1. 9

2. 9.1 . 9.1.1 . 9.1.2 . 9.1.3 . 9.2 . 9.2.1 ASK OOK. 9.2.2 FSK . 9.2.3 PSK. 9.3 TELETEXT . 9.4 16:9 . 9.5 . 9.6 . 3. 9.1 .9.1.1 . , . . .12/28/2012 3 1708 4. 9.1 .9.1.1 . .. . . bits 0,1 .(NRZ Non Return Zero)12/28/2012 4 1708 5. 9.1 .9.1.1 . , , , (bits). . . . .. ASCII .12/28/2012 5 1708 6. 9.1 .9.1.1 . . , , . . (, start, stop). 12/28/2012 7 1708 7. 9.1 .9.1.1 . (decision content) D. 0 1 (bits/). D=log2 K . .. =2 D=1 bit. 1 012/28/2012 8 1708 8. 9.1 .9.1.1 . , : . D bits . . (, , )12/28/2012 9 1708 9. 9.1 .9.1.1 . : , .(, , ) bit, (binary) bit . (,, )12/28/2012 10 1708 10. 9.1.2 . () (), . .12/28/2012 11 1708 11. 9.1.2 . . (t) . 12. 9.1.2 . (t) : f>=2*Fmax fmax s(t). s(t) . .. fmax=3400 Hz f=7000 Hz. Sampling rate, Nyquist frequency and aliasing 12/28/2012 13 1708 13. 9.1.2 . () : RS=R=f=2*Fmax ( V). D bits. PCM (Pulse CodeModulation), .Introduction What isto Pulse Code PCMModulation12/28/2012 14 1708 14. 9.1.2 . (RS SymbolRate) bits bits . ( bits : Bit Rate). R=Rs*D bits/sec12/28/2012 15 1708 15. 9.1.2 . . 30 dB, 1000/1. 2 dB, . 12/28/2012 16 1708 16. 9.1.2 . (, V) : 2 dB. : =30 dB / 2 dB =15 .12/28/2012 17 1708 17. 9.1.2 . 12/28/2012 18 1708 18. 9.1.2 . : D=log2*K=log215=4 bits/. Bit Rate : R=7*103*4=28000 bits/sec.12/28/2012 19 1708 19. 9.1.3 . : RS (SymbolRate). Bd (Baud, / sec). TS, RS=1/TS. R (bit rate). bits/sec. : R=RS*log2*K. =2 R=RS.12/28/2012 20 1708 20. 9.1.3 . R. . RS . 12/28/2012 21 1708 21. 9.1.3 . : RS. , ( ).12/28/2012 22 1708 22. 9.1.3 . ( Niquist) : RSMAX=2*B. , . 12/28/2012 23 1708 23. 9.1.3 . 24. 9.1.3 . ( Shannon) : KMAX=(1+S/N)1/2 .12/28/2012 25 1708 25. 9.1.3 . 12/28/2012 26 1708 26. 9.1.3 . bits : DMAX=(1/2)*log2*(1+S/N). RMAX (bits/sec) : RMAX=B*log2(1+S/N). RMAX . RS=1,25*B ( =0,8RS). 12/28/2012 27 1708 27. 9.2 M(t) ( bits) () log2*K bits. .(, , ) 12/28/2012 28 1708 28. 9.2.1 ASK ASK(Amplitude Shift Keying). . =2 () OOK (On Off Keying).12/28/2012 30 1708 29. 9.2.1 ASK E(t)=a(t)*cos(*t) a(t)=0 1 DSB. . R= =2*0,8*R=1,6*R. 30. 9.2.1 ASKoriginal TTL message (lower),bandlimited message (center),and ASK (above) 31. 9.2.2 FSK FSK (Frequency Shift Keying) 0 1 . 0 : f=fo-f. 1 : f=fo+f. FSK FM. 12/28/2012 33 1708 32. 9.2.2 FSK E (t ) = Eo * COS {2 * p * fo * t + 2 * p * [a (t ) * Df ]* t } a(t)=1 -1 12/28/2012 34 1708 33. 9.2.2 FSK .Fsk-ookFsk 34. 9.2.2 FSK : =2*+2*f. B=0,8*RS. RS=R bits/sec. Carson . 35. 9.2.2 FSK VCO a(t). CPFSK (ContinuousPhase Frequency Shift Keying) f/R.12/28/2012 37 1708 36. 9.2.3 PSK PSK (Phase Shift Keying) . :E(t)= Eo*cos[ *t +fo + a(t) * 2*p / K]oa(t) {0,1,2,...K -1}12/28/2012 38 1708 37. 9.2.3 PSK BPSK (Binary Phase ShiftKeying) =2 a(t)=0 1. E(t)=+- Eo*cos*(*t). DSBsc. (fo).12/28/2012 39 1708 38. 9.2.3 PSK 39. 9.2.3 PSKPSK schemes are typicallydepicted using a constellationdiagram. The red dotrepresents a single point onthe constellation. The distanceof the red dot from thecenter of the graphrepresents the amplitude ofthe transmitted signal. Theangle between the east axis(the one directly to the right)and the line between theconstellation point and thecenter of the graphrepresents the desired phaseshift. 40. 9.2.3 PSK QPSK (Quadrature PhaseShift Keying). =4 : a2, a1 : 00,01,10,11 : E(t)=Eo*cos*(o*t+/4+a*/2). a=0,1,2,3 12/28/2012 42 1708 41. 9.2.3 PSKCos(*t+a1*)a1BPSK B /2 +(t) a2+ a1 , a2 BPSKACos(*t+a2*) 42. 9.2.3 PSK. a2 a1 00Cos(*t) Sin(*t)01Cos(*t)Sin(*t+)10 Cos(*t+)Sin(*t)11 Cos(*t+) Sin(*t+) 43. 9.2.3 PSK . . : , , .12/28/2012 45 1708 44. 9.2.3 PSK : . =R/B. R= , = . . bits/sec/Hz. PSK . (bit error rate) PSK .12/28/2012 46 1708 45. 9.2.3 PSK OOK, FSK PSK () . , , . 12/28/2012 47 1708 46. 9.3 Teletext - teletext , . , , , ,... . , . . . ( ).12/28/2012 48 1708 47. 9.3 Teletext - ASCII . 48. 9.3 Teletext - 49. 9.3 Teletext - 52 s. 360 . 3,46MHz, 5 MHz , 40 MHz. .12/28/2012 52 1708 50. 9.3 Teletext - 360 : 40 . 320 . 40 : 16 clock . 8 . 16 .12/28/2012 53 1708 51. 9.3 Teletext - ASCII 8. (7 1 ). 40 . 24. 1/25 . 50-60 (magazine). , . 12/28/2012 54 1708 52. 9.3 Teletext - . . .12/28/2012 55 1708 53. 9.3 Teletext - . . : , . . . . ... 12/28/2012 56 1708 54. 9.3 Teletext - ASCII . ASCII 128 : 33 . 10 . 52 . 33 (block graphics). . 12/28/2012 57 1708 55. 9.3 Teletext - . ROM / drivers .12/28/2012 58 1708 56. 9.3 Teletext - . . 1999 . . / . . 12/28/2012 59 1708 57. 9.3 Teletext - DVB . . : MHEG-5 Multimedia Home Platform Sky Digital (UK & Ireland) .. 12/28/2012 60 1708 58. 9.4 16:9 & , . 4:3 576 . . , .12/28/2012 61 1708 59. 9.4 16:9 & HDTV (High DefinitionTeleVision) 60. 625. . HDTV.GR12/28/2012 62 1708 60. 9.4 16:9 & NHK HI-Vision, 1125 , 16:9, 60 / sec (30 , 30 ) (20 MHz , 10 MHz ). . DBS (Direct BroadcastSatellites) MUSE (Multiple sUb-nyquist Sampling and Encoding) Nyquist .12/28/2012 63 1708 61. 9.4 16:9 & MUSE 8 MHz, 3:1( ). () .12/28/2012 64 1708 62. 9.4 16:9 & MAC (MultiplexedAnalog Components) 625, 16:9, 50 / sec PAL,SECAM. DAB TV. B-MAC D2-MAC . 12/28/2012 65 1708 63. 9.4 16:9 & PAL+ 16:9. 16:9 4:3 . 4:3 16:9 . .12/28/2012 66 1708 64. 9.4 16:9 & 2015 DVB-T, DVB-T2 . DVB DIGEA DVB project.12/28/2012 67 1708 65. 9.4 16:9 & 14 4, , . . HD 4 standard. DTV (Digital TV). DTV.gov 12/28/2012 68 1708 66. 9.5 , . , . internet. 12/28/2012 69 1708 67. 9.5 , . . : 640480 24 bit 900 kB. . : CD(stereo, 44.100 , 16 bit ) 172 kB. 30 MB. 12/28/2012 70 1708 68. 9.5 , , . , .12/28/2012 71 1708 69. 9.5 : , (Lossy data compressions) . . , (Lossless data compression) . . 70. 9.5 : JPEG, (jpeg.org , jpeg , jpeg wikipedia) . MPEG, (mpeg wikipedia , mpeg working group) . MP-3 , (mp3 wikipedia , mp3 ) . ... : RLE. Run-length encoding . LZW. LempelZivWelch . Huffman. (Huffman wikipedia , Huffman ) . ... 71. 9.5 , . , . .12/28/2012 74 1708 72. 9.5 : . . # # . # # # #. 47 , 27. 1,7:112/28/2012 75 1708 73. 9.5 , 2:1(50%). 10:1 . , . , , , , . , . 74. 9.5 JPEG. (Joint Photographic ExpertsGroup). . 10:1, . .12/28/2012 77 1708 75. 9.5 MPEG. (Motion Pictures Experts Group). JPEG () . , , . (P frames). JPEG . (Iframes).12/28/2012 78 1708 76. 9.5 , MPEG-2 (Bframes) . . (I B B P B B P.)12/28/2012 79 1708 77. 9.5 , , . . ( ).12/28/2012 80 1708 78. 9.5 MPEG , . I frames 7:1 P frames 20:1 B frames 50:1 MPEG-2 5 .(surround) 12/28/2012 81 1708 79. 9.5 MP-3 (MPEG Audio layer 3). . acousticshadowing, . . , () . 20:1 . 80. 9.6 , , . , . .12/28/2012 83 1708 81. 9.6 . . interactive television Interactive tv today.com12/28/2012 84 1708 82. 9.6 . teletext. 83. 9.6 , . , , .12/28/2012 87 1708 84. 9.6 .1. UHF, .2. (ISDN, ADSL).12/28/2012 89 1708 85. 9.6 . .12/28/2012 91 1708 86. 9.6 .. . . . . VOD (VideoOn Demand) . ... Greek Live and On-Demand onlineTelevision from Greece tvand Cyprus 87. 9.6 . . . ...Panasonicinteractive TV wall 12/28/2012 93 1708 88. 9.6 http://www.in.gr/innews/article.asp?lngEntityID=282707 VOD. Connx-x tv http://www.ert-archives.gr/V3/public/index.aspx Philips TV12/28/2012 94 1708