What Is Amplitude Quantization Error?
Amplitude Quantization Error - Summary This article explains what amplitude quantization error is and what can be done to avoid it. Typically quantization error is caused during acquisition of data.…
Speech Articulation Index – What Does It Mean?
There are many ways to calculate speech articulation index and each has its advantages in different applications. Prosig's DATS includes four methods for evaluating the Articulation Index as seen in the table…
Processing pump data – a classic case of amplitude modulation
When dealing with some vibration data from a pump, we observed some strange phenomena in the data. It turned out to be a classic case of amplitude modulation. Here we explain what that means.
Creating An End of Line Vibration Test System
Prosig was contracted by Imperial Electric in Akron, Ohio to integrate a system for end of line vibration test for electric motors they manufacture. The requirement was to qualify motors under…
RMS From Time History And FFT Spectrum
The RMS of a time history is a measure of the signal's overall energy and is often used when extracting features from a signal for prognosis and trending of vibration…
Bearing & Gearbox Vibration Analysis using Demodulation Techniques? (Part 2)
In our previous post on this subject we briefly looked at how we can use the detailed design information of bearings and gearboxes to look for specific fault conditions by collecting vibration information and analysing their frequency spectra. Amplitude modulation of the vibration signatures is common and we have seen how this causes side-bands to be present in the frequency domain.
How do we design or modify a system to avoid resonance?
After finding the natural frequency of a system, what could be done to stop or reduce the systems resonance being excited? Basically put, how do we avoid resonance This is…
Relative signal levels of a sinusoid with and without background noise
In the process of looking at some order data, a question about the accuracy of the measurement of the signal level of discrete frequency signals which were close to the general noise level. To answer this question, a small DATS worksheet was created which generated 2 signals. The first signal was a 35 Hz sinusoid which, by itself the spectrum level was measured to be approximately -9 dB (ref 1 V) as seen in Figure 1.
Understanding Filter Characteristics
Recently when discussing with an engineering student the characteristics of filters, it became clear that some confusion exists around this subject area. This note attempts to explain the differences between types of filter and the effects of the parameters of those filters. (more…)
Understanding Windowing And Overlapping Analysis
[latexpage]The following article was inspired by a question asked by a reader regarding my previous article - Data Windows : What, why and when?. Specifically, the reader asked "Could you please…
Developing an Algorithm for Tick Detection
An investigation was made of a sample of automotive components where some were exhibiting a high frequency “tick” or rattle during each operating cycle. This feature could be heard above the normal operating noise. The problem this posed was to measure and analyze components in an objective fashion and classify components as “good” or “bad”.
