Dynamic calculation of the power during each cycle

Dear all,

I have a source which delivers power to my circuit during each cycle of a certain signal PULSE.The period of the cycle, defined by the signal PULSE, is varying with time. I know how to estimate the power during one specific cycle in the following way:

(t_in = cross(VT("/PULSE) 1.5 1 "rising" nil nil))

(t_fin = cross(VT("/PULSE) 1.5 2 "rising" nil nil))

(power = integ(VT("/VIN") * IT("/V0/MINUS") t_in t_fin) / (t_fin - t_in))

Is there a way to have waves of t_in, t_fin and power in such a way that every cycle it estimate one value equal to the average power delivered to my circuit? I tried to use the option multiple for the number of occurrences in the function cross, but t_in and t_fin in this way have equal values, even if they are values.

Thanks a lot,

Stefano