PAL stands for phase alternation by line, a colour television system developed in Germany and used through European and around the world. PAL consists of 625 lines scanned at a rate of 25 frames per second. 1
PAL was derived from the NTSC system but by reversing the phase of the reference colour burst on alternate lines is able to correct for hue shifts caused by phase errors in the transmission path.
The bandwidth of the 625/50 PAL system is 5 or 5.5 MHz for the luminance signal and 1.3 MHz for the R-Y and B-Y colour difference signals modulating the V and U axes of the PAL subcarrier.
1Kodak: A Concise Glossary for the Non-Technician