Price Range (high - low) averaged across a set of bars: Useful gauging potential trading profits. This was its initial goal, to not measure bars manually!
ATR: As a comparison point for the price range above. Divergence between true range ( TR ) and plain price range might signal changes occurring in the instrument.
Signal line: a moving average of the larger of the average price range and ATR. This takes inspiration from other indicators like and , and is a way of comparing change in recent --- this achieves the momentum part. The larger was chosen to keep things simple, and not have a signal line per range!
avgRange = movingAvg(high - low, avgPeriod)
atr = movingAvg(trueRange, avgPeriod)
signal = movingAvg(max(avgRange, atr), avgPeriod)
Configurable periods and averaging mechanism.