| 摘要 |
1357756 Subaqueous signalling apparatus SNAM PROGETTI SpA 5 Aug 1971 [3 Sept 1970] 36961/71 Heading G4F An underwater transmitter device capable of operating automatically to transmit a warning in the event of an underwater accident comprises an electric pulse generator e, a pulse divider d which transmits pulses at a lower frequency to an oscillator f and an electroacoustic transducer h; an electronic timer b is provided with switches M 1 , M 2 , M 3 , and if these switches are not operated before the end of predetermined time intervals, the pulse divider transmits a higher frequency warning signal to the transducer. Acoustic signals from the transducer h may be received by transducer i and fed through filter l and automatic volume control m to loud-speaker p mounted on a surface vessel. A light c gives warning to the underwater operator of the end of the predetermined time interval. Pressure responsive switch a brings the device into operation at a predetermined depth.
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