ISO 18431-3-2014 pdf free download.Mechanical vibration and shock – Signal processing一 Part 3: Methods of time-frequency analysis.
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.
2 Normative references
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 — Vocabulary
ISO 18431-1, Mechanical vibration and shock — Signal processing — Part 1: General introduction
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 2041. ISO 18431-1, and the following apply.
3.1 short-time Fourier transform
Fourier-related transform used to determine the time dependence of the sinusoidal frequency and phase content of a time-varying vibration
3.2 Wigner-Ville distribution
quadratic time-frequency description of a vibration based on the autocorrelation of a signal
3.3 generalized Wigner-Ville distribution
time-frequency description of a vibration based on a filtered autocorrelation of a signal
3.4 Choi-Williams transform
generalized Wigner-Ville distribution of a vibration using a specific kernel
3.5 wavelet transform
time-frequency description of a vibration based on the scaled frequency transformation of a signal.ISO 18431-3 pdf download.