| 摘要 |
<p>The alarm system has a number of outer stations communicating with a central unit by transmitting radio signals in a given frequency spectrum and contg. data telegrams representing detected conditions, evaluated by the central unit to activate the alarm. The transmission frequency of the outer stations is altered for each new information block, each of which is repeated a number of times, the central unit scanning the transmission spectrum and checking that all stations have responded within a given time frame and that a threshold transmission error rate is not exceeded.</p> |
