| 摘要 |
PURPOSE:To prevent the emission of illegal radio waves by matching a channel specifying signal supplied from the external with an inherent channel No. stored in a ROM at the input of the channel specifying signal, and when both values coincide with each other, starting a transmitter. CONSTITUTION:The channel specifying signal S1 supplied from the external is supplied to and stored in a channel specifying signal matching circuit 16 and matched with the inherent channel specifying signal S7 sent from the channel No. storing ROM4. When both signals coincide with each other, the channel specifying signal S7 outputted from the channel specifying signal storing ROM4 as a channel specifying signal S2 is supplied and a transmitter starting signal S8 is sent from the circuit 16 after a prescribed time. When the transmitter starting signal S8 is sent, an output S5 is generated from the transmitter 5 and guided to an antenna 8 through a transmitter/receiver 7. Thus, the emission of illegal radio waves other than those from fixed channels can be prevented. |
