First_Derivative
/Signal_Types=	The type of signal to be processed
/Signal_Names=	The names of the signals to be processed
/Signal_Folder=	The name of the signal folder

Compute the first derivative at each point of a signal. The first and last data points become DATA_NOT_FOUND (identified in the C3D file as a POINT Reliability value of &endash;1).

Derivatives are calculated using Finite Difference Algorithms.

Given the signal:

x(ti) for i=1, 2, …, n The first derivative is calculated using: xDot(ti)= (x(ti+1)-x(ti-1))/( (ti+1)-(ti-1) )