scte dvac chapter 4/18/12 larry jump jdsu field applications engineer 814 692 4294...

SCTE DVAC Chapter 4/18/12

Larry Jump

JDSU

Field Applications Engineer

814 692 4294

[email protected]

Tap to Outlet Home Certification

mailto:[email protected]

mailto:[email protected]

© 2011 JDSU. All rights reserved. JDSU CONFIDENTIAL & PROPRIETARY INFORMATION2

Home Certification Overview– What is Home Certification?– Why do we need it?– What is the technology?

Certifying the Home– Home Certification Challenges in the field– What affects Services– What can and should be done

Questions and Answers

Today's Agenda


Why Home Network Certification?

Estimated that 70-75% of all trouble calls are due to problems inside the home.

Estimated that between 90-95% of troubleshooting root cause of service issues inside a home is coax path related– Replacing connectors, splitters, faulty coax, etc…– Craftsmanship– This is consistent with both QAM and MoCA services

QAM signals are more susceptible to issues – QAM signals are maxed out – Now more susceptible to other issues

Greater customer satisfaction through a more reliable network

Home certification has been proven to reduce costly repeat truck rolls.


The best answer is:

– to provide short and long term customer satisfaction by:• Reducing repeat visits• Reducing overall truck rolls over time• Reducing unnecessary Refer to Maintenance calls

» Providing test data to tech responding to escalation

• Being prepared for future technologies

Another step closer to One and Done

Why should we do this “certification”?


Find and Fix Dilemma

• Missing marginal installations often leads to 3-1 find and fix scenario

FieldTech

$125 install tech truck roll

$125 network tech truck roll

Network Tech Field

Tech

$125 service tech truck roll

• 3 truck rolls that should have only required 1, 3-1

• At $125/roll, cost for repair was $375 or $250 extra cost!

• At $100/month average customer revenue, and a 50% margin, that means that about 5 months of profit are gone from this customer

• Saving only 1.5 - 2 events per month, pays for a field instrument that can help prevent this scenario in less than 12 months.


What goes wrong?

Excessive attenuation caused by too many splitters or long cable runs

A drop amplifier that does not pass the entire required spectrum

Un-terminated splitters or outlets Poor crimping or other connector issues Cable faults or other conductor flaws

Many of these flaws are caused by poor craftmanship!


Why do we need to certify the home?

Upcoming technologies will require an even more robust home network.

MoCA supports a full-mesh network between all nodes, procedures must be modified to rate all segments, not just from the initial splitter to outlets but also STB-to-STB segments that may not include the initial splitter.

Any number of components could be the cause, including bad connectors and splitters, amplifiers, band pass filters, un-terminated cables or excessive noise, distortion or interference that affects the part of the spectrum.


Benefits of Certification

Customer doesn’t call Boss Boss doesn’t get

mad at tech

Tech doesn’t take it out on dog

Happy Customers

Happy Boss

Happy TechHappy Dog


Find Root Cause of Service Issues

Troubleshooting Philosophy:– Quickly find and fix the root cause of 80-90% of in-home

related issues – the Coax – Allow operators to determine all Triple-Play & other

newer services will work before connecting any CPE devices!• Certify the home’s coax plant over all frequencies is

correct• It doesn’t matter what service is running on the coax• Future proof for eventual additional revenue


Remember the Goal –

Help assure that work (service, install, etc.) is done

correctly the first time, and verified with quantitative test

data, hence reducing repeat service calls.

You can ensure that the proper tests are taken for every

required job and the test data is recorded.

Testing is consistent across all techs and jobs

– Test data is reconciled against the work order system

Quality standards are enforced for each job

Why do we need to do this


Testing – Tap to TV, Modem, or Set Top Box

• The span of the network the Service /Install Tech controls.• Using the test equipment provided

Standardization• All customers get the same tests

All Techs run the same tests• Apple to Apples

Verification– Ensure that the testing was done correctly

Assurance– Ensure that corrective action is taken if required

Reporting– Provide compliance information to managers and technicians

Data Collection

What is Home Cert?


Because you are the one with the tool belt Because you can move the test equipment around while you

troubleshoot.– Outlet to Ground Block to Tap

Know at once when you have fixed, or found the location of the problem

Provide measurement history at that location for future reference.

Why this, instead of other back office tools?


Run the tests at jobs that require a test to be run– Results are compared to user defined Pass/Fail limits– Pass/Fail limits should be such that a fail means “must fix”

Fix problems uncovered– Or validate they need escalation ( via test at Tap)

Re-run test to verify correction of problems Results are reported in terms of number of tests:

– that actually were performed versus number that SHOULD have been performed

– Number of tests passed Reporting is available grouped by System, Manager,

Supervisor, or Technician. Goal is to achieve and maintain high compliance and passing

numbers

Summary so far


• Reduce repeat rate – lowering repeats caused by marginal signal

conditions

• Create a system wide standard for acquiring & interpreting test

results

Results in standard and consistent procedures that ensure

quality based on quantitative test data

• Improve productivity by reducing repeat service calls

• Improve customer satisfaction levels, as customers do not have to

keep experiencing the same problem

• Provide a central repository for test data provides management

reports, trends for data analysis, efficiency of technician and

productivity

By successfully implementing Home Certification


Reports


System Workflow Diagram

TPP RelationalDatabase


Web Server

Daily electronic file with Work

Order Information from billing

system

Import Report

Saved Test Results

sent at end of day.

Management ReportsManagement Reports Test Result Queries

Save test files taken at jobs into Folders


Another view



Web Server

TAP

Drop Cable

High Pass Filter

GROUND BLOCK

DIGITAL SET-TOP

House

2-Way Amplifier

Digital Voice

OLDER TV SET

COMPUTER

ETHERNET

Workorder info from Billing System

Stores test data, Compares test from meter with workorderdata

Work Order File from Billing System


How Work Orders are matched with Test Results

CSG, DST, ICOMSs, Custom– Minor differences between vendors

Information in Work Order File:– assigned Tech, Work Order Type, job number, account number,

completion codes, job status, and completion date, Node, system ID, etc.

Meter saves test named as account number or Job Number Information from meter(saved tests):

– Tech ID, Account Number or Job Number, Date/Time Saved, and of course, the test measurement data

Server:Application andDatabase


Work order Info

Test Data


Meter Synchronization Process

• Synchronization (upload) process allows tech to send

data back to the server

• Also allows channel plans, test plan setup and ,

limit plans to be sent to the meter.

• Assure all meters use proper settings

• Connect via the RF plant (DOCSIS channel) or

Ethernet LAN, or available wireless networks.

• The Certification test data is sent back and saved in

Application Database and the Certification Reports are

created from this database



2-way communication

RF, Wireless, or Ethernet


eMTA-CABLE MODEM

TAP

Drop Cable

High Pass Filter

GROUND BLOCK

3-WaySplitter

DIGITAL SET-TOP

House

2-Way Amplifier

Testing RF networks in the Home

Digital Voice

OLDER TV SET

ONLINE GAMING

COMPUTER

ETHERNET


The Basics…..Where

TAP

Drop Cable

High Pass Filter

GROUND BLOCK

DIGITAL SET-TOP

House

2-Way Amplifier

Digital Voice

OLDER TV SET

COMPUTER

ETHERNET

Which outlet should we test?Pretty much common sense

-Voice-Data-Largest TV


The Basics…What do we test – RF Layer

Downstream RF– Level– C/N ( Analog – Remember Analog?)– Hum ( Analog – yep, still around, sometimes)– Video/Audio Carrier Delta ( difference)– MER– BER– (Drop Frequency Response)

Upstream RF– Upstream Tx Level– Upstream Tx Headroom


What is Comcast doing now?


The Basics…What do we test - DOCSIS

Downstream – Level– MER– BER– Registration

• Configuration file, Gateway IP, Modem IP, BPI Status• DOCSIS 3 Bonding

Upstream– Channel assignment and Bonding– Packet Loss– Throughput ( Speed)– VoIPcheck – simulated Digital Voice Packets


Typical Ingress Test

25


What do we test - Ingress

Ingress can be included as one of the Home Certification tests

Can be run before or after the inside the home test

Attic

POTS

1

5 4

3

2


eMTA-CABLE MODEM

7 dB TAP

Drop Cable

High Pass Filter

GROUND BLOCK

3-WaySplitter

DIGITAL SET-TOP

House

2-Way Amplifier

Testing the Home for Ingress Contribution

VoIP

OLDER TV SET

Return Equalizer

ONLINE GAMING

WIRELESS LAPTOP

COMPUTOR

ETHERNET

Disconnect drop from tap and check for ingress

coming from customer’s home wiring

INGRESS SPECTRUM MEASUREMENTS

If ingress is detected at tap end, repeat at ground block

to localize


Troubleshooting Tests

What other tests does the tech have to troubleshoot if there is a problem:– DQI– QAM Ingress– DOCSIS Tests– Smart Scan


Measurements over time

29


Ingress under QAM Measurements

30


Smart Scan


DOCSIS Measurements

32


Test setup configuration – Video Tests


Test setup configuration – Modem/DOCSIS tests


Test setup configuration – Ingress setup


Limit ( Pass/Fail) Values

Can be set for up to 8 locations


Understand the results screen – and act on what it tells you….know what failed and why


Certification: The tech needs to know how to…..

•Know which job types to test

•Know which outlet to test

•Know which channel plan is the right one to use

•Know how to name and save the test

•Know how to understand what failed, if there is a fail

•Know how to fix or report what failed, know how to escalate and verify why that escalation is needed.

•Know how and when to synchronize the meter with the server.


New and upcoming?

MoCA WiFi DNLA


MoCA Parameters

MoCA uses the existing coaxial cable plant in a subscriber’s home as the connecting media for devices on a home network.

MoCA 1.1 provides a 16-node solution 175 Mbps will always be available to more than 95

percent of the nodes BER target of 1 x 10-9. Communication between devices on a MoCA network is

controlled by a node designated as the network coordinator (NC)

Nodes need to be able to transmit RF carriers at 55 dBmV to overcome splitter port to port isolation. Sometimes 2 splitters.


An In-Home Network, Physical Layer

Attic

Crawl Space

Splitter

Splitter

NC


MoCA Node Discovery

A node joins a MoCA network by listening for a beacon signal from the NC

After receiving the beacon signal, a new node sends an admission request to join the network.

If no beacon is heard, the new node assumes it is the first and begins transmission of its own beacon.

MoCA 1.1 completes the probe and beacon tasks faster than its predecessor MoCA 1.0. This allows an increase in the maximum number of nodes from eight to 16 and provides a throughput increase from 100 to 175 Mbps network throughput for 95 percent of the nodes.


MoCA Optimization In addition to cable, the subscriber’s plant also contains splitters and

sometimes amplifiers. MoCA equipped devices also need to be able to communicate through high-isolation output ports, in the forward as well as reverse directions.

This is accomplished using a form of orthogonal frequency division multiplexing (OFDM) that is dynamically tailored to the individual paths in the subscriber’s coax network.

“Probe” signals are periodically sent to the MoCA nodes on the plant to determine frequency response at each of the OFDM subcarrier frequencies.

The optimal combination of constellation and frequency for each node is determined to achieve a BER of 1 x 10-9, resulting in constellations that can range from no symbols to 256-QAM

Because the electrical characteristics of the plant can change when the subscriber adds or removes devices, probes are sent on a periodic basis, and the OFDM scheme is changed as required.


Operates between 850 and 1525 MHz Each channel is 50 MHz wide in 1.1 or 100 MHz wide in 2.0 In some cases, more than 1 channel is used at the same time

to allow transport of 2 different logical networks.

MoCA 1.1Physical Layer

44


MoCA Frequency Allocations

5 MHz 55 MHz 1 GHz 1.7 GHz

Upstream Range

Downstream Range

MoCA 1.x Range

850 – 1525 MHz55 – 1000 MHz5 – 45 MHz

MoCA 1.x Frequency View

5 MHz 55 MHz 1 GHz 1.7 GHz

Upstream Range

Downstream Range

MoCA 2.0 Range

500 – 1650 MHz55 – 1000 MHz5 – 45 MHz

MoCA 2.0 Frequency View

50 MHz

100 MHz


The NC determines how the nodes gain access the network to transmit and receive Ethernet frames.

2 types of MAC layer frames– Control frames contain management messaging

• Bandwidth requests• Media Access Plans MAPs

– Data frames contain the end user application data

MoCA MAC Layer

46


In-Home Logical Layer Diagram

47

Attic

Crawl Space

NC

Node A Node B


MoCA 2.0 Details

MoCA 2.0 (June 15, 2010) - Similar to MoCA 1.1 but with the following differences:– Three new modes of operation:

• Basline Mode:– 400+ Mbps MAC throughput – 700 Mbps PHY Rate– Single 100 MHz Channel

• Enhanced Mode– 800+ Mbps MAC throughput – 1.4 Gbps PHY Rate– Two bonded 100 MHz Channels (“Channel Bonding”)

• “Turbo” mode for a point-to-point configuration that allows:– 500+ Mbps MAC throughput between two connected devices when operating in

Baseline mode– 1+ Gbps MAC throughput when operating in Enhanced mode

– All three modes now have an extended frequency range• 500 MHz through 1650 MHz (center frequencies)

– Backward compatibility with MoCA 1.0 and 1.1 devices• MoCA 2.0 devices can operate at MoCA 2.0 speeds while MoCA 1.x devices are

communicated to at their maximum respectable speeds on the same network

NOTE: MoCA 2.0 is different hardware than previous MoCA 1.1 HW versions


WiFi has already surpassed wired in home networks– Apple sold 3 million IPads within the 1st 3 months of it’s release– There are now approximately 108 million IPhones worldwide

While WiFi is widely used for data, up until now it has been deemed not reliable enough for video due to interference from such things as microwave ovens and cell phones.

802.11n now provides for data rates up to 600Mbs on a 40MHz wide carrier

802.11n also provides for the concept of multiple input multiple output (MIMO), providing for a maximum of four transmit antennas and four receive antennas.

802.11n also provides for Dynamic digital beamforming,it monitors and adjusts the Wi-Fi signals based on real-time events that could affect performance. In combination with the 4 x 4 antenna scheme, beamforming can provide a 12dB-to-25dB improvement in reliability

With these 2 innovations, video can now be delivered reliably over wireless

What does the future hold for home networks?

49


Digital Living Network Alliance (DLNA) promotes wired and wireless interoperability of PCs, CEs, and mobile devices.

A DLNA device works like any other network device by discovering other DLNA-enabled hosts.

It learns their capabilities and exposes these features on the device's control display.

Through DLNA, a media server can be located and then summoned to play or display a stored family photo, movie, music file, etc.

DLNA-certified devices include TVs, PCs, set-tops, routers, game consoles, tablets, Blu-ray and DVD players, smartphones and audio receivers.

The organization says it has certified more than 9,000 different devices.

More than 440 million DLNA-certified devices were installed in users’ homes by the end of 2010

More not too distant future stuff, DLNA

50


A Wireless In-Home DNLA Network

Crawl Space

Splitter

Wireless Router


We are NOT certifying the whole house (just yet) We ARE certifying an outlet

– Which is way better than not certifying anything The big reasons we don’t certify ALL outlets now

is…….– We don’t know how many there are– We don’t want to spend the time doing all outlets

• 2-3 minutes per outlet, plus ingress scan, plus time to save, etc.

Now – what are we NOT doing?


To completely verify the home network we would need to ….

•Verify signal quality at the Ground Block or Point of Entry

•Verify wiring from POE to each outletLossNoise/Ingress of each legFrequency response of each leg

•If we meet specs at the POE and verify wiring performance from POE to outlet….then

•We don’t need to run RF/MODEM tests at each outlet, do we?


Point of Entry (POE) Filter and Splitter Isolation

A MoCA filter (aka: POE filter) performs two jobs.

– First it prevents the MoCA signal from entering a neighbors house by placing a filter at the input to the home network

– Second it gives MoCA a point of reflection for the signal because it requires the signals to bounce from output port to output port.

There is approximately 30 dB of port to port isolation on a 2 way splitter

POE

MoCA/POEFilter

30 db down from one port to the other

55 dBmV in

25 dBmV out


What if……we could test multiple outlets…at once?

TAP

We could do all our up and downstream tests at the Ground block…

Attic

Crawl Space

Splitter

Splitter

…And then verify that we had good performance from the ground block to each outlet?

X

With 1 button push?


Mini-Probes…

Each probe :• has an F-Connector and a mini-USB port• its own unique identifier letter ( A, B, C, D, etc)• Sweeps 5-1500 Mhz – forward and reverse• Has FDR function to determine distance to faults• Has noise detection to listen for and detect ingress

Meter connects to one probe via USB, and controls test and displays results on screen.


Put a probe at each location inside the home where a Set-top-box or Cable Modem will be located (or is desired to be tested)

Connect that probe to the POE looking into the home toward CPE (ie: drop cable, ground block, or main split)

Connect the probe to the meters USB port

Probe Setup

57

USB toMini-USB Point of Entry

or Main Split

Attic

Crawl Space

Splitter

Splitter

POE = Point of EntryCPE = Customer Premise Equipment


Verify Frequency Response to and from each outlet• So lets sweep forward and reverse from 5 Mhz to 1500Mhz

Calculate loss from Ground Block to each outlet Listen for ingress on each leg

• With some built in intelligence we can map the wiring system too!

We want to ….


Shows POE to outlet frequency response for Forward and Reverse Sweeps

Why not do 5-1500 in one sweep? We want good resolution at the reverse band edges

Sweep Trace – Freq Response

59

Upstream Freq Response Downstream Freq Response – with MoCA filter in place


See each path’s frequency response Sweep graphs can identify many issues in the coax network

– Relative levels are shown at multiple frequencies to give users more information than numbers alone can express• By looking at the sweep response users can identify why the

test failed the limits of the service plan:– Too much overall loss, adjacent points’ difference too

great, overall highest loss to lowest loss (peak to valley) too great

– Users can see and interpret from the sweep response signal degradation caused by:• Frequency cut offs due to poor splitters or inline filters• Amplifiers eliminating the return or MoCA bands• Excessive attenuation• Reoccurring standing waves• Frequency suck outs

60


Seeing how everything is connected

Shows what is connected– The probes should determine how what it sees is connected and

where those elements have common connections– Each element can be shown on the topology map including:

splitters, filters, amplifiers, and found mismatches– Users can easily identify if unexpected elements are discovered

and trace where those elements are located before beginning to troubleshoot the coax network

Note: Not every topology can be mapped with 100% accuracy though most common configurations can. Filters and amplifiers in the path can lead to inaccurate common points being shown on the topology map and are highlighted yellow when present.

61


Run to run details


For whole house certification – Keep It Simple Summary results has all that is needed at a glance:

– Pyramid screen– Overall pass/fail– Pass/fail for each upstream and downstream path from POE to

each outlet– Ingress noise limit check– Pass/fail for MoCA (if desired) between all devices in the

customer premise

Whole home results screen…


We can test RF downstream and upstream and DOCSIS at the ground block or point of entry, and then…

We can test multiple outlets and know how many were tested– One-Button test for all tested outlets saves time– Identify what the inside wiring problem is– Identify where the problem is– Identify hidden amps, splitters and filters

True “Whole House” Certification.

Now – we have whole house Home Certification !


Don’t have regrets…..Certify the home!


Tech Support and information Web Page

WWW.CATVSUPPORT.COM

Thank you!

Extra Slides


Well, we start off with the basics

68


1 Drop – 1 Node – DO NOT NEGLECT DROP INGRESS MITIGATION!!

-60

-50

-40

-30

-20

-10

0

10

20

30

40

Center: 25.000 MHzSpan: 40.000 MHzRBW: 300 KHz VBW: 100 KHz Dwell: 400 µS

In-Band Power 10.393 dBmV

-60

-50

-40

-30

-20

-10

0

10

20

30

40

Center: 25.000 MHzSpan: 40.000 MHzRBW: 300 KHz VBW: 100 KHz Dwell: 400 µS

In-Band Power 8.632 dBmV

•Reverse Spectrum shot at customer's drop


Troubleshooting MoCA

MoCA emulation is currently not solving service problems – Rate Tables between MoCA devices are already available via

diagnostic pages on STB’s (CPE) – Rate Tables only provide techs with information of whether the

MoCA problem still exists or not• Does not provide root cause breakdown or fault identification• Tech must guess as to what is causing the MoCA issue by visually

tracing the coax, making changes, then retesting

Like DOCSIS – MoCA has been revised – Latest is MoCA 2.0 (Released June 2010)– All devices today are still on the MoCA 1.1 chipset hardware – New Hardware will be required to go to MoCA 2.0 – NOT a software

upgrade– Most Operators will want MoCA 2.0 hardware when available in

mass deployments• Capacity gains ensure future functionality support is easier to

deploy • No chipsets/hardware currently exists for MoCA 2.0


JDSU SmartID™ - Advanced Coax Probes

JDSU Solution with SmartIDs: Reduce largest cause of service repeat tickets

– Increase Triple-Play and/or Multi-room DVR subscriber satisfaction through reduced repeat calls

– Speedup troubleshooting by knowing what to fix– Qualify the coax is capable of handing all services, present

and future– Saves operators money by combining with existing DSAMs

and making techs more efficient– Differentiate between Triple-Play or MoCA impairments

Operator Issues: Supervisors – Concerned when subscribers complain due to issues arising

shortly after an installation or the first/second repeat truck roll Technicians – Much of their time spent troubleshooting coax cable attempting to

guess at possible solutions MoCA – A new technology to the industry, therefore there is fear about the

unknown and how to fix issues when they appear


MoCA CPE Diagnostics Information

Good for verifying if MoCA rates are acceptable or failing Troubleshooting problems with MoCA equipment

– Identifies which nodes it can not see– Can identify a problem exists (Tiling, Rate issues, MER, BER, etc…)– Rate Table does not help identify root cause of problems but

identifies which leg problems may exist

Rate TableMAC Addresses


Complete in home certification

USB toMini-USB Point of Entry

or Main Split

Attic

Crawl Space

Splitter

Splitter


Certify each Coax Path Independently

Qualification Screen shows Pass/Fail– If all metrics pass the coax paths are good for the

services its was tested against– If a failure exists then further action is required

• The columns on the left indicate which parameters failed for the movable bold box – Different paths may have different results

• Additional detail about the failure can be collected from the Detail and the Network Overview screens – Accessible by pressing View

• A frequency response graph can be used to help determine why the result was failing the limits set by the test


Seeing how everything is connected

Network Overview shows what is connected– The SmartIDs can determine what it believes is

connected and where those elements have common connections

– Each element is shown on the topology map including: splitters, filters, amplifiers, and found mismatches

– Users can easily identify if unexpected elements are discovered and trace where those elements are before beginning to troubleshoot the coax network

Note: Not every topology can be mapped with 100% accuracy though most common configurations can. Filters and amplifiers in the path can lead to inaccurate common points being shown on the topology map and are identified when present.


Deeper Dive into the Network

Detail view shows additional information about the network– Probe paths are isolated for a deeper view about the

tested coax network– Individual coax segment information is shown –

Lengths and element information are indicated– Additional text is presented to help indicate failed

service tests– Potential causes of the failures and impedance

mismatches are shown on the screen as faults (exclamation points) as well as the distance from other elements to the potential faults are shown

– Elements such as filters, amplifiers, and splitters are also shown with more detail in this view


See each path’s frequency response

Sweep graphs can identify many issues in the coax network– Relative levels are shown at multiple frequencies to

give users more information than words alone can express• By looking at the sweep response users can identify why the

test failed the limits of the service plan

– Users can see and interpret from the sweep response signal degradation caused by:• Frequency cut offs due to poor splitters or inline filters• Amplifiers eliminating the return or MoCA bands• Excessive attenuation• Reoccurring standing waves• Frequency suck outs


Lets have some review of MER…

“MER” is to Digital, what signal to noise is for analog

MER is affected by high noise, low signal– Also ANY other

impairments MER readings are relatively

immune to “brief bursty” interference

MER is a predictor of BER

78

40db is the highest you will see.

256 QAM needs 29dB or better to work.

64 QAM needs 25dB or better to work.

Add 3db to above figures to allow headroom.


Lets Talk a little BER

79

• A 256QAM channel transmits at a symbol rate of 5M symbols per second• Bit rate = 8 bits per symbol X 5M symbol per second =40M bits per second• Error Incident = Bit rate X BER = Errors Per Second

BER Error Frequency Error Incident 10-12 1 in 1 Trillion bits 25000 secs between errs (6.94 hrs) 10-11 1 in 100 Billion bits 2500 secs between errs (41.67 mins) 10-10 1 in 10 Billion bits 250 secs between errs (4.167 mins) 10-9 1 in 1 Billion bits 25 seconds between errors 10-8 1 in 100 Million bits 2.5 seconds between errors 10-7 1 in 10 Million bits 4 errors per second 10-6 1 in 1 Million bits 40 errors per second 10-5 1 in 100 Thousand bits 400 errors per second 10-4 1 in 10 Thousand Bits 4000 errors per second 10-3 1 in 1 Thousand bits 40000 errors per second

•BER responds to changes a faster than MER•BER is ESTIMATED

• Its not like BERT testing where data is looped back


MER and BER Cliff Effect

A small variation in MER (+/- 1 dB) will cause a large variation in BER measurement.

Using BER for trouble-shooting and fault location is not repeatable and very inaccurate.

80

1.10-1

1.10-9

4.10-4

2 23.5 40

4QAM 16QAM 64QAM 256QAM

MER

BER


TAP

Drop Cable

Testing multiple outlets in less steps

eMTA-CABLE MODEM

High Pass Filter

GROUND BLOCK

3-WaySplitter

House

2-Way Amplifier

Test RF quality, upstream levels, DOCSIS test here

Then verify we can deliver that quality from here to each outlet

scte dvac chapter 4/18/12 larry jump jdsu field applications engineer 814 692 4294...

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