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Ea01. Rádiószolgálatok - FNFT A rádió összeköttetések és vezetékes összeköttetések összehasonlítása Rádiórendszerek típusai. Critical Attributes of Telecommunications Systems. • Speed – Ability to transmit information in real-time – Electronic transmission: faster than transportation

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Ea01

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  1. Ea01 Rádiószolgálatok - FNFT A rádió összeköttetések és vezetékes összeköttetések összehasonlítása Rádiórendszerek típusai

  2. Critical Attributes ofTelecommunications Systems • Speed – Ability to transmit information in real-time – Electronic transmission: faster than transportation • Coverage – Beyond regional: national and international in scale • Cost – 1866: 20 word telegram cost $100 (4 months wages) • Security – Transmitted information as knowledge, news, secrets – Always an element of government oversight and control

  3. ie. 2. század - Polybios Oszlopszám: 2 Sorszám: 5 • Fáklyatávíró • nappal max. 1 km • 8 betű/min • 24 betű  ld(24)=4.59 bit • 4.59*8=36,7 bit/min = • 0.61 bit/sec

  4. Claude Chappe (1793) 1852-ben már 4800 km hálózat 12-25km ismétlőállomás távolság 500km/h adattovábbítási seb. 92szimbólum Betűk, vezérlő szimbólumok, kódtábla azonosítók 2-3 szimb./min 6 szimb./min Párizs - Lille : 2 min

  5. Lord George MURRAY (1795) 6 bites kódszavak  64 szimbólum Betűk, vezérlő szimbólumok 6 szimb./min London - Plymouth : 17 min 50 szimbólum  25 min 20 s 0.2 bit/sec

  6. Forráskódolás "H.M.S. ROYAL SOVEREIGN ANCHORED AT SPITHEAD YESTERDAY SAILING FOR PLYMOUTH TOMORROW" (70 Zeichen) "RSOV ANCHOR SPITD YESDA SAIL PLYTH TMRO" (33 Zeichen).

  7. Origins • 1793, Revolutionary France – Aerial Telegraph, invented by Claude Chappe – Extensive network throughout France • 1840s, Samuel F. B. Morse – Coded transmission via electronic means – Rapidly spread throughout US and Europe – International Telegraph Union (ITU) formed in 1865

  8. Submarine Telegraphy: HighTech of the late 19th Century • 1850: Dover-to-Calais, first submarine line • 1858: First transatlantic cable – Breaks after 3 months! – President Buchanan & Queen Victoria exchange telegrams • 1866: Relaid with higher quality cable – Development of cable materials, technology of laying, repair • Typical “Performance”: – 1870: London to Bombay in 4 minutes, 22 seconds – 1901: London to British Guiana, 22 minutes – 1924: Telegram around the world in 80 seconds!

  9. Radio Telegraphy(also know as “Wireless”) • Radio technology – Communicate with ships and other moving vehicles – Messages sprayed into the “ether” crossing natl boundaries – Downfall of the nationally supported monopolistic telegraphCompanies • 1896: Guglielmo Marconi – First demonstration of wireless telegraphy – Built on work of Maxwell and Hertz to send and receive Morse Code – Based on long wave (>> 1 km), spark transmitter technology, requiring very large, high power transmitters – First used by British Army and Navy in the Boer War – 1899: Reported to shore America’s Cup yacht races

  10. Wireless • 1907: Commercial Trans-Atlantic Wireless Service – Huge ground stations: 30 x 100m antenna masts – Beginning of the end for cable-based telegraphy • WW I: Rapid development of communications intelligence, intercept technology, cryptography • 1920: Marconi discovers shortwave (<100 m) radio – Longwave follow contour of land » Very high transmit power, 200 KW+ – Shortwaves reflect, refract, and absorb, like light » Bounce off ionosphere » Higher frequencies made possible by vacuum tube (1906) » Cheaper, smaller, better quality transmitters

  11. Other Important Dates • 1915: Wireless voice transmission NY to SF • 1920: First commercial radio broadcast (Pittsburgh) • 1921: Police car dispatch radios, Detroit • 1935: First telephone call around the world • WW II: Rapid development of radio technology • 1974: FCC allocates 40 MHz for cellular telephony • 1982: European GSM and Inmarsat established • 1984: Breakup of AT&T • 1984: Initial deployment of AMPS cellular system

  12. Rádiószolgálatok (WARC = World Administrative Radio Conference). 1977-ben WARC-77 műholdas TV műsorszóró szolgálatok bevezetésére teremtették meg a feltételeket 1992-ben WARC-92 személyi rádió frekvencia sávjának kijelölése

  13. Rádiószolgálatok a.) Műsorszóró szolgálatok (Broadcast Services) b.) Állandóhelyű szolgálatok (Fixed Services) c.) Mozgó szolgálatok (Mobile Services) d.) Műholdas szolgálatok ( Satellite Services) e.) Hiteles frekvencia és órajel szolgálatok (Standard Frequency and Time Signals Services) f.) Rádiónavigációs szolgálatok (Radio Navigation Services) g.) Rádiólokációs szolgálatok (Radio Location Services) h.) Rádiócsillagászati szolgálatok (Radio Astronomy Services) i.) Amatőr szolgálatok (Amateur Services) j.) Ipari, tudományos és orvosi szolgálatok (ISM = Industrial, Scientific and Medical Services).

  14. Spectrum management

  15. 10-10.7 GHz band allocation

  16. FNFT – Frequency allocation table

  17. Wireless Communication • Tied to electromagnetic radio transmission radio transmission terrestrial orbital (satellite) point-to-point broadcast radio equatorial orbit non-equatorial orbit cellular non-cellular Principles: – Propagation and reception of electromagnetic waves – Modulation methods and their properties – Multiplex methods

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