The present invention has been developed considering the above-described problems and aims to provide various structures and applications for illuminative light communication. According to the first aspect of the prevent invention, a broadcast system includes an LED light source 115 for lighting, a power line 103 that supplies electric power to the LED light source 115, a data modulator 102 that modulates and multiplexes a plurality of pieces of data, superimposes the resulting signal on an electric power waveform, and then transmits the resulting superimposed signal waveform to the power line 103, and a filter 112 that selectively separates one or more of a plurality of pieces of modulated data on the power line so as to control light intensity or blinking of the LED light source. Data is transmitted through changes in light intensity or blinking of the LED light source.