waveform generator through the instrument front panels. Vertical and horizontal axes. Trigger menu. Edge and Pulse Trigger. Cursors. LabVIEW project of the driver for the remote control of the oscilloscope. Waveform importing and visualization.

- Analogue Spectrum Analyzer: Operation of the scalar spectrum analyzer through the instrument front panel. Center frequency, span. Vertical scales. Resolution bandwidth, input attenuation. Criteria for the correct operation of the instrument in linear conditions. Absolute and differential markers. Sensitivity, estimation and control of the noise floor. Methods for the detection of multi-tone signals. Examples of measurement of harmonic distortion, intermodulation distortion and spectra of pulse signals.

- Digital Spectrum Analysis based on DFT/FFT: Implementation of a set-up in LabVIEW for the investigation of the main properties of vector spectral analysis based on sampling and DFT/FFT. Sources of uncertainty due to spectral leakage, the resolution of the method and the resolution of the numerical algorithm. Zero-padding. Time windows for the reduction of spectral leakage. Amplitude and phase spectra. Effects of A/D quantization and of ENOB of the A/D conversion process.

Readings/Bibliography

Educational documentation (slides, user manuals, component datasheets) provided by the professor and/or downloadable from "Insegnamenti Online" platform.

Teaching methods

Laboratory activities and preparatory class lectures.

Assessment methods

Individual oral exam

Office hours

See the website of Pier Andrea Traverso