| 摘要 |
PURPOSE:To automatically switch a receiving frequency and to eliminate trouble caused by switching to a service area having a different frequency by detecting an electric field strength at the frequency of the peripheral service area, comparing it with an electric field strength at the receiving frequency being held and judging whether the radio receiver transfers between the service areas. CONSTITUTION:A control means changes the frequency to the frequency of the peripheral service area of the service area where the receiver exists in the receiving cessation period of intermittent receiving. The detection electric field strength at the changed frequency is obtained and an electric field strength comparing means compares it with the electric field strength by the receiving frequency in a receiving period being held by an electric strength storage means. When the detection electric field strength changes, it is judged that a transfer is made between the service areas and the receiving frequency is automatically switched. Thus, the transfer of the radio receiver between the service areas is detected, the receiving frequency is automatically changed in accordance with that and therefore, it becomes unnecessary to manually switch the frequency each time. |
