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The Voder
The Bell Telephone Laboratory's Voder (from ''Voice Operating Demonstrator'') was the first attempt to electronically synthesize human speech by breaking it down into its acoustic components. It was invented by Homer Dudley in 1937–1938 and developed on his earlier work on the vocoder. The quality of the speech was limited; however, it demonstrated the synthesis of the human voice, which became one component of the vocoder used in voice communications for security and to save bandwidth.Ben Gold, Nelson Morgan, Dan Ellis, ''Speech and Audio Signal Processing: Processing and Perception of Speech and Music''. John Wiley & Sons, 2011; , pages 9‒13 The Voder synthesized human speech by imitating the effects of the human vocal tract. The operator could select one of two basic sounds by using a wrist bar. A buzz tone generated by a relaxation oscillator produced the voiced vowels and nasal sounds, with the pitch controlled by a foot pedal. A hissing noise produced by a white noise ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell Labs
Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by multinational company Nokia. With headquarters located in Murray Hill, New Jersey, the company operates several laboratories in the United States and around the world. Researchers working at Bell Laboratories are credited with the development of radio astronomy, the transistor, the laser, the photovoltaic cell, the charge-coupled device (CCD), information theory, the Unix operating system, and the programming languages B, C, C++, S, SNOBOL, AWK, AMPL, and others. Nine Nobel Prizes have been awarded for work completed at Bell Laboratories. Bell Labs had its origin in the complex corporate organization of the Bell System telephone conglomerate. In the late 19th century, the laboratory began as the Western Electric Engineering Department, l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speech Synthesis
Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware products. A text-to-speech (TTS) system converts normal language text into speech; other systems render symbolic linguistic representations like phonetic transcriptions into speech. The reverse process is speech recognition. Synthesized speech can be created by concatenating pieces of recorded speech that are stored in a database. Systems differ in the size of the stored speech units; a system that stores phones or diphones provides the largest output range, but may lack clarity. For specific usage domains, the storage of entire words or sentences allows for high-quality output. Alternatively, a synthesizer can incorporate a model of the vocal tract and other human voice characteristics to create a completely "synthetic" voice output. The quality of a speech synthesizer is judged by its similarity to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homer Dudley
Homer W. Dudley (14 November 1896– 18 September 1980) was a pioneering electronic and acoustic engineer who created the first electronic voice synthesizer for Bell Labs in the 1930s and led the development of a method of sending secure voice transmissions during World War Two. His awards include the Franklin Institute's Stuart Ballantine Medal (1965). Early life Born in Virginia, Dudley's family moved to Pennsylvania when he was a schoolboy. His father was a preacher, and his parents also gave lessons to students, in classical and religious subjects. Dudley trained to be a grade school and high school teacher. He found it difficult to keep discipline in the classroom and soon gave up teaching. Intending a change in career, he enrolled in Pennsylvania State University, where he developed an interest in the nascent science of electronic engineering. After taking some college courses in electronic engineering, Dudley found employment with Bell Laboratories, which was at that ti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vocoder
A vocoder (, a portmanteau of ''voice'' and ''encoder'') is a category of speech coding that analyzes and synthesizes the human voice signal for audio data compression, multiplexing, voice encryption or voice transformation. The vocoder was invented in 1938 by Homer Dudley at Bell Labs as a means of synthesizing human speech. This work was developed into the channel vocoder which was used as a voice codec for telecommunications for speech coding to conserve bandwidth in transmission. By encrypting the control signals, voice transmission can be secured against interception. Its primary use in this fashion is for secure radio communication. The advantage of this method of encryption is that none of the original signal is sent, only envelopes of the bandpass filters. The receiving unit needs to be set up in the same filter configuration to re-synthesize a version of the original signal spectrum. The vocoder has also been used extensively as an electronic musical instrument. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vocal Tract
The vocal tract is the cavity in human bodies and in animals where the sound produced at the sound source (larynx in mammals; syrinx (biology), syrinx in birds) is filtered. In birds it consists of the Vertebrate trachea, trachea, the Syrinx (biology), syrinx, the oral cavity, the upper part of the esophagus, and the beak. In mammals it consists of the laryngeal cavity, the pharynx, the oral cavity, and the nasal cavity. The estimated average length of the vocal tract in adult male humans is 16.9 cm and 14.1 cm in adult females. See also *Language *Talking birds – species of birds capable of imitating human sounds, but without known comprehension *Speech organ *Speech synthesis *Manner of articulation References {{Reflist Human head and neck Human voice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relaxation Oscillator
In electronics a relaxation oscillator is a nonlinear electronic oscillator circuit that produces a nonsinusoidal repetitive output signal, such as a triangle wave or square wave. on Peter Millet'Tubebookswebsite The circuit consists of a feedback loop containing a switching device such as a transistor, comparator, relay, op amp, or a negative resistance device like a tunnel diode, that repetitively charges a capacitor or inductor through a resistance until it reaches a threshold level, then discharges it again. The period of the oscillator depends on the time constant of the capacitor or inductor circuit. The active device switches abruptly between charging and discharging modes, and thus produces a discontinuously changing repetitive waveform. This contrasts with the other type of electronic oscillator, the harmonic or linear oscillator, which uses an amplifier with feedback to excite resonant oscillations in a resonator, producing a sine wave. Relaxation oscillators are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fricative Consonant
A fricative is a consonant produced by forcing air through a narrow channel made by placing two articulators close together. These may be the lower lip against the upper teeth, in the case of ; the back of the tongue against the soft palate in the case of German (the final consonant of ''Bach''); or the side of the tongue against the molars, in the case of Welsh (appearing twice in the name ''Llanelli''). This turbulent airflow is called frication. A particular subset of fricatives are the sibilants. When forming a sibilant, one still is forcing air through a narrow channel, but in addition, the tongue is curled lengthwise to direct the air over the edge of the teeth. English , , , and are examples of sibilants. The usage of two other terms is less standardized: "Spirant" is an older term for fricatives used by some American and European phoneticians and phonologists. "Strident" could mean just "sibilant", but some authors include also labiodental and uvular fricatives in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Band-pass Filter
A band-pass filter or bandpass filter (BPF) is a device that passes frequencies within a certain range and rejects (attenuates) frequencies outside that range. Description In electronics and signal processing, a filter is usually a two-port circuit or device which removes frequency components of a signal (an alternating voltage or current). A band-pass filter allows through components in a specified band of frequencies, called its ''passband'' but blocks components with frequencies above or below this band. This contrasts with a high-pass filter, which allows through components with frequencies above a specific frequency, and a low-pass filter, which allows through components with frequencies below a specific frequency. In digital signal processing, in which signals represented by digital numbers are processed by computer programs, a band-pass filter is a computer algorithm that performs the same function. The term band-pass filter is also used for optical filters, sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plosive
In phonetics, a plosive, also known as an occlusive or simply a stop, is a pulmonic consonant in which the vocal tract is blocked so that all airflow ceases. The occlusion may be made with the tongue tip or blade (, ), tongue body (, ), lips (, ), or glottis (). Plosives contrast with nasals, where the vocal tract is blocked but airflow continues through the nose, as in and , and with fricatives, where partial occlusion impedes but does not block airflow in the vocal tract. Terminology The terms ''stop, occlusive,'' and ''plosive'' are often used interchangeably. Linguists who distinguish them may not agree on the distinction being made. The terms refer to different features of the consonant. "Stop" refers to the airflow that is stopped. "Occlusive" refers to the articulation, which occludes (blocks) the vocal tract. "Plosive" refers to the release burst (plosion) of the consonant. Some object to the use of "plosive" for inaudibly released stops, which may then instead be ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Affricate Consonant
An affricate is a consonant that begins as a stop and releases as a fricative, generally with the same place of articulation (most often coronal). It is often difficult to decide if a stop and fricative form a single phoneme or a consonant pair. English has two affricate phonemes, and , often spelled ''ch'' and ''j'', respectively. Examples The English sounds spelled "ch" and "j" ( broadly transcribed as and in the IPA), German and Italian ''z'' and Italian ''z'' are typical affricates, and sounds like these are fairly common in the world's languages, as are other affricates with similar sounds, such as those in Polish and Chinese. However, voiced affricates other than are relatively uncommon. For several places of articulation they are not attested at all. Much less common are labiodental affricates, such as in German and Izi, or velar affricates, such as in Tswana (written ''kg'') or in High Alemannic Swiss German dialects. Worldwide, relatively few languages have af ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1939 New York World's Fair
The 1939–40 New York World's Fair was a world's fair held at Flushing Meadows–Corona Park in Queens, New York, United States. It was the second-most expensive American world's fair of all time, exceeded only by St. Louis's Louisiana Purchase Exposition of 1904. Many countries around the world participated in it, and over 44 million people attended its exhibits in two seasons. It was the first exposition to be based on the future, with an opening slogan of "Dawn of a New Day", and it allowed all visitors to take a look at "the world of tomorrow". When World War II began four months into the 1939 World's Fair, many exhibits were affected, especially those on display in the pavilions of countries under Axis occupation. After the close of the fair in 1940, many exhibits were demolished or removed, though some buildings were retained for the 1964–1965 New York World's Fair, held at the same site. Planning In 1935, at the height of the Great Depression, a group of New Yo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Golden Gate International Exposition
The Golden Gate International Exposition (GGIE) (1939 and 1940), held at San Francisco's Treasure Island, was a World's Fair celebrating, among other things, the city's two newly built bridges. The San Francisco–Oakland Bay Bridge opened in 1936 and the Golden Gate Bridge in 1937. The exposition opened from February 18, 1939, through October 29, 1939, and from May 25, 1940, through September 29, 1940. History The idea to hold a World's Fair to commemorate the completion of the Bay Bridge and Golden Gate Bridge started from a letter to '' The San Francisco News'' in February 1933. Architects W.P. Day and George Kelham were assigned to consider the merits of potential sites around the city, including Golden Gate Park, China Basin, Candle Stick Point, and Lake Merced. By 1934, the choice of sites had been narrowed to the areas adjoining the two bridges: either "an island built up from shallow water" north of Yerba Buena Island which would go on to be named Treasure Island, or the P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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