(PAL) The video signal format used in the UK [where else?]. PAL uses Amplitude Modulationfor the video information, and Frequency Modulationfor the audio information. The phase of the colour subcarrier is reversed on alternate lines which (together with the use of a delay line) allows the receiver to cancel any phase errors introduced in the path between the studio and the end-user' s receiver. Such phase errors are quite common and would cause the displayed colours to shift in hue. The US equivalent, NTSC, does not have this feature and thus requires a user control to correct for transmission phase errors, hence the mis-expansion "Never Twice the Same Colour". (2001-06-08)