Seismosoft | Earthquake Engineering Solutions

Thank you for your reply.

However, I found that the Fourier amplitude is relevant to the duration, can you tell me more about the details? I'm interested on the approach of how the amplitude of "2" transform to "0.38008" (when Y=2*sin(100*Pi*X), X's number is 1024 from 0 to 0.5 sec).
When I change ...

I'm notecied that from SeismoSoft Support as follows,

In SeismoSignal Power Spectra Amplitude is computed as follows: PowerAmpl = FFTAmpl *FFTAmpl /(Pi*duration*RmsAcc^2), where 'duration' is the duration of the record, 'RmsAcc' is the acceleration RMS (see 'Ground Motion Parameters' module) and Pi ...