Sound, Vibration & Acoustics Digest #7

Chip/crisp packets, smartphones, the spooky sounds in space and the absolutely fascinating Diana Deutsch Speech to Song Illusion; welcome to our latest digest Extracting audio from visual information https://newsoffice.mit.edu/2014/algorithm-recovers-speech-from-vibrations-0804Algorithm recovers…

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What is waterfall frequency spacing? And how does the DATS parameter ‘Requested Frequency Spacing’ work?

Let us try to understand what waterfall frequency spacing is. Waterfall frequency spacing is the gap between spectral lines in an FFT plot.

For example, if you had an analysis frequency of 0Hz to 100Hz and 100 spectral lines, then Frequency Spacing is 1Hz.

So why is there a ‘Requested Frequency Spacing’ and an ‘Actual Frequency Spacing’? (more…)

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What is “waterfall smearing”?

When analysing a waterfall or performing order analysis it is important to consider the frequency resolution or the frequency spacing.

There is often a desire to increase the resolution to finer and finer detail. But that is a process of diminishing returns, and actually fraught with danger. And that danger is waterfall smearing. (more…)

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Sampling and Filtering Data for ISO8041 Compliance and Human Body Vibration Data Weighting

Various human body vibration measurements and assessments are defined in the ISO2631, ISO5349, ISO6954 standards and also in the EEC vibration directive 2002/44/EC. These assessments are based on the analysis…

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What engineering decisions are made by measuring a power spectrum?

By power spectrum we are talking about an ASD (Auto Spectral Density) or PSD (Power Spectral Density). In fact PSD is often used when really ASD would be more correct.

Taking any signal and performing a frequency analysis using an ASD or a PSD will give the energy over a range of frequencies. (more…)

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