| 摘要 |
A radio system shown in Fig 1 has a main radio transceiver unit 1 and a reserve unit 2. These are both so-called "software "radios i.e. they contain processors 1.5 which are programmed to perform signal processing functions. Conventionally an entirely separate change-over unit of similar size to the radios would be included to detect a fault in the main radio and to switch to the use of the reserve radio. However, the change-over unit may itself fail and because it controls connections to both radio units, any such a failure of the change-over unit could have very serious consequences. The invention resides in the idea of programming the in-built processors (1.5, 2.5) so that they can each monitor the performance of the appropriate unit when it is in use; and effect a change-over (via switch 1.7, 2.7) when a fault is detected. In a preferred arrangement changeover can be performed between just the transmitters or just the receivers. The best effect is achieved if the performance of various different aspects of the radio unit is monitored and a score given for each. The transmitter and receiver having the best score at any one time are then selected for use. In a variation a facility is provided for performing a change-over at regular intervals even if both units are operating perfectly. This guards against the possibility that the reserve unit might develop a fault through aging which is not noticed until a failure of the main unit occurs. |
