Editing
Voder
(section)
Jump to navigation
Jump to search
Warning:
You are not logged in. Your IP address will be publicly visible if you make any edits. If you
log in
or
create an account
, your edits will be attributed to your username, along with other benefits.
Anti-spam check. Do
not
fill this in!
== Working Mechanism == The Voder is a manually operated speech synthesizer that recreates the physiological characteristics of the human voice. It worked by breaking up human speech into its acoustic components using a set of ten contiguous band-pass filters that covered the entire speech frequency range and were chosen after a careful analysis of how the human ear interprets speech sounds. The initial sounds produced by either the oscillator or the gas discharge tube were passed through these filters, and their outputs were then passed through an amplifier that mixed and modulated them and passed it on to a loudspeaker in order to produce an electronic human speech<ref>Dudley, H. (1940). The carrier nature of speech. ''Bell System Technical Journal'', ''19''(4), 495-515.</ref>. Thus, The Voder was designed on the principle that an electrical speech synthesizer must be a functional copy of the human speech source-filter mechanism that consists of the following steps: # '''Initiation: having a steady energy source'''. This is achieved by the compressed air in the lungs. Correspondingly, the Voder had an electric supply for its steady energy source. # '''Phonation: converting the energy into audible vibrations'''. This is achieved by two distinct methods: voiced sounds are produced by the vibration of the vocal cords in the larynx, and unvoiced sounds and whispers are produced by forcing a stream of air through a constriction in the vocal tract, which produced a hissing sound. Likewise, the electrical oscillator in the Voder produced the buzz tone that was used to create vowels and nasal sounds, and the ‘random noise’ source made the hissing sound used for producing fricatives. # '''Articulation: creating various speech sounds'''. This is achieved by adjusting the resonances and couplings of air cavities through the movements of organs such as jaws, lips, and tongue. The air in these cavities resonates in a specific fashion to make certain overtones produced by the larynx to be radiated more efficiently to the atmosphere than others. In the Voder, this was achieved with the help of electrical filters. The potentiometers (devices that control how much electricity flows through a circuit) controlled by the finger keys were used to operate these filters. Pitch control, in turn, was managed by a foot pedal, which also converted tones and hissing sounds into vowels, consonants, and inflections. Three additional keys were dedicated to triggering transient excitation of selected filters to produce plosive sounds, such as 'p' or 'd,' as well as affricative sounds, like 'j' or 'ch.' The overall structure of the device can be seen here: [https://upload.wikimedia.org/wikipedia/commons/c/ca/Homer_Dudley_%28October_1940%29._%22The_Carrier_Nature_of_Speech%22._Bell_System_Technical_Journal%2C_XIX%284%29%3B495-515._--_Fig.8_Schematic_circuit_of_the_voder.jpg<nowiki>]</nowiki> Overall, the Voder machine was designed with ergonomics in mind, intended to function within the capabilities of a human operator. A normal human operator would only be able to control a maximum of ten keys at a time, and hence the spectrum keys were limited to ten. In practice, Voder was not an easy machine to work with, and it could take more than a year to become a professional operator of the machine<ref>Mills, M. (2012). Media and prosthesis: The vocoder, the artificial larynx, and the history of signal processing. ''Qui Parle: Critical Humanities and Social Sciences'', ''21''(1), 107-149.</ref>.
Summary:
Please note that all contributions to MSc Voice Technology are considered to be released under the Creative Commons Attribution (see
MSc Voice Technology:Copyrights
for details). If you do not want your writing to be edited mercilessly and redistributed at will, then do not submit it here.
You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource.
Do not submit copyrighted work without permission!
Cancel
Editing help
(opens in new window)
Navigation menu
Personal tools
Not logged in
Talk
Contributions
Create account
Log in
Namespaces
Page
Discussion
English
Views
Read
Edit
Edit source
View history
More
Navigation
Main page
Recent changes
Random page
Help about MediaWiki
Tools
What links here
Related changes
Special pages
Page information