Robotics Reference
In-Depth Information
perfecting the machine, he discovered that few people showed any inter-
est in it. In America Faber achieved little more success with his machine
than he had experienced in Europe and so, with the state of his mind also
affected by the fact that his eyesight was failing, he destroyed his machine
and then committed suicide around 1850.
Electrical Speech Synthesis
The first electrical speech synthesis device was introduced by John Stew-
art in 1922, while he was employed in the Development and Research
Department at the American Telephone and Telegraph Company (now
known as AT&T). This synthesizer had a buzzer to simulate the human
vocal cords and two resonant circuits to model the acoustic resonances
of the throat and mouth. The machine was able to generate single vowel
sounds, but not any consonants or connected utterances. The same kind
of synthesizer was also built by Harvey Fletcher of the Bell Telephone
Laboratories and demonstrated to the New York Electrical Society in
February 1924—it could utter a limited number of sounds including
the words “mama” and “papa”.
The Voder
The first electrical synthesizer which attempted to produce connected
speech was the Voder (Voice Operated Demonstrator), developed by
Homer Dudley, a research physicist at Bell Laboratories in New Jersey.
It was first demonstrated on 5 January 1939 at the Franklin Institute in
Philadelphia (see
Figure 8)
and presented later that year on the Bell Sys-
tem exhibit at the San Francisco and New York World's Fairs. The device
synthesized the entire spectrum of human speech sounds and was oper-
ated by a young woman using a finger keyboard with additional wrist
and foot controls.
The Voder was a compact machine with a pair of keyboard units,
more than a dozen other controls and an electrical circuit featuring a
vacuum tube and a gas-filled discharge tube. It built up its speech from
the same fundamental sounds from which the human speech organs cre-
ate spoken words. A trained operator would analyse each word the ma-
chine was required to speak, then duplicate the sounds (and therefore
the words) by pressing a combination of the keys and the other controls.
When the Voder was demonstrated at the World's Fair, members of the
