| 摘要 |
PURPOSE:To enable to select the radio channel of the mobile station automatically, by providing transmitter which transmits the channel designation signal of radio channel selection designation in low level at all times, in the mobile communication system such as train telephone. CONSTITUTION:The mobile communication system consists of the radio units 9 and 11 to which the first and second radio channels eH1, CH2 are assigned, leakage coaxial cables 16 to 19, channel selection transmitters 25,26 and mobile station 20. The transmitter 25 modulates the carrier frequency of CH2 with the selection designation signal to CH1, transmitter 26 modulates the carrier frequency of CH1 with selection designation signal to CH2, and they are normally transmitting in lower level than the radio units 9 and 11. When the mobile station 20 progresses toward the boundary A between the section 10 and the section 12 and it reaches the point A, the output electric field level from the radio units 9 and 12 is equal. When it reaches point B, the electric field level by the CH2 selection transmitter 26 is in excess of the electric field level from the radio unit 9, the FM receiver of the mobile station 20 receives the designation signal of CH2 to select the radio CH to CH2. |
