NCT 4 Test
CLI
The mathematical value derived from the number and severity of leaks in a system
Mop up/Response EQ
This amplifier circuit is used to compensate for amplifier signatures?
UDP
This assumes a noiseless transmission path so it will not retransmit data that was not received. This protocol is used in real time applications like VOIP?
BER
What detects erorred bits in the system?
Analog signal
a continuous signal or carrier that varies in amplitude or frequency as a function of changes at its input
Baud
or symbol, refers to the number of changed states or "events" that can occur per Hertz (second)
Digital Signal
A discontinuous signal whose various states are discrete intervals apart
Signal Level Meter (SLM)
A frequency selective receiver capable of tuning in a desired frequency/channel with a display showing the RF signal strength (dBmV)?
Power passing chokes or capacitor leak in passive devices.
A primary source of hum modulation is?
Common Path Distortion (CPD)
A return path impairment that can have a severe effect on return path signal quality.
Protocols
A set of rules for how devices on a network will communicate?
Peak
Analog measurements are a________ power
quasi-square wave
CATV network powering is generally ?
26.9-27.1
CB Radio frequency
Channel bonding
Combining 4 or 8 6hz channels to form a wideband 24mhz or 48mhz channel?
Isolation
Cross talk between passive device ports can be minimized when the passive device has good?
Channel bonding, Ipv6
DOCIS 3.0 brought 2 noteable enhancements over prior versions?
Digitizer
Device used to convert an analog signal to a digital signal
Discrete Second Order Composite Second Order (CSO) Discrete Third Order Composite Third Order or Composite Triple Beat (CTB) Cross Modulation (XMOD)
Different types of distortions
Average
Digital measurements are a ________ power
RMS
Elevated AC voltage in the network. Using a true_ volt meter allows for an actual voltage measurement, rather than one that reads higher because it has been averaged.
Ghosting
For analog T.V, receiving a signal of the same content and same frequency just before or just after the desired signal will produce what visual result
ASK
Frequency and phase of the signal carrier is constant but the amplitude is varied
DMM
How can optical power be measured non intrusively?
Total internal reflection
How does light propagate through the fiber?
3b
If direct or reflected beam is viewed
Amplifier
Inter Modulation Distortion (CSO +CTB) is created in what device
Co- Channel interference
Is caused in one channel by the carrier from another transmitter operating on the same channel
Coaxial, Dielectric,shield distance
List 3 Physical things that determine a coaxial cables impedance
Resistance, Capacitance,inductance
List 3 electrical properities that cables impedance looks like to RF signal
Cross Modulation (XMOD)
Literally means the "crossing" of modulation from one channel to another.
mw, dbm
Optical power is measured in these units___ or ____-
A partial open
Refers to a cable that has not been completely cut
Bit
Refers to an electrical impulse representing a zero or one—the smallest unit of measurement a computer can handle
MPEG Compression
Removing Redundant static information to save bandwidth without losing digital quality
Voice of America, CB, and Amateur Radio transmitters
Return direction can suffer ingress from which transmitters operating in that frequency?
Hum Modulation
Superimposing 60hz AC onto RF signal
0,1
The RF signal level in CATV is reported in dBmV. The baseline,_____ dBmV, is equal to _____ millivolt
Quantization
The assigning of a specific value to each of the samples
Impedance mismatch
The condition that results when two components of a system are operating at different impedance ?
Structural Return loss, Return loss
The difference between the desired signal level and the reflected(return) signal level with the coaxial cable? At active and passive device connections?
C/N ratio
The difference between the peak carrier level, measured in dB, and the noise level, also measured in dBmV.
6 MHz
The difference in frequency between any two adjacent channels is
NF, Flat
The first stage amp.(sometimes called trunk) is selected to have a low _____ and it should have ____ levels across the bandwidth it input?
Amplitude Shift Keying (ASK) Frequency Shift Keying (FSK) Phase Shift Keying (PSK) Quadrature Phase Shift Keying (QPSK) Quadrature Amplitude Modulation (QAM
The five most common digital modulation schemes used today are:
FM
The means of superimposing sound on an RF carrier of a particular frequency,the frequency changes in relation to the voltage detected by the analog input.
AM
The means of superimposing sound on an RF carrier. The frequency stays constant but the amplitude of the carrier varies in proportion to the voltage detected by the analog input.
0 dBmV, with a maximum of 15 dBmV.
The minimum signal level at the input to the customer's television is?
Amplitude
The peak of an AC waveform is known as
Encoding
The process by which these specific values are converted into a data or bit stream
Impedence
The resistance a cable has to AC
Impedance
The resistance of a circuit (cable, passive devices are examples) to alternating current.?
Beat
The unwanted sum of and/or difference in frequencies resulting from the heterodyning (mixing) of two or more signals
−59.2
Thermal noise (The noise floor in a 4 MHz bandwidth at 68º F, in dBmV)
Boot file
This file controls and configures all aspects of the CM(US,DS, Bondin,Mac,etc)
Spectral Re-growth. Multipath and Reflections. Phase Noise.
Three digital distortions you should be concerned with are
Spectral re-growth
Typically an overload effect noted through digital signal processing equipment.
CMTS, Cable modem
What 2 components are required in a docsis compliant system?
3a
What Laser class is an eye hazard if the beam is collected or focused on the eye?
Root Mean Square Meter (RMS)
What accurately measures AC voltages of signals other than pure analog sine waves ?
video, color, and audio
What are the three carriers of Analog signal/
Water migration
What can cause a change in the characteristic impedance of the cable, resulting in reflections and signal distortions?
Reverse Sweep
What can uncover mismatch problems, revealed as standing waves, or diplex filter roll-offs that can severly degrade the quality of services carried in the reverse band
improve by 3db
What happen to c/n if the input are raised by 3db_______
108-137Mhz
What is Aeronautical frequency
Cycles per second, hertz
What is CPS? And is the same as ?
88-108Mhz
What is FM Radio frequency
700-800MHz
What is LTE frequency
Ingress
What is a Passage of an outside signals into the cable; can result in noise and disruption of the desired signal?
A short
What is a situation where the center conductor comes in contact with the shield ?
MER
What is an indicator of transmission quality degradation resulting from noise, ingress, and composite distortions, What is an overall quality measurement that can be performed on a digital QAM carrier?
Sampling Quantization Encoding
What is the 3 step process of converting an analog signal into a digital signal (ADC)
108-137Mhz
What is the aeronautical frequency range
700-800Mhz
What is the frequency range of LTE
8-9 microns,125microns,250microns
What is the size of the Core, Cladding and Coating in (SM) fiber?
(SLM) Signal Level Meter
What is used to measure signal level (in dBmV) at specific tunable frequencies?
100%
What percent of signal is reflected through open ports or shorts
A sweep trace
What reveals every physical error in the network that influences transmitted signals?
59.2db
Whats the output c/n when the input level = NF________
Cable Locator
Whats used to find the location or path of underground cables?
Compare out to in
When Sweeping how can you identify if a response problems is before it or only at its output
Unit gain
When sweeping if the amps have the same response and tilt as the node, then _____ ______ has been achieved?
Waveform TDR
Which is more accurate than digital TDRs or waveform TDR and can detect smaller faults and multiple faults?
SCDMA
With this the CMTS allows multiple CMs to transmit on the same carrier at the same time?
Digital Transmission
a non-continuous signal or carrier that changes its output in discreetly timed steps of voltage level and/or phase that can represent numerical values or other information
Byte
is a group of eight bits used to represent a letter or numeral, or a measurement unit representing storage capacity.
Db or bel
is the unit for expressing, in logarithmic terms, the ratio between two power levels.
T4 timeouts
A CM did not receive a maintenance opportunity from the CMTS within the 30-35 second time window?
T3 timeouts
A CM sent 16 RNG Req and did not receive any Rng -RSp from the CMTS?
Oxidation
A chemical change caused by a reaction to oxygen, such as rust.
Harmonics
A component frequency of the signal that is an integer multiple of the fundamental frequency.
54-216mhz
Across what frequency range does the fcc require signal leakage to be less than 20mv/m@3 meters
Docsis
An international Telecom standard for high speed data transfer on a CATV system?
No
Does fiber have impedance?
FEC
In Docsis additional bits are added to the codeword these additional bits are for what purpose?
No
Is Common Path Distortion, ingress related?
Ghost
Is caused when an analog TV signal (of the same frequency and video content) arrives at a receiver just before, or just after, the desired TV signal
Length, Diameter
List 2 things that determine a cables DC loop Resistance
Sampling
The "measuring" of the analog signal at specific intervals
TDMA
The CMTS allocating specific times for CMs to transmit data?
