Derivative Filter
Theory:The D term: noise, derivative filter and set-point kick
N means different things: dimensionless in the ideal form (Tf = Td/N), 1/s in the parallel (MathWorks) form (Tf = 1/N).
Equations
D(s) = Kd·s / (Tf·s + 1)ideal: Tf = Td / N (N dimensionless)parallel: Tf = 1 / N (N in 1/s, MathWorks)ωc = 1/Tf, fc = 1/(2π·Tf)