NCT 4 16 Flashcards
A measure of an amplifier’s output level to the level of distortion it produces.
Output Capability
used to set the amplifier’s output tilt
Interstage Equalizer
The deviation in response at the output of an amplifier or passive device when compared to the response at its input
Signatures:
used to correct for a frequency response problem seen at the output of the amplifier station where installed
Mop-up
A circuit, usually within a forward amplifier module, which monitors temperature changes and causes an increase or decrease in its attenuation (and sometimes tilt as well) in an attempt to hold the amplifier’s output constant with ambient temperature changes
Thermal Level Control
To energize or power the equipment (nodes, amplifiers, and other active devices in the RF portion of the network
Activation
Refers to the percentage of optical modulation, per channel, driving a laser transmitter
Optical Modulation Index (OMI)
This device produces a “light” on which the RF signals from the return path are modulated
The Laser
Device used to convert an analog signal to a digital signal
Digitizer
The unwanted sum of and/or difference in frequencies resulting from the heterodyning (mixing) of two or more signals
Beat
caused in one channel by the carrier from another transmitter operating on the same channel
Co-Channel Interference
Outline or multiple images of the primary TV picture offset to either side.
Ghosts
characterized by a significant rise in the noise floor in the return portion of the spectrum
Common Path Distortion
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
Harmonics
A theoretical temperature equivalent to the absolute absence of heat and equal to -273.15 degrees C, -459.67 degrees F, or 0 degrees Kelvin.
Absolute Zero
Noise added to the response due to a lack of, or improper termination.
Termination Noise
Amplifier circuit paths that allow AC voltage to be directed onto specific distribution cables
Power Passing Chokes
an overload effect noted through digital signal processing equipment.
Spectral Re-growth
FCC
Federal Communications Commission
When and where was the was a problem caused in leakage to make FCC create a standard for leakage
In 1976, signal leaking from a cable system in Harrisburg, PA, interfered with air traffic communication
Cumulative Leakage Index
A figure of merit derived mathematically from the number and severity of signal leaks in a cable system
Environmental Factors That Affect Signal Leakage
static electricity, temperature ,lightning, solar emmisions, and UV rays
sun transit (sun outage), and happens twice a year in
March and October
LTE stands for
Long-Term Evolution
LTE operates in the
700 MHz to 800 MHz frequency range
cable operator arrives at a cumulative (average-weighted) score. The pass/fail score is
64
The FCC requires that cable operators file an annual CLI calculation, using a Form 320. The completed Forms 320 are kept in
your system’s public file.
During a flyover, an airplane flies over the system, measuring any detectable leaks. This is done at an altitude
1500 feet
Subatomic particles found in atoms that balance out the positive charge of a proton (within the nucleus) with their negative charge
Electrons
Substance that allows heat or electricity to pass along or through it, for example, cables, wires, metal surfaces, and water
Conductor
The device that uses the electricity. It is any device that draws current
Load
electromotive force (or pressure) that causes electrons to flow in a circuit
Voltage
opposition a material offers to the flow of current
Resistance
The amount of electrons that pass a given point in the conductor in one second
Coulomb
The difference in voltage between one point and another
Potential Difference
defined as one complete sine wave.
cycle
the physical length of one cycle of the voltage waveform.
Wavelength
the amount of time it takes an AC waveform to complete one cycle
Period
the position of the amplitude value as related to time.
Phase
peak value of an AC waveform
Amplitude
Span Current × Span Resistance =
Voltage Drop
The amount of energy available to move a certain number of electrons from one point to another in an electrical circuit.
Voltage
stop working (and descend pole or ladder) for 15 minutes when you see lightning; resume work if no lightning is observed, what is this rule
15 minute wait rule
There are three methods for testing batteries:
Battery load test
Battery voltage test
Battery conductance test
Always wear______ when working with batteries
acid-resistant hand protection and apron, safety glasses, and face shields
Compares the speed of light through a material to the speed of light through a vacuum
Index of Refraction
occurs when light strikes an interface at an angle of incidence (with respect to the normal) greater than the critical angle, allowing it to be continually reflected from the interface between two materials with different refractive indices.
Total Internal Reflection
In the 1960s, _____ work with lasers gave us the ability to add information to light waves.
Theodore Maiman’s
your system adds or changes information on the design map. The corrected map is called an
As-Built Map
anchors are designed for use in soft soil where screw anchors are less effective
Never Creep Anchors
designed to expand in holes bored in rock or concrete
Rock or concrete anchors
A cable positioner is pushed in front of a lasher by a cable block pusher to uniformly position multiple cables that are being lashed
magic box
This device is used to push equipment ahead of a pulled lasher
Cable block pusher, also known as a shotgun or a shuttle.
8-16 bit Hexidecimal numbers seperated by colons
IPV6
Additional bits (symbols) added to data to detect + correct errrors
FEC
the number of errored bits compared to the total number of bits
BER
an overall digital signal quality measurement
MER
the standard for HSI in a CATV system
DOCSIS
According to the book, fwd levels could be as high as
50dBmv
in watchtower jobs, TSI, outages, are associated to what network element
Node
List two items that TSI checks
911 check and % of commercial customers
what is the importance of suspending a job when you will temporary stop working on it
time accountabliity
combining multiple QAM to form a single “wide band channel”
channel bonding
a set of rules for how devices on a network exchange information
Protocol
DOCSIS 3.0 two new advanatage
IPV6 and channel bonding
what would be a likely reason for having excessive distortions at the output of an amp
overdriving, high input hybrid to amp
what would be a likely reason for having a low CNR at the input of and amp
starving, low inputs into hybrid to amp
a card that can detect if light is on a fiber
photosensitive card
when the amp gain = the losses before the amp
unity gain
what 2 factors impact a cables DC Loop resistance
Length and diameter
In analog NTSC tv analog channel, how man MHZ away from the video carrirer is the color and audio
3.58 is the color, and 4.5 mhz is the audio
when information is superimposed onto a carrier
modulation
audio carrier is how many db lower than the video carrirer
10-17db
A distortion caused from oxidation between 2 dissimilar metals
common path distortion
a mode in flux used to identify multiple DOCSIS devices that share one common problem
signature
the most effective method for measuring and correcting frequency response problems
sweep
whats the most accurate way to test PS batteries
under load
a graphic representation of the 4 phase states of a QPSK and QAM signal
constellation
it measures pulling tension applied to cables
dynanometer
strand splices should be within ____ to ____ from the pole
18’ to 24” inches
the most commonly used hardline connector
pin
what 3 electrical characteristics impact a cables impedance
capacitance, inductance, resistance
most used fiber type used in HFC plant
single mode
prevents the cable from being over tensioned during pulling
breakaway swivel
sending AC power from 2 different Power Supplies
bucking power
32 bit address 8 bit per octet written in dotted decimal notation
IPV4
aeronautical frequency range
108 to 137 MHZ
the position of the amplitue of an AC waveform as it relates to time
Phase
used to determine the distance to a known fault from a specific location
TDR
TDR has same polarity causes an
OPEN
TDR has different polarity causes a
SHORT
failure to get a response from the CMTS to a RNG-REQ
T3 (200ms)(16 missed in a row)
Failure to get a response to a station maintenance request
T4 (30-35 sec)
a CM modulates in ____path and it demodulates in the ___path
Return and Forward
SCDMA manages
Code
TDMA
Time slots
this protocol Does NOT allow for data retransmissions
UDP
this protocol Does allow for data retransmissions
TCP
a simple mathematical representation of an analog signal
digital signal
3 steps of digitizing and analog signal
- sampling(Nyquist rule)
- quanitization(signing values to the samples)
- encoding(convert binary bit stream)
varying amplitude, frequency, or phase of a carrier wave by superimposing information (data) onto it
modulation
superimposing 60 Cycles Per Second AC onto RF signals
Hum modulation
unwanted sum/diff frequencies resulting from heterodyning (mixing) of 2 or more carriers
Beats
undesired change in the shape of a waveform
distortion
combonation of QPSK and ASK
QAM
digital modulation that varies phase and amplitude
QAM
If the input level (in dBmV) numerically equals an amplifier’s NF, the output C/N ratio will always be
59.2 dB.
