Method for coordinating propagation delays in a satellite linked simulcast network using a benchmark station

摘要

A clock synchronization system for synchronizing a number of paging stations (24) with a system controller (23). Each paging station has a clock that includes a counter (52) that indicates the current local time and which is sequentially incremented by a counter advance signal applied thereto. A voltage controlled oscillator (58) generates the clocking signal that controls the advancement of the counter. A CPU (50) in the system controller monitors the time indicated by the counter and compares it to timing information received from a system clock. The timing information includes a time mark and a time mark send time. The system clock transmits to each paging system the time mark. At a future time, the system clock transmits the time mark send time which is the precise time at which the time mark was transmitted. The paging stations each measure the time interval between the time at which the time mark arrived and the time at which the time mark was transmitted by the system clock period. By subtracting the time at which the time mark was transmitted by the system clock and the propagation time to each paging station, each paging station can determine and correct the error in its clock.