Your Presenter Today is…

Joseph Cornwall, CTS, ISF-C, DSCETechnology Evangelist

Email - jcornwall@lastar.comTwitter - @JoeCornwall

LinkedIn - /in/josephcornwall

Today’s Presentation: An Introduction and Overview of MATV Technology

Our Agenda…Our Agenda…

Our Agenda

• What Is MATV?• Bandwidth And The RF

Spectrum– What Does An MATV Installation

Distribute?

• Understanding Coaxial Cable– The Basic MATV “Pipe”

• Head-End Building Blocks– Amplification, Equalization

And Notch Filters• Distributing The Signal• Balancing An MATV Installation

What is MATV?

• Master Antenna Television System

– A System By Which A Building Or Zone Is Fed From A Common Set Of Antennas

• MATV Systems Can Distribute Many Different Signals

– RF Broadcast TV And Radio– Locally Modulated Sources

– Satellite IF– Bi-Directional Broadband Data

• Coax Provides From 370 To 1,000 Times More Capacity Than Unshielded Twisted-Pair (UTP)

Broadcast Spectrum – Off Air

• OTA (Over The Air) Broadcasts Encompass “Channels” 2 Thru 51

– Channels 52 To 69 No Longer Operate Due To The Transition To Digital TV

• In Most Regions, New Digital Television Stations Are Placed On UHF Or High-VHF Channels

– 7 To 13 And 14 To 51, Except 37– VHF 2 To 6 Are Rarely Used Due To Impulse

Noise

– VHF /H Or Channels 7 To 13 Broadcast From 174 To 216 MHz

– UHF Channels 14 To 36 Broadcast From 470 To 608 MHz

– UHF Channels 38 To 51 Broadcast From 614 To 698 MHz

– In Comparison, FM Radio Broadcasts From 87 To 108 MHz

Broadcast Spectrum - CATV

• Subband “T”– Used By Cable Modems For Sending Upstream

Data To The Headend's CMTS (Cable Modem Termination System)

• Cable Channels 2 Through 13 Operate On The Same Frequencies As Broadcast Television (The VHF Band)

• Cable Channels 14 To 22 (Mid Band) Operate From 123 to 171 MHz

• Cable Channels 23 to 36 (Super Band) Operate From 219 To 297 MHz

• Cable Channels 37 To 64 (Hyper Band) Operate From 303 to 465 MHz

• Cable Channels 65 To 94 (Ultra Band) Operate From 471 To 645 MHz

• Cable Channels 100 To 158 (Jumbo Band) Operate From 651 To 999 MHz

Satellite Television• C-Band TVRO Broadcasts From 4 To

8 GHz• Ku-Band TVRO Broadcasts From 12

To 18 GHz– DirecTV, Dish Network

• Satellite Signals Are “Folded” To A Lower Frequency By The Low Noise Block Amplifier (LNB) At The Receiving Dish

– Superheterodyne A Wide Block Of Relatively High Frequencies, Amplify And Convert Them To Similar Signals Carried At A Much Lower Frequency (Called Intermediate Frequency Or IF

• Satellite IF Frequencies Operate From 950 To 1450 MHz

– Can Be Piggybacked In The Same Coaxial Cable That Carries Lower-Frequency Terrestrial Television From An Outdoor Antenna

The Nature Of Coaxial Cable

• One Conductor Is Formed Into A Tube And Encloses The Other Conductor

– This Confines The Radio Waves From The Central Conductor To The Space Inside The Tube

• Dimensions And Spacing Of The Conductors Must Be Uniform

• All Components Of A Coaxial System Should Have The Same Impedance

– Reduce Internal Reflections At Connections Between Components

– Abrupt Change May Reflect Signal Causing Standing Waves

Frequency Loss And Coax

• Cable Television Systems Consist Of UNITY GAIN Building Blocks– Every Run Is Followed By An Amplifier With A Compensating Amount Of RF Gain And Equalization

• Capacitive Losses In Cable Reduce High Frequencies More Than Low Frequencies– Low Pass Filter– Compensation Requires Tilt Adjustment– Head End Output Level Of +42 dBmV On Cable Channel 118 And A Level Of +35 dBmV On Channel 2

Types Of RF Coaxial Cable

RG-59u RG-6u RG-11uCharacteristic Impedance 75Ω 75Ω 75ΩPropagation Velocity 0.66 0.75 0.66

Diameter 0.242 in 0.270in 0.412in1GHz Loss @ 100 Feet -8.09dB -6.54dB -4.23dB1GHz Loss @ 100 Meters -26.54dB -21.46dB -17.22dB3GHz Loss @ 100 Feet -14.29dB -11.45dB -7.8dB3GHz Loss @ 100 Meters -46.88dB -37.57dB -25.29dB

• RG-59/U– Coaxial Cable With 20 AWG Center

Conductor And 75Ω Characteristic Impedance

– Used For Low-power Video And RF Signal Connections At Short Distance , High-Frequency Losses Are Too High To Allow Its Use Over Longer Runs

• RG-6/U– Coaxial Cables With An 18 AWG Center

Conductor And 75Ω Characteristic Impedance

– CATV Distribution Coax Typically Has A Copper-Coated Steel Center Conductor And A Combination Aluminum Foil/Aluminum Braid Shield

• RG-11/U– Coaxial Cable With A 14 AWG Center

Conductor And 75 Ω Characteristic Impedance

– The Correct Choice For Runs Over 300 Feet

MATV System Parameters• Measurements Are Done With A Signal Level Meter

– Determine If Levels Are Sufficient For Further Processing, Amplifying And Distributing

– If Needed, Preamplifiers Should Be Used

• All Programs Should Have The Same Power Level– Maximum Differences Between Signal Levels

• - 3dB For Neighboring Channels• - 6dB (Within Any Band 60 MHz Wide)• - 10dB (Within The Whole Spectrum)

– Minimum Isolation Between Two Receivers: -44 dB

• All Parameters Of Distributing Installation Should Be Kept At 95% Stability

– As Ambient Temperatures Increase, So Does System Loss

• Gain Of The Antennas Used Shouldn't Change More Than 0.5 dB Within 1 TV Channel

Thoughts On Antennae

• There’s No Such Thing As A Digital HD Antenna!

– Now That The Spectrum Is Compressed , Antennae Are Easier To Select

• Most Suburban Or Urban Installations Will Benefit From Simple Vertically-Stacked Dipole Designs

– Omni-Directional Reception Optimizes Easy Installation In Areas With Low Multipath Interference

• Yagi Antennae Offer The Highest Gain

– Decreased Bandwidth And High Directionality

Television Standards

• The Days Of Analog And NTSC Are Over

• ATSC Is A Set Of Standards Developed By The Advanced Television Systems Committee For Digital Television Transmission Over Terrestrial, Cable, And Satellite Networks

• Terrestrial (Local) Broadcasters Use 8VSB

– Sufficient To Carry Several Video And Audio Programs And Metadata

• Cable Television Stations Use 256-QAM

Amplification

• Signal Processors (Strip Amplifiers) Are Single Channel Amplifiers Designed To Receive A Single Television Signal From An Antenna And Control Its Output To A Steady Level.

– Strip Amplifiers Do Not Alter The Input Frequency Of The Received Television Signal

• Broadband Amplifiers Boost Gain For All Channels In The System

– Most Feature Tilt Compensation– Broadband Amplifiers Also Boost System

Noise!

Isolation Amplifiers

• Used On The Antenna Or Incoming Cable Feed To Process, Amplify And Isolate It’s Signal

– Relatively Low Gain Designed Into System Only To Compensate For Near Zero dBmV sources

– Prevents The Antenna From Becoming A Sink For System Power

• Not All Systems Benefit From A System Isolation Transformer

– Simple Two To Four Input Head End Designs With A Single Off-Air Local Antenna Will Not Typically Siphon Power From The System

Notch Filters And Modulation

• Modulators Take Video And Audio Signals From Satellite Receivers, Video Servers Or Cameras And Produce A Standard Modulated Television Channel

– The Signal Output Level From A Modulator Is Constant And Can Be As Much As +60 dBmV

– This Value Is 60 Decibels Above 1 mV As Measured Across A 75 Ohm Source Impedance

– This Value Is 1 Volt Of RF Carrier At The Peak Amplitude Of The Signal

• A Notch Filter Or Band-rejection Filter Is A Filter That Passes Most Frequencies Unaltered, But Attenuates Those In A Specific Range To Very Low Levels

– Often Used To Remove OTA Broadcast From An MATV System To Improve Performance Or Replace Content

Signal Combiners

• In MATV RF Installations, Addition Is The Same As Subtraction

– An RF Splitter Is Composed Of Two Transformers That Approximately Split Signal Power While Maintaining 75Ω Characteristic Impedance

– A Splitter Used “Backwards” Is A Combiner

• Signals Being Combined Must Be Of Similar Power Levels As Measured In dBmV

• Signals Being Combined MUST NOT Have The Same Channel Embedded

Splitting The Signal• RF Distribution Scheme Is Based

On 75 Ohm Terminated Transmissions

– Transmitting Side Interfaces With 75Ω Load On The Receive End To Provide Maximum Signal Power Transfer

• Splitters– MTransformers That Split The Power In

The Input Signal To Multiple Outputs, Whileaintaining The 75 Ohm Impedance

• Directional Couplers, aka Taps– Asymmetrical Splitter Where “Through

“ Port Exhibits Minimal Loss And Each “Drop” Exhibits Multi-Decibel Loss

Calculating System Gain

• MATV Is A Game Of Unity Gain– The Secret Is To End Up With The

Same Power Level In Each Band And That Power Level Should Match The Incoming Broadcast Feed

• There Are Two Sections Of Gain To Be Considered:

– Locally Modulated And Mixed Sources Must Be Gain Matched To The Broadcast Feed So One Trunk Contains All Programming To Be Distributed At A Constant Power Level Across All Bands

– The Trunk/Zone/Room Delivery Devices Must Have All Insertion Losses Compensated

Calculating System Gain – Source Side

RF Amp

Antenna

Output toHead End

Source 2

Source 1

Mod 2

Mod 1

100’

100’

Combiner

?

Calculating System Gain - Source Side• Incoming Feed Measures +5dBmV

– FCC Cable Rules 76.605 Requires A Minimum Signal Level Of 1 mV Across 75 Ohms, AKA 0dBmV

• Locally Modulated Sources Are Located In A Rack 100-Feet From RF Head End

– Output Of ATSC 8VSB RF Modulator # 1 Measures +25dBmV

– Output Of ATSC 8VSB RF Modulator # 2 Measures +25dBmV

• Modulators #1 & #2 Combined Through 3-Port Combiner With -4dB Signal Loss Per Port

• +25dB + ( -6.5dB Cable Loss) + (-4dB Combiner Loss) = +14.5dB When Signal Arrives At Head End

• +14.5dB Modulated Signal – 5dB Broadcast Feed = +10dB Difference

• Use A 10dB Broadband Isolation Amplifier To Achieve Balanced RF Sources At Head End

Combiner

+10dbRF Amp

Antenna

Output toHead End

Source 2

Source 1

Mod 2

Mod 1

100’

100’

+25db

+25db

-6.5db

-6.5db

-4db

-4db

+5db

Calculating System Gain – Drop Side

Output ofCombiner

Distribution Amp4-portTrunk

Splitter

?

4-PortTap

4-PortTap50’

50’

4-PortTap

4-PortTap50’

50’ 4-PortTap

50’4-PortTap

50’ 4-PortTap

50’4-PortTap

The Drop Side• Now We Need To See The “Other” Side Of The Equation

– How Much Amplification Do We Need To Service All Displays?

• 4 Trunks Serve 4 Discreet Areas Of The Project Through A 4-Port Splitter

– Assume Trunks Are All Identical For This Exercise– 4-Port Splitter Has Insertion Loss Of -8dB Per Trunk

• Each Trunk Is 100-Feet With Two 4-Port Taps Spread Equally – At 50-Foot And 100-Foot Point– Each Tap Has An Insertion Loss Of 2dB– Each Tap Port Is -12dB

• For Proper Calculations The Starting Signal Levels And Losses Must Be Calculated At Several Frequencies To Determine Tilt Compensation

– For This Exercise We Will Assume A Tilt Of -6dB Across The Specified Bandwidth

Calculating Gain Of The Distribution Amplifier…

• Input Feed To Distribution Amplifier Is +11dB• 4-Port Trunk Splitter Loss Is -8dB• 50-Foot Cable Loss Is -3dB

• Unidirectional Coupler (Tap) Insertion Loss Is -2dB• Second 50-Foot Cable Run Loss Is -3dB• Unidirectional Coupler (Tap) Insertion Loss Is -2dB• Tap-to-Port Loss Is -12dB • Tilt Loss Is -6dB

• +11dB -8dB-3dB-2dB-3dB-2dB-12dB-6dB = -25dB• Select A +25dB RF Broadband Amplifier To Provide +0dBmV Per Display

Drop

The Drop Side

50’

4-PortTap

4-PortTap

50’

50’4-PortTap

50’4-PortTap

50’ 4-PortTap

50’4-PortTap

Output ofCombiner

Distribution Amp4-portTrunk

Splitter

+25dB

4-PortTap

4-PortTap50’

75Ω

75Ω

75Ω

75Ω

-2dB-2dB

-2dB -2dB

-2dB -2dB

-2dB -2dB

-12dB -12dB

-12dB -12dB

-12dB -12dB

-12dB -12dB

-8dB

-8dB

-8dB

-8dB

-3dB

-3dB

-3dB

-3dB

In Conclusion…

• MATV Installations Offer Significant Value In Distribution Of Cable And Broadcast Video Sources Across Multiple Displays And Devices In Any Project From Small To Large Scale

• Coaxial Cable Offers Significantly More Bandwidth Than Unshielded Twisted Pair Making MATV Installations A Cost-Effective And High Performance Alternative To Distributing Content Over An IT Network

– Ideal For Digital Signage (DOOH) Installations

• MATV Systems Are Designed As A Zero Loss (Unity Gain) Project Where Signal Levels Are Not Allowed To Drop Below 0dBmV At Any Point

• Success In MATV Installation Is Only Ensured When You Know The Quality Of The Starting Signal And Accurately Account For All Insertion Loss, Slope Loss And Drop Loss Across The Distribution Network

• Satellite RF Signals Are Easily Incorporated Into MATV Systems, Allowing For Convenient Placement Of TVRO Set-Top Boxes

• The Quality Of An MATV Installation Depends On The Quality And Condition Of The Coaxial Cable Used In The Project

• MATV Systems Are Flexible, High-Performance, Cost Effective And Adaptable!

Questions ?Questions ?

Thank You!Thank You!