vibration readings/octave center frequency 1

[spike]

I have received a chart which is supposed to be a vibration plot. The y axis is labeled vibration velocity in mms. The x axis is labeled "One twelfth octave band centre frequency (Hz)".
I do not have a clue as to how to interpret the horizontal axis. I am used to seeing this axis as Hz. or CPM.

Can someone help me out?

 

[GregLocock]

1/12 octave is just a way of splitting the octave up, into twelve parts, ie it is similar to third octaves.

If you aren't familiar with that then each bin runs from cf*2^(-1/24) to cf*2^(1/24) (I think) and contains all the energy in the linear spectrum between those two limits.



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.