Phonovision
Encyclopedia
Phonovision is a proof of concept
format and experiment for recording a mechanical television
signal on phonograph records. The format was developed in the late 1920s in London by Scottish television pioneer John Logie Baird
. The objective was not simply to record video, but to record it synchronously, as Baird intended playback from an inexpensive playback device, which he called a "Phonovisor".
, and the record-mastering turntable. The video signal from the Nipkow disc scanner was amplified and connected to the cutting stylus of the turntable. Baird had to make a number of compromises to get the process to work, among them using a picture rate of only 4 frames per second. Unlike Baird's other experiments (including stereoscopy, colour and infra-red night-vision), there is no evidence of a public demonstration of playback of pictures. The results were considered a failure at the time, and Baird moved on leaving behind several discs in the hands of museums and favoured company members.
Despite its technical problems, Phonovision remains the very earliest means ever invented of recording a television signal. In a sense, it can be seen as the progenitor of other disc-based systems, such as the European TelDec
system of the early 1970s and RCA's capacitance-based discs, known as SelectaVision
.
An equivalent system was marketed by Cairns and Morrison Ltd of London under the name Silvatone from 1930, with at least one early recording of transmitted television still in existence from April 1933.
The earliest surviving Phonovision disc depicts one of the "Stooky Bill
" dummy heads which Baird employed for tests, and was recorded on September 20, 1927. The earliest recording of a human face is of Wally Fowlkes, and was made on January 10, 1928. On March 28, 1928, a recording of "Miss Pounsford" was made which is, in many ways, the best of the experimental discs. In the 1990s, her relatives identified Mabel Pounsford as the early TV star.
From 1982, Scottish image processing expert Donald F. McLean developed software to capture and restore the video recorded on the Phonovision discs. Analysis of the recordings by McLean revealed that serious problems had occurred during the making of the recordings, due mostly to the mechanical linkage that was necessary to allow simple playback. The problems were largely corrected by software, and the resultant images give us a far better image quality than what would have been seen in Baird's laboratories at the time.
Proof of concept
A proof of concept or a proof of principle is a realization of a certain method or idea to demonstrate its feasibility, or a demonstration in principle, whose purpose is to verify that some concept or theory that has the potential of being used...
format and experiment for recording a mechanical television
Mechanical television
Mechanical television was a broadcast television system that used mechanical or electromechanical devices to capture and display video images. However, the images themselves were usually transmitted electronically and via radio waves...
signal on phonograph records. The format was developed in the late 1920s in London by Scottish television pioneer John Logie Baird
John Logie Baird
John Logie Baird FRSE was a Scottish engineer and inventor of the world's first practical, publicly demonstrated television system, and also the world's first fully electronic colour television tube...
. The objective was not simply to record video, but to record it synchronously, as Baird intended playback from an inexpensive playback device, which he called a "Phonovisor".
Technical information
The process involved mechanically linking the television scanning mechanism, a Nipkow diskNipkow disk
A Nipkow disk , also known as scanning disk, is a mechanical, geometrically operating image scanning device, invented by Paul Gottlieb Nipkow...
, and the record-mastering turntable. The video signal from the Nipkow disc scanner was amplified and connected to the cutting stylus of the turntable. Baird had to make a number of compromises to get the process to work, among them using a picture rate of only 4 frames per second. Unlike Baird's other experiments (including stereoscopy, colour and infra-red night-vision), there is no evidence of a public demonstration of playback of pictures. The results were considered a failure at the time, and Baird moved on leaving behind several discs in the hands of museums and favoured company members.
Despite its technical problems, Phonovision remains the very earliest means ever invented of recording a television signal. In a sense, it can be seen as the progenitor of other disc-based systems, such as the European TelDec
Television Electronic Disc
Television Electronic Disc is a discontinued video recording format, released in 1975 by Telefunken and Teldec. The format used flexible foil discs, which spun at 1,500 rpm on a cushion of air...
system of the early 1970s and RCA's capacitance-based discs, known as SelectaVision
SelectaVision
The Capacitance Electronic Disc was an analog video video disc playback system developed by RCA, in which video and audio could be played back on a TV set using a special needle and high-density groove system similar to phonograph records....
.
History
The earliest surviving Phonovision disc depicts one of the "Stooky Bill
Stooky Bill
Stooky Bill was the name given to the head of a ventriloquist dummy that John Logie Baird used in his early experiments to transmit a televised image between rooms in his laboratory at 22 Frith Street, London....
" dummy heads which Baird employed for tests, and was recorded on September 20, 1927. The earliest recording of a human face is of Wally Fowlkes, and was made on January 10, 1928. On March 28, 1928, a recording of "Miss Pounsford" was made which is, in many ways, the best of the experimental discs. In the 1990s, her relatives identified Mabel Pounsford as the early TV star.
From 1982, Scottish image processing expert Donald F. McLean developed software to capture and restore the video recorded on the Phonovision discs. Analysis of the recordings by McLean revealed that serious problems had occurred during the making of the recordings, due mostly to the mechanical linkage that was necessary to allow simple playback. The problems were largely corrected by software, and the resultant images give us a far better image quality than what would have been seen in Baird's laboratories at the time.