In recent years, a new approach to the application of modal analysis has appeared. We call it "operational modal analysis." It is not beyond reason to ask if this is yet another "flash in the pan," but maybe, just maybe, it could be a very important advancement in this sophisticated application. Of course, the future will tell us what was right, what was wrong, and perhaps what we could have done better. It appears that the industry stands on the edge of a new era with new applications and a new basis for professional activity within the field of sound and vibration. Operational modal is the name for the technique to do modal analysis on operational data - cases where we do not excite the structure artificially but just allow the natural operating loads to excite the structure. This is why new names are appearing, like ambient modal or natural input modal. It is also common to use the name "output only." We tend to dislike this name, since it gives the impression that there is no input - which is wrong. In reality, there is an inherent input in the output signal, but it is not as obvious as what is found in classical modal analysis techniques.
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