Circuit for image signal transmission and reception by adaptive modulation and a method therefor

A circuit and a method for transmitting and receiving the image signal by adaptive modulation and for image band compressing by subband coding. The present invention improves the problems that degradation of the picture quality is more serious rather than the noise reduction effect in the edge of the picture even if the channel noise of the low band signal component can be reduced through the noise reducer by using correlation between the picture elements, and that it is waste of the quantity of transmission information that the high band image signal is transmitted in 8-bit pattern because the high band image signal component usually has narrow distribution of its level. According to the present invention, adaptive modulation is applied to the high band image signal and low band image signal respectively and the high band image signal is transmitted in 6-bit pattern, so that the channel noise and the quantity of the transmission information are reduced.