Xfinity NCT4

2

# of expansion loops for an aerial span 250 ft or greater

1

# of expansion loops for an aerial span less than 250 ft

DC Loop Resistance

(Footage / 1000) * Spec sheet Resistance

0

1 mV across a 75 ohm impedance is equal to ____dBmV

IPv6

128 bit address written in colon-hexidecimal notation

IPv4

32 bit address written in dotted decimal notation.

Single Stacked

A ________ ___________ device that is configured for IPv4-only or IPv6-only.

Dual Stacked

A ________ _____________ device that is configured for both IPv4 and IPv6.

Ground

A connection to earth or a conductor serving as earth potential, and can be intentional or accidental.

Analog Signals

A continuous signal that varies in amplitude or frequency

Design Map

A design map that displays the locations of electronic equipment, including the headend and any hubs, as well as the amplifiers, power supplies, and taps.

Unity Gain

A design philosophy where the loss of the cable and other passive devices before an amplifier station equal the gain of the amplifier station.

Short

A downward trace on a TDR waveform indicates what type of fault?

CLI

A figure of merit derived mathematically from the number and severity of signal leaks in a cable system.

SLM (Signal Level Meter)

A frequency selective receiver capable of tuning in a desired frequency/channel with a display showing the RF signal strength (dBmV)

Group Delay

A function of transit time across a circuit

AC Waveform

A graph that shows the relationship between voltage/current and elapsed time

Warning Tape

A highly visible tape usually used when burying fiber optic cable, buried directly above the cable to point out the existence of the cable to anyone digging in that location.

Expansion Loop

A loop intentionally formed in the cable to compensate for expansion and contraction caused by temperature changes.

Shunt

A low-resistance connection between two points in an electric circuit that forms an alternative path for a portion of the current.

Strand Map

A map depicts streets with pole and pedestal locations and includes the span length or footage between these items.

As-Built Map

A map that is typically issued after the cable network is constructed.

Output Capability

A measure of an amplifier's output level to the level of distortion it produces.

Divide and Conquer

A method used to lessen the amount of time required to solve an outage problem.

Lockout Tag-out

A method used to lock and mark one end of a line in order to allow someone to safely work on the other end.

Hybrid Fiber Coax (HFC)

A network architecture developed by the cable industry, which uses fiber optic cables to bring signals to selected areas of the system called the Node Service Area.

Ring

A network architecture where nodes, hubs, or headends may be connected with fiber optic cables to provide redundancy or increase services.

Spatial Offline

A program that gives us the ability to submit map changes (markups) when we discover inaccuracies in the field.

Riser Guard

A protective covering placed over exposed cable where it makes the transition from aerial to underground.

dB

A ratio between two signal levels

Protocol

A set of rules that govern how the devices message each other to transport data, and allow interoperability of devices from different vendors.

Isolation

A signal's inability to be transmitted from one cable or device to another cable or device and measured in dB.

DQI

A simple indicator of the overall quality of a QAM digital stream.

I-Stop Reverse Test Probe

A test accessory that simplifies the location of reverse ingress sources.

Lashing Wire

A thin wire wrapped around the fiber and coaxial cables to secure them to the strand.

TDMA

Allocates traffic in bursts to a time slot assigned to a specific carrier. At that moment in time, the cable modem has the use of the entire carrier.

SCDMA

Allows multiple modems to transmit on the same carrier at the same time.

Noise Figure

Amount of noise an amplifier adds

30 seconds

Amount of time you allow the meter to sync while testing digital measurements.

Power Pack

Amplifier component that converts 60 or 90 VAC to the approximately 24 VDC required for the amplifier to operate.

ASK

Amplitude Shift Keying

dBmV

An absolute amount of signal

DOCSIS

An international telecommunications standard that permits the addition of high-speed data transfer to an existing CATV system

Open

An upward trace on a TDR waveform indicates what type of fault?

Peak

Analog measurements are a _____ power

ADC

Analog to Digital Conversion

Form 320

Annual CLI Calculation Form

Distortion

Any undesired change in the waveform of a signal.

Quantization

Assigning specific values to each sample of a signal that is taken

Single Stacked

At Comcast, a cable modem has a __________ ____________ configuration.

FVD

Before checking out any active or passive device, your _____ should be used to check for foreign voltage

Anchor

Buried metal device used to transfer force from the pole to the ground.

64 or less

CLI figure of merit

Signature

CM's that have been grouped together for showing common issues with their responses are said to have the same ___________________?

P Picture

Calculated by comparing previous and successive pictures

Dead Zone

Can be found at the beginning of the cable caused by the time lag needed for the pulse width to launch into the cable.

DMM (Digital Multi Meter)

Can be used to measure AC and DC voltages and currents, as well as resistance.

Double Hum Bar

Caused by a failure of filters in power packs

Single Hum Bar

Caused by a failure of power passing chokes.

CPD (Common Path Distortion)

Caused by oxidation/corrosion between two dissimilar metals connected together.

Modulation

Changing or varying of the amplitude, frequency, or phase of a carrier.

CTB (Composite Triple Beat)

Combined effect of all combinations of 3 channels mixing

CSO (Composite 2nd Order)

Combined effect of all combinations of two channels mixing.

Channel Bonding

Combining four or eight 6MHz channels to form a wideband 24 or 48 MHz channel

Index of Refraction

Compares the speed of light through a material to the speed of light through a vacuum.

Codec

Compression/Decompression

T4 Timeout

Condition where a cable modem (CM) did not receive a maintenance opportunity from the CMTS within the 30-35 second time window.

T3 Timeout

Condition where a cable modem (CM) sent 16 RNG REQ and did not receive a RNG RSP from the CMTS

Carrier to Sustained Impairments

Continuous unwanted signal within the channel pass band that can affect digital decoding.

Digitization

Conversion of an analog to digital signal

Encoding

Conversion of quanitfied samples to binary data

300 ft

Coverage range of Xfinity WiFi Access Points.

Isolation

Crosstalk between passive device ports are minimized with good __________________

CLI

Cumulative Leakage Index

CPS

Cycles per Second, Hertz, Frequency

DOCSIS

Data Over Cable Service Interface Specifications

Outage

Defined as two or more customers without service or with impaired service, due to the same root cause.

RMS Meter

Device that accurately measures AC voltages of signals other than pure analog sine waves.

Cable Locater

Device used to find the location or path of underground cables

TDR (Time Domain Reflectometer)

Device used to locate faults in cables.

Dynamometer

Device used to measure the dynamic tension in the cable.

Breakaway Swivel

Device which ensures that the maximum allowable tension for that cable is not exceeded.

C/N (Carrier to Noise Ratio)

Difference between the peak carrier level and the noise level.

Spectral Regrowth

Digital effect due to power loading on amplifier circuits or laser overdrive.

Average

Digital measurements are a _____ power

DAC

Digital to Analog Conversion

Digital Signals

Dis-continuous signals that changes output in discrete intervals

2 Times the Height

Distance cable reel should be placed from lashing point to ensure no kinks or bends.

4.5 Mhz

Distance from the peak of a video carrier to the audio carrier

3.58 MHz

Distance from the peak of a video carrier to the color carrier

1.25 MHz

Distance from the start of an analog carrier to the peak of the video carrier

12 inches

Distance warning tape should be placed under the surface of the ground

3.01

Doubling a cascade causes a ___ dB worsening of C/N

6.02

Doubling a cascade causes a ___ dB worsening of both XMOD and CTB

Inductance, Resistance, Capacitance

Electrical characteristics of Impedance

E

Electromotive Force, Pressure, Voltage

Code of Federal Regulations, Title 47, Telecommunication, Part 76, Cable Television Service

FCC Regulations dealing with signal leakage

MPEG

Family of standards for compression/decompression of A/V signals in digital format

FCC

Federal Communications Commission

2

For every 1dB change in input level, there is a ___dB change in XMod and CTB

1

For every 1dB change in input levels, there is a ___dB change in output C/N

FEC

Forward Error Correction

FSK

Frequency Shift Keying

QPSK or 4 QAM

Has 2 bits of information per symbol

16 QAM

Has 4 bits of information per symbol

64 QAM

Has 6 bits of information per symbol

256 QAM

Has 8 bits of information per symbol

I Picture

Has all spatial information

Total Internal Reflection

How light propagates through fiber

Dipole

In order to measure a leak, a ______ antenna should be used.

54, 216

In the ______ to ______ MHz frequency range, leakage above the threshold must be logged and fixed

75 in/lb

Installation torque spec of battery terminal connectors

I

Intensity, Current, Flow of Electrons

Current

Is inversely proportional to resistance, and directly proportional to voltage

Digital Signal

Is regenerated rather than amplified

700 MHz to 800 MHz

LTE operates in the ______MHz to _____MHz frequency range.

Class 4

Laser that can harm eyes and skin.

Class 3A

Laser that is an eye hazard if collected or focused on the eye

Class 3B

Laser that is an eye hazard if the direct, or reflected, beam is viewed

Class 2/2A

Laser that is an eye hazard if viewed directly

Class 1

Laser that is safe if not disassembled

2

Leakage logs must be kept on file for at least ____ years.

20 uV/m

Leaks of ________ and higher must be logged and fixed during leakage monitoring

Laser

Light Amplification by Stimulated Emission of Radiation

LPI

Line Power Inserter

LTE

Long Term Evolution

.35 db/km

Loss of signal strength at 1310 nm

.25 db/km

Loss of signal strength at 1550 nm

60 in/lb

Maintenance torque spec of battery terminal connectors

Yellow

Marking color that denotes gas, oil, petroleum

Blue

Marking color that denotes potable water

Red

Marking color that denotes power

White

Marking color that denotes proposed excavation

Green

Marking color that denotes sewage, drain lines

Orange

Marking color that denotes telecommunications

Pink

Marking color that denotes temporary survey marks

.3

Maximum VDC difference between any batteries

80%

Maximum load of a power supply

3

Maximum number of errored codewords FEC can compensate for.

.3 V

Maximum voltage difference between any battery in a series.

Sampling

Measuring of an analog signal at specific intervals

Parallel Connection

Method of connecting batteries together to increase total capacity

Series Connection

Method of connecting batteries together to increase voltage

Triangulation

Method used to accurately locate a leak

Discrete 2nd Order

Mixing of 2 carriers

Discrete 3rd Order

Mixing of 3 carriers

Status Monitoring

Monitoring of the network remotely

Load Test

Most effective battery testing method

Load Test

Most reliable battery test

nm

Nanometer

Termination Noise

Noise in a 4 MHz bandwidth on a 75 Ohm cable at 68 degrees Fahrenheit.

Baud

Number of changed states per second

Pathtrak

Online tool that gives you a spectrum analyzer view of the return path for the entire node.

Watchtower

Online tool that proactively identifies problems in the HFC network.

50

Only leakages of __ μV/m or greater are included in the CLI calculations.

50 uV/m

Only leaks of ________ or greater are used during the CLI calculation.

100

Open ports and shorts reflect ____% of the signal

mW, dbm

Optical power units are measured in _____ or _____

PSK

Phase Shift Keying

10

Power and Noise measurements are a ___ log function

Distributed

Power architecture that can have multiple power supplies per node

Centralized

Power architecture that has one power supply per node

40 inches

Proper clearance distance from commercial power secondaries to our strand.

QAM

Quadrature Amplitude Modulation

QPSK

Quadrature Phase Shift Keying

mV, dBmV

RF power units are measured in _____ or _____

Thermal Noise

Random movement of electrons.

Ghost

Receiving a signal of the same frequency and content before or after the desired signal.

Multipath and Micro-reflections

Reflections that, if high enough in level in relation to the carrier, cause digital decoding problems.

R

Resistance, Opposition to Current Flow

50 ft, or 1/3 distance of the next span, whichever is greater

Safe lashing distance before you can remove the expansion loop form/bender.

Bug Nut

Secures one end of the lashing to the strand

Bucking power

Sending AC voltage from two different power supplies, causing a large spark.

Yes

Should battery terminals be greased with corrosion inhibitors?

ALS (Automatic Level and Slope Control)

Similar to an AGC, but also corrects the signals tilt as well.

125 microns

Size of the cladding in SM fiber

250 microns

Size of the coating in SM fiber

8-9 microns

Size of the core in SM fiber

Guy

Strand that connects the pole line hardware to the anchor.

Hum Modulation

Superimposing 60 CPS onto RF signals, appears as a horizontal bar in the picture

Modulation

Superimposing a signal onto a carrier wave

SCDMA

Synchronous Code Division Multiple Access

Funnel Effect

Term for the additive quality of return path issues.

Receiver, Transmitter, Power Pack, Amplifier

The 4 parts of an optical node.

FCC

The U.S. government agency established in 1934 to regulate electronic communications.

3rd Stage

The ______________, or output stage, is typically chosen for its output capability.

1st Stage

The _______________ in an amplifier is chosen for its low noise figure and typically wants flat inputs

2nd Stage, Inter-Stage

The _______________ in an amplifier is commonly referred to as the _______________, and is typically a power double configuration.

Response

The amplitude of the sweep across the frequency range being swept is called _______________

FM (Frequency Modulation)

The audio carrier in an analog signal uses this type of modulation

MER

The average power difference of where the symbols landed versus the power at where they should have landed.

PM (Phase Modulation)

The color carrier in an analog signal uses this type of modulation

Impedance Mismatch

The condition that results when two components of a system are operating at different impedance.

XMOD (Cross Mod)

The crossing of modulation from one channel to another, appears as a vertical bar in an analog picture.

Seizure Mechanism

The device, usually a screw, used to connect the coaxial cable's center conductor to an active or passive device.

Return Loss

The difference between the desired signal level and the reflected signal level at active and passive device connections.

Structural Return Loss

The difference between the desired signal level and the reflected signal level within the coaxial cable.

Port to Port Isolation

The difference in dB, of a signal level, injected into one output port, and the measured level of the same signal on another output port, with the input port properly terminated.

Potential Difference

The difference in voltage between one point and another

Wavelength

The distance between two points of like phase in a wave.

MER

The indicator of transmission quality degradation resulting from noise, ingress, and composite distortions.

Bond

The interconnection through good conductors of the cable plant with the phone and power systems to eliminate potential voltage differences.

Strand

The load-bearing, steel support wire to which the coaxial and fiber optic cables are lashed in aerial installations.

15 dB

The maximum signal level at the input to the customer's television

43 dB

The minimum FCC required analog C/N on the system

Nyquist Rule

The minimum sampling rate equal to twice the highest frequency contained in a signal.

0 dB

The minimum signal level at the input to the customer's television.

Sweep

The most effective method of measuring gain versus frequency

Optical Modulation Index

The percentage of optical modulation, per channel, driving a laser transmitter. OMI

wavelength

The physical length of one cycle of a waveform

LPI

The point on the plant where power in inserted

BER

The ratio of the number of wrong bits over the number of total bits.

Impedance

The resistance of a circuit (cable, passive devices are examples) to alternating current.

20, 3

The signal leakage limit, in between 54 MHz and 216 MHz, should be no more than ___ microvolts (μV/m) @ __ meters

Map Grid System

The system is used to catalogue your system maps.

Center Conductor, Distance from the CC to the Shield, Dialectric Material

The three factors of a coaxial cable that determine its impedance to AC.

Sampling, Quantization, Encoding

The three parts of digitization

Tree and Branch

The topology where signals originate in the headend and are transmitted long distances via trunk cables, which have branches for directing the signal to customers.

MER and BER

The two basic parameters used to evaluate the quality and performance of digital signals.

AM (Amplitude Modulation)

The video carrier in an analog signal uses this type of modulation

Telemetry

The____________ value in a return sweep is used to ensure unity gain.

AGC (Automatic Gain Control)

This device monitors a pilot channel, and is used to compensate for fluctuations of the signal input.

Load, Voltage, Conductance

Three types of battery tests

TDMA

Time Division Multiple Access

True

True or False, The current at any point is equal to the sum of the current after that point.

Distortions, Low

Trunk amps are used to keep ______________ minimized by keeping the output levels _______.

1310 nm and 1550 nm

Two most common wavelength lasers used for telecommunications.

NCP-2, NO-OX

Two types of corrosion inhibitors

Wet and Dry

Two types of fiber optic cleaning

Single Mode Fiber (SM)

Type of optical fiber that Comcast primarily uses.

Sine

Typical commercial power waveform

Ampere

Unit of Measurement for Current (I)

Volts

Unit of Measurement for Electromotive Force (E)

Ohm

Unit of Measurement for Resistance (R)

UDP

Universal Datagram Protocol

Beat

Unwanted sum/difference of frequencies resulting from the heterodyning (mixing) of two or more signals.

Guy and Anchor

Used to counteract the horizontal component of forces placed on poles by the strand and cable.

Sweep

Used to view the frequency response in a cable system

B Picture

Uses both past and subsequent pictures

Phase Noise

Usually caused due to oscillator instability in processing equipment.

QAM

Varies the phase AND amplitude

QPSK

Varies the phase only

VOP

Velocity of Propagation

20

Voltage, CTB and Cross-mod distortions are a ___log function

TCP

Was developed as a way to tell the sending server that not all the packets got to their destination, and to please resend them.

Quasi-Square

Waveform generated by a power supply

Square

Waveform generated by an amplifiers DC power packs

Sawtooth

Waveform generated by oscillators

High Pass Filter

What a power inserter (LPI) uses to allow RF to flow from port to port.

Low Pass Filter

What a power inserter (LPI) uses to prevent RF from entering the power supply.

Core, Cladding, Coating

What are the three parts of an optical fiber?

54 - 216 MHz

What frequency range does the FCC require signal leakage to be less than 20uV at 3m?

Crosstalk

When a portion of the signal present on a passive device's port is seen on another port.

Bad, Good

When a tap is cut in backwards, the signal on the tap ports will be ______, and the through put signal will be ______.

Feeder Dominant

When the loop location is dictated by the signal flow direction of the feeder cable.

Double Dead End

When two perpendicular strands end at the same pole.

FEC

Where additional bits are added to a codeword for this purpose.

No

Yes or No, Can you see the end of a properly terminated cable in a TDR trace?

3.01

dB change of a doubling or halving of power

6.02

dB change of a doubling or halving of voltage

mV

millivolt