Distortions which are independent of signal amplitude.

These distortions occur as a result of the system’s inability to uniformly transfer amplitude and phase characteristics at all frequencies.

When fast signal components such as transitions and high frequency chrominance are affected differently than slower line-rate or field-rate information, linear distortions are probably present. These distortions are more commonly caused by imperfect transfer characteristics in the signal path. However linear distortions can also be externally introduced. Signals such as power-line hum can couple into the video signal and manifest themselves as distortions.