A signal transmission system: that includes a signal transmission unit (101) that includes a MPEG decoder (102), which receives digital broadcasting and outputs a luminance signal Y and two color difference signals PB/PR, and a transmission path encoding circuit (103), which encodes the YPBPR outputted from the MPEG decoder (102) into signals in the forms suited to a transmission path and transmits the encoded signals; and a signal reception unit (104) that includes a transmission path decoding circuit (105), which receives the encoded YPBPR and decodes them, a Y processing circuit (106), which processes the decoded luminance signal Y, a chrominance processing circuit (107), which processes the respective decoded color difference signals PB/PR, a signal conversion circuit (108), which converts the YPBPR outputted from the Y processing circuit (106) and the chrominance processing circuit (107) into RGB signals, and a display device (108) which displays the RGB signals.