| 摘要 |
An alarm system 40 for an unmanned radio transmitter installation for relaying a stereo radio signal from an associated radio station. The alarm system 40 has one or more sensors 41 to monitor a desired condition such as the fuel level in a fuel tank for an emergency generator at the installation. Means 43 is provided for stripping off the stereo pilot tone form the radio signal in response to a sensed alarm condition, the transmitter installation then broadcasting a mono radio signal. A tuner 31 provided at the radio station operates a warning lamp 46 upon reception of the mono radio signal. <IMAGE> |
