Digital Data Acquisition and Analysis

Strether Smith

A Digital data acquisition/recording system is the fundamental component of almost every experiment performed today. The success of the experiment is entirely dependent on the capabilities of the system and it is almost universally assumed that it will provide the correct answer. Unfortunately, life is not so simple.

All systems produce a distorted version of the signal being measured. If the system is properly designed the distortions will be understood and the results will be repeatable and comparable. However, the results from systems with different architectures will not match but, with appropriate processing, they can be aligned. In the worst case (when sampling rules are violated) the results will be completely incorrect even though they may look perfectly reasonable.

At Sensors Expo, the Digital Data Acquisition and Analysis all-day seminar will provide participants with the knowledge required to specify, evaluate, and use digital data acquisition systems in laboratory and field applications. Topics will include principles of sampling and digitizing theory, reinforced with practical examples from everyday testing operations; aliasing-error-protection strategies and the resulting data distortion; system hardware components and their interaction; and how component-type selection affects overall performance.

The session will use computer/graphic demonstrations (which are available for download by seminar participants), rather than equations and mathematics, to illustrate the principals involved. This greatly improves understanding for many people.

I'll explain (and demonstrate) how common system design shortcomings will result in good looking but incorrect data and describe a set of simple tests for evaluation of acquisition systems, using hardware found in most laboratories. Post-test analysis techniques that compensate for data distortions and interpolate/resample sparse data sets will also be described and demonstrated.

The course is intended for people with all levels of expertise. Beginners will find that the course builds from basics and that they will come away with the tools needed to acquire accurate data. Experienced participants will discover powerful new ways to view the process that will result in more accurate and repeatable results from their experiments. This seminar is a must for data acquisition system builders, vendors, and users that think that their systems are telling them the truth.

Session presenter Strether Smith is the proprietor of Structural/Signal Analysis Consultants (S/SAC), a consulting company advising a variety of clients in computer-based techniques for the experimental analysis of structural-dynamic response. He has 35 years of experience in both the user side and the design/development aspects of data acquisition and is the author of more than eighty publications in the areas of experimental mechanics and computer aided testing techniques.

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