The Price Oscillator is the difference between moving averages over a term you specify. You should enter the longer-term first. Then a positive Price Oscillator signals a bullish trend and a negative Price Oscillator signals a bearish trend. If you enter the shorter term before the longer term, the signals are inverted.

References

Colby and Meyers (1988). The Encyclopedia of Technical Market Indicators. Dow Jones-Irwin.