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Larry Jump JDSU Field Applications Engineer 814 692 4294 TAC 866 228 3762 Opt. 3 / 2 Plant Reliability.

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Presentation on theme: "Larry Jump JDSU Field Applications Engineer 814 692 4294 TAC 866 228 3762 Opt. 3 / 2 Plant Reliability."— Presentation transcript:

1 Larry Jump JDSU Field Applications Engineer 814 692 4294 larry.jump@jdsu.com TAC 866 228 3762 Opt. 3 / 2 Plant Reliability

2 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION2 Agenda 3 major areas of concern Coax Fiber Inside plant

3 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION3 Purpose To provide better service to our customers in light of competition –Maintain plant instead of reacting to problems –Be alerted to issues before the customer notices –Maintain reliability for essential services To increase revenues

4 The outside plant

5 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION5 Less manpower needed Sweeping can does reduce the number of service calls VOD not working Internet not working Channel 12 video problems Cracked hardline found with SWEEP WHY SWEEP?

6 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION6 WHY SWEEP? Loose Face Plate No Termination

7 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION7 Sweep vs. Signal Level Meter Measurements References: Sweep systems allow a reference to be stored eliminating the effect of headend level error or headend level drift. Sweep Segments: Referenced sweep makes it possible to divide the HFC plant into network sections and test its performance against individual specifications. Non-Invasive: Sweep systems can measure in unused frequencies. This is most important during construction and system overbuilding. BEST Solution to align: Sweep systems are more accurate, faster and easier to interpret than measuring individual carriers.

8 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION8 Frequency Response Definition Systems ability properly to transmit signals from headend to subscriber and back throughout the designed frequency range Expected Results (Traditionally): n/10 + x = max flatness variation where n = number of amplifiers in cascade where x = best case flatness figure (supplied by manufacturer) Expected Results in current HFC Networks: Typically < 3 to 4 dB max flatness variation anywhere in the network (check with your Manager for max flatness variation limits)

9 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION9 Forward Path Considerations Diverging System Constant Outputs Channel Plan to Match Fixed Signals –video / audio / digital carriers Sweep Telemetry Carriers, 1MHz wide System Noise –is the sum of cascaded amplifiers Balance or Align (Sweep) –compensate for losses before the amp

10 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION10 Sweep Reference Considerations Typically the node is used for the reference Use test probe designed for node/amp Its a good engineering practice to store a new reference each day Establish reference points to simplify ongoing maintenance (sweep file overlay) Need to know amps hidden losses in return path (Block diagrams / Schematics) Need to know where to inject sweep pulses and the recommended injection levels

11 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION11 Unity Gain in the forward path R H L R Each amplifier compensates for the loss in the cable and passives before the amplifier under test. The system is aligned so that the levels at each green arrow are exactly the same. Each amplifier compensates for the loss in the cable and passives before the amplifier under test. The system is aligned so that the levels at each green arrow are exactly the same.

12 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION12 Why do we need Unity Gain? 22 32/26 31/25 30/24 29/23 23 If Unity Gain is not observed distortions and or noise build up quickly!

13 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION13 Forward Sweep Display Markers Max/Min Reference Name dB/div

14 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION14 A Sweep Finds Problems That Signal Level Measurements Miss Standing Waves Roll off at band edges Misalignment

15 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION15 Sweeping Reverse Path Goals The objective in reverse path alignment is to maintain unity gain with constant inputs and minimize noise and ingress. Set all optical receivers in the headend to same output level and ideally the same noise floor to optimize C/N ratio. –The reverse path noise is the summation of all noise from all the amplifiers in the reverse path. Adjust sweep response to match 0dB flat line Sweep reference and 0dBmV Telemetry level

16 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION16 Before reverse sweeping begins…. Optimize the upstream node Splitting, combining and padding considerations in the headend.

17 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION17 Return Optics We discuss this first because it has the greater impact on the MER at the CMTS input because it has the lowest dynamic range Optimized by measuring NPR at the input to the CMTS by injecting different total power at the input to laser. Carriers should be derated according to bandwidth using power per hertz. Not part of the unity gain portion of the HFC plant. Set up is laser and node specific

18 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION18 NPR Measurement Measured by injecting a wideband noise source with a notch filter at the input. Then measuring essentially the noise to the notch at the output. Measured as 10 log Power/hz of the signal / Power/hz of the notch noise The lower the signal the lower the CNR, the higher the signal, the more distortion. Input starts low and then raised in 1 dB steps

19 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION19 Power per Hertz Calculation Power per Hertz dBmV/Hz = Total Power – 10 Log (BW) dBmV/HZ = 45 – 10 Log (37,000,000) dBmV/ Hz = 45 – 10 (7.57) dBmV/ Hz = 45 – 75.7 dBmV/ Hz = -29.3 Total Power Input for 6.4 MHz 64 QAM dBmV = -29.3 + 10 Log (BW) dBmV = -29.3 + 10 Log (6,400,000) dBmV = -29.3 + 10 (6.8) dBmV = -29.3 + 68 dBmV = 38.7

20 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION20 REVERSE LEVEL All signal levels must be set to same output level at the optical receiver in the headend or hubsite with the same input at the node. Reverse Combiner Optical Receiver Optical Receiver Optical Receiver Optical Receiver NODE 20 dBmV FREQ CHAN ENTER FCNCLEAR help status alpha light abcdefghi jkl mnopqr stuvwx yz space +/- 1 2 3 456 78 9 0 x. FILE AUTO SETUP TILT SCANLEVEL C/NHUM MOD SWEEP SPECT PRINT System Sweep Transmitter 3SR Stealth Sweep Pad for 0 dBmV

21 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION21 REVERSE LEVEL All signal levels must be set to same output level at the optical receiver in the headend or hubsite with the same input at the node. Reverse Combiner Optical Receiver Optical Receiver Optical Receiver Optical Receiver NODE 20 dBmV FREQ CHAN ENTER FCNCLEAR help status alpha light abcdefghi jkl mnopqr stuvwx yz space +/- 1 2 3 456 78 9 0 x. FILE AUTO SETUP TILT SCANLEVEL C/NHUM MOD SWEEP SPECT PRINT System Sweep Transmitter 3SR Stealth Sweep Pad for 0 dBmV

22 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION22 All signal levels must be set to same output level at the optical receiver in the headend or hubsite with the same input at the node. Reverse Combiner Optical Receiver Optical Receiver Optical Receiver Optical Receiver NODE 20 dBmV FREQ CHAN ENTER FCNCLEAR help status alpha light abcdefghi jkl mnopqr stuvwx yz space +/- 1 2 3 456 78 9 0 x. FILE AUTO SETUP TILT SCANLEVEL C/NHUM MOD SWEEP SPECT PRINT System Sweep Transmitter 3SR Stealth Sweep Pad for 0 dBmV REVERSE LEVEL

23 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION23 All signal levels must be set to same output level at the optical receiver in the headend or hubsite with the same input at the node. Reverse Combiner Optical Receiver Optical Receiver Optical Receiver Optical Receiver NODE 20 dBmV FREQ CHAN ENTER FCNCLEAR help status alpha light abcdefghi jkl mnopqr stuvwx yz space +/- 1 2 3 456 78 9 0 x. FILE AUTO SETUP TILT SCANLEVEL C/NHUM MOD SWEEP SPECT PRINT System Sweep Transmitter 3SR Stealth Sweep Pad for 0 dBmV REVERSE LEVEL

24 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION24 REVERSE NOISE Reverse Combiner Noise -35 dBmV FREQ CHAN ENTER FCNCLEAR help status alpha light abcdefghi jkl mnopqr stuvwx yz space +/- 1 2 3 456 78 9 0 x. FILE AUTO SETUP TILT SCANLEVEL C/NHUM MOD SWEEP SPECT PRINT System Sweep Transmitter 3SR Stealth Sweep Optical Receiver Optical Receiver Optical Receiver Optical Receiver NODE Ideally all combined nodes should have same noise floor to maximize C/N ratio.

25 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION25 Headend combining and splitting Set top converter PathTrak CMTS Other Return Services FREQ CHAN ENTER FCNCLEAR help status alpha light abcdefghi jkl mnopqr stuvwx yz space +/- 1 2 3 456 78 9 0 x. FILE AUTO SETUP TILT SCANLEVEL C/NHUM MOD SWEEP SPECT PRINT System Sweep Transmitter 3SR Stealth Sweep

26 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION26 Return Sweep considerations Instead of point to multipoint, the system is multipoint to point Unity gain at the inputs to the amplifiers Telemetry carriers upstream and downstream Noise and ingress are additive from the entire node. One bad drop can take down the entire node. Channel Plan to match bursty digital signals. No sweep points on upstream carriers Return Sweep compensates for losses after the amp Set telemetry carrier level and sweep level to the same thing.

27 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION27 Advantages of return sweep over the older methods Not as labor intensive as the older methods. Align forward and reverse with the same stop at the amplifier No cumbersome equipment in the field or the headend Minimum use of bandwidth for test equipment Control over the measurements We are aligning the entire spectrum in both directions, not just 2 carriers!

28 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION28 5 things you need to know to set up your return path correctly Know your equipment –Block diagrams of amplifiers, nodes, receivers, etc. –Test Equipment Determine reverse sweep input levels Determine reference points Optimize return lasers portion first Sweep coaxial portion of the plant

29 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION29 Typical Node RF Block Diagram Fwd Signal from Optical Rcvr. Return Signal to Optical Transmitter

30 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION30 (1) Test Points are Bi-Directional Notes: ALL test points can be -20 or -25dB ALC PIN DIODE ATTEN Interstag e EQ Pre- Amplifier Plug-In EQ Plug-In PAD High Pass Filter Diple x Filter HLHL IGC Main Amplifier Reverse Amplifier Plug-In EQ Plug-In PAD Low Pass Filter ALC Circuit Bridger Amplifier AC Powe r RF/AC Filter RF AC Diple x Filter HLHL AC Powe r RF/AC Filter RF AC Powe r RF/AC Filter RF AC Aux EQ Bridger Amplifier AC Powe r RF/AC Filter RF AC Diple x Filter HLHL AC Powe r RF/AC Filter RF AC REV PAD REV PAD TRANSPONDER RF INTERFECE BRIDGER RF TEST REVERSE RF TEST STATION PORT 1 PORT 5 PORT 2 PORT 3 PORT 6 Plug-In EQ Plug-In PAD BRIDGE (1) Typical RF Bridging Amplifier Block Diagram

31 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION31 Know your test equipment Different test equipment operates differently. Size Matters!

32 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION32 How is a reference level determined? H L H L H L H L 23 From trunk return 52 dBmv max modem output 23db tap 2 dB drop loss 7 dB directional coupler 20dBmV at the reference point Does your system use this as the reference point?

33 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION33 ALIGNING THE RETURN PATH

34 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION34 Constant outputs in the return path? Return Equip. R H L R If the return amplifiers were balanced with constant outputs, the levels would vary widely by the time they got back to the headend. This is due to return amplifiers having several inputs. If the return amplifiers were balanced with constant outputs, the levels would vary widely by the time they got back to the headend. This is due to return amplifiers having several inputs.

35 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION35 How does reverse sweep work? Return Equip. R H L R RF in RF out The field unit initiates the sweep through the return path at the reference level. 1. The headend unit receives the sweep from the field unit, digitizes its own trace, and sends out on a forward telemetry pilot. 2. The DSAM receives data from the transmitter and displays sweep from the headend unit 3. FREQ CHAN ENTER FCNCLEAR help status alpha light abcdefghi jkl mnopqr stuvwx yz space +/- 1 2 3 456 78 9 0 x. FILE AUTO SETUP TILT SCANLEVEL C/NHUM MOD SWEEP SPECT PRINT System Sweep Transmitter 3SR Stealth Sweep

36 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION36 Normalizing or Storing a Sweep Reference, reverse Return Equip. R H L R RF in RF out 1.Inject correct input sweep level 2.Check for adjust raw sweep level 3.Store reference file FREQ CHAN ENTER FCNCLEAR help status alpha light abcdefghi jkl mnopqr stuvwx yz space +/- 1 2 3 456 78 9 0 x. FILE AUTO SETUP TILT SCANLEVEL C/NHUM MOD SWEEP SPECT PRINT System Sweep Transmitter 3SR Stealth Sweep

37 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION37 Continuing On Return Equip. R H L R RF in RF out 1.Inject correct input sweep level 2.Use the reverse sweep reference to compare and adjust amplifier output levels FREQ CHAN ENTER FCNCLEAR help status alpha light abcdefghi jkl mnopqr stuvwx yz space +/- 1 2 3 456 78 9 0 x. FILE AUTO SETUP TILT SCANLEVEL C/NHUM MOD SWEEP SPECT PRINT System Sweep Transmitter 3SR Stealth Sweep

38 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION38 Reverse Sweep Display Markers Start Frequency Stop Frequency Marker Frequencies Marker Relative Levels Scale Factor Max Variation within Frequency Range

39 Fiber Optics

40 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION40 After Before Loose Fiber Connector : A display an RF guy can understand SC connector not pushed in all the way

41 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION41 9 125 250 Cross section of an Single Mode optical fiber

42 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION42 Refraction

43 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION43 n = c / v n = refractive index c = velocity of light in a vacuum v = velocity of light in glass IOR = Index of Refraction

44 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION44 Reflection

45 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION45 Light in an optical fiber – Total Internal Reflection

46 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION46 Bending

47 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION47 100 km Attenuation

48 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION48 Optical Return Loss = Optical Reflectance Loss

49 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION49 Common Connector Types SC Commonly referred to as Sam Charlie FC Commonly referred to as Frank Charlie ST Commonly referred to as Sam Tom LC Commonly referred to as Lima Charlie

50 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION50 Connector Configurations PC or UPS vs APC SC - PC SC - APC

51 Inspect Before You Connect sm

52 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION52 Focused On the Connection Bulkhead Adapter Fiber Connector Alignment Sleeve Physical Contact Fiber Ferrule Fiber connectors are widely known as the WEAKEST AND MOST PROBLEMATIC points in the fiber network.

53 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION53 What Makes a GOOD Fiber Connection? Perfect Core Alignment Physical Contact Pristine Connector Interface The 3 basic principles that are critical to achieving an efficient fiber optic connection are The 3 Ps: CLEAN Light Transmitted

54 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION54 What Makes a BAD Fiber Connection? A single particle mated into the core of a fiber can cause significant back reflection, insertion loss and even equipment damage. Visual inspection of fiber optic connectors is the only way to determine if they are truly clean before mating them. CONTAMINATION is the #1 source of troubleshooting in optical networks. DIRT Back ReflectionInsertion LossLight

55 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION55 Illustration of Particle Migration Each time the connectors are mated, particles around the core are displaced, causing them to migrate and spread across the fiber surface. Particles larger than 5µ usually explode and multiply upon mating. Large particles can create barriers (air gap) that prevent physical contact. Particles less than 5µ tend to embed into the fiber surface creating pits and chips. 11.8µ 15.1µ 10.3µ Actual fiber end face images of particle migration Core Cladding

56 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION56 Types of Contamination A fiber end-face should be free of any contamination or defects, as shown below: Common types of contamination and defects include the following: DirtOilPits & ChipsScratches SimplexRibbon

57 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION57 Contamination and Signal Performance Fiber Contamination and Its Affect on Signal Performance CLEAN CONNECTION Back Reflection = -67.5 dB Total Loss = 0.250 dB 1 DIRTY CONNECTION Back Reflection = -32.5 dB Total Loss = 4.87 dB 3 Clean Connection vs. Dirty Connection This OTDR trace illustrates a significant decrease in signal performance when dirty connectors are mated.

58 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION58 Test! Basic Tests –Visual Fault Locator (VFL) –Optical Insertion Loss –Optical Power Levels Advanced Tests –Optical Return Loss (ORL) –Optical Time Domain Reflectometer (OTDR) –Chromatic Dispersion (CD) –Polarization Mode Dispersion (PMD) –Optical Spectral Analysis (OSA)

59 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION59 Visual Fault Locator VFLs provide a visible red light source useful for identifying fiber locations, detecting faults due to bending or poor connectorization, and to confirming continuity. VFL sources can be modulated in a number of formats to help identify the correct VFL (where a number of VFL tests may be performed). FFL-050 FFL-100

60 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION60 Advanced Tests Optical Return Loss (ORL) Optical Time Domain Reflectometer (OTDR) –Detect, locate, and measure events at any location on the fiber link Fiber Characterization –Determines the services that the fiber can be carry –Basic tests plus: Chromatic Dispersion (CD) Polarization Mode Dispersion (PMD) Optical Spectrum Analysis (OSA) –Spectral analysis for Wavelength Division Multiplexing (WDM) systems

61 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION61 Introduction to OTDR Its the single most important tester used in the installation, maintenance & troubleshooting of fiber plant T-BERD 4000 FTTx / Access OTDR Most versatile of Fiber Test Tools Detect, locate and measure events at any location on the fiber link Identifies events & impairments (splices, bends, connectors, breaks) Provides physical distance to each event/ impairment Measures fiber attenuation loss of each event or impairment Provides reflectance / return loss values for each reflective event or impairment Manages the data collected and supports data reporting.

62 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION62 Background on Fiber Phenomena OTDR depends on two types of phenomena: -Rayleigh scattering -Fresnel reflections. Rayleigh scattering and backscattering effect in a fiber Light reflection phenomenon = Fresnel reflection

63 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION63 How does it work ? The OTDR injects a short pulse of light into one end of the fiber and analyzes the backscatter and reflected signal coming back The received signal is then plotted into a backscatter X/Y display in dB vs. distance Event analysis is then performed in order to populate the table of results. OTDR Block DiagramExample of an OTDR trace

64 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION64 Type of Fiber and Wavelengths Single Mode (SM) 1310 & 1550nm are primary wavelengths used in SM OTDR measurements 1625nm is used in trouble- shooting when testing on active networks is needed Multimode (MM) 850 & 1300nm are dominant wavelengths used in MM transmission & testing

65 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION65 Dynamic Range & Injection Level Dynamic Range determines the observable length of the fiber & depends on the OTDR design and settings Injection level is the power level in which the OTDR injects light into the fiber under test Poor launch conditions, resulting in low injection levels, are the primary reason for reductions in dynamic range, and therefore accuracy of the measurements Effect of pulse width: the bigger the pulse, the more backscatter we receive

66 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION66 What does an OTDR Measure ? Distance –The OTDR measurement is based on Time: The round trip time travel of each pulse sent down the fiber is measured. Knowing the speed of light in a vacuum and the index of refraction of the fiber glass, distance can then be calculated. Fiber distance = Speed of light (vacuum) X time 2 x IOR

67 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION67 What does an OTDR Measure ? Attenuation (also called fiber loss) Expressed in dB or dB/km, this represents the loss, or rate of loss between two events along a fiber span

68 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION68 What does an OTDR Measure ? Event Loss Difference in optical power level before and after an event, expressed in dB Fusion Splice or Macrobend Connector or Mechanical Splice

69 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION69 Reflectance Ratio of reflected power to incident power of an event, expressed as a negative dB value The higher the reflectance, the more light reflected back, the worse the connection A -50dB reflectance is better than -20dB value What does an OTDR Measure ? Typical reflectance values Polished Connector ~ -45dB Ultra-Polished Connector~ -55dB Angled Polished Connector ~ -65dB

70 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION70 What does an OTDR Measure ? Optical Return Loss (ORL) Measure of the amount of light that is reflected back from a feature: forward power to the reflected power. The bigger the number in dBs the less light is being reflected. The OTDR is able to measure not only the total ORL of the link but also section ORL Distance (km) Attenuation (dB) ORL of the defined section

71 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION71 Optical Return Loss (ORL) Light reflected back to the source P T : Output power of the light source P APC : Back-reflected power of APC connector P PC : Back-reflected power of PC connector P F : Backscattered power of fiber P B : Total amount of back-reflected power ORL (dB) = 10Log > 0 P APC P PC P APC PTPT PFPF PFPF PFPF Light Source Photo- diode

72 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION72 Effects of High ORL Values All laser sources, especially distributed feedback lasers, are sensitive to optical reflection, which causes spectral fluctuation and, subsequently, power jitter. Return loss is a measure of the amount of reflection accruing in an optical system. A -45dB reflection is equivalent to 45dB return loss (ORL). A minimum of 45-50dB return loss is the industry standard for passive components to ensure normal system operation in singlemode fiber systems. Increase in transmitter noise –Reducing the OSNR in analog video transmission –Increasing the BER in digital transmission systems Increase in light source interference –Changes central wavelength and output power Higher incidence of transmitter damage The angle reduces the back-reflection of the connection. SC - PC SC - APC

73 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION73 OCWR method Optical Return Loss Ratio between the transmitted power and the received power at the fiber origin 2 different test methods: –Optical Continuous Wave Reflectometry (OCWR): A laser source and a power meter, using the same test port, are connected to the fiber under test. –Optical Time Domain Reflectometry (OTDR) OTDR method

74 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION74 Accuracy (typ.)± 0.5dB Typical Application - Total link ORL & isolated event reflectance measurements during fiber installation & commissioning Strengths- Accuracy - Fast & real time info - Simple & easy results (direct value) Weaknesses- No localization Process Controller Display Coupler Photodetector Pulsed Light Source Optical Continuous Wave Reflectometer Optical Time Domain Reflectometer ORL Measurement Methods Termination Plug Process Controller Display CW Stabilized Light Source Power Meter Coupler Accuracy (typ.)± 2dB Typical Application - Perfect tool for troubleshooting- Spatial characterization of reflective events & estimation of the partial & total ORL Strengths- Locate reflective events - Single-end measurement Weaknesses- Accuracy - Long acquisition time

75 OTDR Events How to interpret a trace

76 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION76 How to interpret an OTDR Trace

77 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION77 Front End Reflection Connection between the OTDR and the patchcord or launch cable Located at the extreme left edge of the trace Reflectance: Polished Connector ~ -45dB Ultra-Polished Connector~ -55dB Angled Polished Connector up to ~ -65dB Insertion Loss: Unable to measure

78 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION78 Dead Zones Attenuation Dead Zone (ADZ) is the minimum distance after a reflective event that a non-reflective event can be measured (0.5dB) In this case the two events are more closely spaced than the ADZ, and shown as one event ADZ can be reduced using shorter pulse widths Event Dead Zone (EDZ) is the minimum distance where 2 consecutive unsaturated reflective events can be distinguished In this case the two events are more closely spaced than the EDZ, and shown as one event EDZ can be reduced using shorter pulse widths

79 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION79 Connector A connector mechanically mates 2 fibers together and creates a reflective event Reflectance: Polished Connector ~ -45dB Ultra-Polished Connector~ -55dB Angled Polished Connector up to ~ -65dB Insertion Loss: ~ 0.5dB (loss of ~0.2dB w/ very good connector)

80 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION80 Fusion Splices A Fusion Splice thermally fuses two fibers together using a splicing machine Reflectance: None Insertion Loss: < 0.1dB A Gainer is a splice gain that appears when two fibers of different backscatter coefficients are spliced together (the higher coefficient being downstream) Reflectance: None Insertion Loss: Small gain

81 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION81 Fusion Splices Direction A-B Direction B-A

82 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION82 Macrobend Macrobending results from physical bending of the fiber. Bending Losses are higher as wavelength increases. Therefore to distinguish a bend from a splice, two wavelengths are used (typically 1310 & 1550nm) Reflectance: None Insertion Loss: Varies w/ degree of bend & wavelength

83 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION83 Mechanical Splice A Mechanical Splice mechanically aligns two fibers together using a self-contained assembly. Reflectance: ~ -35dB Insertion Loss: ~ 0.5dB

84 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION84 Fiber End or Break A Fiber End or Break occurs when the fiber terminates. The end reflection depends on the fiber end cleavage and its environment. Reflectance: PC open to air ~ -14dB APC open to air~ - 35dB Insertion Loss: High (generally)

85 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION85 Ghosts A Ghost is an unexpected event resulting from a strong reflection causing echos on the trace When it appears it often occurs after the fiber end. It is always an exact duplicate distance from the incident reflection. Reflectance: Lower than echo source Insertion Loss: None

86 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION86 Typical Attenuation Values 0.2 dB/km for singlemode fiber at 1550 nm 0.35 dB/km for singlemode fiber at 1310 nm 1 dB/km for multimode fiber at 1300 nm 3 dB/km for multimode fiber at 850 nm 0.05 dB for a fusion splice 0.3 dB for a mechanical splice 0.5 dB for a connector pair (FOTP-34) Splitters/monitor points (varys with component)

87 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION87 Monitoring the Reverse Path Inside Plant

88 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION88 Major Operational Challenges Plant Certification and Maintenance: –Elevate plant performance to ensure reliable service –HFC: Sweep & advanced return path certification –Metro Optical: Fiber and transport analysis Monitor Performance: –Continuously monitor the health of your upstream and downstream carriers –Proactively identify developing problems before customers do –Monitor both physical HFC & VoIP service call quality –Utilize advanced performance trending and analysis to prioritize Get Installations Right the First Time –Improve installation practices to prevent service callbacks & churn –Verify physical, DOCSIS® and PacketCable performance –Drive consistency across all technicians Troubleshoot Fast: –When issues occur, find and fix fast –Isolate and segment from NOC, dispatch right tech at right time –Field test tools that can find problems and verify fix

89 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION89 Return Path Monitoring Benefits Troubleshoot nodes faster to reduce MTTR and increase workforce efficiency Identify impairments before rolling a truck using both spectrum and packet monitoring technology Use field meters to quickly locate ingress, the most common impairment View performance history to understand transient problems to roll a truck at the right time to find and fix the issue Reduce trouble tickets and customer churn by identifying problems before your subscribers Rank nodes using convenient web-based reports for proactive maintenance Easily and quickly detect impairments such as fast impulse noise, ingress, CPD, and laser clipping on all nodes 24/7 View live spectrum, QAMTrak analyzers and a wide array of reports conveniently via the web

90 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION90 DOCSIS® 3.0 adds Capability to Bond up to 4 Upstream 64QAM Carriers! Four times 6.4 MHz = 25.6 MHz! (without guard-bands) Increased chances for laser clipping Increased probability of problems caused by ingress, group delay, micro-reflections and other linear distortions Inability to avoid problem frequencies such as Citizens Band, Ham, Shortwave and CPD distortion beats Where are you going to place your sweep points?

91 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION91 Live Spectrum Display

92 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION92 Choose a carrier for QAMTrak

93 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION93 Getting To Know The QAMTrak Analyzer QAMTrak Sections Impairment Dashboard Impairment Charts FFT Spectrum Display Constellation Strip Chart Data Tables Control/Information Bar

94 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION94 QAMTrak Analyzer: Primary Sections Impairment Dashboard Display in simple red light / green light format which impairments have violated admin-defined thresholds and what % of packets affected by each (rollup status) Shows min/max/average for health metrics and impairments Provides single-click launch points to detailed charts for each impairment type

95 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION95 Impairment Dashboard – Two Main Sections Top three boxes indicate HFC health –Is data corruption occurring within packets being demodulated? –How tight are the constellation points before CMTS compensation –How well is the CMTS likely able to compensate for impairments present Bottom six boxes indicate how frequently each impairment type is occurring –How often does a packet come across which violates threshold? –What is min/max/average for each impairment type? –Which impairment(s) are my biggest problem right now? Clicking any button will launch a maximized impairment chart window within the QAMTrak Analyzer

96 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION96 Impairment Dashboard – General Interpretation Impairment/Health Metric Label Rollup Counter Percent of packets since start of QAMTrak session which have violated admin defined threshold for that impairment or metric Latest Value Value for last packet demodulated or current packet highlighted for historical packet analysis Min/Max/Average Minimum, Maximum, Average values for all packets captured during current QAMTrak session or since last reset Caveats: Only the latest 600 packets are displayed on strip chart and in tables Min/Max/Average and Rollup Counter can reflect packets which are not visible in strip chart of tables for sessions with >600 packets captured! Latest Status Pass/Fail status for last packet demodulated or current packet highlighted for historical packet analysis ( or ) Session Status (Background Color) Indicates whether impairment threshold has been violated during session

97 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION97 Primary Impairments Impairment Dashboard Provides detailed display for five primary impairment types plus codeword error strip chart – supplement Impairment Dashboard Charts update for each packet in live mode or historical packet review mode Y-Axes can be manually rescaled or auto-scaled, charts can be resized, many other options available through Flash interface Impairment Dashboard Impairment Charts

98 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION98 Primary Measurements Provides Spectrum Analyzer display without opening a separate window FFT-based spectrum analyzer – will look different than standard PathTrak SA Display will show what spectrum looked like at time of packet capture when reviewing captured packets in paused mode Impairment Dashboard Impairment Charts FFT Spectrum Display

99 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION99 Upstream Constellation Can display Equalized, UnEqualized symbol locations, or both Can show latest packets, all historical packets, or both Displays constellation packet by packet when reviewing historical packets Impairment Dashboard Impairment Charts FFT Spectrum Display Constellation

100 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION100 QAMTrak Analyzer: Primary Sections Separate chart traces for Equalized MER, Unequalized MER, and Carrier Level (on second Y-Axis) Detailed packet info available using hover function Can use arrow keys to review historical packets one at a time Impairment Dashboard Impairment Charts FFT Spectrum Display Constellation Strip Chart

101 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION101 QAMTrak Analyzer: Primary Sections Users can toggle between strip chart, all-packet data table, and unique MAC data table Tables are sortable by all rows, can be exported to.csv file Data can be copied from tables to clipboard for pasting into other apps Impairment Dashboard Impairment Charts FFT Spectrum Display Constellation Strip Chart Data Tables

102 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION102 PathTrak WebView CPE MAC Address Code Word Errors

103 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION103 PathTrak WebView QAMTrak CPE MAC Address Codeword Error Detection Equalized and UnEqualized MER Micro-reflections In Band Response – Ripple Group Delay Ingress Under the Carrier Impulse Noise Detection

104 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION104 DOCSIS Downstream Codewords 122 of each RS codewords 128 symbols are data symbols, and the remaining six are parity symbols used for error correction. –ITU-T J.83, Annex B states that the data is …encoded using a (128,122) code over GF(128)… which shows each RS codeword consists of 128 RS symbols (first number in first parentheses) and the number of data symbols per RS codeword is 122 (second number in first parentheses), leaving six symbols per RS codeword for error correction. DOCSIS downstream RS FEC is configured for what is known as t = 3, which means that the FEC can fix up to any three errored RS symbols in a RS codeword.

105 Downstream Monitoring

106 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION106 Home Hub/HFC The Cable Video Network Master/Super Headend MPEG Headend IP Transport Video Passes Through Four Separate Operational Layers Before it Reaches the Home. But The MPEG Edge is the most critical layer and poses the most significant risk to video quality. Outside Plant CMTS STB Phone PC Modem DPI MPEG Mux. Encryption Modulation IP L2/L3 Core Network Origination and processing Transport through the IP network MPEG edge- processing RF combining VOD Distribution over HFC CombinerCombiner Inside Plant Off-air Ingest

107 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION107 The RF edge is home to the most complex equipment in the network Current monitoring solutions focus on the national backbone and on validating the content when programming first enters the network. Often QoS issues (like tiling) are introduced by the complicated equipment at the network edge If you arent monitoring at the RF edge, only the subscriber will have visibility to the impairments –Youve caused these problems, but you dont see them Troubleshooting is initiated by a customer complaint and without this edge visibility you may spend multiple truck rolls and weeks isolating the source. CMTS DPI MPEG Mux. Encryption Modulation MPEG edge- processing RF combining CombinerCombiner Off-air Ingest

108 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION108 Often QoS issues are introduced by the complicated equipment at the network edge CMTS DPI MPEG Mux. Encryption Modulation MPEG edge- processing RF combining CombinerCombiner Off-air Ingest Local Off-Air Ingest: Provider issues Antennas 8VSB Receivers Muxes to groom for regional networks Program Insertion: Quality of ad being spiced PCR Discontinuity Decoding/Timing of DPI information Multiplexing: Streams from regional networks Grooming Transrating Over-compression Equipment configuration Encryption: Encryption not-enabled Equipment configuration Modulation: MPEG to RF Equipment configuration Oversubscription RF Combining: Poor cabling Poor Isolation Loose connectors Driver/Isolation amp issues And currently this is the last place youre monitoring the video?

109 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION109 You may already have monitoring… … but your customers are still seeing issues Outside Plant CMTS STB Phone PC Modem DPI MPEG Mux. Encryption Modulation IP L2/L3 Core Network VOD CombinerCombiner Inside Plant Off-air Ingest Content monitoring has traditionally been expensive. Typically deployed only where content enters the network. Content Monitoring is typically not deployed at the very edge of the network That leaves the most vulnerable spot in the network, in the dark

110 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION110 Detailed MPEG analysis detects the important issues Video/Audio QoS issues caused by equipment in the headend or local network are transport related and can be identified without performing content analysis –Video freeze result of lost programs or video PIDs –Audio loss as a result of missing audio PIDs Other frozen/black/no-audio that are the result of content (and not the programs) in almost all cases isnt anything local system personnel can do anything about. Content analysis also limited to unencrypted programming – preventing use at edge of the network. Content analysis is impractical and costly at the edge of the network. Investment is significantly more effective if focused on transport tools that provide complete visibility and troubleshooting directly at the edge modulator.

111 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION111 Get complete visibility – Wrap the Edge MVP-200 RSAM Video Monitoring is a video monitoring solution optimized for the network edge –MVP-200 probe (full line-rate MPEG over GigE) –RSAM probe (Digital video RF, Analog video RF, DOCSIS) –PVM – Simple, lightweight, centralized system to tie it all together. Outside Plant CMTS STB Phone PC Modem DPI MPEG Mux. Encryption Modulation IP L2/L3 Core Network Origination and processing Transport through the IP network MPEG edge- processing RF combining VOD Distribution over HFC CombinerCombiner Inside Plant Off-air Ingest

112 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION112 Example – Tiling The RF probe consistently reported Continuity error alarms on a QAM. This clip shows what your Customer experienced –the impact of these CC errors

113 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION113 Another Example - Video Freeze How do you explain this to your customer?? HLN_13 (27) MVP Trap QAM 28 OUTPUT Trap Console received trap traps/event. Time: January 6, 2011 6:03:10 AM EST STB: 27 PID ID: -1 PID: -1 PID Type: Event ID: programLost Event Severity: minor From MVP: 10.15.21.24 Card: 2 Source IP: XX.240.203.206:60000 Dest. IP: XXX.48.81.115:28115 HLN_13 (27) MVP Trap QAM 28 OUTPUT Trap Console received trap traps/event. Time: January 6, 2011 6:03:17 AM EST STB: 27 PID ID: -1 PID: -1 PID Type: Event ID: programLost Event Severity: major From MVP: 10.15.21.24 Card: 2 Source IP: XX.240.203.206:60000 Dest. IP: XXX.48.81.115:28115 HLN_13 (27) MVP Trap QAM 28 OUTPUT Trap Console received trap traps/event. Time: January 6, 2011 6:03:21 AM EST STB: 27 PID ID: -1 PID: -1 PID Type: Event ID: programLost Event Severity: clear From MVP: 10.15.21.24 Card: 2 Source IP: XX.240.203.206:60000 Dest. IP: XXX.48.81.115:28115 Below are the alarms generated for the above event from the MVP: Click on video to play

114 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION114 Knowing is only half the battle… Monitoring tells you when you have a problem. –To isolate the problem source, the ops staff needs troubleshooting tools as well. Remote access via PVM gives service level visibility at the edge of your network, from anywhere. –Critical in digital video, where problems are intermittent and spurious. –Critical at the edge, where staff may be hours from the equipment. JDSUs monitoring probes are unique in providing integrated real- time analyzers for troubleshooting. Troubleshoot anytime, anywhere.

115 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION115 Video Monitoring Application Identify and segment problems using intuitive displays –RF or MPEG? –Outside plan, headend or source issue –Widespread or localized? –Intermittent or persistent problem? Find root-cause with advanced troubleshooting –Click an event or status bar to get a live display –Capture transport streams to share with your network equipment suppliers –View table decodes to understand impairments Access Historical PM Reports –NetComplete –Per Program, Per Node –Worst Offenders –Key Performance Indicators

116 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION116 Network Management System Integration SNMP and XML API: –Designed to be flexible and easily integrated Per Program and Per Stream, real-time data –Real-time per program status to one system view

117 © 2011 JDSU. All rights reserved.JDSU CONFIDENTIAL & PROPRIETARY INFORMATION117 Why Video Monitoring? Solve real problems today –Optimized for an operations staff Real-time alarming direct to local staff Complete RF component for analog, digital and DOCSIS –Cost-Efficient Fraction of the cost of conventional content monitoring –Proximity to the Edge Monitor right at hand-off to access network, visibility for entire digital network –Isolate problem sources Integrated remote analyzers at IP and RF

118 Thank You


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