I am trying to study the frequency response of the output acceleration of an object versus the input acceleration. In order to do that, I am inputting an increasing frequency sine wave acceleration to the object and measuring the output acceleration to get a frequency response. I read in different articles that since my input acceleration has a varying frequency, I cannot simply find the Fast Fourier Transform of the Response as my signal is non-stationary.
My solution now has been to calculate the envelope of the acceleration using a Hilbert Transform and plot the response of these envelopes versus the instantaneous frequencies of the acceleration. Is the second method an accurate way to determine the frequency response of acceleration outputs/inputs?