  The higher order differential energy operator (DEO), denoted via
$\Upsilon_k(x)$, 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.
