CHAPTER ONE
INTRODUCTION
1.1 Background of the Study
Unlike many other inventions throughout history, the history of the television credits many inventors instead of just one. In this case, there were many inventors working on the idea of watching pictures on the screen.
The earliest proposal was in 1908, in a paper by A.A Campbell-Swinton which postulated the use of Cathode rays. The First Practical demonstrations of television, however, were developed using electromechanical methods to scan, transmit, and reproduce image. As electronic camera and display tubes were perfected, electromechanical television gave way to all-electronic systems in nearly all applications.
The beginnings of mechanical television can be traced back to the discovery of the photoconductivity of the element selenium by Willoughby by Smith in 1873, the invention of a scanning disk by Paul Gottlieb Nipkow in 1884 and John Logie Baird’s demonstration of televised moving Images in 1926. (Wikipedia, 2010).
A 23 year old German University student, Paul Nipkow proposed and patented the first electromechanical television system in 1884. Although he never built a working model of the system, variations of Nipkow’s spinning – disk “image rasterizer” for television became exceedingly common, and remained in use until 1939. Constantin Perskyi coined the word television in a paper read to the International Electricity Congress at the international world fair in Paris on August 25, 1900. Perskyi’s paper reviewed the existing electromechanical technologies, mentioning the work of Nipkow and others.
However, it was not until 1907 that developments in amplification tube technology, by Lee Deforest and Arthur Kom among others, made the design practical. The first demonstration of the instantaneous transmission of still Sillhoutte images was by Georges Rigrioux and as a Fournier in Paris in 1909, using a rotating mirror – drum as the scanner and a matrix of 64 selenium cells as the receiver.
In 1911, Boris Rosing and his student Vladimir Zworykin created a television system that used a mechanical mirror – drum scanner to transmit, in Zworykin’s words, “very crude images” over wires to the “Braun Tube” (Cathode ray tube or “CRT”) in the receiver. Moving images were not possible because, in the scanner, “the sensitivity was not enough and the selenium cell was very laggy”. On March 25, 1925, Scottish Inventor John Logie Baird gave the first public demonstration of televised silhouette images in motion, at Selfridge’s Department store in London. AT & T’s bell Telephone laboratories transmitted halftone still images of transparencies in May 1925. On June 13 of that year, Charles Frances Jenkins transmitted the silhouette image of a toy windmill in motion, over a distance of five miles from a naval radio station in Maryland to his laboratory in Washington, using a lensed disk scanner with a 48-line resolution.
However, if Television is defined as the live transmission of moving images with continuous tonal variation, Baird first achieved this privately on October 2, 1925. But strictly speaking Baird had not yet achieved moving images on October 2. His scanner worked at only five images, per second, below the threshold required to give the illusion of motion usually defined as at least 12 images per second. By January, he had improved the scan rate to 12.5 images per second.
Television Broadcasting in Nigeria started with the initiative of the first Western Region premier Chief Obafemi Awolowo who on October 31, 1959 launched television broadcasting at Ibadan the head quarters of the region. The Western Region went into partnership with the Overseas Rediffusion Limited. The Western Nigerian Radiovision services limited were created with the responsibility of radio and television broadcasting under one management.