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Hfc a catv-101

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  • 1. Broadband System - A Satellites are spaced every 2nd degrees above earth"C" BandToward satellite 6.0 GHz "L" BandToward earth 4.0 GHz Toward satellite 14.0 GHz Toward earth 12.0 GHz TV TRANSMITTER Headend Cable area 1 CATV - 101.
  • 2. Broadband System - ATo give you plenty of time to read the details of each presentation,you’ll need to press the RIGHT ARROW KEY on your PC, so youhave access to the next slide on this and in all futurepresentations. 2
  • 3. Broadband System - ABefore we start the Seminar on Broadband system, let have a lookat the beginning of the CATV industry.This will help you better understand what are the requirements forto-day’s Broadband System.This presentation is only a general idea and every subjectdemonstrated in this presentation will be explained in more details. future presentations.in 3
  • 4. Broadband System - A 4
  • 5. Broadband System - A 5
  • 6. CATV : Community Antenna TelevisionCATV systems started in around 1952 and were a one waycommunication system, using coaxial cable and RF amplifiers.These CATV system distributed television signals, from adistribution center (Headend) to all the homes in a the cabledarea.Then, these systems were capable of distributing between 2 to4 TV channels. From been able to distribute 2 to 4 TV channel attheir start, some of the systems finally carried as much as 12television channels and some FM music. 6
  • 7. In both country, Canada and the USA, you required a license to operate a CATVsystem.In the United States, the cities give the permit to operate a CATV system andthe FCC controls the technical data.FederalCommunicationsCommissionIn Canada, the license is warded by the CRTC•Canadian•Radio•Telecommunications•Commission 7
  • 8. • TV Stations, VHF or UHF.• FM Stations.• Satellites, 4 and 12 GHz (around 1975).• AML (microwave system).• TV Program from local studio. 8
  • 9. 6.0 MHz 0 -10 -20 -30 Audio sectionVideo section dB -40 0.9 MHz 4.2 MHz FM technology Analog -50 technology -60 Color section -70 3.59 MHz 4.5 MHz 9
  • 10. VHF Television Signal.CH-2 : 55.25 MHz CH-7 : 175.25 MHzCH-3 : 61.25 MHz CH-8 : 181.25 MHzCH-4 : 67.25 MHz CH:-9 : 187.25 MHz* 73.5 MHz Int. disaster freq. CH-10 : 193.25 MHzCH-5 : 77.25 MHz CH-11 : 199.25 MHzCH-6 : 83.25 MHz CH-12 : 205.25 MHzFM : 88 to 108 MHz CH-13: 211.25 MHz* Notice, the difference in frequency, between CH-4 and CH-5, which isnot a multiple of 6 MHz. The reason being, that 73.5 MHz is allocated asan international disaster frequency, that is used by the Red Cross andsome other international organization. 10
  • 11. UHF Television signal. CH-14 : 471.25 MHz to CH-69 : 805.25 MHzAll UHF signals, like the VHF signals, are located in a 6.00MHz spacing, the UHF stations are located between 471 to810 MHz.UHF channel, CH-37, 609.25 MHz, in generally not used as itis employed for Radio Astronomy. 11
  • 12. Each television channel leaving the headend are controlled by;•Channel processor, ( RF in, RF out)•Modulator, ( Baseband in, RF out)•Satellite Receiver, (4 or 12 GHz in, RF out)All the television channels are combined together with a channelcombiner before they are sent on to the coaxial system. 12
  • 13. Processor Input IF Output ch. freq. ch. Modulator Baseband IF Output signal freq. ch. RF Combiner Satellite First Amplifier Receiver of the C T system AV Modulator Baseband IF Output signal freq. ch. Microwave ReceiverCombining Signal at a CATV Headend 13
  • 14. 12 channel plan2 6 FM stations 7 13 This number television channels (12) was the maximum possible before the coming out of Push Pull amplifier. 14
  • 15. 21 channel plan2 6 FM stations 14 22 7 13 With Push Pull amplifier, it became possible to carry Mid Band channels (9) between 121 to 170 MHz, for a total of 21 channels 15
  • 16. Satellites 12 Satellite GHz reception TV transmitter FM transmitter FM transmitter 4 GHz Headend CATV system Up Link TVTransmission transmitter Microwave System 16
  • 17. Coaxial cable consist of : •75 ohms cable. •Center conductor. •Foam (hold the center conductor in place) •Aluminum tube. •Sometimes covert with PVC jacket.Coaxial cable are the most common way to distribute television channel.•It frequency range is from 5 to 1000 MHz•It is also capable of handling 90 Volts AC requires to operate RF amplifiers. 17
  • 18. TYPE 5 50 300 550 865 1,000 MHzMain coaxial cable: LossP-III-500 0.16 0.52 1.31 1.82 2.33 2.52 dB/100’P-III-625 0.13 0.42 1.08 1.51 1.94 2.07 “ “P-III-750 0.11 0.30 0.78 1.25 1.60 1.74 “ “Main drop installation cable:RG-59 0.86 1.95 4.45 5.95 7.52 8.12 “ “RG-6 0.58 1.53 3.55 4.90 6.10 6.55 “ “Above loss are giving @ 68 degrees F. or 20 degrees C. 18
  • 19. Behaviour of the coaxial cable response versus temperature change Output previous amplifier Input next amplifier after 30 dB spacing at 860 MHz 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 85049 49 31 3148 48 30 3047 47 29 2946 46 28 2845 45 27 2744 44 26 2643 43 25 2542 42 24 2441 41 -40 o 23 2340 40 22 2239 39 60 o 21 2138 38 20 20 140 o37 37 19 19 ble equalizer36 36 18 Signal after ca 18 17 17 Signal after cable equalizer 16 16 Signal after cable equalizer 4 15 9 15 9 . 14 14 2 5 13 13 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 19
  • 20. RF amplifier amplifies the signal when it becomes weak 20
  • 21. Ingress Sleeve Connection to Outside tube Connection to central conductorConnectors are required to make a connection between theamplifiers and the passives equipments on the coaxial cable. 21
  • 22. OutInput cablecable Out cable RF splitter and coupler give the possibly to send coaxial cable into two or more directions. 22
  • 23. Standby power supply are working on 110 volts AC or 36/48 Volts DCPower supply delivers 60 or 90 volts AC thru the coaxial cable, to permit RF amplifiers to work. 23
  • 24. RG-59 or RG-6Multitap make the connection between the CATV system and the customer. 24
  • 25. Power 5-40 MHz 50-750 MHz Passing TapFrom Headend BTD BLE RG-59 or RG-6 A CATV system 25
  • 26. RF amplifier Coaxial cable Power Supply 26
  • 27. 27
  • 28. Broadband CATV systems are now a very complex, Bi-directionalcommunications network, called; HFC (Hybrid Fiber Coaxial) usingFiber Optic and Coaxial Cable technologies.These systems are now delivering the following;•Analog Television programs.•Television on demand or pay per view television.• Digital Television.•HDTV (High Definition Television).•High speed Internet service, by Cablemodem.•Security system.•IP telephony (VoIP). 28
  • 29. HFC Broadband systems are using fiber optic technology totransport the signals for the longest distance, between the headendto a NODE (optical receiver). The node transfers the light signal to RFsignal. The signals then continue thru the coaxial system to feed allthe customers. The coaxial system permits to deliver the signals atless cost. Fiber optic delivers a better quality signal than coaxialcable, this is why fiber optic is used to transport the signal for thelong distance.A HFC system is a bi-directional system, and the working bandwidthfrom the headend to the customer is: 50 to 870-1,000 MHz, and fromcustomer to the headend is: 5 to 40 or 42 MHz. 29
  • 30. 30
  • 31. In a modern Broadband system, the frequencies below 550 MHz are generallyused for the transport analogical channels (NTSC). 225 50 F M s t a t io n s 14 22 MHz MHz 380 225 MHz 23 40 43 50 MHz 380 MHz 51 77 550 MHz 31
  • 32. In a modern Broadband system, the frequencies above 550 MHz are generally used for the transport of the digital portion of the HFC system. QAM digital channels and a standard television channels can well exits side by side. D D D D D D D D D D D D D 78 103 870550 MHzMHz D = Digital, Data, IP Telephony, Video On Demand Standard Television channels can be replaced by digital television or other digital services (Data, Cablemodem, Security system, IP Telephony system, etc.) on a modern HFC system. 32
  • 33. Response of a 870 MHz HFC system 15 to 20 dBmV 50 108 121.25 225 300 450 550 750 870MHz MHz MHz MHz MHz MHz MHz MHz MHz 80 NTSC, Analog channels. 220 MHz of 64 or 256 QAM signals. 33
  • 34. 34
  • 35. coating cladding core 9 mcThe transmitted light is guided down the fiber by reflecting off the outside of thecore. The cores index of refraction is slightly higher than that of the surroundingcladding to insure internal refraction. The core is surrounded by optical materialcalled the cladding. The cladding causes the light to remain inside the core. Thecore and the cladding are usually made of ultra-pure glass called silica. Thematerials need to be ultra-pure because impurities in the material can lead to areduction of power output. Impurities can add to absorption and scattering,which would reduce the effectiveness of the fiber. The buffer coating covers thecore and the cladding. The buffer coating is generally made of plastic, whichprotects the fiber from moisture and other damages. 35
  • 36. T k’TMono-mode fiber optic operating frequencies in a HFC system are 1310 or 1550 nanometers. 36
  • 37. Performance Characteristics of single mode fiber optic. SINGLE-MODE STANDARD FIBER OPTIC ALLWAVE SINGLE-MODE FIBER OPTIC Spectral Attenuation ( typical fiber ): Spectral Attenuation ( All Wave fiber ): 4.0 4.0 Loss at : Loss at : 3.5 850 nm = 1.31 dB/km 850 nm = 1.31 dB/km 1310 nm = 0.33 dB/km 3.5 1310 nm = 0.33 dB/km 1550 nm= 0.19 dB/km 1550 nm= 0.19 dB/km 3.0 3.0 2.5 2.5dB a dB 2.0 2.0 1.5 1.5 1.0 1.0 0.5 b c d e 0.5 0.0 0.0 800 1000 1200 1400 1600 800 1000 1200 1400 1600 nm nm The standard fiber optic is mostly used for every day signal transport. The new AllWave fiber is used for the DWDM and long distance transport.Notice that the humidity peak at 1400 nm, have been removed on AllWave fiber 37
  • 38. Dual armored fiber optic cable.Non-metallic covert fiber optic cable.Fig-8 Self supporting fiber optic cable. 38
  • 39. 5-40 MHz 50-870 MHz 50- Optical Transmitter and Optical NodeReturn Optical Receiver 39
  • 40. 30 kilometers of P-III-625 coaxial cable RF Amp. RF Amp. RF Amp. RF Amp. RF Amp. RF Amp. RF Amp. RF Amp. RF Amp. RF Amp. RF Amp. RF Amp. RF Amp. RF Amp. RF Amp. This coaxial length spaced at: 22 dB spacing at 450 MHz, able to carry 60 NTSC TV signal, C/N here will be: will requires 80 RF Amplifiers. 40.97 dB for 4.2 MHz spacing. 30 kilometres of fiber optic, operating at 1310 nm will means a 9.9 dB loss C/N here will be: 53.00 dB for 4.2 MHz spacing.Above, shows advantage of fiber optic, over coaxial cable, which are:•Better Carrier to Noise, CTB, CSO specifications at the end of the system. Noise, specifications•The 30 km fibre link will give more stable signal even with temperature change.•The fibre optic link will require less actives equipments than the coaxial link. the•A 30 km coaxial section will require 80 amplifiers.•A 30 km fiber optic link will require a 12 dBm optical transmitter and one optical receiver. 40
  • 41. An OTDR uses microwave technology to verify the quality and the length of fiber optic. 41
  • 42. Coaxial Section NODE Coaxial Return 5 / 40 MHz Fiber optic Return 5 / 40 MHz RSVP Coaxial Forward 50 / 870 MHz Fiber Optic Forward 50 / 870 MHz Optical Interconnection Monitoring System T1 / OC 192 Optical Equipment to Tel Co RF Interconnection 5 to 42 MHz CablemodemHeadend Equipment IP-Telephone RF Interconnection 50 to 870 MHzRF Sweep Return Alignment and Ingress Control System 50 to 52 or 73.5 MHz 42
  • 43. Response of a Optical Receiver or a RF amplifier for a 870 MHz HFC system. 48.5 dBmV 47.0 dBmV 10 dB 11.5 dB 6 dB4 dB 37.0 dBmV 50 108 121.25 225 300 450 550 750 870 MHz MHz MHz MHz MHz MHz MHz MHz MHz 80 NTSC, Analog channels. 220 MHz of 64 or 256 QAM signals. 43
  • 44. Each pocket (section) of a HFC system can have 50 to 1,500 subs. Optical receiver Coaxial cable Fiber optic cable Bi-directional RF amplifier 44
  • 45. •Headend of a HFC system.•Description of a HFC Headend.•Coaxial cable - Fiber optic.•Passive equipments for a HFC system.•Description of the outside plan.•RF Amplifiers.•Fiber optic.•Fiber optic management.•System distortion calculation.•Understanding bi-directionality.•Adjusting a HFC system.•Home installation.•Test equipments required for a HFC system.•CLI. (Ingress & Egress)•CMTS, DOCSIS, QAM signal. Cablemodem. 45
  • 46. 46