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sectional views of FFT plot

sectional views of FFT plot

sectional views of FFT plot

20 years ago, a long lost friend showed me the output from a vibration analysis recording he carried out using his DSO and some other piece of kit.

I can't remember the name of the plot type or the kit he used, but it was showing a series of sectional views through an FFT analysis plot.

He could animate his recording, thereby showing the sectional view at various frequencies, the end result being lots of circles.

As the animation was run, circles diameters decreased, then disappeared, as the amplitude slice height was increased.

The idea was to look for spaces within the mass of circles, to find a zone where he could safely add a device of a specifically tuned frequency, thereby knowing the device would not suffer from any harmonics.

Does anyong know the name of such a plot, or the name of this technique for frequency analysis, whereby it displays slices through the amplitude axis of a normal FFT plot?

Maybe another way to describe it is an animation of a slice through a waterfall plot.


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