| 摘要 |
PURPOSE:To improve the synchronizing accuracy of modulation regardless of the fluctuation of the transmission delay amount of paging signals between transmission stations in a wide area radio paging system transmitting each radio frequency carrier wave of the same frequency modulated by the same paging signal from plural transmission stations. CONSTITUTION:A paging controller 10 generates a highly accurate time signal based on the reference signal from a GPS satellite 90 by a GPS receiver 150, and when the controller 10 receives the calling from a PSTN 40, it prepares a paging request signal, adds the time delayed more than the maximum delay time required for the signal transmission on preliminarily stored transmission lines 60 and 61 and the processings on sides of transmission stations 20 and 21 as transmission start designation time information and transmits it to each transmission station 20 and 21. Each transmission station 20 and 21 generates the highly accurate time signal and the clock pulse signal of the bit unit of a modulation signal by a GPS receiver 230 in the same way, performs the format conversion of a request signal to a digital paging signal at a designated time and modulates carrier waves by synchronizing them with each other.
|
