| 摘要 |
<p>The system includes fixed stations in which are evaluated the radio messages, transmitted by the moving subscribers, this evaluation being carried out w.r.t. the information contents and direction of transmission. Each fixed station has a direction finder with an omnidirectional diagram and a single-channel receiver. Pref. the message comprises, in addition to the information part, a preposition signal for synchronisation of the receiver. The radio message, transmitted by a moving subscriber, may consist of two subsequent, identical signals. On reception in the fixed station the circulation direction of the omnidirectional diagram is reversed between the two subsequent signals. An Adcock aerial with a rotary goniometer may be used as the direction finder aerial. The latter may contain an array of directional aerials, aligned on different azimuths, these aerials being connected to the receiver in a cyclic sequence via switches.</p> |
