0
$\begingroup$

I am about to present my work on vibrations to a NVH specialist at work and he is supposed to help me.

I have calculated PSD's, now my question (subjective, I know) is how should I plot the data? I've been plotting $PSD \big[\frac{g^2}{Hz}\big]$ against frequency $\big[Hz\big]$, both in linear axes. I've been told the frequency axis should be in logarithmic scale, which makes sense, what about the PSD axis?

$\endgroup$
4
  • 1
    $\begingroup$ Surely the idea of using a log axis or log-log axis was to get a straight line plot - do you get one or what you get is sufficient. If you can explain your results then the chart you have is sufficient for the purpose. $\endgroup$ – Solar Mike Jun 20 '17 at 14:15
  • $\begingroup$ One can "prefer" Log PSD-Log f or Log PSD-f for PSD-f plotting, it is preference because this selection may change according to plotted data. Main purpose is to visualize the results in linear. I think the use of "Best Plot" is wrong but there might be a common one. My suggestion is to try both and choose the one suits your plot. $\endgroup$ – F.Bek Jun 20 '17 at 14:38
  • $\begingroup$ @SolarMike Good point! $\endgroup$ – jonathan.charbonneau Jun 20 '17 at 14:41
  • $\begingroup$ @F.Bek You're right, I should've asked if there was a standard instead of "what is best". $\endgroup$ – jonathan.charbonneau Jun 20 '17 at 14:42
1
$\begingroup$

Typically, a PSD for vibration will have a log scale for both axes.

$\endgroup$
2
  • $\begingroup$ Thanks! I spoke to a NVH specialist and this is also what he said. For reference if anyone in the future sees this thread, I used dB on y axis and log on x axis which is apparently not common. As @DLS3141 suggested, log-log is the proper format. $\endgroup$ – jonathan.charbonneau Jul 6 '17 at 12:14
  • $\begingroup$ This is highly dependent on the application. Floor vibration data is typically plotted in 1/3rd octave bands and can have logarithmic y axes or not; sometimes it is also plotted in true-partite format. Other applications use any combination of linear and/or logarithmic axes depending on what is convenient. $\endgroup$ – user883521 Jul 31 '17 at 16:07

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.