| 摘要 |
A self-testing radio-frequency (RF) communications system having a transmitter module which transmits a pulsed RF test signal at discrete time intervals and a receiver module for receiving the RF communications signal having means for indicating the status of the link between transmitter and receiver module in dependence on the pulsed RF test signal, thereby, in use, verifying the integrity of the RF communications link. Also provided is a remote security system which uses the self-testing RF communications system and in which the transmitter transmits an RF alarm signal which can be received over the RF communication link by the receiver module and an alarm raised. The alarm function may be self-enabling in dependence on the relative proximity of the transmitter and receiver module. |
