What Order Analysis Is

This section introduces order analysis, a method used to study the noise or vibration produced by rotating machines.

Each part of rotating machines produces a sound and a vibration pattern that contributes to the whole machine's sound and vibration. This type of sound is generally related to a RPM profile, which is the evolution in time of the Revolution Per Minute (RPM). The harmonics and partial components related to this rotational speed are called orders. Their respective frequency is directly proportional to the speed of revolution. Usually the fundamental frequency of this phenomenon is called order #1, and order #N is the N^-th harmonic of this fundamental.