| 摘要 |
1,222,654. Direction-finding. E.M.I. ELECTRONICS CANADA Ltd. 25 March 1968 [28 March, 1967], No. 14012/67. Heading H4D. Portable direction-finding apparatus comprises two transducers mounted one at each end of a rod-like member and responsive to incident sound pulses, two lamps mounted one at each end of the member, and a circuit for causing one or the other lamp to light according to which transducer first receives a sound pulse. An embodiment enabling a diver to home on an underwater acoustic beacon comprises aperiodic ceramic transducers 15, 16 on a tube housing tuned amplifiers 31, 32 and phase comparison circuitry 34, 35 in which the respective phases of the amplified transducer outputs are compared with a reference signal synthesized by adding the two amplifier outputs. A phase advance causes energization of the appropriate lamp 6 or 7.
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