Basic principle of phase distortion
Phase distortion refers to the time delay of the signal during transmission and amplification. As shown, the two waveforms in the figure represent the signals at the input and output, respectively. It can be seen that there is no change in the shape of the two signals, the difference is that the signal below is "a little later" than the time above. The time difference (Δt) can be converted into a phase difference based on the frequency of the signal. Phase difference, the unit is "degree", where f is the frequency of the signal.