Article View: sci.crypt
Article #4202Re: Understanding scrambled speech without a descrambler
From: David Govett
Date: Thu, 21 Apr 1988 16:54
Date: Thu, 21 Apr 1988 16:54
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in article <1988Apr20.075217.761@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) says: > Xref: octopus rec.ham-radio:1388 sci.crypt:1137 > >> One of my favorite daydreaming topics is how humans might >> develop the ability to understand scrambled speech, >> without using a descrambler... > > There are instances of this on the record. In mid-WW2, Bell Labs > demonstrated that about half of a conversation using the then-current > A-3 scrambler -- used by Roosevelt and Churchill, among others -- > could be understood by the unaided ear, with some practice. It is > really quite hard to scramble speech well with pre-digital techniques. > There is too much redundancy in it. > Speaking of "on the record," I remember reading about an engineer at Columbia Records, I think, who could recognize any piece of classical orchestral music by the groove pattern on the disk.
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Path: arc1-ca.pugleaf.net!utzoo!mnetor!uunet!lll-winken!lll-lcc!lll-tis!ames!pasteur!ucbvax!decwrl!pyramid!octopus!avsd!govett From: govett@avsd.UUCP (David Govett) Newsgroups: sci.crypt Subject: Re: Understanding scrambled speech without a descrambler Message-ID: <118@avsd.UUCP> Date: 21 Apr 88 16:54:40 GMT References: <1988Apr20.075217.761@utzoo.uucp> Organization: Ampex Advanced Technology Division, Redwood City, CA Lines: 18