A follow on question form this one (What is meant by "spectral moment"?)
In answers to the above referenced question spectral moment is defined as:
$$ m_k=\int_{-\infty}^{\infty} f^k|X(f)|^2\ df $$
The limits on the integral include negative frequency. So is the negative frequency really important?
If I filter out all negative frequencies before calculating the moments will they be wrong?
If $|X_f|^2$ is symmetrical about zero then does this not mean that $m_k=0$ for all odd values of $k$?
