HELIUM SPEECH DESCRAMBLER

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Authors
  1. Bryden, K.
  2. Hassanein, H.
  3. Marceau, F.
Corporate Authors
Communications Research Centre, Ottawa ONT (CAN);Defence Research Establishment Ottawa, Ottawa ONT (CAN)
Abstract
A helium speech descrambler made by Hele Co, is used by the Canadian Navy. This unit is expensive, and is often found to operate ineffectively. Other available descramblers such as those made by Stocktronics are extremely expensive. In order to provide a low cost alternative to these descramblers, the Defence and Civil Institute of Environmental Medicine (DCIEM) tasked the Communications Research Centre (CRC) to investigate the problem and design a new descrambler. CRC had previously simulated a new descrambler and used it successfully to descrambel a sample of helium speech recorded at the Naval Ocean System Centre (NOSC) in San Diego Ca. This algorithm was transferred to a digital signal processing (DSP) chip and tested during a set of helium divers performed at the Fleet Diving Unit (Atlantic) in Shearwater NS in Sept 1993. The Model 1 unit performed as well as, and in some cases better than the Hele unit, in spite of its simplicity. Recordings made during the trials were brought back to Ottawa and used during the development of a Model 2 descrambler. In Jan, 1994, during subsequent helium chamber dives at DCIEM, divers were asked to speak a set of isolated words from a subjective listening test at representative depths. The divers speech was recorded and later passed through both the Hele descrambler and the Model 2. TRUNCATED
Keywords
Helium Speech Descrambler
Report Number
CRC-95-004 — Final Report
Date of publication
01 Jun 1995
Number of Pages
30
DSTKIM No
96-00425
CANDIS No
154895
Format(s):
Document Image stored on Optical Disk;Hardcopy

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