The subject of the lecture is the system-technical basics of measurement technology. First, the terms measurement and measurement characteristic curve are introduced. Possible causes for the occurring measurement deviations are introduced and a classification into systematic and random measurement deviations is made. For both classes of deviations, ways to reduce them are shown in the further course of the lecture.

Since the characteristic curve of real measurement systems is generally not given analytically, but must be derived from existing measurement points, basic procedures of curve fitting are presented. Here, methods for approximation (least squares estimator) as well as for interpolation (polynomial interpolation according to Lagrange and Newton, spline interpolation) are discussed.

Another part of the lecture deals with the steady-state behavior of measurement systems. For this purpose, the ideal characteristic curve is introduced and the resulting deviations from the real characteristic curve are considered. Subsequently, concepts for the reduction of these characteristic curve deviations are presented.

In order to be able to consider also random measurement deviations, the most important basics of probability theory are briefly repeated. Samples are introduced as a new method to obtain information about the generally unknown probability densities of the considered quantities. Furthermore, with parameter and goodness-of-fit tests, statistical test procedures are introduced with which obtained assumptions about the sought densities can be confirmed or refuted.

As a further powerful tool of the measurement technique the correlation measurement technique is discussed. Stochastic processes are briefly repeated as necessary basics and applications from the fields of time-of-flight and Doppler measurements based on the correlation measurement technique are presented. Using the power density spectrum as a Fourier transform of the correlation function, possibilities for system identification are shown and the Wiener filter is presented as an optimal filter for signal reconstruction.

Since real measurement values are nowadays almost exclusively processed in digital computers, the errors that arise during analog-to-digital conversion are also examined in more detail, both in the time and amplitude domain. Sampling and quantization theorems as well as methods to satisfy them (anti-aliasing filters, dithering) are presented, as well as some of the most common A/D and D/A conversion principles.

Accompanying the lecture material, exercise problems are handed out, discussed in lecture hall exercises, and the corresponding solutions are provided.

Since October 2019, the 11th, revised edition of the book "Messtechnik - Grundlagen, Methoden und Anwendungen" (in german) by Prof. Puente León is available. The book covers the topics discussed in the lecture. The book can be downloaded free of charge from the Springer-Verlag via the KIT intranet: F. Puente León: Measurement Technology, Springer-Verlag, Berlin Heidelberg, 2019, ISBN 978-3-662-59767-5.

Please visit the German version of this site to obtain up-to-date information about the lecture and the written exams.

Please visit the German version of this site to obtain up-to-date information about the lecture and the written exams.

For further information, please contact Prof. Dr.-Ing. M. Heizmann.