The higher order differential energy operator (DEO), denoted via $Υ_k(x)$, is an extension to the second order famous Teager-Kaiser operator. The DEO helps measuring the higher order gauge of energy of a signal which is useful for AM-FM demodulation. However, the energy criterion defined by the DEO is not compliant with the presumption of positivity of energy. In this paper we introduce a higher order operator called Positive Differential Energy Operator (PDEO). This operator which can be obtained using alternative recursive relations, resolves the energy sign problem. The simulations demonstrate that the proposed operator can outperform DEOs in terms of Average Signal to Error Ratio (ASER) in AM/FM demodulation.