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Helium-speech communication

  • US 4,342,104 A
  • Filed: 10/30/1980
  • Issued: 07/27/1982
  • Est. Priority Date: 11/02/1979
  • Status: Expired due to Term
First Claim
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1. A method of through-water communication of helium speech in which the bandwidth of a leading part of each pitch period of a diver'"'"'s helium speech is reduced by waveform time expansion to provide a signal bandwidth acceptable for modulating a carrier wave of a frequency selected for optimum through-water transmission, the carrier wave being modulated and fed directly into the water to a listening station, the degree of waveform time expansion effected at the diver'"'"'s location being preset and the listening station including means to modify the time expansion of the received signal to optimise intelligibility of the received speech.

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