MULTICHANNEL MEASUREMENT SYSTEM FOR MODAL ANALYSIS OF PASSENGER CARS

Our aim was to design a multichannel data-acquisition system front-end for our H.P. 1000 computer. This system (Digital Data Harvester) should be easily expandable and flexible enough to be used with a wide range of mini and micro computers. Although the original design purpose was to develop such a system for Modal Analysis, its application area is likely to be much wider. The design of this system is related to the evolution of Fourier Analysis equipment in two directions: the small, but powerful systems, based on a microcomputer or even a microprocessor, with a limited number of channels, will remain a good solution for many problems; and the "big" systems, which are expensive as they are inflexible to be used for other purposes, will be more and more replaced by general purpose computers with a data-acquisition front-end and eventually upgraded by a preprocessing unit or an array processor. As the expandability to a great number of channels was the most important design requirement, some attention is paid to the reasons for this demand. After a summary of the other requirements, our solution proposals are discussed in more detail.