I am trying to write mathematically how to calculate the power of a finite signal. I know the general formula $P_{\mathrm{x}}=\lim_{T\to\infty} \frac{1}{T} \int_{t=0}^{T} x^{2}(t) \mathrm{d} t$ used to calculate the power of a signal which has infinite Energy and finite power. But how do you express it when the does not go to infinity, is not period and does not have infinite energy?
I know its a basic but i have searched all over and have not been able to find a proper answer.
Thanks in advance.