part 3 transmission media & em propagations. provides the connection between the transmitter...
TRANSCRIPT
![Page 1: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/1.jpg)
Part 3 Part 3 Transmission Media & EM Transmission Media & EM PropagationsPropagations
![Page 2: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/2.jpg)
Provides the connection between the transmitter and receiver.1. Pair of wires – carry electric signal.2. Optical fiber – carries the information
on a modulated light beam.3. Free space – information-bearing signal
is radiated by antenna
![Page 3: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/3.jpg)
Signal transmission problem
additive noise – generated internally by
components used to implement the
communication system.
Interference from other users of the channel.
![Page 4: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/4.jpg)
Minimizing noise effects
◦ Increasing the power of transmitted signal.
Constraint
◦ Limited power level
◦ Channel bandwidth availability
![Page 5: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/5.jpg)
Underwater acoustic
Fiber optics
Wireless electromagnetic
Wire lines
Channels
![Page 6: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/6.jpg)
Wire Lines Channel
◦ Signals transmitted are distorted in both
amplitude and phase.
– corrupted by noise.
◦ Carry a large percentage of daily
communication around the world.
![Page 7: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/7.jpg)
Twisted pair Coaxial cable
![Page 8: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/8.jpg)
Fiber Optics Channel◦ Low signal attenuation◦ Highly reliable photonic devices◦ Large bandwidth available◦ Services : voice, data facsimile and video◦ Tx – light source
(e.g. LED, laser)◦ Rx – photodiode◦ Noise source : photodiodes & amplifiers
![Page 9: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/9.jpg)
![Page 10: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/10.jpg)
Wireless Electromagnetic Channels◦ Electromagnetic energy is coupled to the
propagation medium by antenna (radiator)◦ Antenna size & configuration – Frequency of
operation◦ Efficient radiation – antenna longer than 1/10
λ
![Page 11: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/11.jpg)
Example A radio station transmitting in AM
frequency band, fc = 1MHz, λ = 300 m,
requires antenna at least 30 m.
![Page 12: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/12.jpg)
Various frequency bands of the electromagnetic spectrum
![Page 13: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/13.jpg)
◦ Ground-wave propagation
◦ Sky-wave propagation
◦ Line-of-sight (LOS)
![Page 14: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/14.jpg)
Surface-wave propagation Dominant mode of propagation Frequency band: 0.3 – 3 MHz Applications: AM broadcasting, maritime
radio broadcasting Disturbances for signal transmission: atmospheric noise, man-made noise,
thermal noise.
![Page 15: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/15.jpg)
![Page 16: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/16.jpg)
Transmitted signals being reflected from ionosphere
Frequency : above 30 MHz Little loss Problem : Signal Multipath Application : Satellite communications
![Page 17: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/17.jpg)
![Page 18: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/18.jpg)
VHF band and higher Limited by curvature of earth Problem : Thermal noise (Rx front end) Cosmic noise (pick-up by antenna) Application: A TV antenna mounted on a
tower of 300 m height to provide a broad coverage area (67km)
![Page 19: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/19.jpg)
![Page 20: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/20.jpg)
Underwater acoustic channels◦ EM waves do not propagate over long distances
under water except at extremely low frequencies◦ Expensive – because of the large and powerful
transmitters required◦ Problem : Attenuation – skin depth
![Page 21: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/21.jpg)
Multipath channel – signals reflections from the surface and the bottom of the sea.
Noise : ambient ocean acoustic noise, man-made acoustic noise
![Page 22: Part 3 Transmission Media & EM Propagations. Provides the connection between the transmitter and receiver. 1.Pair of wires – carry electric signal](https://reader035.vdocuments.mx/reader035/viewer/2022062807/5697c0081a28abf838cc69aa/html5/thumbnails/22.jpg)