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The effect of sampling rate and anti-aliasing filters on high-frequency response spectra

Bulletin of Earthquake Engineering

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DOI: 10.1007/s10518-013-9574-9

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Abstract

The most commonly used intensity measure in ground-motion prediction equations is the pseudo-absolute response spectral acceleration (PSA), for response periods from 0.01 to 10 s (or frequencies from 0.1 to 100 Hz). PSAs are often derived from recorded ground motions, and these motions are usually filtered to remove high and low frequencies before the PSAs are computed. In this article we are only concerned with the removal of high frequencies. In modern digital recordings, this filtering corresponds at least to an anti-aliasing filter applied before conversion to digital values. Additional high-cut filtering is sometimes applied both to digital and to analog records to reduce high-frequency noise. Potential errors on the short-period (high-frequency) response spectral values are expected if the true ground motion has significant energy at frequencies above that of the anti-aliasing filter. This is especially important for areas where the instrumental sample rate and the associated anti-aliasing filter corner frequency (above which significant energy in the time series is removed) are low relative to the frequencies contained in the true ground motions. A ground-motion simulation study was conducted to investigate these effects and to develop guidance for defining the usable bandwidth for high-frequency PSA. The primary conclusion is that if the ratio of the maximum Fourier acceleration spectrum (FAS) to the FAS at a frequency fsaa corresponding to the start of the anti-aliasing filter is more than about 10, then PSA for frequencies above fsaa should be little affected by the recording process, because the ground-motion frequencies that control the response spectra will be less than fsaa . A second topic of this article concerns the resampling of the digital acceleration time series to a higher sample rate often used in the computation of short-period PSA. We confirm previous findings that sinc-function interpolation is preferred to the standard practice of using linear time interpolation for the resamplin

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
The effect of sampling rate and anti-aliasing filters on high-frequency response spectra
Series title:
Bulletin of Earthquake Engineering
DOI:
10.1007/s10518-013-9574-9
Volume
12
Issue:
1
Year Published:
2013
Language:
English
Publisher:
Springer
Contributing office(s):
Earthquake Science Center
Description:
14 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
203
Last page:
216