The Carrier Nature of Speech

The Carrier Nature of Speech By HOMER DUDLEY Speech synthesizing is here discussed in t h e terminology of carrier circuits. T h e speaker is pictured as a sort of radio broadcast t r a n s m i t t e r with the message to be sent o u t originating in t h e studio of t h e t a l k e r ' s brain a n d manifesting itself in muscular w a v e motions in t h e vocal t r a c t . Although these motions contain t h e message, t h e y are inaudible because t h e y occur at syllabic rates. An audible sound is needed to pass t h e message i n t o t h e listener's ear. T h i s is provided by t h e carrier in t h e form of a g r o u p of higher f r e q u e n c y waves in t h e audible range set up by oscillatory action at t h e vocal cords or elsewhere in t h e vocal t r a c t . T h e s e carrier waves either in their generation or their transmission are m o d u l a t e d by t h e message waves to form t h e speech waves. As t h e speech waves contain t h e message i n f o r m a t i o n on an audible carrier t h e y are a d a p t e d to broadcast reception by receiving sets in t h e form of listeners' ears. T h e message is then recovered by t h e listeners' minds.