A video signal occupies a wide spectrum of frequencies, from nearly DC (0 Hz) to 6 MHz. If the output impedance of either the video source, cable, or input impedance of the receiving equipment are not properly matched, a series of problems may arise. Loss of high-frequency detail and colour information as well as image instability, oscillations, snow, ghost images, and component heat-up may result.

Proper connexions and cable types provide correct impedances. See Load Resistance.