John Ehlers' Distance Coefficient Filter.
Even though a lot of times it is mistaken for Ehlers Nonlinear Filter, they are not the same.
This version is coded exactly a Ehlers described it in his book "Rocket science for traders".
This is the "zone" indicator using Ehlers Nonlinear Filter for calculation.Ehlers Nonlinear Filter
Ehlers Nonlinear Filter provides extraordinary smoothing in sideways markets and aggressively follow major price movements with minimal lag.