NCT4 v2 Flashcards
Random electron activity in the atoms that make up the conductor
Thermal Noise
Noise floor in a 4MHz bandwidth @ 68*F is called:
Termination Noise
Difference in a peak carrier level to the noise floor:
Carrier to Noise
Amount of noise in a 4MHz bandwidth on a 75 Ohm cable @ 68*F
-59.16dB
FCC Spec for C/N
43dB
Undesired change in the waveform of a signal
distorion
Crossing of Modulation from one channel to another
XMOD or Cross Modulation
XMOD appears as
Vertical bars in the picture
2nd harmonics of any 2 channels are typically _____ below the sum/difference products
6dB
CTB products fall within _____ of the video carrier
30 KHz
Tilting the output of an amplifier improves:
Distortion performance
CSO beats fall @ __________ above the video carrier
1.25MHz +/- 15 KHz
unwanted sum/difference frequencies resulting from heterodyning of 2 or more signals
Beats
A horizontal bar in the picture is _______ Modulation
Hum
Primary cause of Hum (60Hz)
Power Passing Choke (60Hz)
A source of hum in older systems (120Hz)
Series regulated DC Power supplies (120Hz)
3 parts of fiber
Coating, Cladding, Core
When light stays in the core, this is called
Total Internal Reflection
2 wavelengths used in HFC Networks
1550nm & 1310nm
Most common type of fiber used in the cable industry
Single Mode Fiber
Wavelength is ________ proportional to frequency
Inversely
A shorter wavelength means a _______ Frequency
Higher
Compares the speed of refracted light in a material to the speed of light in a vacuum
Index of Refraction
One Billionth of a meter
nanometer
Device that takes the RF and modulates it onto an optical wavelength
Optical Transmitter
Optical transmitters use this type of diode
Laser Diode
What device detects light and demodulates it to RF
Optical Receiver
An optical receiver uses this type of Diode
Photo Diode
C/N Formula
L1-(NF-59.2)
Formula for C/N @ end of cascade
C/N1-10logN (C/N1 is equal to the C/N of a single amplifier in the cascade, N=Number of amplifiers)
XMOD Formula
XMOD1 - 20logN
CTB Formula
CTB1 - 20logN
Devices that are used to compensate for the forward and return loss
Amplifiers
What device compensates for the uneven cable loss in coax?
Equalizer
Amplifier input EQs are selected to do what?
Provide flat inputs to the first stage of amplification
amplifier interstage EQs are selected to do what?
Provide output tilt
Forwards trunk amplifiers are selected for their what?
Low Noise Figure (NF)
What compensates for fluctuations in the input signal?
AGC
The name of the frequency that is monitored by the AGC
Pilot
It provides a means to monitor levels with out interrupting service
Test Point
This device has substantial isolation between it’s output & tap port:
Directional Coupler (DC)
What device has both a DC & Splitter built into it?
Tap
What device is considered to be the customer interface point?
Tap
This device compensates for reverse tilt on the feeder
In-Line EQ
This device has a diplex filter & a pad that will only affect the return
In-Line Conditioner
This device uses a low pass filter to prevent RF from entering the Power Supply
Line Power Inserter (LPI
This map only shows the poles & Strand
Strand Map
This map is the point where actives are added to the network
Design Map
This map shows the network changes from the original design as the design needed to be modified when it was being built
As-Built
This map shows only one Node
HFC Plant Map
The numbering system used to catalog plant maps is called:
Map Grid System
CLI
Cumulative Leakage Index
Leaks _____ and greater are included in the CLI calculation
50uV/m
CLI is performed how often?
annually
What form is used to submit CLI to the FCC?
320
Leakage monitoring must be performed how often?
Every 90 days
During Leakage monitoring, leaks _____ and greater must be logged and repaired
20uV/m
Leakage logs must be kept on file for how many years?
2
Signal levels that are ________ or higher must be offset
38.75dBmV
A method used to pin point a leak
Triangulation
FCC requires that measurements are made with a ______ antenna
Dipole (1/2 Wave Pole)
CTB falls within ______ of the video carrier
30KHz (all channels EXCEPT 5 & 6)
AM
Amplitude Modulation
PM
Phase Modulation
FM
Frequency Modulation
Modulation used for Video
Amplitude Modulation
Modulation used for Color
Phase Modulation
Modulation used for Audio
Frequency Modulation
The video carrier is ______ higher than the lower edge of the channel
1.25 MHz
The color carrier is ________ from the video carrier
3.58 MHz (4.83MHz from lower edge of channel)
The audio carrier is _________ from the video carrier
4.5 MHz
CSO fall ________ above the video carrier
1.25MHz +/- 15KHz
CTB are within _______ of the video carrier
30KHz
The speed at which a wavefront passes through a medium, relative to the speed of light.
Velocity of Prorogation
The difference in voltage between one point and another is called
Potential Difference
Substance that allows heat or electricity to pass along or through it is called
A Conductor
The difference of an electrical field in radiated wave is
Polarity
Subatomic particles found in atoms that balance out the positive charge of a proton (within the nucleus) with their negative charge
Electrons
An electrical current, of which the polarity is periodically reversed
Alternating Current
Frequency Divided by the speed of light =
Wavelength
_____ is the amount of time it takes an AC waveform to complete one cycle
Period
The peak value of an AC waveform is also known as its
amplitude
1 complete sine wave =
Cycle
number of an AC waveform that occur in 1 second
Frequency
Ohms Law
E=IxR
R=
the resistance in Ohms
E=
The electromotive force (EMF) in volts
I=
The current in Amperes
A design philosophy where the loss of the cable and other passive devices before an amplifier station equal the gain of the amplifier
Unity Gain
A representation of the networks response to a sweep signal and the effects of all the network components such as cable, connectors, passive devices, and the signatures added by the amplifiers
Sweep Response
The difference in cable attenuation or amplifier gain between lower and higher Frequencies on the network
Tilt
The difference in gain between the ends of a band of frequencies
Slope
A gradual or sharp attenuation of gain (versus Frequency) at either or both ends of the spectrum
Roll-off
a sharp reduction in the amplitude of a narrow band of frequencies within the networks overall response
Suck out
an active device used to increase the level of an input signal. Used in a cable system to compensate for the effect of attenuation caused by coaxial cable and passive devices
Amplifier
Small plug-in device used to attenuate signals to the correct operating levels
Pad
A device used to reduce signal strength
Attenuator
In a cable amplifier it is typically a small, plug in device used to compensate for the fact that coaxial cable attenuation varies as the square root of frequency
Equalizer
The effect a particular type of amplifier has on the overall frequency response
Signatures
the difference between in amplitude between the most positive (Peak) and the most negative (Valley) levels of a electrical signal
Peak to Valley
Outline or multiple images of the primary TV picture offset to either side
Ghost
Caused by direct pickup (off air signal getting into the cable system)
Leading Ghost
An oscillator controlled so that it maintains a constant phase angle relative to a reference signal source
Phase Locked
Usually caused by signal reflection
Following Ghost
The unwanted sum and/or difference frequencies resulting from heterodyning (mixing) of two or more signals
Beat
A method of reception using an RF current of the proper magnitude and phase relation so the received voltage is if the same nature as the original wave
Zero Beat
caused in one channel by the same carrier from another transmitter operating on the same channel
Co Channel interference
chemical change caused by a reaction to Oxygen such as rust
Oxidation
A theoretical temperature equivalent to the absolute absence of heat equal to - 273.15 degrees C or -459.67 degrees F
Absolute Zero
Noise added to the response due to a lack of or improper termination
Termination Noise
A frequency selective receiver capable of tuning in a desired frequency/Channel with a display showing RF signal strength (dBmV)
Signal Level Meter (SLM)
The minimum signal level at the input to the customers TV is
0dBmV to 15dBmV
what do you need to do to maintain an SLM
Keep the battery charged, clean the battery terminals regularly,keep the SLM clean by wiping it gently:dry the display screen to prevent spots, do not use any type of polish or cleaner on the display ,and a regular calibration should be made and logged,
The ratio of error power to average power in an ideal QAM signal is
MER
Average power =
Digital power
Peak Power=
Analog power
Optical power units
mW or dBm
RF power units
mV or dBmV
Attenuation/ gain units
dB
what mode monitors up to 12 chs at a time on your meter
Miniscan
what mode monitors the entire Ch plan on your meter
Full scan
what mode check s the forward low frequency and high frequency channel tilt
Tilt mode
Detects errored bits in the system
Bit error Rate (BER)
used for troubleshooting connections with intermittent bit errors occuring over a period of time
Errored Seconds
passage of an outside signal into the cable; can result in noise and disruption of the desired signal
Ingress
shows impairments on the networks with the patterns on display and can be identified by figuring out the patters
Constellation Graph
Displays intermittent short duration impairments missed by MER and BER on your meter.
Digital quality index (DQI) mode
this mode shows you if ingress is within the downstream digital spectrum without turning of service
QAM ingress mode
This mode greatly improves the success rate and efficiency in locating return-path ingress
Fieldview Option
Service quality depends on transmitting signals with the highest carrier to composite noise and the lowest intermodulation distortion. The majority of all transmission errors can be detected by measuring the frequency response of the network is
Sweep
Provides a quick method to check cable system integrity, using active channels to sweep the forward path is
Sweepless Sweep
Using a unique method to accurately reveal any problem in the system without interfering with any of the analog/ Digital carriers is
Forward Sweep
Helps find mismatches or other problems in the upstream transmission path
Reverse Sweep
Accurately measures Ac voltages of signals other than pure analog sine waves
Root Mean Square Meter (RMS)
This meter is used to measure AC and DC voltages and currents as well as resistance and has a digital display
Digital Multi meter (DMM)
is used to find the location/path of underground cables
Cable locator
has a transmitter and receiver. it could include the following components a test lead, inductive frame and A-frame.
A locator
The resistance of a circuit to alternating current.
Impedance
The condition that results when two components of a system are operating at different impedance
Impedance Mismatch
is used to determine the distance of a known fault from a specific location
Time Domain Reflectometer (TDR)
Is used to locate: bad or unknown splices, opens, shorts, and kinked cable.
TDR
A reflection with the same polarity indicates an
open
is a situation where the center conductor comes in contact with the shield
Dead Short
A reflection with the opposite polarity indicates that the fault is
Short
refer to a cable that has not been competely cut
Partial Open
The contact between the center conductor and the shield is not complete
Partial Short
The distance that cannot be seen by the TDR because its too close to the TDR source
Deadzone
two types of TDRs
Waveform and Digital
extremely thin flexible thread of pure cladded glass able to carry millions of times the information of a traditional copper wire and do it over greater distances
Optical Fiber
A device that generates a light source used in fiber communication
Laser
LASER
Light Amplification by Stimulated Emission Radiation
Most light generated by lasers for telecomm use exists in the infrared band of 1310nm and 1550nm wavelengths
Infrared Light
the distance between two points of like phase in a wave
Wavelength
A card made up of material similar to photographic film that changes colors when exposed to light
Photosensitive Card
Laser Classification
Class1-safe as long as they are not disassembled.; Class-2/2A Eye hazard if beam is viewed.;Class-3A Eye hazard if collected or focused on the eye.; Class3B Eye hazard if the direct or reflected beam is viewed.; Class4 eye and skin hazard.
what is the laser standard
ANSI Z-136
A method to lock and mark one end of a line in order to allow someone to safely work on the other end
Lockout Tag-out
what are the two methods of fiber cleaning
Wet and Dry
Materials needed for wet method
Lint free wipes, Isopropyl(better than 90%) as recommended by the manufacturer, and lint free swabs or urethane foam heads
rotate a cleaning cloth over the end of a fiber connector by pushing down toward the connector
Push Pen
A battery or generator that provides electrical power to the circuit. For example, batteries and generators
Power Source
A conductor such as copper wire
Path
the device that uses the electricity. it is any device that draws current
Load
Substance that allows heat or electricity to pass along or through it
Conductor
Subatomic particles found in atoms that balance out the positive charge of a proton with their negative charge
Electrons
is the electromotive force that causes electrons to flow in a circuit
Voltage (E)
The pressure that causes electrons to flow in a circuit
Electromotive Force
is the flow of electrons through a conductor. is measured in amperes and is designated mathematically in ohms law as the letter I
Current (I)
The amount of electrons that pass a given point in the conductor in one second
Coulomb
is the opposition a material offers offers to the flow of current
Resistance (R)
the difference in voltage between one point and another
Potential Difference
the direction of an electrical field in a radiated wave
Polarity
An electrical current of which the polarity is periodically reversed.
Alternating Current (AC)
the point at which the filament reaches a temperature that causes it to glow
incandescence
the relationship between current or voltage and elapsed time
AC Waveform
what are the 4 types of AC Waveforms
Sine Wave, Square Wave, Quasi-square wave, and Sawtooth Wave
this waveform represents the characteristics of the voltage/current that feeds homes, powers power supplies, and the television channels that carry the program information to your customers homes
Sine Wave
This waveform is often found within the switching regular DC output power supplies in Amplifiers
Square Wave
A CATV power supply without a load produces a near square wave that combines a non linear increase and decrease of voltage or current with extended maximum positive and negative peak value.
Quasi Square Wave
Types of signals carried on the HFC system
Modulated RF carriers, Modulated analog carriers, DC power and AC power
one complete sine wave is
Cycle
Number of cycles of an AC waveform that occur in one second
frequency
the speed of the light/Frequency=
Wavelength
the amount of time it takes a waveform to complete one cycle
Period(T)
peak value of a waveform
Amplitude
states that current is directly proportional to voltage and inversely proportional to resistance
Ohms Law
R=
The resistance in ohms
E=
the Electromotive force(EMF) in volts
the rate a which work is done or the rate at which energy is used
Power
I=
current in Amperes
Resistance is measured between the center conductor and sheath with the other end
DC Loop Resistance
P=
WAtts
Current at any point in the line in the HFC plant is equal to the sum of the individual Ampere current draws of the active devices being fed from that point.
AC Current in the Broadband Network
the amount of voltage loss over the span is referred to as
Voltage drop
At lower voltages the current is higher in the HFC plant
Current at lower voltages
the amount of energy available to move a certain number of electrons from one point to another in an electrical circuit
Voltage
to be subjected to the action of an electrical discharge
Shock
to kill by electrical shock
Electrocute
a connection to the earth or a grounding device
Ground
power supplies reduce the secondary power (120 or 240) to the 60 or 90VAC for insertion in the cable
Line power supply
the electricity provided by the local power company
commercial power
2 types of line power supplies
standby and non standby
reduction of voltage by a transformer
stepped down
conversion of voltage, in this case from 36 or 38VDC to 60 or 90VAC
Inverted
the point where AC power from the power supply is placed on the coax portion of the distribution network.
Power inserter
a filter that will only allow the higher RF frequency signals to pass directly from RF port to port
high pass filter (relating to power inserter)
a filter present on each leg to direct the flow of the lower frequency AC power, which prevents the RF Signal from traveling into the power supply and causing signal leakage
Low Pass filter(Relating to power Inserter)
the two types of network powering
Distributed and centralized powering
batteries produce what kind of gas during charging operations
Hydrogen
three methods for testing batteries
battery load test, battery voltage test, battery conductance test
the most accurate and reliable test involves testing the batteries under a load condition
Load Test
the difference between any batteries in the set should not be greater than
0.3VDC
measuring the impedance of the battery with a conductance meter and documenting that value when its new. Batteries less than 50% of their as new conductance values are known to be bad
Battery conductance test
means of testing the network remotely that saves numerous problems in respect to downtime and customer dissatisfaction
status monitoring
according to manufacturers the terminals should be torqued to_____and then retorqued to _____ during routine maintenance.
75inch lbs and 60 inch lbs
what points should be kept in mind while checking battery terminals
is there an in line fuse in the battery cable, check the fuse holder and fuse. make sure the terminals are properly greased with an approved corrosion inhibitor such as NCP-2 or NO-OX
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
Tree and Branch
Forward signals originate at the headend are transmitted downstream by way of the trunk to the ends of the service.
Transportation (Trunk)
In a Tree and Branch system the feeder is considered what
The distribution System (Branches)
in a tree and branch system RG-6 and 11 is considered
The Drop(Leaves)
A network architecture developed by the cable industry which typically uses fiber optic cables to bring signals to selected areas of the system called Node Service Area, which are usually based on the number of subscribers to be served
Hybrid Fiber Coax(HFC)
what are the two wavelengths of fiber do we use
1310 nm and 1550nm
a network architecture where nodes, hubs, or headends may be connected with fiber optic cables to provide redundancy or increase services.
Ring
What are the advantages of fiber
Greater Bandwith and can travel greater distances without Amplification
what are the two types of Fiber
Single mode and Multi mode(we use single mode)
what is the attenuation of single mode fiber
1310nm=.35dB/km, 1550=.25dB/km
the distance between two points of like phase in a wave
wavelength
compares the speed of light through a material to the speed of light through a vacuum
Index of Refraction
the reflection that occurs when light strikes an interface at an angle of incidence greater than the critical angle allowing it to be continually reflected from the interface between two materials with different refractive indices
Total Internal Reflection
Single mode core is how many microns
8 to 9 microns
single mode cladding is how many microns
125 microns
single mode coating is how many microns
250 microns
what is the primary loss in fiber called
Scattering
separates(and recombines) the forward and reverse signals from the coax cable so they can be routed to and from the appropriate components within the amplifier station
Diplex filter
separates or combines the AC currents two parts-( AC power and RF broadband signals)
Power Diplex
attenuates the signal in order to bring it to within the acceptable range of the amplifier
Pad
compensates for the unequal attenuation properties of the coaxial cable. usually selected to produce flat broadband signals to the input of the first stage of Amplification
Equalizer
Usually selected for low noise figure. Amplifies forward signal passing through the trunk and distribution lines
Forward Amplifier Module (TRUNK)
Used to compensate for fluctuations of the input signal
AGC
Similiar to an AGC maintains the proper tilt(caused by temperature change in a specified amount of coaxial cable) and output level despite changes in the input signals
ALS
Signal splitting device that plugs into a trunk/bridger chassis
directional plug ins (feedermaker)
Converts AC power(60V-90V Quasi Square wave) to DC power(typically 24VDC)needed to operate the stations modules and regulates the DC output voltages to provide a stable and constant output
DC Power Pack
used to direct AC power into and out of specific ports of the amplifier station
Power Director
provides a means of monitoring the various inputs and outputs without interrupting service
Test Points (TP)
will have substantial isolation between the output and tap ports if all ports see a good 75 ohm match. Isolation for signal paths between the tap and output port is usually 25dB or greater
Directional Coupler (DC)
A tap is used to extract a specific amount of signal from the feeder system and distribute it for connection of customer drops and contains a directional coupler that feeds a single splitter.
Taps (Customer interface point)
Low frequency signals are not attenuated as much as high frequency signals in a coaxial cable
In line Equalizers
LIke in line EQs these devices are sometimes installed in the distribution cable where low value taps are used
in line conditioners
in a housing like the splitter is used to introduce AC power into the network
Power Inserter
A design philosophy where the loss of the cable and other passive devices before an amplifier station
Unity Gain
similar to a street map and includes features like lakes and rivers, streets, and boundaries
Base Map
Displays streets with poles and pedestals locations and includes the span length or footage between these items
Strand Map
Shows the locations of electronic equipment. including headend and any hubs,amplifiers, power, supplies, and taps.
Design Map
Offer the layout of the system in a condensed form. shows how active devices are cascaded and how they are connected to the headend, hub, or node. power supplies are also noted
Amplifier schematics or Tree Map
A corrected map that represent the addition or changes in information on the design map
As Built map
Map that covers a single node
HFC Plant map
documents a fiber plant
fiber design map
catalogs the system maps
Map Grid System
is the measure of the cables ability to maintain impedance at all frequencies due to the many micro reflections introduced during manufacturing. The industry Specs call for a minimum of 15dB, but the higher the better
Structural Return Loss (SRL)
What do reflections do on a coaxial cable
They distort the carriers, causing bit errors in the modulated data streams.
a thin wire wrapped around the fiber and coaxial cables to secure them to the strand
Lashing wire
load bearing component of an aerial coaxial cable installation. Its usually a 1/4 or3/8 inch zinc coated steel wire to which the cable is lashed
Strand
A loop intentionally formed in the cable to compensate for the expansion and contraction caused by temperature changes
Expansion Loop
used to counteract the horizontal component of forces placed on poles by the strand and cable
Guy and Anchor
Strand that connects the pole line hardware to anchor
Guy
Buried metal device used to transfer force from the pole to ground
Anchor
strand that connects the pole line hardware, particularly the guy attachment hardware to the anchor.
Guy Wires
is a yellow plastic cover used to protect the guy wire and make it more visible
Guy Wire Guard
Different types of Guys
Down Guy, Head Guy, Terminal Guy, Side Guy, Pole to stub guy, pole to pole guy, sidewalk guy, and storm guy
Different types of anchors
screw anchor, never creep anchor, rock anchor, anchor rods(AKA Guy rods)
the device usually a screw used to connect the coax’s center conductor to an active or passive device
Seizure Mechanism
is used to remove the outer jacket of a typical underground cable
stripping tool
may remove the jacket, but primarily removes the outer sheath and dielectric within the cable
Coring Tool
having a saw toothed edge or margin notched with tooth like projections
Serrated
these tools are specifically designed to cut coaxial cables
banana cutters
what are the two steps in building the aerial portion of the network
the strand system must be built and properly tensioned and the cable must be lashed onto the strand.
to wrap a thin wire around the cable in order to secure it to the strand.
Lashed
this device is selectively placed at pole hardware locations to prevent dangerous sag while strand is being installed
Strand Brake
used in conjunction with a lay up stick to lift cable blocks and strand
Wire raising tool
used to prevent unwanted payoff of strand from the cable trailer or reel stand
Reel Brakes
are portable bonding connections installed at the location where the strand is spooled from the cable trailer or reel stand. can be removed only after the strand is bonded to the grounding network
Traveling grounds
two types of strand methods
Stationary reel method and Moving reel method
installation of pole hardware allowing for hanging of strand
Framed
the trailer should be at a minimal distance (two times the hardware attachment height) from the pole at which the strand first contacts the pole line hardware
Stationary reel method
the strand is installed by mounting a reel to a vehicle and driving the vehicle from pole to pole stopping to install the strand and hardware at each location
Moving reel method
Strand splices should be placed outside the pole framing hardware, but within 18 to 24 inches of the pole . traveling grounds should always be used when placing the strand
Stationary reel method
uses a mechanical wrenching action to bend expansion loops into coaxial cable prior to lashing or during splicing
Mechanical Bender
used to measure the pulling tension applied to cables
Dynamometer
allows cables that are being pulled to swivel and are used to ensure that the cables are not over-tensioned during pulling
Breakaway swivel
used to support a single lashing may be used when cables are lashed directly to the strand or in overlash applications
Single roller Block
used to install self support cable and is attached to the pole hardware support the cable as it is pulled out
Pole Mount Cable Block
used to support a single cable prior to lashing
Economy Block
This device is used to route cables through inside or outside corners up to 90degrees. it minimizes drag on the cable in corners and ensures that the minimum bend radius of the cable, as specified by the manufacturer is not exceeded
90 degree corner block
used to route cables through inside or outside corners up to 45degrees. it minimizes drag on the cable in corners and ensures that the minimum bend radius of the cable is not exceeded
45 degree corner block
used to guide cables from the cable trailer or reel strand to the strand
Set up Chute
this bracket is used to support 45 and 90 degree corner block or setup chutes at the mid span
set up bracket
used to lash cable directly to installed strand or cable bundles
cable lasher
allows multiple cables to be pulled into place when lashing cable directly to strand
Multiple cable puller
allows multiple cables to be pulled into place in overlash applications
Overlash cable puller
device is used to push equipment ahead of a pulled lasher
Cable block pusher
pushed in front of a lasher by a cable block pusher to uniformly position multiple cables that are being lashed
Cable positioner (Magic Box)
is the tension caused by the mass of cable on the reel and reel brakes.
tail loading
what two methods control tail loading
can be minimized by using minimal braking during the payoff of the cable from the reel. and at times no braking is preferred.
If a span is _____ or longer place ____ expansion loops on each pole. one is placed on the input side and one is placed on the output side of the pole
250ft and 2
is when two perpendicular strands end at the same pole
Double dead end
the mechanical bender must remain in place until the lasher is transferred and the next span of cable is
lashed 50ft or 1/3 the distance to the next pole whichever is greater
An expansion loop should be formed on the ___ side of every pole for all sizes of coaxial cable being used
Output
When the loop location is dictated by the signal flow direction of the feeder cable
Feeder Dominant
the trailer should be positioned in line with the strand and twice the distance _____
of the set up chute to the ground from the chute (Stationary Reel method)
The cable should payofff the___
Top of the cable reel
Use a cable block lifter to place _____ on the strand every 30 to 50ft
cable blocks
the ends of the cable left at the pole for splicing
Cable Tail
it is essential that double lashing be used when___
two or more cables, all trunk cables, and at street crossings.
how many feet do you stop the lasher to form an expansion loop
6FT
is a connection to earth or a conductor serving earth potential and can be intentional or accidental
Ground
is the interconnection through good conductors of the cable plant with power and phone systems to eliminate potential voltage differences
Bond
is a pipe usually made of PVC and used to house cable and protect it from dirt, moisture, and outside forces.
conduit
is a protective covering for hardline cable, typically made from galvanized steel or plastic over the exposed cable where it makes the transition from aerial to underground.
Riser Guard
conduit for underground drops must be buried to a minimum depth of
8inches
installing all underground drops emerging from the ground must have physical protection (cable guard or conduit) to a point at least ________located at the house
4ft above ground or until reaching the service enclosure.
underground drop cables routed down a pole must have physical protection, cable guard, or conduit, to at least
8ft above ground and at least 8inches below ground
a high visibility tape usually used when burying fiber optic cable, buried directly above the cable point out the existence of the cable to anyone digging in that location
Warning Tape
bury warning tape above the cable at a depth of___ during the back fill process
12inches
Locate the midpoint of the pull. while monitoring pulling tension, pull the cable from the mid point to the end of one direction.(Used for installing long fiber runs)
Mid point cable pull
what u do with the remaining fiber optic cable
figure eighting
while doing the figure eights with fiber u set the cones up ____ apart
10-15 paces
the US government agency established in 1934 to regulate electronic communications
Federal Communications Commission(FCC)
In 1990, the FCC required that system perform s CLI test ____
Annually
a figure of merit derived mathematically from the number and severity of signal leaks in a cable system.
Cumulative Leakage Index
the figure of merit for CLI has to be
64 or less
your CLI test that you do annually has to be submitted using what form
FCC form 320
a system in which transported signals are completely contained within the medium is called
a closed system
Leakage is emitted RF energy and is called
Egress
Noise is received energy and is called
Ingress
what % of leakage is found between the tap and bonding block
70%
LTE
Long Term Evolution
LTE operates in the ____frequency range
700 to800 MHz
No more than 15 microvolts per meter @30 meters
0-54MHz
No more than 15 microvolts per meter @30 meters
More than 216MHz
No more than 20 microvolts @3 meters
54MHz and 216MHz
the aeronautical frequencies are
108-139MHz
two ways to do the CLI test
Ground based and flyover
Leakage monitoring must be done
Quarterly
Leakage logs must be kept on file for
2yrs
Only Leakages___ or greater are included in the CLI calculations
50 microvolts
CW
continuous wave
three methods to calibrate your leakage detector
Done by the manufacturer, Direct coupling, and Antenna
what method do you use to pinpoint a leak
Triangulation Method
a leakage log should include
Date;location;leakage cause;strength;distance to leak; Date;Strength after repair.
leaks__ or greater must be logged for regular monitoring
20 microvolts
the FCC requires that __ of the plant be tested for CLI. The comcast standard is _____
75% and 100%
The CLI is done at an altitude of ____, using 108 to 137MHz band
1500ft(450Meters)
Sending AC from two different power supplies, causing a large spark
bucking power
Comcast troubleshooting steps
Identify, Isolate,Fix,Verify
a low resistance connection between two points in an electric circuit that forms an alternative path for a portion of the current
Shunts
Steps for verifying a backwards tap
1) the tap plate and re-check the input port. 2)if there is no signal present, check the output port. 3) if signal is present here, the housing is backwards and requires re-splicing.
if you encounter a conductor that is 300v or less
avoid contact with the conductor
if you encounter a conductor that is between 300V and 750V
stay at least 12 inches away from this conductor
do foreign voltage detectors DC voltage
NO
Divide and conquer does what
reduces repair time.
the reverse path must be balanced for___ just as the with the forward system
unity gain
threshold for ingress at 5-18mhz
-20dBc (Decibels relative to carrier)
threshold for ingress at 18-42mhz
-35dBc (Decibels relative to carrier)
Max min sweep formula
N/2+1.5=
telemetry reverse sweep formula
N/2+1=
is defined as two or more customers without service or with impaired service, due to the same root cause
outage
is a plant fault with overlapping correlated trouble call
priority plant fault
is a signals inability to be transmitted from one cable or device to another cable or device and measured in dB
Isolation
is 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
port to port isolation
is the interface location in a cable system where a fiber enters a neighborhood and the optical signal is converted into an electrical signal to connect to coaxial cables serving individual homes.
Node
a node has a minimum of
One optical receiver, one optical transmitter, power supply, and a forward and return amplifier module
is an amplifier used to transport signals to longer distances
trunk amplifier
used to add to the strength of signals in order to compensate for higher loss of the feeder and to provide enough signals for the drop cables and for multiple customers
Bridger amplifiers
are high gain amplifiers and are operated so that the output levels are higher as well
Line extenders
samples the stations output level using the directional coupler 15 usually at a specific frequency or channel. used to compensate for fluctuations of the input
Automatic gain control
recovers the RF information modulated onto the optical carrier at the headend
Optical detector
refers to the percentage of optical modulation, per channel, driving a laser transmitter
Optical modulation Index(OMI)
for every db change in optical power there is a 2db change in RF
know that rule
to energize or power the equipment( nodes amplifiers and other active devices in the rf portion of the network). usually includes checks for continuity, shorts, and signal flow.
activation
whatever tilt u need multiply by 1.25 to get desired eq
know this rule
has attenuation that duplicates that of a cable.
Cable Equivalency (Cable simulator)
used for the first stage of amplification for a trunk or multi output station, picked for its low noise figure
integrated circuit (IC)
this device monitors the change in temperature and makes an attenuation and tilt change based on typical cable spacing between stations
thermal level control
this is usually a power double device
second stage gain
is used to compensate for frequency response signatures of passive and active devices in the system,
Response network/Mop up
circuitry used to adjust the frequency of an amplifier
response network
usually a passive network placed between the input and output amplifier module. it is used to correct fro a frequency response problem seen at the output of the amplifier
mop up
the deviation in response at the output of an amplifier or passive device when compared to the response st its input.
signatures
used to set the amplifiers output tilt.
interstage Equalizer
a measure of an amplifiers output level to the level of distortion it produces
output capability
is used to inject return test signals for alignment/sweep of the return portion of the amplifier
Insertion point
Reverse pad=amplifier upstream design gain-total span loss
know this rule
have forward and return on the same test point
bi directional test points
RF portion of the cable plant fed from a node
Node service area
we can utilize a 3% ____ without excessive distortion with a carriage of 100 channels
OMI
is the actual seep response before normalization
raw sweep
is the exponent or the power to which a fixed number(the base) must be raised in order to produce a given number
logarithm
the number of times the base is multiplied by itself
exponent
1)any number raised to the exponent 0 is equal to 1.2)any number raised to the exponent 1 is equal to itself. 3) two multiply two or more numbers with the same base, simply add the exponents. 4) to divide two or more numbers with the same base simply subtract the exponents.
Exponent rules
is a number where the base is 10
power of 10
one tenth of a bel=
Decibel
is the unit for expressing in logarithmic terms, the ratio between two power levels
Bel
with the 10 log function each double in value is equal to 3.01db increase, while -3.01 divides the value in half
know this rule
an absolute level that describes the amount of signal at a specific location in the system.
dBmV
10log=
wattage
20 log=
voltages
0dBmV=
1mV
each 6dB change either doubles or halves the voltage, and each 20dB change affects the voltage by a factor of ten
know this rule
a discontinuous signal whose various states are discrete intervals apart
digital signal
used to convert an analog signal to a digital signal
Digitizer
are a continuous signal or carrier that varies in amplitude or frequency
analog signals
this term is short for binary digit. refers to an electrical impulse representing a zero or a one. the smallest unit of measurement a computer can handle
bit
a set of bits that represent a single character. usually there are eight bits in a
Byte
the number of changed states that can occur per second
Baud
advantage of analog transmissions are
1) no conversion necessary for human recognition 2) economical over short distances (up to 25miles)
disadvantages of analog transmission are
1) added distortion and noise when employing amplification. 2) electrical interference modulating the waveform. 3) limited distance for acceptable performance.
digital conversion consists of
sampling, quantization, and encoding
is the measuring of the analog signal at specific intervals
Sampling
is the assigning of a specific value to each of the samples
Quantization
is the process by which these values are converted into a data or bit stream
Encoding
can interfere with an analog signal and reduce its clarity
thermal or interfering noise
is synchronized with that of the transmitter so its available to read the digital sample when it arrives
digital receiver or regenerator
are regenerated rather than amplified
Digital bits
is the means of superimposing sound on an RF carrier
AM
is the means of superimposing sound on an RF carrier of a particular frequency
FM
3 different types of modulation in analog
Amplitude(AM),Frequency(FM), and Phase(PM)
five most common modulation schemes are
1)Amplitude shift keying(ASK) 2) Frequency shift keying(FSK). 3) Phase shift keying(PSK). 4) Quadrature phase shift keying(QPSK). 5) Quadrature amplitude modulation(QAM)
frequency and phase of the signal carrier are constant. amplitude is varied
Amplitude shit keying(ASK)
amplitude and phase of the signal are constant. frequency is varied. used in pathrak telemetries
Frequency is varied (FSK)
amplitude and frequency are constant. phase is varied.
Phase shift keying (PSK)
defined as the position on a waveform cycle at a specific point in time. on cycle is defined as 360 degrees of phase
Phase
the two most common digital modulation schemes that use a combination of changes are
QPSK and QAM
unwanted sum of and difference in frequencies resulting from the heterodyning of two or more signals
Beat
are caused when an analog TV signal arrives at a receiver just before or after the desired TV signal
Ghost
caused when the same channel from two or more different TV stations is received by the same antenna
co channel interference
caused by power line arcing, lightning, electrical motors, automobile ignition, and other sources of high rise time energy entering the cable system from the tap up to and including the TV receiver
Electrical interference
ingress from transmitters operating in the upstream frequency bandwith
return path interference
often caused by poorly made or corroded connectors ,it actually changes the shape of the RF wave from(disimilar metals)
common path distortion (CPD)
what causes CPD
when two or more carries encounter a non linear device, such as a connection where oxidation has occurred, harmonics and difference are produced
a chemical change caused by a reaction to oxygen, such as rust
Oxidation
a component frequency of the signal that is an integer multiple of the fundamental frequency.(twice whatever original frequency is)
Harmonics
the amount of noise an amp adds
noise figure
is caused by random electron activity of the atoms that make up the conductor, resistor, or any part of the passive circuit in question at any temperature above absolute zero
thermal noise
a theoretical temperature equivalent to the absolute absence of heat and equal to -273.15 degrees C, -459.67F, or zero degrees Kelvin
absolute zero
change in termination noise amounts to approximately .17dB per 20 degree fahrenheit change in temperature
know this rule
C/N Rules
Rule 1) if the input level numerically equals an amplifiers NF, the output ratio will always be 59.2dB. Rule 2) for each dB when the input level is raised above the amplifiers NF, the output ratio improves by an equal amount above 59.2. Rule3) C/N ratio at the output of a single amplifier is always worse than that at the input an amount equal to the amplifiers NF
log uses
10logN for C/N, 12 logN for composite second order (CSO), and 20 logN for Xmod and CTB
undesired change in the waveform of a signal
distortions
the second harmonic products of any two channels are typically 6dB below the level of the sum and difference products
Discrete second order
the combination of the amplitude and the logarithmic sum of the number of beats that fall in a channel determine the level of interference
composite second order
when a carrier is applied to an amplifier, it will produce the second order beats and will produced third order products as well
discrete third order
as each carrier is added to the system , it interacts with all the other carriers producing more and more second and third order beats.
composite third order
C/CTB follows a 20log relationship, and each dB raise in the levels of an amplifier, the carrier to CTB gets worse by two dB
know this rule
adding two devices with the same C/CTB ratios degrades the result by 6dB
know this rule
the crossing of modulation from one channel to another. typically manifests itself as a vertical bar in the viewed picture
cross modulation(XMOD)
this is a third order product and follows a 20log function for every dB that the levels of an amplifier are raised the carrier to cross mod ratio gets 2db worse
know this rule
doubling the number of channels carried degrades this ratio by 6dB and so does doubling the cascade
know this rule
appears as horizontal bars in the picture . a primary source is the power passing chokes or capacitor leak in passive devices.
Hum modulation
amplifier circuit paths that allow AC voltage to be directed onto specific cables
Power passing chokes
hum modulation is a low frequency signal, which the FCC states must be less than 3% of the video carrier level
Hum modulation Test
are the two basic parameters used to evaluate the quality and performance of the digital signals
MER and BER
is defined as the ratio of the number of wrong bits over the number of total bits
Ber
is typically an overload effect noted through digital signal processing equipment. this is an overdrive, or over modulation of the single carrier
Spectral re growth
an international telecommunications standard that permits the addition of high speed data transfer to an existing CATV system
DOCSIS
generates light in the transmitter
Laser Diode
is a family of standards for compressing decompressing A/V in a digital format
MPEG
advantages of MPEG are
remove redundant info without losing quality while saving bandwith
MPEG1
video CD
MPEG2
HDTV/DVD
MPEG4
streaming video
has all the spatial info
I picture
use both past and subsequent pictures
B picture
is calculated by comparing previous and successive picture
P picture
a cable version of CDMA , a cell phone technology that allows many users to access the network at the same time
SCDMA
provides the ability to control latency
QOS
how many channels can u bond with docsis 3.0
4 or 8 down 4 up
number of timeouts caused by the cmts not receiving a response within aspecified time from the cmts to a ranging request. upstream errors
T3
number of timeouts caused by the modem not receiving a response within a specified time from the cmts to a periodic maintenance request. downstream errors
T4
the operational settings for the cable modem
Boot file
a series of Reed -Solomon symbols forms the codeword. it s a series of values that conforms to a known pattern.
codewords
when there are more than___ errored symbols in a codeword the entire codeword is errored
3
technologies that allow cable modems to share the upstream carriers in the hfc network with multiple devices like cable modems, emtas, and set top boxes
TDMA and SCDMA
method for transferring data across the network
Trivial file transfer protocol (TFTP)
assigns time slots for when modems can speak. configured in the CMTS
TDMA
instead of a time slot, the modem gets a code for all the data it is sending
SCDMA
is a set of rules that govern how devices transport data
Protocol
allows interoperability of devices from different vendors
protocols
is a way to tell the sending server that not all packets got to their destination, and please resend them.
Transmission control protocol/ internet protocol (TCP/IP)
used to transport voice and video media
Real Time Transport Protocol (RTP)
unlike tcp/ip it has no error correction
Universal Datagram Protocol (UDP)
UTP
unshielded twisted pair
has a field of 32 bits and dotted decimal
ipv4
written in colon hexidecimal format and uses numbers and letters
ipv6
can be configured for ipv4only or ipv6only
singlestacked device
can be configured fro both ipv4 or 6
dual stacked device
rules for writing ipv6 addresses
1) omit leading zeros, meaning zeros at the beginning of each set of four characters. 2) replace consecutive all zero chunks within an address by using a double colon
What component is known as the brain of the cable system?
Headend
What are the signals that are used to pass channels to the customer?
Analog and Digital
Any device which does not require electricity to perform its function?
Passive Device
Any device which requires electricity to perform its function?
Active Device
Blocks interference resulting from other electrical appliances being used
such as microwaves, hairdryers, etc.
Voltage Blocker
What 5 parts make up a coax cable?
- Center Conductor
- Dielectric (Foam)
- Foil
- Braid
- Outer Jacket
