PURPOSE: To secure the high-efficiency DPCM coding by giving the isolation and extraction to the chroma signal component forming the TV signal and then carrying out the DPCM coding after giving the phase inversion to the signal component with every scanning line.

CONSTITUTION: The TV signal is supplied to Y/C isolation circuit 1 to be isolated into luminance signal component Y and chroma signal component C. Component C is supplied to adder 3 after receiving the phase inversion process via chroma inverter 2 to be compounded with component Y. Inverter 2 gives the phase inversion to component C every scanning line through horizontal synchronous detection circuit 4, and the compound signal obtained through adder 3 is supplied to DPCM coder 5. Coder 5 gives coding to the compound signal via at least 1-scanning line preceding predictive value. This coded signal is transmitted through transmission line 6 and then decoded at DPCM decoder 7. This composite signal is then isolated into signal components Y and C through Y/C isolation circuit 8, and component C is compounded with component Y at adder 10 after receiving the phase inversion through chroma inverter 9.