MULTIPLEXING AND TRANSMISSION MEDIUMS NOOR AMANI BINTI SALLEH NURZALIZA BINTI GHAZALI IRMA SURYANI BINTI ABU BAKAR DEPARTMENT OF ELECTRICAL ENGINEERING
Multiplexing And Transmission Mediums Noor Amani Binti Salleh Nurzaliza Binti Ghazali Irma Suryani Binti Abu Bakar
Noor Amani Binti Salleh Nurzaliza Binti Ghazali Irma Suryani Binti Abu Bakar 2023 Jabatan Kejuruteraan Elektrik Politeknik Sultan Abdul Halim Mu'adzam Shah (POLIMAS) ©All rights reserved. No part of this publication may be translated or reproduced in any retrieval system, or transmitted in any form or by any means, electronic, mechanical, recording, or otherwise, without prior permission in writing from Politeknik Sultan Abdul Halim Mu'adzam Shah (POLIMAS) Published by Politeknik Sultan Abdul Halim Mu'adzam Shah (POLIMAS) Bandar Darulaman, 06000 Jitra, Kedah Darulaman. Tel : 04-9146100 Fax : 04-9174232 / 04-9146323 Email: [email protected] [email protected] ii
Acknowledgement We would like to express our gratitude to the many people who saw us through this book; to all those who provided support, talked things over, read, wrote, offered comments, allowed us to quote their remarks and assisted in the editing, proofreading and design. Above all we want to thank our partner and family, and the rest of our family, who supported and encouraged us despite all the time it took us away from them. It was a long and difficult journey for them. Thanks to Head of Department, whom without support this book would never find its way to been produce and could be used as reference for our students. We wish to thank our superiors, colleagues, and friends for their helps and encouragement in designing this book besides improving the plot and topics from time to time. Last and not least: we beg forgiveness of all those who have been with us over the course of the years and whose names we have failed to mention. Hoping this book is useful for students in gaining good result for their subjects. iii
Preface This book was developed as a quick and easy reference to help students understand the most basic concepts in the topic of multiplexing and transmission medium for the course DEP30013 - Communication System Fundamentals. This book is divided into 2 sections namely multiplexing and transmission medium. Section 1 describes the definition of multiplexing and demultiplexing, advantages, categories and comparisons between types of multiplexing. While section 2 discusses the types of transmission medium, construction structure, uses and advantages and disadvantages. At the end of each section, examples of final exam questions and answers are included to familiarize students with the question format and as a drill for students' understanding of this topic. iv
TABLE OF CONTENTS 2 CONCEPTS OF MULTIPLEXING 4 CATEGORIES OF MULTIPLEXING 10 COMPARISON OF FDM, TDM AND WDM 12 PAST YEAR FINAL EXAM QUESTIONS [PART 1] 13 INTRODUCTION TO TRANSMISSION 21 MEDIUMS v APPLICATIONS OF MULTIPLEXER
TABLE OF CONTENTS 22 COAXIAL CABLE 25 FIBER OPTIC CABLE 28 GUIDED MEDIAS COMPARISON 33 UNGUIDED MEDIAS 40 42 vi TYPES OF TRANSMISSION MEDIUM TWISTED PAIR CABLE
TABLE OF CONTENTS 43 RADIO WAVE 44 MICRO WAVE 45 INFRARED 46 PAST YEAR FINAL EXAM QUESTIONS 48 [PART 2] UNGUIDED MEDIAS COMPARISON 53 REFERENCES vi
0 1 S E C T I O N
Concepts of Multiplexing Multiplexing (MUX) Process and technique of transmitting multiple analog or digital input signals or data streams over a single channel. This process is made by MULTIPLEXER Demultiplexing (DEMUX) Process reconverting a signal containing multiple analog or digital signal streams back into the original separate and unrelated signals. This process is made by DEMULTIPLEXER 1 link, n channels M U X n Input Line n Output Line D E M U X 2
Categories of Multiplexing TDM : Time Division Multiplexing Analog Digital WDM : Wavelength Division Multiplexing FDM : Frequency Division Multiplexing Concepts of Multiplexing Advantages of Multiplexing Could increase the number of channels in a single transmission line. Therefore, more information can be transmitted. Reduce cost of transmission because higher utilization of transmission medium. Efficiency of bandwidth utilization 3
TDM : Time Division Multiplexing TDM is a digital multiplexing technique for combining several low-rate digital channels / sources into one high-rate one. With TDM, the transmission of info signals from various sources occur on the same transmission medium but NOT at the same time The communication resources (CR) is shared by assigning each of signals for a short duration of time called a time slot. Each time slot is assigned as a channel. TDM Data Flow M U X D E M U X Categories of Multiplexing Digital 4
TDM : Time Division Multiplexing Categories of Multiplexing Digital 5 In figure below, the data rate for each input connection is 2 Mbps. If 1 bit at a time is multiplexed (a unit is 1 bit), what is the duration of (a) each input slot, (b) each output slot, and (c) each frame? M U X 2Mbps 2Mbps 2Mbps 2Mbps 1 1 0 1 1 1 0 0 1 0 0 1 0 0 0 0 1 0 0 1 1 0 0 1 0 0 1 1 0 0 0 0 Frames a. The bit rate of each input connection is 1 Mbps. The input one bit duration is the inverse of the bit rate: T = 1/2Mbps = 0.5μs. The duration of the input time slot is 0.5µs (same as bit duration). b. The duration of each output time slot is one-fourth of the input time slot. This means that the duration of the output time slot is = T/n = 0.5µs/4= 0.125µs c. Each frame carries four output time slots. So the duration of a frame is 4 × 0.125µs = 0.5µs. (The duration of a frame is the same as the duration of an input unit).
FDM : Frequency Division Multiplexing M U X D E M U X FDM channel CH1 CH2 CH3 Guard band Categories of Multiplexing Analog FDM : Frequency Division Multiplexing FDM is an analog multiplexing technique that combines analog signals With FDM, the info signals from multiple sources that originally occupied the same frequency spectrum (BW) are each converted to a different frequency bands. The communication resources (CR) is shared by allocate each of signals to a different frequency band. Each frequency band is assigned as a channel. 6
FDM : Frequency Division Multiplexing Categories of Multiplexing Analog FDM : Frequency Division Multiplexing 7 Assume that a voice channel occupies a bandwidth of 4 kHz. We need to combine three voice channels into a link with a bandwidth of 12 kHz, from 20 to 32 kHz. Show the configuration, using the frequency domain. Assume there are no guard bands. We shift (modulate) each of the three voice channels to a different bandwidth, as shown in figure below. We use the 20- to 24-kHz bandwidth for the first channel, the 24- to 28-kHz bandwidth for the second channel, and the 28- to 32-kHz bandwidth for the third one. Then we combine them as shown below 20 24 24 28 28 32 Modulator 0 4 20 24 Modulator 0 4 24 28 Modulator 0 4 28 32 20 32 20 32 Bandpass filter Bandpass filter Bandpass filter 0 4 0 4 0 4 Shift and combine Filter and shift
FDM : Frequency Division Multiplexing Categories of Multiplexing Analog FDM : Frequency Division Multiplexing 8 Five channels, each with a 100-kHz bandwidth, are to be multiplexed together. What is the minimum bandwidth of the link if there is a need for a guard band of 10 kHz between the channels to prevent interference? For five channels, we need at least four guard bands. This means that the required bandwidth is at least (5 × 100 kHz) + (4 × 10 kHz) = 540 kHz 100kHz 100kHz 100kHz 100kHz 100kHz Guard band of 10kHz 540kHz
WDM : Wavelength Division Multiplexing Analog WDM is an analog multiplexing which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths. WDM is used to overcome the growth in data traffic because WDM capable to increase the bandwidth capacity. In WDM, the communication resources (CR) is shared by allocate each of signals to a different wavelength. One wavelength = one channel. Different wavelength of light give a different colors of light Categories of Multiplexing M U X D E M U X Optical Fiber Communication Channel CH1 CH2 CH3 1 Transmitter 1 2 Transmitter 2 3 Transmitter 3 1 Transmitter 1 2 Transmitter 2 3 Transmitter 3 1 2 3 9
Comparison of FDM, TDM and WDM Features FDM TDM WDM Concept FDM is a transmission technique in which multiple data signals are combined for simultaneous transmission via a shared communication medium. TDM is a transmission technique that allows multiple users to send signals over a common channel by allocating fixed time slot for each user. WDM is a transmission technique that modulates numerous data streams, optical carrier signals of varying wavelengths into a single light beams through a single optical fiber. Meaning FDM stands for Frequency Division Multiplexing. TDM stands for Time Division Multiplexing. WDM stands for Wave Length Multiplexing. 10
Features FDM TDM WDM Functionality FDM divides the bandwidth into smaller frequency ranges and transmit data simultaneously through a common channel within their frequency range. TDM allocates a fixed time slot for each user to send signals through a common channel. User gets the entire bandwidth within that time slot. WDM combines multiple light beams from several channels and combine them to a single light beam and sends through a fiber optic strand similar to FDM. Type of signal FDM uses analog signals. TDM uses digital and analog signals. WDM uses optical signals. Comparison of FDM, TDM and WDM 11
Applications of Multiplexer 12 Communication system – Communication system is a set of systems that enable communication like transmission system, relay and communication network. The efficiency of communication system can be increased considerably using multiplexer. Multiplexer allow the process of transmitting different type of data such as audio, video at the same time using a single transmission line. Telephone network – In telephone network, multiple audio signals are integrated on a single line for transmission with the help of multiplexers. In this way, multiple audio signals can be isolated and eventually, the desire audio signals reach the intended receivers. Computer memory – Multiplexers are used to implement large amount of memory into the computer, at the same time reduces the number of lines required to connect the memory to other parts of the computer circuit. Satellite system – Multiplexer can be used for the transmission of data signals from the computer system of a satellite or spacecraft to the ground system using the GPS (Global Positioning System) satellites.
Comparison of FDM, TDM and WDM ii PAST YEAR FINAL EXAM QUESTIONS (JUN 2019) 13 (a) Define Multiplexing and Demultiplexing with the aid of a diagram. [4 marks] Multiplexing is a technique that combine the information signals (in any form) from more than one information sources over the same transmission medium. Demultiplexing is a technique to separate the multiplexed(merged) signal from one link back to its component transmissions. [1 mark] [1 mark] [1 mark] [1 mark]
Comparison of FDM, TDM and WDM ii PAST YEAR FINAL EXAM QUESTIONS (JUN 2019) TDM is a digital multiplexing technique for combining several low-rate digital channels/sources into one highrate one. With TDM, the transmission of info signals from various sources occur on the same transmission medium but NOT at the same time. The CR is shared by assigning each of signals for a short duration of time called a time slot. Each time slot is assigned as a channel. 14 (b) Multiplexing technique can be divided into 3 categories; Time Division Multiplexing, Frequency Division Multiplexing and Wavelength Division Multiplexing. Explain Time Division Multiplexing with the aid of a diagram. [6 marks] [Any 3 answer = 3 marks] Diagram = 2 marks Labelling = 2 marks
Comparison of FDM, TDM and WDM ii PAST YEAR FINAL EXAM QUESTIONS (JUN 2020) 15 [1 mark] [1 mark] (b) In Frequency Division Multiplexing (FDM), there are six channels, each channel with 120kHz bandwidth, are to be multiplexed together. i. Calculate the bandwidth of the link if the guard band between channel is 15kHz. ii. Draw the configuration of the FDM. [6 marks] i. For six channels, we need at least five guard bands. [2 marks] [1 mark] ℎ ℎ =(6×120)+(5×15) =720+75=795 ii. Configuration of FDM [1 mark]
Comparison of FDM, TDM and WDM ii PAST YEAR FINAL EXAM QUESTIONS (SESI I : 2021/2022) FDM is an analog multiplexing technique that combines analog signals It can be applied when the bandwidth of a link is greater than the combined bandwidth of the information signals to be transmitted With FDM, the info signals from multiple sources that originally occupied the same frequency spectrum (BW) are each converted to a different frequency bands. The CR is shared by allocate each of signals to a different frequency band. Each frequency band is assigned as a channel. 16 [Any 4 answer = 4 marks] (b) Multiplexing technique can be divided into 3 categories. Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM),and Wavelength Division Multiplexing (WDM). Write Frequency Division Multiplexing (FDM) with aid of a diagram. [8 marks] Diagram = 2 marks Labelling = 2 marks
Comparison of FDM, TDM and WDM ii PAST YEAR FINAL EXAM QUESTIONS (SESI I : 2021/2022) Frame size, 1 frame = 3 byte = 3 x 8 bit (1 byte = 8 bit) = 24 bit 17 (c) Three channels are multiplexed using Time Division Multiplexing (TDM). Each channel sends 100 bytes/second and are multiplexed 1 byte (8 bit data) per channel. Using the data in Table 1, sketch the Time Division Multiplexing (TDM) configuration and calculate the size of the frame in bit unit. [9 marks] [1 mark] [1 mark] x 4 [2 marks] Table 1 [2 marks]
Comparison of FDM, TDM and WDM ii PAST YEAR FINAL EXAM QUESTIONS (SESI II : 2021/2022) 18 [1 mark] (a) Construct the configuration of FDM if two voice channels, each with a 4 kHz bandwidth, are to be multiplexed together into a link of 8 kHz, from 20 to 28 kHz. Assume there no guard band. [8 marks] [2 marks] CHANNEL 1 [1.5 marks] CHANNEL 2 20kHz 24kHz 28kHz BW=4 kHz BW=4 kHz Link = 8 kHz [1.5 marks] [2 marks]
Comparison of FDM, TDM and WDM ii i. The bit rate of each input connection is 1 Mbps. The input one bit duration is the inverse of the bit rate: T = 1/1Mbps = 1 μs. The duration of the input time slot is 1 µs (same as bit duration). ii. The duration of each output time slot is one-fourth of the input time slot. This means that the duration of the output time slot is = T/n = 1µs/4= 0.25µs iii. Each frame carries four output time slots. So the duration of a frame is 4 × 0.25µs = 1µs. (The duration of a frame is the same as the duration of an input unit). PAST YEAR FINAL EXAM QUESTIONS (SESI II : 2021/2022) 19 ((b) In Figure A2(b), the data rate for each input connection is 1 Mbps. If 1 bit at a time is multiplexed (unit is 1 bit), write the value of the first four of output unit frames and the duration of one input slot and one output slot. [8 marks] [3 marks] [3 marks] [2 marks]
0 2 S E C T I O N
Introduction to Transmission Medium Sender Receiver Transmission Medium Transmission Medium Block Diagram DEFINITION Transmission Medium can be broadly defined as anything that can carry information from a source to a destination. 21 In telecommunications, the transmission medium is the physical road or channel used to send data, signals, or information between devices, networks, or systems. It can be wired or wireless and is critical in influencing the speed, efficiency, and reliability of data transfer.
ii Types of Transmission Medium Guided Media Guided transmission media consists of a physical link between the source and destination via a wire or cable. Unguided Media There is no physical link between source and destination in unguided transmission media; instead of air is used. 22 Unguided Radio Wave Micro Wave Infrared Coaxial Twisted Pair Fiber Optic Guided Types of Transmission Medium
ii Types of Transmission Medium Physical Pathway: Guided transmission mediums use physical conductors or cables to transmit data. Examples include twisted-pair cables, coaxial cables, and optical fiber. Directionality: Guided media have well-defined paths that guide the signals in specific directions, ensuring controlled transmission. Signal Attenuation: In guided mediums, signal attenuation is generally lower compared to unguided media. This allows for longer transmission distances without significant loss of signal quality. Physical Pathway: Unguided transmission mediums use the air or free space to transmit signals without the need for physical cables. Examples include radio waves, microwaves, and infrared signals. Directionality: Unguided media transmit signals in multiple directions, making them susceptible to signal scattering and diffusion. Signal Attenuation: Unguided media experience more signal attenuation compared to guided media, especially over longer distances or through obstacles in the propagation path. The major differences between guided and unguided transmission mediums are as follows: 23
ii Types of Transmission Medium Interference: Guided media are more resistant to external electromagnetic interference as they are shielded by the physical cables. Security: The physical nature of guided media offers some level of security as it is more challenging to intercept or tamper with signals traveling through cables. Interference: Unguided media are more susceptible to external interference, such as from other wireless devices or environmental factors. Security: Unguided media may be less secure than guided media as signals are broadcasted openly and can be intercepted more easily. The major differences between guided and unguided transmission mediums are as follows: 24
ii Guided Coaxial Cable 25 Coaxial Cable 24 January 2023 Coaxial cable was invented in 1880 by English engineer and mathematician Oliver Heaviside, who patented the invention and design that same year. AT&T established its first cross-continental coaxial transmission system in 1940. https://www.techtarget.com/ A coaxial cable is an electrical cable with a copper conductor and an insulator shielding around it and a braided metal mesh that prevents signal interference and cross talk. The core copper conductor is used for the transmission of signals and the insulator is used to provide insulation to the copper conductor and the insulator is surrounded by a braided metal conductor which helps to prevent the interference of electrical signals and prevent cross talk. This entire setup is again covered with a protective plastic layer to provide extra safety to the cable.
ii Structure of Coaxial Cable Outside Insulation Insulation Copper Mesh Copper wire An external polymer layer, which has a plastic coating. It is used to protect internal layers from damages. Dielectric plastic insulation around the copper conductor. It is used to maintain the spacing between the center conductor and shield. A braided mesh of copper helps to shield from electromagnetic interference. The braid provides a barrier against EMI moving into and out of the coaxial cable. A central conductor, which consists of copper. The conductor is the point at which data transmits. 26 Coaxial Cable
ii The coaxial cables are also used in CCTV systems and both RG-59 AND RG-6 cables can be used. CCTV Video The coaxial cables are also used in video Transmission the RG-6 is used for better digital signals and RG-59 for lossless transmission of video signals. Television Coaxial cable used for television would be 75 Ohm and RG6 coaxial cable. Coaxial cables are also used for carrying internet signals, RG-6 cables are used for this. Internet The HDTV uses RG11 as it provides more space for signals to transfer. HDTV Applications of Coaxial Cable 27 Coaxial Cable
Twisted pair cables have two conductors that are generally made up of copper and each conductor has insulation. These two conductors are twisted together, thus giving the name twisted pair cables. Each pair would consist of a wire used for the +ve data signal and a wire used for the -ve data signal. Any noise that appears on 1 wire of the pair would occur on the other wire. Twisted Pair cables are most effectively used in systems that use a balanced line method of transmission. Twisted Pair Cable Guided 28 Twisted Pair Cable Twisted-pair cabling was invented by Alexander Graham Bell in 1881. By 1900, the entire American telephone network was either twisted pair or open wire with transposition to guard against interference. Today, most of the millions of kilometres of twisted pairs in the world are outdoor landlines, owned and maintained by telephone companies, used for voice service. https://www.techtarget.com/ 25 January 2023
ii Structure of Twisted Pair Cable Unshielded twisted pair (UTP). These cables generally comprise wires and insulators. Shielded twisted pair (STP). These cables come with a braided, wired mesh that encases each pair of insulated copper wires. Twisted-pair cables are of two types: 29 Insulator Conductor Unshielded twisted pair (UTP) Shielded twisted pair (STP) No shielding Shielding Twisted Pair Cable
ii Comparison between STP and UTP cables 30 STP Cable: STP cables consist of twisted pairs of copper wires, just like UTP cables. However, each twisted pair is enclosed in a metal foil or braided shielding, which helps to reduce electromagnetic interference (EMI) and radio frequency interference (RFI). UTP Cable: UTP cables also consist of twisted pairs of copper wires, but they lack any additional shielding. Instead, the pairs are individually insulated, and all the pairs are bundled together in the cable. Construction: STP Cable: Due to its shielding, STP provides better protection against electromagnetic interference, making it more suitable for environments with high EMI/RFI, such as industrial settings or areas with many electronic devices. UTP Cable: UTP cables are more susceptible to EMI/RFI interference due to the absence of shielding. They are better suited for typical office environments or residential use where the level of interference is relatively low. Performance: Twisted Pair Cable
ii Comparison between STP and UTP cables 31 STP Cable: The additional shielding in STP cables makes them generally more expensive than UTP cables. UTP Cable: UTP cables are cost-effective and widely used for everyday networking applications. Cost: STP Cable: The shielding in STP cables makes them thicker and less flexible than UTP cables. UTP Cable: UTP cables are thinner and more flexible, making them easier to install and work with. Flexibility and Size: Both STP and UTP cables have similar performance in terms of distance and bandwidth for standard Ethernet (up to 100 meters at speeds up to 1 Gbps). However, advancements in UTP cable technology (such as Cat6a and Cat7) have enabled higher data rates and longer transmission distances. Distance and Bandwidth: Twisted Pair Cable
ii Applications of STP and UTP cable 32 STP Cable: STP cables are commonly used in industrial environments, healthcare facilities, or areas with high interference potential. UTP Cable: UTP cables are widely used in offices, homes, and most general networking applications. Twisted Pair Cable
ii 33 Guided Fiber Optic Fiber optics use thin glass or plastic tubes to transmit data as light pulses. These pulses represent data as 0s and 1s and travel very fast, enabling high-speed communication. Fiber optic cables can carry large amounts of information over long distances without losing signal quality and are immune to electrical interference. They provide secure, reliable, and fast communication, making them essential for modern networks and services like the internet, phone calls, and video streaming. Fiber technology was first called light cable. The definition of the light cable, which was used for the first time in 1842, in the article Collado prepared in 1884, “a cable flows through a cable by reflecting.” He made it in the form.An alternative to this, along with the lightweight cable, was the Photophone, which transmits sound waves over the beam of light, in 1880 by Graham Bell. https://turkuazcable.com/a-briefhistory-of-optical-fiber/?lang=en 24 Julai 2023 Fiber Optic
ii Structure of Fiber Optic Cable 34 Fiber Optic A protective covering of protection for the sensitive optical fibers contained within a fiber optic cable. The innermost part is the core (core) which is made of glass or plastic. The inner core conducts light rays. The cable jacket is a fiber cable's first layer of defense against moisture, mechanical damage, flame, and chemical attack. The layer just outside the core is the cladding. The cladding is glass or plastic material that reflects light rays emitted from the core and sends them back. Buffer Core Outer jacket Cladding Buffer Coating Buffer Coating Cladding Cladding Core
ii Element in Optical Fiber Communication 35 Fiber Optic Transmitter - Light source Fiber Optic Cable Light Source (Transmitter) - converts the pulses of electrical current to light pulses. eg: LED (light emitting diode) and ILD(Injection laser diode). Fiber Optic Cable (Transmission Medium) - transmit the light-beam pulses. Photo Detector (Receiver) - converts the received light pulses back to pulses of electrical current. Eg: APD (Avalanche Photodiode) and PIN (Positive Intrinsic Negative) photodiode. There are 3 elements in Optical Fiber Communication; 1. 2. 3. Receiver - Photo Detector
ii Propagation Modes 36 Fiber Optic Single Mode - step index Multimode - graded index Fiber-optic cable has two propagation modes: multimode and single mode. They perform differently with respect to both attenuation and time dispersion. The single-mode fiber-optic cable provides much better performance with lower attenuation. 1. 2. - step index Single Mode - step index Multimode Mode - step index Multimode Mode - graded index A single mode or monomode step index fiber allows the propagation of only one traverse electromagnetic mode Graded Index refers to the fact that the refractive index of the core gradually decreases farther from the center. Step-index multimode fibers operate on the principle of total reflection and allow traveling of light across the fiber/core axis in a zigzag pattern.
ii Propagation Modes Comparison 37 Fiber Optic SINGLE MODE STEP INDEX MULTIMODE STEP INDEX MULTIMODE GRADED INDEX Small diameter of core (7 - 10µm) Big diameter of core (50µm - 100µm). Modest diameter of core (50µm - 85µm). The fastest transfer rate Slower transfer rate Modest transfer rate Low attenuation High attenuation Modest attenuation No modal dispersion High modal dispersion Low modal dispersion Suitable for long distance transmission For short distance (high attenuation) For modest distance Expensive because hard to build Cheapest because easy to build Cheaper
ii Fiber Optic Applications of Fiber Optic Cable 38 Telecommunication 01 02 Medical Applications Fiber optics is widely used in telecommunications to transmit data, voice, and video over long distances. It provides high bandwidth and low signal loss compared to traditional copper wires. Fiber optics is used in medical applications such as endoscopy and laser surgery. It allows doctors to see inside the body and perform precise surgeries with minimal invasiveness.
ii Fiber Optic Applications of Fiber Optic Cable 39 Industrial Applications 03 04 Military Applications Fiber optics is used in industrial applications such as sensing and monitoring. It can detect changes in temperature, pressure, and other parameters in harsh environments where traditional sensors cannot operate. Fiber optics is used in military applications such as surveillance and communication. It provides secure and reliable communication channels and can be used in unmanned vehicles and weapons systems.
ii Guided Medias Guided Medias Comparison 40 Basis Twisted Pair Coaxial Fiber Optic Electromagnetic interferenc e (EMI) EMI can take place. EMI is reduced to shielding. EMI is not present Installatio n Easy installation. Fairly easy installation. Difficult to install. Attenuation In twisted pair cable has very high attenuation. In coaxial cable has low attenuation. In optical fiber cable has very low attenuation. Data rate Twisted pair cable supports a low data rate. Moderately high data rate. Very high data rate. Cost The cost is very low. Cost is moderate Cost is expensive.
ii Guided Medias Guided Medias Comparison 41 Basis Twisted Pair Coaxial Fiber Optic Repeater Spacing Repeater spacing is 2- 10 km. Repeater spacing is 1- 10 km. Repeater spacing is 10-100 km. Security Security is not guaranteed of the transmitted signal. Security is not guaranteed of the transmitted signal. Security is guaranteed of the transmitted signal. Types Unshielded Twisted Pair (UTP) Shielded Twisted Pair (STP) RG59 RG6 Single mode fiber Multi mode fiber Power loss reasons conduction and radiation absorption, scattering dispersion and bending conduction
ii Unguided Medias 42 Radio wave Microwave Infrared 100m 1m 1cm 0.01cm 1000nm 3kHz 300GHz 400THz Electromagnetic waves are transported across the air or free space by unguided medium without the use of a physical conductor. This kind of communication is frequently referred to as wireless communication. Signals are often transmitted using an antenna through open or free space, making them accessible to anyone with an equipment to capture the signals.