PENGENALAN TEKNIK TELEKOMUNIKASI Modul : 07 Transmisi Faculty of Electrical Engineering BANDUNG, 2015 PengTekTel-Modul:7

Loss, Distorsi, Noise, Interferensi BLOK SISTEM KOMUNIKASI TI Tx Rx TO Media Communication Transducer Input Transducer Output Transmitter Receiver Message Input Sinyal Input Message Output Sinyal Kirim Loss, Distorsi, Noise, Interferensi Sinyal Output Signal Terima Message : informasi seperti suara, data, gambar, video, kode Signal : bentuk listrik dari informasi Transducer : mengubah informasi menjadi sinyal listrik dan sebaliknya Salam & Greeting : Ass.Wr.Wb…Selamat pagi/siang dan Salam Sejahtera bagi kita semua Yth………. Ucapan Syukur kepada Tuhan YME dan ucapan terima kasih kepada PM yang telah berkenan menerima team Perkenalan : (jika ada Team yang berasal dari luar) PengTekTel-Modul:7

BLOK SISTEM KOMUNIKASI RADIO ANALOG PA Baseband from Multiplex Baseband Equipment Modulator Analog IF Equipment Limiter Up-Converter Waveguide Filter Local Oscillator ANTENNA Local Oscillator Salam & Greeting : Ass.Wr.Wb…Selamat pagi/siang dan Salam Sejahtera bagi kita semua Yth………. Ucapan Syukur kepada Tuhan YME dan ucapan terima kasih kepada PM yang telah berkenan menerima team Perkenalan : (jika ada Team yang berasal dari luar) Baseband Equipment Demodulator Analog IF Filter & Amplifier Down -Converter Waveguide Filter Base band to Demultiplex PengTekTel-Modul:7

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Modulasi / Demodulasi Modulasi adalah proses menumpangkan sinyal informasi kedalam gelombang pembawa Demodulasi adalah proses mengambil kembali sinyal informasi yang ditumpangkan Teknik Modulasi / Demodulasi dilakukan dengan mengubah parameter gelombang pembawa, antara lain : Amplitudo Frekwensi Phasa PengTekTel-Modul:7

PCM Sisi Kirim Sampling,Compressing, Quantizing, Coding Sisi Terima Decoding,Expanding,Low Pass Filter T CH.1 CH.n LPF Sampling Compressor Quantizing Coding Transmisi R CH.1 CH.n LPF Ch Gate Expandor Decoding PengTekTel-Modul:7

Sampling Adalah proses modulasi amplitudo yang merupakan langkah persiapan untuk merubah sinyal analog menjadi sinyal digital atau sinyal PAM Sinyal PAM Sinyal Input LPF Freq Sampling PengTekTel-Modul:7

Sinyal PAM Ter-Kuantisasi Quantizing Adalah proses awal untuk merubah sinyal PAM menjadi susunan digit, dimana sinyal hasil sampling dihargakan pada tegangan pembanding terdekat Quantisasi Uniform Quantisasi Non-Uniform Sinyal PAM Sinyal PAM Ter-Kuantisasi PengTekTel-Modul:7

Coding Pada tahapan ini semua sinyal yang sudah dikuantisasi diubah menjadi kode 8 bit S A B C W X Y Z S = Polaritas sinyal PAM ABC = Nomor Segmen dalam 0 s/d 7 (biner) WXYZ = Nomor interval 0 s/d 15 (Biner) PengTekTel-Modul:7

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Multiplexing Adalah proses penggabungan beberapa saluran atau kanal pembicaraan (VBW) menjadi satu kedalam bentuk sinyal lain, untuk disalurkan secara bersamaan tanpa saling mengganggu Jenis-jenis Multiplexer FDM (Frequency Division Multiplex) TDM (Time Division Multiplex) PengTekTel-Modul:7

Multiplexing Multiplexing is sending more than one signal on a carrier. There are two standard types of multiplexing. Frequency-Division Multiplexing (FDM): the medium carries a number of signals, which have different frequencies; the signals are carried simultaneously. Time-Division Multiplexing (TDM): different signals are transmitted over the same medium but they do so at different times – they take turns. PengTekTel-Modul:7

Multiplexing There are several data inputs and one of them is routed to the output (possibly the shared communication channel). Like selecting a television channel (although that example is FDM). In addition to data inputs, there must be select inputs. The select inputs determine which data input gets through. How many select pins are needed? Depends on number of data inputs. PengTekTel-Modul:7

Multiplexing allows one to select one of the many possible sources. Mutiplexing Multiplexing allows one to select one of the many possible sources. PengTekTel-Modul:7

Typical Application of a MUX Multiplexers & Demultiplexers Digital Electronics Lesson 2.4 – Specific Combo Circuits & Misc Topics Typical Application of a MUX Multiple Sources Selector Single Destination MP3 Player Docking Station Surround Sound System Laptop Sound Card D0 D1 D2 D3 MUX Y This slide shows a typical application of a multiplexer (in this case a 4-to-1 MUX). Have the students share other common applications of MUXs. http://images.tigerdirect.ca/skuimages/large/Logitech-X-540-L23-7250-mai.jpg Digital Satellite B A Selected Source MP3 1 Laptop Satellite Cable TV Digital Cable TV PengTekTel-Modul:7 Project Lead The Way, Inc. Copyright 2009

4-to-1 Multiplexer (MUX) Multiplexers & Demultiplexers Digital Electronics Lesson 2.4 – Specific Combo Circuits & Misc Topics 4-to-1 Multiplexer (MUX) MUX D0 D1 D2 D3 Y B A B A Y D0 1 D1 D2 D3 SSI logic diagram, block diagram, and truth table for a 4-to-1 MUX PengTekTel-Modul:7 Project Lead The Way, Inc. Copyright 2009

4-to-1 Multiplexer Waveforms Multiplexers & Demultiplexers Digital Electronics Lesson 2.4 – Specific Combo Circuits & Misc Topics 4-to-1 Multiplexer Waveforms Input Data D0 D1 D2 D3 A B Y Select Line Waveform diagram for a 4-to-1 MUX. The input data signals (D0-D3) are colored RED to indicate when its is connected to the output Y. Note: There is no significance to the values of the four input data signals; they are intended solely to demonstrate that the select lines (A & B) will select what input data signal will be connected to the output. Output Data PengTekTel-Modul:7 Project Lead The Way, Inc. Copyright 2009

Demultiplexing Demultiplexing allows one to select one of the many possible destinations. PengTekTel-Modul:7

Typical Application of a DEMUX Multiplexers & Demultiplexers Digital Electronics Lesson 2.4 – Specific Combo Circuits & Misc Topics Typical Application of a DEMUX Single Source Selector Multiple Destinations B/W Laser Printer Fax Machine D0 D1 D2 D3 X DEMUX Color Inkjet Printer This slide shows a typical application of a demultiplexer (in this case a 1-to-4 DEMUX). Ask students to share other common applications of DEMUXs. B A Selected Destination B/W Laser Printer 1 Fax Machine Color Inkjet Printer Pen Plotter Pen Plotter PengTekTel-Modul:7 Project Lead The Way, Inc. Copyright 2009

1-to-4 De-Multiplexer (DEMUX) Multiplexers & Demultiplexers Digital Electronics Lesson 2.4 – Specific Combo Circuits & Misc Topics 1-to-4 De-Multiplexer (DEMUX) D0 D1 D2 D3 X B A DEMUX B A D0 D1 D2 D3 X 1 SSI logic diagram, block diagram, and truth table for a 1-to-4 De-MUX PengTekTel-Modul:7 Project Lead The Way, Inc. Copyright 2009

1-to-4 De-Multiplexer Waveforms Multiplexers & Demultiplexers Digital Electronics Lesson 2.4 – Specific Combo Circuits & Misc Topics 1-to-4 De-Multiplexer Waveforms Input Data X S0 S1 D0 D1 D2 D3 Select Line Output Data Waveform diagrams for a 1-to-4 De-MUX. The output signals (D0-D3) are colored RED to indicate when its is connected to the input X. Note: There is no significance to the value of the input data signal; it is intended solely to demonstrate that the select lines (A & B) will determine what output signal is connected to the input. PengTekTel-Modul:7 Project Lead The Way, Inc. Copyright 2009

Multiplexing Techniques Frequency Division Multiplexing (FDM) Each signal is allocated a different frequency band Usually used with analog signals Modulation equipment is needed to move each signal to the required frequency band (channel) Multiple carriers are used, each is called sub-carrier Multiplexing equipment is needed to combine the modulated signals Time Division Multiplexing (TDM) Usually used with digital signal is carrying digital data Data from various sources are carried in repetitive frames Each frame consists of of a set of time slots Each source is assigned one or more time slots per frame Frequency division multiplexing can be used with analog signals. A number of signals are carried simultaneously on the same medium by allocating to each signal a different frequency band. FDM is possible when the useful bandwidth of the transmission medium exceeds the required bandwidth of signals to be transmitted. A number of signals can be carried simultaneously if each signal is modulated onto a different carrier frequency and the carrier frequencies are sufficiently separated that the bandwidths of the signals do not significantly overlap. A general case of FDM is shown in Stallings DCC8e Figure 8.2a. Six signal sources are fed into a multiplexer, which modulates each signal onto a different frequency (f1, …, f6). Each modulated signal requires a certain bandwidth centered on its carrier frequency, referred to as a channel. To prevent interference, the channels are separated by guard bands, which are unused portions of the spectrum. The composite signal transmitted across the medium is analog. Note, however, that the input signals may be either digital or analog. In the case of digital input, the input signals must be passed through modems to be converted to analog. In either case, each input analog signal must then be modulated to move it to the appropriate frequency band. PengTekTel-Modul:7

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FDM PengTekTel-Modul:7

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Frequency-Division Multiplexing (FDM) All signals are sent simultaneously, each assigned its own frequency Using filters all signals can be retrieved PengTekTel-Modul:7

FDM System Overview A generic depiction of an FDM system is shown in Stallings DCC8e Figure 8.4. A number of analog or digital signals [mi(t), i = 1, n] are to be multiplexed onto the same transmission medium. Modulation equipment is needed to move each signal to the required frequency band, and multiplexing equipment is needed to combine the modulated signals. Each signal mi(t) is modulated onto a carrier fi; because multiple carriers are to be used, each is referred to as a subcarrier. Any type of modulation may be used. The resulting analog, modulated signals are then summed to produce a composite baseband signal mb(t). Figure 8.4b shows the result. The spectrum of signal mi(t) is shifted to be centered on fi. For this scheme to work, fi must be chosen so that the bandwidths of the various signals do not significantly overlap. Otherwise, it will be impossible to recover the original signals. The composite signal may then be shifted as a whole to another carrier frequency by an additional modulation step. The FDM signal s(t) has a total bandwidth B = Sum Bi . This analog signal may be transmitted over a suitable medium. At the receiving end, the FDM signal is demodulated to retrieve mb(t), which is then passed through n bandpass filters, each filter centered on fi and having a bandwidth Bi, for 1 ≤ i ≤ n. In this way, the signal is again split into its component parts. Each component is then demodulated to recover the original signal. PengTekTel-Modul:7 5/28

FDM example: multiplexing of three voice signals The bandwidth of a voice signal is generally taken to be 4KHz, with an effective spectrum of 300-3400Hz Such a signal is used to AM modulate 64 KHz carrier The bandwidth of the modulated signal is 8KHz and consists of the Lower Side Band (LSB) and USB as in (b) To make efficient use of bandwidth, transmit only the LSB If three voice signals are used to modulate carriers at 64, 68 and 72 KHz, and only the LSB is taken, the resulting spectrum will be as shown in (c) Stallings DCC8e Example 8.2 illustrates a simple example of transmitting three voice signals simultaneously over a medium. As was mentioned, the bandwidth of a voice signal is generally taken to be 4 kHz, with an effective spectrum of 300 to 3400 Hz (Figure 8.5a). If such a signal is used to amplitude-modulate a 64-kHz carrier, the spectrum of Figure 8.5b results. The modulated signal has a bandwidth of 8 kHz, extending from 60 to 68 kHz. To make efficient use of bandwidth, we elect to transmit only the lower sideband. If three voice signals are used to modulate carriers at 64, 68, and 72 kHz, and only the lower sideband of each is taken, the spectrum of Figure 8.5c results. This figure points out two problems that an FDM system must cope with. The first is crosstalk, which may occur if the spectra of adjacent component signals overlap significantly. In the case of voice signals, with an effective bandwidth of only 3100 Hz (300 to 3400), a 4-kHz bandwidth is adequate. The spectra of signals produced by modems for voiceband transmission also fit well in this bandwidth. Another potential problem is intermodulation noise. On a long link, the nonlinear effects of amplifiers on a signal in one channel could produce frequency components in other channels. PengTekTel-Modul:7 6/28

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TDM 1 2 4 3 1 2 4 3 CH.1 CH.2 CH.3 CH.4 CH.2 CH.1 CH.4 CH.3 SISI KIRIM SISI TERIMA PengTekTel-Modul:7

Time-Division Multiplexing Transmitting digitized data over one medium Wires or optical fibers Pulses representing bits from different time slots Two Types: Synchronous TDM Asynchronous TDM Bandwidth is limited because each switching must occur at a rate fast enough for each line to have a continuous conversation. PengTekTel-Modul:7

Pengenalan PDH PengTekTel-Modul:7

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Pengenalan SDH PengTekTel-Modul:7

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BIT RATE SDH PengTekTel-Modul:7

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