ISO 18431-2:2004

Name: ISO 18431-2:2004 — Mechanical vibration and shock — Signal processing — Part 2: Time domain windows for Fourier Transform analysis
SKU: ISO 18431-2:2004
Price: 18000 RUB
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Mechanical vibration and shock — Signal processing — Part 2: Time domain windows for Fourier Transform analysis

Название (английский):

ISO 18431-2:2004

Mechanical vibration and shock — Signal processing — Part 2: Time domain windows for Fourier Transform analysis

Статус документа:: Действующий
Формат:: Электронный (PDF)
Количество страниц:: 10
Дата публикации:: 21 октября 2004 г.
Издание:: ISO IS 18431 edition 1 version 1
ICS:: 17.160

Тип поставки:

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Описание (английский):

ISO 18431-2:2004 specifies the algebraic functions which describe a selected set of time domain windows used for pre-processing digitally sampled vibration and shock data as a precursor to Discrete Fourier Transform spectral analysis. This selected set consists of Hanning, flat-top and rectangular time windows.

Abstract

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Стандарты, упомянутые в описании

Overview

ISO 18431-2:2004 - "Mechanical vibration and shock - Signal processing - Part 2: Time domain windows for Fourier Transform analysis" specifies the algebraic functions for a selected set of time-domain window functions used to pre‑process digitally sampled vibration and shock data before Discrete Fourier Transform (DFT/FFT) spectral analysis. The standard defines the commonly used Hanning, flat‑top, and rectangular windows and provides examples showing their effects on amplitude and spectral leakage.

Key topics

Window function definitions

Hanning: w(ν) = 1 − cos(2πν/N), ν = 0..N−1 - a tapered window that reduces sidelobes.
Flat‑top: w(n) = 1 + a1 cos(2πn/N) + a2 cos(4πn/N) + a3 cos(6πn/N) + a4 cos(8πn/N) with coefficients:
- a1 = −1.933, a2 = +1.286, a3 = −0.388, a4 = +0.0322 - optimized for accurate amplitude measurement.
Rectangular: w(n) = 1 - the no‑window case (included for completeness).

Performance trade‑offs

Amplitude accuracy vs. frequency resolution: flat‑top gives best amplitude accuracy (useful for calibration); rectangular gives best frequency resolution; Hanning is a compromise.
Spectral leakage and equivalent noise bandwidth: the document discusses how window choice influences leakage and noise bandwidth.

Examples and illustrations

Worked examples applying each window to truncated and non‑truncated sinusoidal signals show differences in amplitude error and noise bandwidth.

Normative reference

ISO 2041 (vibration and shock vocabulary) is cited for terms and definitions.

Applications

ISO 18431-2 is directly applicable to engineers and practitioners working on:

Vibration and shock measurement and analysis (acceleration, velocity, displacement)

FFT/DFT spectral analysis in condition monitoring, modal testing, NVH (noise, vibration & harshness), and calibration laboratories

Data preprocessing in signal processing toolchains where window selection affects spectral estimates, amplitude accuracy, and sideband identification

Who uses it:

Test engineers, vibration analysts, calibration labs, acoustic/NVH specialists, and software developers implementing DFT/FFT routines for instrumentation and measurement systems.

Related standards

ISO 18431-1: General introduction (part of the same series)

Other parts in the ISO 18431 series (time–frequency methods and shock response analysis) are noted in the standard as under preparation.

ISO 2041:1990 - Vibration and shock - Vocabulary (normative reference)

Keywords: ISO 18431-2, time domain windows, Hanning window, flat-top window, rectangular window, Fourier Transform, DFT, FFT, vibration and shock, spectral leakage, window functions, equivalent noise bandwidth.

ISO 18431-2:2004

Abstract

Похожие стандарты

Overview

Key topics

Applications

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