01-06-2017 08:36 AM
Hello All,
I'm trying to interpret the output from the Derivative x(t).vi and want to make sure I'm doing so appropriately. The default value for the "dt" input is 1.0. I have force plate data that are sampled at 1200Hz. I interpret this to mean that the value of 1.0 for "dt" represents a real time interval of 0.833ms [(1200pts/1s) x (1s/1000ms) = 0.833ms/pt] and that the units of the derivative (i.e. loading rate = change in force/unit time) will be in N/0.833 ms. I would then need to convert this to N/s by multiplying by 1000ms/1s.
can anyone confirm (or deny!) this? Thanks for the help.
01-06-2017 08:51 AM
Yes, it is correct.
Interval is constant so it simply divides differences (dx = dN array) by interval (dt = 0.833 ms = 0.000833 s)
BTW, you can verify it if you input x = [1 2 3] and check how result depends on dt...
01-06-2017 01:07 PM
Excellent - thanks so much for your help!