| 摘要 |
PURPOSE:To avoid the mismatching and the occurrence of reflection to ensure a good isolation, by giving a division between the switch circuit which is terminated by the line impedance and the switch circuit which gives an earth to the leak signal. CONSTITUTION:The TV broadcast signals supplied through the antenna 51 are distributed by the distributor 52 to the TV receiver 53 and the antenna changeover switch 55. And the signal is supplied to the TV receiver 60 through the antenna input terminal 54 of the switch 55 plus the antenna side relays 56 and 58 and via the output terminal 59 each. When the output signal supplied from the additional device 64 is switched to be applied to the receiver 60, the relay 61 at the additional device side is actuated by the selection switch signal given from the device 64. Then the output given from the device 64 is supplied to the receiver 60 through the terminal 59 of the switch 55. The termination of the distributor 52 of the switch 55 is divided to the relay 56 which performs a switching to the matching impedance 57, the relay 61 which introduces the output of the device 64 to the terminal 59 and the relay 58 which prevents the leak given from the terminal 54 each. Thus the mismatching can be prevented. |
