Discrete Fourier transform mirrored?

by lordchaos
Tags: discrete, fourier, mirrored, transform
 P: 2,251 because $$\cos(\omega t + \phi) = \frac{1}{2} \left( e^{+i \omega t} + e^{-i \omega t} \right)$$ so there is a frequency component at $+\omega$ and at $-\omega$. because of aliasing due to sampling, negative frequencies are displayed in the upper half of the output of the DFT.