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
