SECAM (Sequential Couleur Avec Memoire)

A 625 line 50 interlaced field per second analog broadcast standard used in Europe. Alternating scan lines carry R-Y and B-Y color difference signals respectively. The TV must contain delay (memory) circuits to make available both the R-Y and B-Y signals, which are then shared by (as common to) the two scan lines. Chroma resolution is half the luminance resolution vertically. Programs are not interchangeable with NTSC even though they may occupy the same broadcast channels or be recorded on videocassettes of the same size and shape. Programs can be played back on PAL equipment where they come out in black and white. There exist VCR's and TV sets that will play all three formats but they are not common in the U.S.A.