what is the physical meaning of getting peak of higher amplitude in frequency domain by using FFT??

what is the physical meaning of getting peak of higher amplitude in frequency domain by using FFT?? In this picture i am having an original signal as well as reconstructed signal from EEMD method and i have done fft of both, but i am getting peaks at same frequency but in different amplitude...what is the physical significance of higher amplitude in fft domain???.....does it reffer that the signal with higher amplitude is having higher strength..............pls reply as soon as possible...........thanks in advance

[JOSE SANTOS]

Hello Arka, 

I was wondering if you found the answer to this question. I have the same inquiry. 

Jose Santos. 

[Arnold Sullivan]

On 3rd Dec. 2008, Dr. Huang said:

FFT gives you the total energy density, the RMS value.

Marginal Hilber spectrum is giving you the total energy.

Amplitude in MHS vs in FFT :: MHS = 2*N/T * FFT

N/T is the sampling rate

so that apply MHS on FFT you need to multiply 2*N/T back to get the real value.

Details in https://www.youtube.com/watch?v=6RhFvRvtEPs&list=PL2RhbQA4R2LVKOZH53JGaK6ALpza_KEe2&index=18

Answer 1

[Sindar]

Assuming you kept track of normalization correctly(*), yes, a higher amplitude of the fft corresponds to higher signal strength at that frequency.

* if the number of elements didn't change, this should be fairly easy. Did you multiply the signal (in time or freq) by something that is ever larger than 1? If the number of elements changed (e.g., you padded the data with zeros), then you must be more careful