Broadband System - A - Catv Expert A catv101.pdf · CATV CATV -- 101. 101. 2 Broadband System - A To give you plenty of time to read the details of each presentation, ... Input next

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Broadband System - A

Satellites are spaced every2nd degrees above earth

TVTRANSMITTER

Cable area

"C" BandToward satellite 6.0 GHzToward earth 4.0 GHz

"L" BandToward satellite 14.0 GHzToward earth 12.0 GHz

Headend

CATV CATV -- 101.101.

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Broadband System - A

To give you plenty of time to read the details of each presenta tion,you’ll need to press the RIGHT ARROW KEY (����) on your PC, soyou can have access to the next slide. This will be the same for allfuture presentations in this seminar.

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Before we start the Seminar on Broadband system, let have a lo okat the beginning of the CATV industry in North America.

This will help you better understand what are the requiremen ts forto-day’s Broadband System.

This presentation is only a general idea and every subject in thispresentation will be explained in more details in futurepresentations.

Broadband System - A

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Broadband System - A

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Broadband System - A

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CATV : Community Antenna TV television

CATV systems started in around 1952 and were a one waycommunication system, using coaxial cable and RF amplifier s.These CATV systems distributed television signals, from adistribution center (Head end ) to all the homes in a the cabledarea.

These systems then, were capable of only distributing betwe en2 to 4 TV channels. From been able to distribute 2 to 4 TVchannel at their start, some of the systems finally carried a smuch as 12 television channels and some FM music.

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In both country, Canada and the USA , you required a license tooperate a CATV system.

In the United States, the cities give the permit to operate a C ATVsystem and the FCC controls the technical data.

Federal

Communications

Commission

In Canada, the license is warded by the CRTC

•Canadian

•Radio

•Telecommunications

•Commission

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• TV Stations, VHF or UHF.

• FM Stations.

• Satellites, 4 and 12 GHz (around 1975).

• AML (microwave system).

• TV Program from local studio.

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4.5 MHz 3.59 MHz

6.0 MHz 0

-10

-20

-30

-40

-50

-60

-70

dBVideo section4.2 MHzAnalog

technology

Audio section0.9 MHz

FM technology

Color section

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CHCH--22 :: 5555..2525 MHzMHz CHCH--77 :: 175175..2525 MHzMHz

CHCH--33 :: 6161..2525 MHzMHz CHCH--88 :: 181181..2525 MHzMHz

CHCH--44 :: 6767..2525 MHzMHz CHCH::--99 :: 187187..2525 MHzMHz

** 7373..55 MHzMHz IntInt.. disasterdisaster freqfreq andand otherother .. CHCH--1010 :: 193193..2525 MHzMHz

CHCH--55 :: 7777..2525 MHzMHz CHCH--1111 :: 199199..2525 MHzMHz

CHCH--66 :: 8383..2525 MHzMHz CHCH--1212 :: 205205..2525 MHzMHz

FMFM :: 8888 toto 108108 MHzMHz CHCH--1313:: 211211..2525 MHzMHz

** Notice,Notice, thethe differencedifference inin frequency,frequency, betweenbetween CHCH--44 andand CHCH--55,, whichwhichisis notnot aa multiplemultiple ofof 66 MHzMHz TheThe reasonreason being,being, thatthat 7373..55 MHzMHz isisallocatedallocated asas anan internationalinternational disasterdisaster frequency,frequency, thatthat isis usedused byby thetheRedRed CrossCross andand somesome otherother internationalinternational organizationorganization..

VHF Television Signal Frequency.

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UHF Television signal.

CH-14 : 471.25 MHz to CH-69 : 805.25 MHz

All 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.

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Each television channel leaving the head end are controlled by;

•Channel processor, ( RF in, RF out)

•Modulator, ( Baseband in, RF out)

•Satellite Receiver, (4 or 12 GHz in, RF out)

All of the television channels are then combined together wi th achannel combiner before they are transmitted to the coaxialsystem.

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Processor

Modulator

SatelliteReceiver

Microwave

Receiver

RF Combiner

First Amplifier

of the CATV system

Inputch.

IFfreq.

Outputch.

Outputch.

IFfreq.

Basebandsignal

ModulatorOutput

ch.IF

freq.Baseband

signal

Combining Signal at a CATV Head end

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FM stationsFM stations22 66 77 1313

12 channel plan12 channel plan

This number television twelve (12) channels was the maximum possible before the delivery of Push Pull amplifier .

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FM stationsFM stations2 6 7 131414 2222

21 channel plan21 channel plan

With Push Pull amplifier, it became possible to car ry Mid Band channels nine (9) between 121 to 170 MHz, for a tot al of 21 channels

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FM

transmitter

TV

transmitter

Head end

CATVsystem

Satellitereception

TVtransmitter

FMtransmitter

4GHz

12GHz

MicrowaveSystem

SatellitesSatellites

Up LinkUp LinkTransmissionTransmission

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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 is 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.

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5 50 300 550 865 1,000 MHz

TYPEMain 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 degre es C.

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50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 80031

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30

850

50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850

Input next amplifier after 30 dB spacing at 860 MHz

60 o

-40 o

140 o

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9.

25

Signal after cable equalizer

50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850

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Output previous amplifier

Behaviour of the coaxial cable versus temperature c hange

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RF amplifier amplifies the signal when it becomes w eak

4 output amp. 2 output amp. 1 output amp.

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Connectors are required to make the connection betw een the amplifiers and the passives equipments on the coaxi al cable.

Ingress Sleeve

Connection toOutside tube

Connection to

central conductor

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RF splitter and coupler give the possibly to send s ignal into two or more directions.

Inputcable

Outcable

Outcable

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Standby powersupply are working

on 110 volts ACor

36/48 Volts DC

Power supply delivers 60 or 90 volts AC thru the coaxial cable, to permit RF amplifiers to work.

They can be Non-Standby and Stand-By

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RG-59 or RG-6

Multitap make the connection between the CATVsystem and the customer equipment.

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BTD BLE

Power Passing

Tap50-750 MHz5-40 MHz

From Headend

RG-59 or RG-6

A CATV system

26RF amplifier Coaxial cable Power Supply

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Broadband CATV systems are now a very complex, Bi-direction alcommunications 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).

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HFC Broadband systems are using fiber optic technology totransport the signals for the longest distance, between the head endto 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 sig nals 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 band widthfrom the head end to the customer is: 50 to 870-1,000 MHz, and fromcustomer to the head end is: 5 to 40 or 42 MHz .

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23 40 43 50

51 77

50MHz

225MHz

225MHz

380MHz

380MHz

550MHz

F M s t a t io n sF M s t a t io n s 1 4 2 2

In a modern Broadband system, the frequencies below 550 MHz a re generallyused for the transport analogical channels (NTSC).

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DD = Digital, Data, IP Telephony, Video On Demand= Digital, Data, IP Telephony, Video On Demand

78 103

DD DD DD DD DD D DD

550MHz

870MHz

Standard Television channels can be replaced by digital tel evision or otherdigital services (Data, Cable modem, Security system, IP Te lephonysystem, etc .) on a modern HFC system.

In a modern Broadband system, the frequencies above 550 MHz a re generallyused for the transport of the digital portion of the HFC syste m. QAM digitalchannels and standard television channels can well exits si de by side.

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Response of a 870 MHz HFC system

15 to 20dBmV

300MHz

450MHz

225MHz

121.25MHz

108MHz

50MHz

550MHz

750MHz

870MHz

80 NTSC, Analog channels. 220 MHz of 64 or 256 QAM signals.

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core

cladding

coating

9 mc

The transmitted light is guided down the fiber by reflecting off the outside of thecore. The core's index of refraction is slightly higher than that of the surroundingcladding to insure internal refraction. The core is surroun ded 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 ca lled silica. Thematerials need to be ultra-pure because impurities in the ma terial can lead to areduction of power output. Impurities can add to absorption and scattering,which would reduce the effectiveness of the fiber. The buffe r coating covers thecore and the cladding. The buffer coating is generally made o f plastic, whichprotects the fiber from moisture and other damages.

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T k’T

Mono-mode fiber optic operating frequencies in a HF C system are 1310 or 1550 nanometers .

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Performance Characteristics of single mode fibre op tic.

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0800 1000 1200 1400 1600

nm

a

b c d e

Spectral Attenuation ( typical fiber ):

SINGLE-MODE STANDARD FIBER OPTIC

dB

ALLWAVE SINGLE-MODE FIBER OPTIC

Spectral Attenuation ( All Wave fiber ):

dB

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0800 1000 1200 1400 1600

nm

Loss at :850 nm = 1.31 dB/km

1310 nm = 0.33 dB/km1550 nm= 0.19 dB/km

Loss at :850 nm = 1.31 dB/km

1310 nm = 0.33 dB/km1550 nm= 0.19 dB/km

The standard fiber optic is mostly used for every d ay 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

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Dual armored fiber optic cable.

Non-metallic covert fiber optic cable.

Fig-8 Self supporting fiber optic cable.

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Optical Transmitter (5-1,000 MHz)

Return Optical Receiver

5-40 MHzOptical Node

5050--870 MHz870 MHz

55--40 MHz40 MHzCoaxial CableCoaxial Cable

55--40 / 5040 / 50--870 MHz870 MHz

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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.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.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.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.

30 km of P-III-625 coaxial cable

The amplifiers are spaced at 22 dB @ 450 MHz, for th is distance80 RF amplifiers will be required

Above, shows advantage of fiber optic, over coaxial cable, which are:

•Better Carrier to Noise, CTB, CSO specifications at t he end of the system.

•The 30 km fibre link will give more stable signal e ven with temperature change.

•The fibre optic link will require less actives equi pments than a coaxial link.

•A 30 km coaxial section will require 80 amplifiers ( with P-III-625 cable).

•A 30 km fibre optic link will require a 10 dBm optical transmitter (operating @ 1310 nm) at the head end and one optical receiver at the other end.

C/N will be: 40.97 dBC/N will be: 40.97 dB

30 Kilometres of fibre optic, operating at 1310 nm will means a 9.9 dB loss.

C/N will be: 52.00 dB

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An OTDR uses microwave technology to verify the qua lity and the length of fiber optic.

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Headend EquipmentCablemodem

IP-Telephone

RSVP

Monitoring System

NODE

Fiber optic Return 5 / 40 MHz

Fiber Optic Forward 50 / 870 MHz

Coaxial SectionCoaxial Section

Optical EquipmentOptical Equipment

Optical InterconnectionOptical Interconnection

RF InterconnectionRF Interconnection5 to 42 MHz5 to 42 MHz

RF Sweep

Coaxial Return 5 / 40 MHz

Coaxial Forward 50 / 870 MHz

50 to 52 or 73.5 MHz

Return Alignment andReturn Alignment and

Ingress Control SystemIngress Control System

RF InterconnectionRF Interconnection50 to 870 MHz50 to 870 MHz

T1 / OC 192to Tel Co

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300MHz

450MHz

225MHz

121.25MHz

108MHz

50MHz

550MHz

750MHz

870MHz

47.0 dBmV

37.0 dBmV

4 dB6 dB

10 dB 11.5 dB

48.5 dBmV

Response of a Optical Receiver or a RF amplifierfor a 870 MHz HFC system.

80 NTSC, Analog channels.80 NTSC, Analog channels. 220 MHz of 64 or 256 QAM signals.

44Optical receiver Coaxial cable Fiber optic cable Bi-directional RF amplifier

Each pocket (Each pocket (sectionsection) of a HFC system can have 50 to 1,500 subs.) of a HFC system can have 50 to 1,500 subs.

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•Head end of a HFC system.

•Description of a HFC Head end.

•Coaxial cable - Fibre optic.

•Passive equipments for a HFC system.

•Description of the outside plan.

•RF Amplifiers.

•Fibre optic.

•Fibre 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. Cable modem.

•Mode on DOCSIS.

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We will come back in more details in all the subjects seen so far in future seminar.

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