Is That Tone Significant? – The Prominence Ratio
The Prominence Ratio is a technique designed to see if there are any aurally prominent tones in a signal. Primarily, it is applicable where we have a noise source with…
Generating speed v time information from noise & vibration signals
Picture the scenario; you have captured some noise & vibration data from a rotating machine. Typically, this might be noise in a vehicle cabin, but could have been anything from…
Waterfall Analysis: Frequency Spectrum or Order Spectrum?
This article addresses two basic approaches to analyzing rotating machinery during transient (sweeping rpm) conditions. The first is the traditional method which uses Frequency (FFT) Spectrum analysis at target rpm…
Don’t Let Spikes Spoil Your Data
In many real-world applications it is impossible to avoid “spikes” or “dropouts” in data that we record. Many people assume that these only cause problems with their data if they become obvious. This is not always the case. Consider the following two time histories.
