发明名称 |
Remote underwater device activating system |
摘要 |
An apparatus for activating a remote underwater device comprising detecting means responsive to incident acoustic waves provides signal indication of the presence or absence of predetermined frequencies thereof. A logic arrangement decodes only those signal indications indicating a joint presence of some of the pre-selected frequencies and the absence of others of the pre-selected frequencies. This discriminates signals against broad-band acoustic noise. The logic arrangement further includes means for activating the remote underwater device only if the decoded successive signal indications match a predetermined pattern. This further discriminates between a present received acoustic wave and a prior transmitted acoustic wave present because of multipath or reverberation. Lastly, a timing and gating means responsive to a first decoded signal indication couples the detecting means to the logic arrangement only at periodic intervals thereafter. The time gating also reduces the chances of obtaining a prior multipath and reverberation signal because the pulse repetition period of the successive acoustic waves is predetermined.
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申请公布号 |
US3939465(A) |
申请公布日期 |
1976.02.17 |
申请号 |
US19700048891 |
申请日期 |
1970.06.15 |
申请人 |
RAYTHEON COMPANY |
发明人 |
HELTON, ROBERT A.;WALSH, GEORGE M.;ALARIE, ALLAN P. |
分类号 |
H04B11/00;H04L27/26;(IPC1-7):H04B11/00 |
主分类号 |
H04B11/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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