parnass@ihuxz.ATT.COM (Bob Parnass, AJ9S) (04/17/88)
x The discussion of copying RTTY by ear is interesting, and I've often thought about such things. One of my favorite daydreaming topics is how humans might develop the ability to understand scrambled speech, without using a descrambler. I'm talking here about speech inversion type scrambling, not digital voice encryption, or time domain rolling code scrambling. Could this ability be developed in a child raised (from infancy) by parents and teachers who communicate only through use of a speech inversion scrambler? I've been able to understand SSB transmission fragments without a product detector. However, this is probably due to the cadence and context (e.g., recognizing someone calling CQ is much easier than understanding an operator describing the weather). -- ===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-=== Bob Parnass AJ9S - AT&T Bell Laboratories - ihnp4!ihuxz!parnass - (312)979-5414
henry@utzoo.uucp (Henry Spencer) (04/20/88)
> 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. (For more detail, see Kahn's 'The Codebreakers'.) -- "Noalias must go. This is | Henry Spencer @ U of Toronto Zoology non-negotiable." --DMR | {ihnp4,decvax,uunet!mnetor}!utzoo!henry
leonard@bucket.UUCP (Leonard Erickson) (04/23/88)
I remember seeing a reference somewhere regarding this. It was in some work dealing with either espoinage or cryptography during WWII. It stated that speech inversion was quickly dropped as it was possible to understand without a descrambler "with practice". Possible it was in The Codebreakers by Kahn? -- Leonard Erickson ...!tektronix!reed!percival!bucket!leonard CIS: [70465,203] "I used to be a hacker. Now I'm a 'microcomputer specialist'. You know... I'd rather be a hacker."