nct4 v2 edited Flashcards
3 parts of fiber
Coating, Cladding, Core
Most common type of fiber used in the cable industry
Single Mode Fiber
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
Devices that are used to compensate for the forward and return loss
Amplifiers
What device compensates for the uneven cable loss in coax?
Equalizer
It provides a means to monitor levels with out interrupting service
Test Point
What device has both a DC & Splitter built into it?
Tap
What device is considered to be the customer interface point?
Tap
This map is the point where actives are added to the network
Design Map
CLI
Cumulative Leakage Index
CLI is performed how often?
annually
Leakage monitoring must be performed how often?
Every 90 days
Leakage logs must be kept on file for how many years?
2
AM
Amplitude Modulation
PM
Phase Modulation
FM
Frequency Modulation
The speed at which a wavefront passes through a medium, relative to the speed of light.
Velocity of Prorogation
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
_____ 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
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
The difference in gain between the ends of a band of frequencies
Slope
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 difference between in amplitude between the most positive (Peak) and the most negative (Valley) levels of a electrical signal
Peak to Valley
An oscillator controlled so that it maintains a constant phase angle relative to a reference signal source
Phase Locked
chemical change caused by a reaction to Oxygen such as rust
Oxidation
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
this mode shows you if ingress is within the downstream digital spectrum without turning of service
QAM ingress mode
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
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
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
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
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
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
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
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,
Sawtooth Wave
one complete sine wave is
Cycle
peak value of a waveform
Amplitude
states that current is directly proportional to voltage and inversely proportional to resistance
Ohms Law
the rate a which work is done or the rate at which energy is used
Power
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
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
batteries produce what kind of gas during charging operations
Hydrogen
the most accurate and reliable test involves testing the batteries under a load condition
Load Test
means of testing the network remotely that saves numerous problems in respect to downtime and customer dissatisfaction
status monitoring
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)
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
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
provides a means of monitoring the various inputs and outputs without interrupting service
Test Points (TP)
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
a thin wire wrapped around the fiber and coaxial cables to secure them to the strand
Lashing wire
is the tension caused by the mass of cable on the reel and reel brakes.
tail loading
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
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
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
Leakage is emitted RF energy and is called
Egress
Noise is received energy and is called
Ingress
LTE
Long Term Evolution
Leakage monitoring must be done
Quarterly
Leakage logs must be kept on file for
2yrs
CW
continuous wave
the FCC requires that __ of the plant be tested for CLI. The comcast standard is _____
75% and 100%
Comcast troubleshooting steps
Identify, Isolate, Repair, Verify
Divide and conquer does what
reduces repair time.
is defined as two or more customers without service or with impaired service, due to the same root cause
outage
is a signals inability to be transmitted from one cable or device to another cable or device and measured in dB
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
is an amplifier used to transport signals to longer distances
trunk amplifier
are high gain amplifiers and are operated so that the output levels are higher as well
Line extenders
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
the number of times the base is multiplied by itself
exponent
is a number where the base is 10
power of 10
an absolute level that describes the amount of signal at a specific location in the system.
dBmV
a discontinuous signal whose various states are discrete intervals apart
digital signal
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
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
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)
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
often caused by poorly made or corroded connectors ,it actually changes the shape of the RF wave from(disimilar metals)
common path distortion (CPD)
a chemical change caused by a reaction to oxygen, such as rust
Oxidation
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
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
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
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
single stacked 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 requires electricity to perform its function?
Active Device
