spectreRF pss analysis : formula for PAE

Hi,

When using the direct plot option to  trace out the PAE (= Pout - Pin / Pdc) after a pss analysis, if the PAE is added to the outputs the formula which gets added to Output window reads as follows :

 ((100.0 * harmonic ((spectralPower(i("/PORT1/PLUS" ?result "pss_fd") v("/P_out" ?result "pss_fd")) + spectralPower(i("/PORT0/PLUS" ?result "pss_fd") v("/P_in" ?result "pss_fd"))) '(120))) /  -harmonic ((spectralPower(i("/V1/PLUS" ?result "pss_fd") v("/Vdc" ?result "pss_fd"))) '(0)))

Here, PORT1 is my output port and Port0 is my input port. P_out and P_in are the output and input nets respectively. 120 refers to the index of the harmonic of interest in my analysis.

Intuitively, I do not understand the following :

• The addition (highlighted in bold) of the two powers in the numerator, whereas from the formula of PAE, I expect there should be a difference.
• The negative sign (highlighted in bold) associated with the DC power in the denominator