In this article we will look at why we need to consider energy correction when producing frequency spectra and how we go about it. We will use a perfect, ’special case’ signal to keep the explanation as simple as possible. The signal we will use is periodic within the time record used to calculate the [...]
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Order cuts are taken from a set of FFTs, each one at a different rpm. The rms level is then found as the Square root of the Sum of the squares of each of the FFT values. Mathematically, if Xks is the modulus (magnitude) of the kth value of the FFT at speed s for [...] Share:
In many cases only significant events, such as bumps or other transients in a signal are of relevance. The objective is to be able to isolate these events in a meaningful manner so that they may be automatically recognised and either removed or extracted for analysis in a structured way. Share:
Accurate measurement of a signal depends on the dynamic range and the overall level of the data acquisition system. The overall level setting may be thought of as determining the [...] Share:
The PROB module in DATS for Windows provides, amongst other options, a probability density analysis. Also, the signal generation suite has a module, GENPRB, which generates a classical Gaussian probability density curve (and others). How then may these be used to compare the probability density of our measured signal with that of a true Gaussian [...] Share:
A common requirement in noise and vibration analysis is to find the overall level of a signal as a function of time. Now the overall level is a measure of the total dynamic energy in the signal. That is it does not contain the energy due to the DC level, which is the same as [...] |
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