Attenuation compensation volume computing means (60, 61, 62, 63, 67, 68, 69, 70) of a signal receiver computes attenuation compensation volume of a video signal (GL, GH) on the basis of attenuation of pulses which are arranged in a digital sound signal LRD from the signal transmitter, and video signal attenuation compensation means (60, 61) of the signal receiver compensates the attenuation of the video signal (RAT, GAT, BAT) on the basis of the computed attenuation compensation volume (GL, GH), thereby stably compensating the attenuation of the video signal irrespective of kinds of displays or resolution of an image, and outputting good sounds to a video output machine as well as good videos.