Скачать презентацию l 1 From its very beginning radio fully
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Скачать презентацию l 1 From its very beginning radio fully
Скачать презентацию l 1 From its very beginning radio fully
l 1. From its very beginning radio fully benefited from" Servant Sciences". Radio always managed to meet the challenges of new technologies, and exploit them fully. Today the question is again: "Will it manage to meet the challenge of going digital as well as Digital Terrestrial Television does? l 2. The idea of the physical reality remained intimately connected to a purely mechanist representation of all phenomena. One always looked at it only as the movement of inert bodies. One even never imagined there could be other ways of considering things. Then arrived the great revolution to which Faraday, Maxwell and Hertz have attached their names forever. (Albert Einstein) 3. Ampère, the French scientist, was first in 1820 to reveal that an electric current actually creates a magnetic field and was not transforming the connecting wire into a magnet. A solid Electrodynamics Theory was born. l 4. Faraday, another genius, and a self-taught one, explained that "electrical forces can subsist in space even if cut off from their source". Electromagnetism Theory was thus firmly established around the intuitive concept of "lines of forces", a concept that Maxwell will adopt and exploit
l 5. So, appeared on the firmament of modern science the Great John Clerk Maxwell, a Scot like Faraday, a giant physicist and mathematician who wrapped all that in his "Wonderful for ever valid Equations" l Maxwell certainly is equal to both Newton before him and Einstein after him. He predicted that light was an electromagnetic affair and that other but invisible radiation should exist which propagates freely in space. This is the fundamental principle underpinning all modern electronic media, including, of course, the great ancestor, radio. l 6. It belonged to the German physicist Heinrich Hertz, seventy years after Ampère's theory, to double check by experiments Maxwell's Theory, so revealing what is now known after him: the Hertzian Waves. One further merit of Hertz was to convince the scientific milieu of the soundness of the Maxwellian theory, which some still doubted. But, when asked what physical application could be made of his discovery, Hertz answered: "It's of no use whatsoever. This is just an experiment that proves Maestro Maxwell was right. " l "100 Essential Scientists", Jon Balchni Enchanted Lions Books, N. Y. 2005 l 7. Time was ripe for wireless to come to fruition. A host of engineers, inventors and governments develop these practical applications, civilian and military-so well missed before by pure scientists. When asking who invented wireless, the answer depends on the nationality of the respondents: for the UK, this is for sure Lodge, for Russia, Popov, for France Branly and for Italy, Marconi. In the case of the latter, Maurice Ponte, a French scientist and Chief Executive of Electronic firms, said: "To take credit for their action, engineers have actually to work out operational equipment"-which well applies to the Italian inventor.
l 8. Marconi, a businessman as well as a gifted inventor, was the first to convince governments and telegraph operators that a wireless industry was quite useful and operational. He had to face a strong competition from land networks. In 1901, he gained his repute with a successful transmission between Wales and Newfoundland. The King of Italy sent him compliments: "per la prima trasmesso al traverso lo spazia del nuovo al vecchio mondo". . . Marconi also pioneered radio broadcasting with his British Broadcasting Company ancestor of Auntie Beeb, the famous BBC. Everywhere, governments were quick to snatch power out of private enterprises, the new comer. But first, there were other hurdles to overcome. . l 9. The proof that wireless was something practical for business happened in 1901 at a time when there still was no idea of sound broadcasting except some exotic tentative with spark-gap transmitters or high-frequency alternators (e. g. by Reginald Fessenden, Goldschmidt and Braillard). The real start had to wait for thermo ionic valves in the wake of the discovery of electron, by JJ Thomson, and the "Audion" triode by Lee De Forest, patented in 1907, the "granddaddy of the vast progeny of electronic tubes that have come into existence since". Just a few years between those two discoveries- the particle electron and the electron tube- that opened the door to sound radio broadcasting. l 10. The First World Ware made an intensive use of wireless. In France then Captain, later general, Ferrié who had watched Marconi's tests across the Channel played a prominent role and brought about many improvements, notably to the triode electron tube. The "TM model". So much so that when peace was restored all components were available to start sound broadcasting in earnest. Much was due to private initiative. Soon at least in Europe -the new media was tightly controlled by the governments. Regulatory Authorities granted however reluctantly- licences to pioneer broadcasters. Not before the International Convention signed in 1927 in Washington, broadcasting was recognized as a legitimate operator and obtained some meagre allocation of electromagnetic spectrum. Anyhow great advances were accomplished. . . Reichsrunfunk, BBC, Paris PTT. . . Many channels invaded the world. High-power tubes helped extend coverage but till a comprehensive frequency allocation planning has been set up in the early thirties; sound radio suffered from bad interferences delivering a rather poor quality.
The Union Internationale de Radiodiffusion (UIR founded 1925) efficiently acted to clear the sky, a "Policeman of Ether" within the Intergovernmental International Telecommunications Union, the global watchdog of the electromagnetic spectrum. That UIR also played an important role in defining the social remit of sound broadcasting, well in advance of UN and UNESCO recommendations, for instance. . . 11. Technical advances never stopped. A technical, apparently minor progress but fraught with social consequences for the success of radio, appeared in the late twenties with receivers directly connected to the mains, thus freed from heavy lead acid batteries. Powerful loud speakers were not less important to make of radio a family device freed from headphones. . 12. The 1930 -40 decade conferred to sound broadcasting a global power statute with all its political implications and influence. Again during WW 2 radio was to play a major role, this time extended to civilian population submitted to a strong propaganda by all belligerents. Technically mastering short waves broadcasts proved a key factor in waging audiovisual war. Marconi has had a good vision of the short-wave potentialities. 13. In 1948 a major step forward occurred again: the invention of the transistor by Bardeen, Brattain to be improved later on, by Shockley. A fine team of scientists fully aware of the most recent advances in fundamental physics, including quantum theory. They carried out their research at the Bell Laboratories. They opened the way to the progeny of semiconductors, a prerequisite to digital radio, thus allowing cost-effective devices throughout the whole networks. 14. Meantime, back in early thirties, another epoch-making invention by Major Edwin Armstrong- -the Frequency Modulation-proved to be a major step forward in terms of quality, and better use of the frequency spectrum, i. e. operating on metric wavelengths. All the engineering talents were constantly called for to improve "spectrum efficiency'.
15. All necessary factors were then available for developing digital radio. Integrated circuits, elaborate software, completely change the radio systems abandoning conventional amplitude and/or frequency modulation. However, radio broadcasting was already intensively using digital technologies for the electro acoustics segment (Low-Frequency) of the 'chain of value", also in Direct Broadcast Satellites. (DBS) 16. "One of the advantages of digital radio content is that it occupies comparatively small amounts of capacity and can easily be delivered through a wide range of digital technologies" Digital Britain. Radio: going digital, BIS & DCMS, June 2009 17. It so happens that television was to be first in the race to a fully digitized broadcasting world. This is a strange story of "technical inversion. . . while the sound always comes first because it's easier", market forces pushed television at center-stage claiming more and more spectrum space from the regulators, while broadcasters have not been too keen on developing sound radio. . . Technically, the bit rates required for television, i. e. after "compression", is over 8 Mb/s (270 Mb/s before compression) as compared with the bit rate for sound radio, 1. 5 Mb/s But it doesn't at all mean that digital radio is that simple! For instance, in order to ensuring a high quality level, the protection against spurious signals in a sound digital channel requires a much lower level of those spurious signals than is the case for digital images. By and many physiologist phenomena in human hearing process are involved with digitized radio. By and large, if DTT has been to television what FM was to radio, what may Digital Radio be to analogue radio? It offers a defined space where radio can be master of its own destiny and have the freedom to take risks. Télévision Numérique Terrestre, Bernard Denis Laroque, Dunod 2005 / Digital Britain, Radio going digital, Barry Cox, 2009
18. People like the idea that DTT-Digital Terrestrial Television- operates through a miraculous process involving "1" and "0" so that TV images are duly "compressed "so permitting any channel to carry five or more programmes instead of a single one with analogue technology. Amusing to note, there still are some "analogical-dependent" viewers after switch-off on full DTT coverage. . . Inventing Digital Television, Martin L. Bell, The London Press, 2006 (Note)The vision of a "compressed TV image', of course is false but popular. . . The real DTT process consists (a) in eliminating redundancies in a pertinent way, and (b) resorting to software, both operations being based on highly refined " algorithms" 19. Digital Radio had to wait its turn. It still has to demonstrate how it can supplant present FM networks in a sound economy. Its best trump is likely to be the abundance of channels that comes first before enhanced quality, the latter already reaching a satisfactory level for the average listener via FM networks. Collateral advantages could also be found in entirely new services such as fixed or slow motion image, sophisticated traffic information. 20. Two major points are most favourable: no problem of frequency allocations as the Band III will be freed with analogue FM networks switch -over on digital networks. Managing the spectrum is quite manageable as forecast by experts. Second point: Digital Radio can and will ensure complete coverage of the territory. Regulatory Authorities should prove a fair degree of flexibility in granting broadcast licences. Malthus time is finished! Each and every stakeholder, broadcasters, transmitter and receiver vendors, imaginative content producers, spectrum and standard planners, regulators and law-makers are got to be able to cope with the massive, fundamental shifts that are going on. That requires at least a partially new mindset. Desperate Networks, Television, RTS magazine, October 2009
What future for Digital Terrestrial Sound Broadcasting? The Comité d'Histoire de la Radiodiffusion CHR - enjoys a thorough expertise in telling stories of the neverending broadcasting saga. Today, not everybody seems convinced there is a need for digitalized radio when the FM networks apparently do so pretty well their job ! However, it is interesting clearly to show constantly techno sciences, the prime mover, industrial developers, broadcasting institutions both public service and commercial channels, lawmakers and regulators have been closely inter related with each other. But André Levy-Lang could write (in La Lettre d'Illissos, N° 67) “So far, we have neglected the third factor of growth (alongside with financial and economic policy factors) all that feeds innovation, productivity, ideas and TECHNIQUES. " Radio, first of all, is a matter of programme. We'll always find where to buy transmitters and other gear. However, good advances in technology certainly help produce good and innovative programmes. René Duval President CHR"I have always preferred radio to television. Its screen is larger » . Jean Paul Sartre As well as being a flexible medium, radio appeal to the listener is that it is more than simply a stream of audio: it is an intimate, portable and ambient medium; and it is a very personal medium: the pictures that it forms inside our heads are different for every listener (. . . ) Whatever the convergence of broadcasting, telecoms and the Internet, Sound Radio will keep a platform of its own where it can be master of its own destiny and have the freedom to take risks. Digital Britain, Radio: going digital, Barry Cox As concluding remarks and forecast: Sound broadcasting will stay in its unassailable position. As compared with its media companions, radio needs no special regulation to prevent harmful content or to protect minors. . . as television and the Internet cruelly need. SOUND RADIO BROADCASTING, A Short History of a Long Journey. Pierre Braillard, Délégué Général - International Institute of Communications, Comité d'Histoire de la Radiodiffusion (CHR), a presentation at GRER (Groupe de Recherches et d'Etudes sur la Radio) Seminar 26, 27 28 November 2009 held at Sorbonne University and INA.
Скачать презентацию l 1 From its very beginning radio fully
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