Abstract: The disclosure is an improvement in a three-line sequential transmission system for a color television signal, particularly for recording, and where the sequential signal is transformed again, during reproduction with a series-connection of line delay lines, into three simultaneous color signals, and a luminance signal is obtained by composing the signals from several successive lines. In accordance with the disclosure, the luminance signal has an amplitude ratio between these signals, to increase the picture sharpness in the vertical direction, such that the amount of the luminance transmission function of the entire system, including recording and reproduction, at the frequencies (n+1/2)f.sub.H is substantially equal to those of the frequencies n.multidot.f.sub.H where n=0, 1, 2 . . . and f.sub.H is the line frequency. The composition is effected such that zeros appear in the low frequency range of the transmission function at the frequencies (n.+-.1/3)f.sub.