00000nam 2200000zi 4500 9.892298 CaOODSP 20221107173131 m o d f cr |n||||||||| 201008s1995 oncd ob f|0| 0 eng d CaOODSP eng rda CaOODSP eng fre n-cn--- Co24-3/7-95-004E-PDF Bryden, Karen, author. Helium speech descrambler final report (U) / by Karen Bryden, H. Hassanein and François Marceau. Ottawa : Communication Research Centre, Industry Canada, 1995. 1 online resource (1 volume (various pagings)) : charts. text txt rdacontent computer c rdamedia online resource cr rdacarrier CRC report ; 95-004 Digitized edition from print [produced by Innovation, Science and Economic Development Canada]. "June 1995." Includes bibliographical references. "The presence of helium in the breathing gas used in certain military diving operations renders the divers' speech unintelligible. This distortion represents a danger to the divers. A new, lower cost device was developed to "descramble" the divers speech. The device is based on linear prediction and uses interpolation of the autocorrelation function to remove the nonlinear frequency distortion. It is implemented on a digital signal processing chip in both fixed and floating point arithmetic. Another algorithm based on frequency domain manipulation is described. During tests, it became apparent that distortion caused by the diver's face mask and limitations of the microphone in the diver's helmet were major contributors to communication problems"--Abstract. Includes abstract in French. Signal processing Digital techniques. Traitement du signal Techniques numériques. Canada. Industry Canada, issuing body. CRC report ; 95-004. (CaOODSP)9.882492 PDF 1.23 MB https://publications.gc.ca/collections/collection_2020/isde-ised/Co24/Co24-3-7-95-004-eng.pdf