MATLAB: Central difference approximation scripts to calculate first derivatives of smoothed signal got from smooth function, Method: ‘Savitzky-Golay’

Question

I want to calculate first derivatives with respect to time for my smoothed data. I used Savitzky-Golay method in 'smooth' matlab function.I need information where I can get:

1. Any downloadable matlab scripts that can do this first derivative calculation by employing central difference approximation.

2. Any matlab function (in-built or user-written that can be downloaded) that can do the same exclusively for this smoothed result using Sgolay method in smooth function. Something like how 'fnder' is to 'csaps'.

Thanks in advance Harish

Answer 1

For central difference: http://www.mathworks.com/help/matlab/ref/gradient.html

For SG: http://www.mathworks.com/matlabcentral/fileexchange/30299-savitzky-golay-smoothdifferentiation-filters-and-filter-application