Seismosoft | Earthquake Engineering Solutions

hi
I want to find the dominant period of a base shear time history.
1- when the logarithmic scale is chosen for the horizontal axes, there are 2 distinct pick in the Fourier Amplitude (we know the frequency pertaining to the pick is the dominant frequency), but when i use ordinary scale there are a lot of pick and there isnt 2 distinct pick.
2- I imported the data to Microsoft Excel. Then, i used the ordinary scale, the result was like the seimosignal, but when i changed the horizontal scale to logarithmic, the result was not like the seimosignal.
Could you help please.

Dear beiraghii,

Your question is not really related to SeismoSignal or Fourier Spectra, but rather regards the much more general topic of logarithmic scales.

If you carry out a Google search on "logarithmic scales" you will find many resources discussing/explaining the sort of issues that you raise in your post.

Best,

Rui