How the Voice Typewriter Works 



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This is the machine itsed to 

 evolve the natural alphabet. 

 The man at the left is whispering 

 into an acoiistieon or loud- 

 speaking transmitter, which is 

 attached to a heavyweight, in turn 

 suspended by springs. The 

 inertia of the weight and the 

 resiliency of its spring supports, 

 prevent exterior vibrations of arty 

 kind from jarring the extremely 

 sensitive transmitter. Connected 

 with its circuit is a siring 

 galvanometer. The whole ar- 

 rangement is so sensitive that 

 faint whispers readily cause the 

 "siring" to vibrate. Light from 

 t!:e arc light throws a shadow of 

 this vibrating string on to the 

 camera at right. A revolving 

 drum carries a strip of photo- 

 graphic film and rnakes a 

 permanent record of the vibra- 

 tions. Sample records are given 

 at left, together with an explana- 

 tion helo;i' of what those par- 

 ticular curves signify. 



These strange curves are records of the whispered and spoken vowel " U" 



The strange curves sho-wn aitove 

 are records obtained from the ap- 

 paratus. Upper Curve: Man's 

 voice pronouncing the letter " U" 

 bringing out in striking fashion 

 the fact that any underlyiyig curve 

 is obscured by extra humps due 

 to the peculiar nature of the 

 particular speaker's voice. 

 Middle Curve: Woman's voice 

 pronouncing the same tetter 

 " U ." Note differences from 

 same letter pronounced by man's 

 voice. Lowermost Curve is ob- 

 tained when the letter " U" is 

 whispered. Whispering is the 

 most elemental way one can 

 transmit speech, since it does not 

 require use of the vocal cords. 

 Contrast this curve with the two 

 preceding. Note that instead of 

 a series of repealing diagrams 



peculiar to a particular speaker's 

 voice, a definite undulation or 

 wave-shape now appears. In the 

 two upper curves this under- 

 lying wave-shape was blotted out 

 by extra curves or humps knmvn 

 as "higher harmonics" which 

 arose from the use of vocal cords 

 and were different for different 

 men's and women's voices. This 

 underlying wave-shape 7uas none 

 the less present in the two upper 

 curves, because a sound shaped 

 in this precise manner is neces- 

 sary before the twain recognizes 

 the letter " U" as such, Mr, 

 Flowers' feat consists in recog- 

 nizing this principle, and in 

 demonstrating it. He whispers 

 the whole alphabet into the 

 transmitter of the apparatus 

 shown altove, and secures ac- 



curate pliotographs of the undula- 

 tions, or "letter patterns" result- 

 ing, A complete set of these is 

 shown on Page 68. Mr, 

 Floivers found that it makes no 

 difference who does the whisper- 

 ing; the same wave form for the 

 same letter always results. Scien- 

 tists recognize this as an immense 

 step in advance, because hereto- 

 fore men attempting to get at 

 the real nature of speech have 

 always been frustrated because 

 the higher harmonics blurred out 

 the true wave present. They 

 could not deal with whispered 

 speech because no apparatus 

 sensitive enough to record whis- 

 pered speech existed, and the 

 curves they obtained with spoken 

 speech varied hopelessly with 

 each different speaker's voice. 



66 



