Detrended Price Oscillator   

The Detrended Price Oscillator (“DPO”) attempts to eliminate the trend in prices & smoothes the trend in prices. It compares closing price to a prior moving average, eliminating cycles longer than the moving average. It is used to isolate short-term cycles. Short-term cycles add together like musical harmonics to create longer-term cycles. By studying the shorter-term harmonics of a long-term cycle, turning points in the major cycle can be determined. The DPO removes the longer-term cycles from prices, making the shorter-term cycles more visible. The Detrended Price Oscillator is most effective with indicator periods of 21 or less.
Usage:

Detrended prices allow to more easily identifying cycles and overbought/oversold levels. Short- term cycles add together to create longer-term cycles. Analyzing these shorter-term components of the long-term cycles can be helpful in identifying major turning points in the longer-term cycle. The DPO helps to remove these longer-term cycles from prices.