This indicator was originally developed by John F. Ehlers (Stocks & Commodities , V.33:10 (September, 2015): "Decyclers").
Ehlers recommended to use two instances of the Decycler Oscillator with different parameters (high-pass filter period and multiplier). As a result, he got the Decycler Oscillator pair. This version is doing that and is showing the expected trend based on those two oscillators
Download Simple decycler oscillator - indicator for MetaTrader 4