Translations:Magnitude spectrum and phase spectrum/23/en

The frequency spectrum (or transfer function) can be written in polar form as $B\left(f\right)={|}B\left(f\right){|}e^{i\psi (f)}$, which generally is complex. The magnitude ${|}B\left(f\right){|}$ of the transfer function is called the filter’s magnitude spectrum (or amplitude spectrum), whereas its phase lead $\psi \left(f\right)$ is called the filter’s phase-lead spectrum. Thus, the magnitude spectrum of the filter $b_{0}=-{0.5}$ is 0.5, and its phase-lead spectrum is $\pi$.