Software Open Access
The present submission introduces a simple function ASD.m that is inspired by  but includes also the possibility to use the double integration technique instead of the Discrete Fourier Transform (DFT) when transforming acceleration records to displacement records. The simple right-hand difference technique is also implemented as an alternative to the DFT for transforming displacement data to acceleration data.
The function also includes the possibility to compute the velocity histories from the acceleration of displacement records.
The submission contains three files:
The is the second version of the submission, Several typos may still be present as well as bugs. Any suggestion, comment or question is welcomed. Credits for the present submission should also go to ref.  for the function iomega.