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Chapter 3 Data Transmission

Chapter 3 Data Transmission. KONSEP DAN TERMINOLOGI. TERMINOLOGI TRANSMISI. Transmitter Receiver Medium Guided medium  kabel Contoh , kabel koaksial , twisted pair , serat optik Unguided medium  nirkabel Contoh , udara , ruang hampa udara dan air. Con’t. Direct link

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Chapter 3 Data Transmission

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  1. Chapter 3Data Transmission

  2. KONSEP DAN TERMINOLOGI

  3. TERMINOLOGI TRANSMISI • Transmitter • Receiver • Medium • Guided medium  kabel • Contoh, kabelkoaksial, twisted pair, seratoptik • Unguided medium  nirkabel • Contoh, udara, ruanghampaudaradan air

  4. Con’t • Direct link • Tidakadaalatperantara / langsung • Point-to-point • Direct link • Hanya 2 device yang berbagi link • Multi-point • Lebihdaridua device yang berbagi link

  5. Con’t • Simplex • Sinyalditransmisikansatuarah Televisi • Half duplex • Sinyalditransmisikanduaarah, tapihanyasatutransmisispadasatuwaktu, contoh police radio • Full duplex • Sinyalditransmisikanduaarah, dandapatdilakukanpadasatuwaktusecarabersamaan, contoh telephone

  6. Frequency, Spectrum and Bandwidth • Transmisi pengirimansinyal • Sinyal fungsiwaktu / frekwensi • Konsep domain waktu • Sinyal Analog • Tidakadasinyal yang terputus. • percakapan • Sinyal Digital • Mempertahankan level konstanpadabeberapawaktu, danberubahke level konstanlainnya. • Biner 1 dan 0 • SinyalPeriodik • Polasinyal yang samaberulangsepanjangwaktu • SinyalAperiodic • Polasinyaltidakberulangspeanjangwaktu

  7. Analogue & Digital Signals

  8. PeriodicSignals

  9. Gelombang Sinus Tiga Parameter • Peak Amplitude (A)  amplitudotertinggi • maximum strength of signal • volts • Frequency (f) • Rate of change of signal • Hertz (Hz) or cycles per second • Period = time for one repetition (T) • T = 1/f • Phase () • Relative position in time

  10. Varying Sine Wavess(t) = A sin(2ft +)

  11. Wavelength • Jaraksatusiklustunggal • Jarakantaraduatitikdarifase yang bersesuaiandariduaputaran yang berurutan. • Simbol  • Diasumsikan, sinyalbergerakdengankecepatanv, makahubunganpajanggelombangdenganperiodeadalah: •  = vT • f = v • Untukkasus v =c, makakecepatancahayadalamruangbebas= 3*108 ms-1

  12. Frequency Domain Concepts • Sinyaldibentukdaribanyakfrekuensi • Komponennyaadalahgelombang sinus

  13. Addition of FrequencyComponents(T=1/f) Gel. Sinus, frekuensi f Gel. Sinus, frekuensi 3f Gabungan a dan b

  14. Spectrum & Bandwidth • Spectrum • Rentangfrekuensidimanaspektrumberada • Absolute bandwidth • Lebar spectrum • Effective bandwidth • bandwidth • DC Component • Komponenfrekeunsinol = arud DC

  15. Signal with DC Component

  16. Analog and Digital Data Transmission • Data • Entitas yang menyampaikaninformasi • Signals • Representase data electric atau electromagnetic • Transmission • Komunikasi data melaluiperambatandanpemrosesansinyal

  17. Analog and Digital Data • Analog • Menerimanilai yang kontiyupadabeberapa interval • Contoh, suara, video, suhu, tekanan. • Digital • Menerimanilaidiskrit • Contohteks, bilanganbulat, dll

  18. Data analog • Contoh AUDIO

  19. Analog and Digital Signals • Dalamkomunikasi, data disebarkan • Analog • Gelombangelektromagnetik yang selalubervariasi • media • wire, fiber optic, space • Speech bandwidth 100Hz to 7kHz • Telephone bandwidth 300Hz to 3400Hz • Video bandwidth 4MHz • Digital • Use two DC components • Bit 0 & bit 1

  20. Advantages & Disadvantages of Digital • Lebihmurah • Tidakrentandengan noise • Memilikiatenuasilebihbesar • Kekurangandarikekuatansinyal atenuasi • Pulsamembulatdanmenjadilebihkecil • Menyebabkankehilanganinformasi

  21. Attenuation of Digital Signals

  22. Components of Speech • Frequency range (of hearing) 20Hz-20kHz • Speech 100Hz-7kHz • Lebihmudahdikonversimenjadisinyal electromagnetic untuktransmisi • Frekuensisuaradenganberagam volume dikonversimenjadifrekuensi electromagnetic denganberagamteganganlistrik • Batas rata-rata frekuensiuntuk voice channel • 300-3400Hz

  23. Conversion of Voice Input into Analog Signal

  24. Video Components • USA - 483 lines scanned per frame at 30 frames per second • 525 lines but 42 lost during vertical retrace • So 525 lines x 30 scans = 15750 lines per second • 63.5s per line • 11s for retrace, so 52.5 s per video line • Max frequency if line alternates black and white • Horizontal resolution is about 450 lines giving 225 cycles of wave in 52.5 s • Max frequency of 4.2MHz

  25. Binary Digital Data • Dari terminal komputer, dll • Two dc components  bit 0 dan 1 • Bandwidth depends on data rate

  26. Conversion of PC Input to Digital Signal

  27. Data and Signals • Penggunaansinyal digital untuk data dgitaldansinyal analog untuk data adanalog • Menggunakansinyal analog untukmembawa data digital Modem • Menggunakansinyal digital untukmembawa data analogcompact disc audio

  28. Analog Signals Carrying Analog and Digital Data

  29. Digital Signals Carrying Analog and Digital Data

  30. Analog Transmission • Sinyal analog ditransmisikantanpamempedulikanisinya • Isi ==. Data analog atau data digital • Sinyal analog akanlemahpadajaraktertentu • Digunakan amplifiers untukmenaikkan signal • Dengan amplifier  noise meningkat

  31. Digital Transmission • Isi biner • TransmisiJarakterbatas • Jarakjauh Repeater • Repeater menerimasinyal digital, mempeerolehkembalipola 0 dan 1 danmentransmisikankembalisinyalbaru.

  32. Advantages of Digital Transmission • Digital technology • Low cost LSI (large scale integration)/VLSI technology • Data integrity • Transmisijarakjauh kualitaslebihrendah  repeater bukan amplifier • Capacity utilization • Lebihekonomis bandwith yang tinggi • High degree of multiplexing easier with digital techniques • Security & Privacy • Encryption • Integration • Can treat analog and digital data similarly

  33. Gangguantransmisi • Sinyalditerimaberbedadengansinyal yang dikirim • Analog  menurunkankualitassinyal • Digital - bit errors • Disebbkanoleh • Attenuation and attenuation distortion • Delay distortion • Noise

  34. Attenuation • Kekuatansinyalberkurang jarakjauh • Attenuation  pertimbanganuntuk transmission engineer. • Sinyal yang diterimaharuscukupkuatsehinggasirkuitelektronikdapatmendeteksisinyaltersebut • Sinyalharusdijagapada level yang cukuptinggidibandingkan noise sehinggadapatditerimatanpa error • Atenuasibervariasisesuaidenganfrekuensi • Solusi repeater  digital amplifier  analog

  35. Delay Distortion • attenuation bervariasisepertifungsidarifrekuensi • Sinyal yang diterimamengalamidistorsi /menyimpanh • Solusi • Menyamakan attenuation melintasi band frequencies. • Umum voice-grade telephone lines menggunakan coils yang menggantipropertielekrtikaldari line • amplifiers  frekuensilebihtinggidibandinkanfrekuensiterendah

  36. Noise (1) • Additional signals inserted between transmitter and receiver • Thermal • Pergelokanthermal dari electrons • Uniformly distributed • White noise • Intermodulation • Sinyal-sinyal yang bertambahdanberbedadarifrekuensiasli Signals that are the sum and difference of original frequencies sharing a medium

  37. Noise (2) • Crosstalk • A signal from one line is picked up by another • Impulse • Irregular pulses • e.g. External electromagnetic interference • Short duration • High amplitude

  38. Channel Capacity • Data rate • In bits per second • Rate at which data can be communicated • Bandwidth • In cycles per second of Hertz • Constrained by transmitter and medium

  39. Nyquist Bandwidth • If rate of signal transmission is 2B then signal with frequencies no greater than B is sufficient to carry signal rate • Given bandwidth B, highest signal rate is 2B • Given binary signal, data rate supported by B Hz is 2B bps • Can be increased by using M signal levels • C= 2B log2M

  40. Shannon Capacity Formula • Consider data rate,noise and error rate • Faster data rate shortens each bit so burst of noise affects more bits • At given noise level, high data rate means higher error rate • Signal to noise ration (in decibels) • SNRdb=10 log10 (signal/noise) • Capacity C=B log2(1+SNR) • This is error free capacity

  41. Required Reading • Stallings chapter 3

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