| 摘要 |
PURPOSE:To simplify the system constitution by constituting the system with one system of transmission line, plural terminal devices and antenna equipments and detecting an idle channel of a broadcast band to set automatically a modulation frequency for reverse broadcast to the idle channel. CONSTITUTION:The home bus system is constituted of a transmission line 1 using a coaxial cable, tap-offs 2-1, 2-n, interface units 3-1-3-n, AV devices 4-2-4-n as terminal devices and antenna equipments 10-1-10-3 or the like. An electric field intensity meter 8 is connected to the equipments 10-1-10-3 via the coaxial cable 7 to measure the electric field intensity of each channel of a TV broadcast band to the devices 4-2-4-n. The data measuring the electric field intensity is fetched to a logical circuit 15 of a data processing section 13 in the devices 4-2- 4-n, the idle channel is detected and the data of a modulation frequency is fed to a modulator 11. Moreover, the modulation for reverse broadcast is set automatically to simplify the system constitution. |
