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ISO 18431-3:2014 pdf free

ISO 18431-3:2014 pdf free.Mechanical vibration and shock一Signal processing
This part of ISO 18431 specifies methods for the digital calculation of a time-frequency analysis of a given sampled measurement of a physical or engineering quantity, such as acceleration, force, or displacement,over an interval of time. Several mathematical formulations of time-frequency transformations are given with requirements for recording of parameters and recommendations.
The data can be obtained experimentally from measurements of a mechanical structure or obtained from numerical simulation of a mechanical structure. This category of data is very broad because there is a wide variety of mechanical structures, e.g. microscopic instruments, musical instruments,automobiles, manufacturing machines, buildings, and civil structures. The data can determine the response of machines or of humans to mechanical vibration and shock.
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 2041, Mechanical vibration, shock and condition monitoring一Vocabulary
ISO 18431-1, Mechanical vibration and shock一Signal processing一Part 1: General introduction
For the purposes of this document, the terms and definitions given in ISO 2041, ISO 18431-1, and the following apply.
Fourier-related transform used to determine the time dependence of the sinusoidal frequency and phase content of a time-varying vibration
quadratic time-frequency description of a vibration based on the autocorrelation of a signal
time-frequency description of a vibration based on a filtered autocorrelation of a signal
generalized Wigner-Ville distribution of a vibration using a specific kernel
time-frequency description of a vibration based on the scaled frequency transformation of a signal
NOTE 2 The Wigner distribution is derived from the autocorrelation of the complete data block. This allows greater accuracy in the resolution of time and frequency components, but also generates spurious components in the distribution.
NOTE 3 The sample period of time in the Wigner distribution is twice that of the sample period of the original data x(n) because the time increments of the autocorrelation have twice the period.
NOTE 4 An example of the resolution and spurious components are shown in AnnexA.ISO 18431-3 pdf download.

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