NCT Distortions 10/17 Part 3
The two carriers are called _______________ and _______________ - shifted 90 degrees or one quarter of a cycle).
"I" (in-phase),"Q" Quadrature
What is the Infrasonic range?
0-12Hz and extends up to the cosmic rays (8x10^21)
237^0 =
1
The visual signal level must not be less than_________across an internal impedance of 75 ohms (__dBmV)
1 millivolt ,0
There are many different types of servers that are found in a broadband network. A few of the more common servers are:
1. DHCP 2. TOD 3. TFTP 4. Proxy
Two types of filters are generally used. They are:
1. High Pass Filter 2. Band Pass Filter
There are several different methods of 'cabling' a network they are?
1. Star 2. Bus 3. Ring
The three major concerns/ limitations of the tree and branch architecture are:
1.Bandwidth 2.Impairments 3.Dependency on power
There are three Color Performance tests and they are all performed at the headend: What are they?
1.Chrominance to Luminance Delay Inequality 2.Differential Gain 3.Differential Phase
Three types of optical transmitters are typically used in broadband HFC networks.
1.Fabry-Perot (F-P) 2.Distributed Feedback (DFB) 3.Yttrium-Aluminum-Garnet (YAG)
10^9/10^4=
10^5
10^2 × 10^3 × 10^4 =
10^9
What are the two most commonly used optical wavelengths by the broadband industry?
1310 nm & 1550 nm
What are the two wavelengths most commonly used by the CATV industry?
1310 nm & 1550 nm
The upstream is either at ______ or ______ transmission.
16 QAM or 64 QAM
"What is the most commonly used quadrature amplitude modulation in our networks?"
256 QAM DS and 64 QAM US
When performing a proof of performance test, what is the maximum variation within a 24 hour adjacent channel interval?
3 dB
Ensure that you allow the meter __________ or more while testing digital measurements.
30 seconds
What range of frequencies are used by satellite systems?
4 Ghz - 14 GHz
With the "I" carrier at 0 degrees and the "Q" at90 degrees. What degree phasestate or symbol is produced?
45
Usually the frequencies above ________ are designated for transmitting signals from the headend out through the network.
50 MHz
A built-in AC/DC blocking circuit protects the SLM or analyzer from damage from online power up to
90 volts
923,478,321^1=
923,478,321
What is Comcast's goal for network reliability?
99.99% / 52.42 minutes a year
I-Stop Probe Insertion Loss
<1 dB, 5 to 50 MHz; <3.5 dB, 50 to 750 MHz; <1.5 dB, in any 150 MHz span
What is meant by the term "isolation"?
A signal's ability to be transmitted from one cable or device to another cable or device, measured in dB
this is used to provide all of the Information you will need to know about the adjacent amplifier,
Amplifier Data Box (Tombstone)
These are one of the few devices in a broadband network that only operate properly if signals are fed into them it in the proper direction.
Amplifier Modules
This is referred to as start (0) and stop bits (1). It is the method, which most PCs use to communicate with each other and mainframes.
Asynchronous
To accurately measure digital channel's strength how must it be calculated?
Average power
A TDR is used to locate:
Bad or unknown splices, Opens, Shorts, Kinked cable
What are the three major concerns/limitations of the tree and branch architecture?
Bandwidth, Impairments & Dependency on Power
In Logarithms is the number being raised
Base
It detects erorred bits in the system.
Bit Error Rate (BER)
The "local" phone office where the subscriber's lines are connected to the switching equipment.
Central Office
Safe as long as they are not disassembled. (CD ROM players)
Class 1
Eye hazard if beam is viewed. Bar code scanner
Class 2/2A
Eye hazard if collected or focused on the eye. (Laser pointer)
Class 3A
Eye hazard if the direct or reflected beam is viewed.
Class 3B
Eye and skin hazard.
Class 4
There are two major types of distortions that are typically associated with CATV.
Composite Second Order (CSO) & Composite Triple Beat (CTB)
This is defined as a form of interference or noise resulting from the mixing of all of the various carriers in a CATV network.
Composite Triple Beat (CTB)
one tenth of a bel
Decibel (dB)
"What process allows multiple wavelengths above and below a center wavelength to be carried on a single optical fiber."
Dense Wave Division Multiplexing (DWDM)
With what process are lasers at different wavelengths (all near 1550 nm) are combined in a multiplexer, and inserted into an optical fiber.
Dense Wave Division Multiplexing (DWDM)
DMM
Digital Multimeter
This is a simple indicator of the overall quality of a QAM digital stream. (JDSU exclusive measurement)
Digital Quality Index (DQI) Mode
List the types of TDRs
Digital and Waveform
A _________ filter is designed to allow signals of one bandwidth to pass through one port and the signals of another bandwidth to pass through the other port.
Diplex
What is the device that helps to route signals within an amplifier station?
Diplex Filters
This server sets up the MAC and IP addresses for the cable modem.
Dynamic Host Configuration Protocol Server
This measurement is for troubleshooting connections with intermittent bit errors occuring over a period of time.
Errored Seconds
the number of times the base is multiplied by itself
Exponent
These are bi-annual tests, performed in the headend and at a number of end-of-line locations, to determine if the network meets minimum specifications set by the FCC.
FCC Proof of Performance
FCC
Federal Communications Commission
is a test accessory that simplifies the location of reverse ingress sources.
I-Stop Reverse Test Probe
Most light generated by lasers for telecommunications use exists in what band of 1310 nm and 1550 nm wavelengths.
Infrared
Visible light falls between the upper portion of the ________ spectrum and the lower portion of the ________ light spectrum.
Infrared, Ultraviolet
A method used to lock and mark one end of a line in order to allow someone to safely work on the other end.
Lockout Tag-out:
Is the exponent or the power to which a fixed number must be raised in order to produce a given number
Logarithm
An indicator of transmission quality degradation resulting from noise, ingress, and composite distortions.
Modulation Error Rate(MER)
This is an electronic process that combines several individual signals into a single medium.
Multiplex
What is the process of combining multiple carriers onto a single medium?
Multiplexing
NFPA
National Fire Protection Association
This can be described as an overall grainy-ness or snowiness to the picture and is measured as its carrier-to-noise ratio (C/N).
Noise
This is defined as the lowest possible power level determined by the thermal noise generated within the electrical components being tested.
Noise Floor
The use of the return path was extremely limited due to the _________ and _________ _________ associated in the return spectrum.
Noise, Funnel Effect
NPRM
Notice of Proposed Rule Making
An 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
What is the highest power level (amplitude) reached by a carrier?
Peak
PEL
Permissible Exposure Limit
These servers store commonly used (or contractually stored) data.
Proxy Server
To facilitate this, a single carrier is split into two carriers with one carrier shifted 90 degrees out of phase with the other.
Quadrature PSK or QPSK
Usually a passive device such as a splitter or directional coupler used to combine radio frequency signals from one source with those from another.
RF Combiner
Usually a passive device that divides a signal into two equal paths. It may be found on trunk, feeder, or drop cable.
RF Splitter
Tree and Branch architecture uses the _____________ Spectrum for signal transmission.
Radio Frequency (RF)
The wavelengths above this range are not visible to the human eye.
Red Light (650 nm)
The voltage required to "ring" the phone, typically between 70 and 90 volts at 17 to 20 Hz.
Ringing voltage
RMS
Root Mean Square
The square root of the sum of the squares of the amplitudes of individual components of a function, such as the frequency components of a signal.
Root Mean Square (RMS)
This server sets up a common clock between the CM and the CMTS.
TOD
What does a CMTS do?
Terminates, manages, and translates high-speed Internet sessions between cable modems
this is used to catalog system maps (numbering system)
The Map Grid System
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 & Branch
This server allows non-protected file transfers, such as a configuration file for a modem.
Trivial File Transfer Protocol Server
Twice a year. These must be performed at the coldest time of the year, in January or February, and again at the warmest time of the year, in July or August. These months typically represent the seasonal extremes for AGC performance.
Video Carrier Level Stability (24-hour) test
This Combines multiple optical signals in order to amplify them as a group and transported over a single fiber.
Wave Division Multiplexing (WDM)
The distance between two points of like phase in a wave.
Wavelength
The "real" bandwidth of an optical fiber is defined by the bandwidth of the ________ ________ in the system.
Weakest Link
This is the resistance of a circuit to alternating current. Although measured in ohms, it can't be measured with the ohm portion of a volt-ohm meter.
What is Impedance
WAN
Wide Area Network
ANSI separates lasers into various classes that take into consideration the operating wavelength, output power level, and whether the laser operates as a continuous or pulsed light output.
Z-136
1. Enhanced Picture Quality 2. Increased Reliability 3. Decreased Cost of System Maintenance 4. Cost Effective Means of System Upgrade Requiring a Complete Change Out of Electronics 5. Small Segmented Areas Allow Greater Return Path Functionality
benefits of implementing fiber optics in broadband networks?
What bandwidth do satellite systems use?
between 4 and 14GHz.
When all the forward frequencies are in use, and the operator is unable to offer any additional programming, the system is considered to be
channel locked
The tests must be made on a ______________ channels plus _____________________, or fraction thereof, of cable distribution system upper frequency limit.
minimum of four (4),one additional channel for every 100 MHz
A card made up of material similar to photographic film that changes colors when exposed to light.
photosensitive card
Visual Signal Level FCC Performance Specification is Do not overload subscriber terminal, Comcast Expectations are Recommend level not exceed ___ dBmV for any given analog channel at television terminals.
positive 20
I-Stop Probe Insertion Loss Insertion Loss with Button Depressed
≥5 dB, ≤ 8 dB @ 5 to 30 MHz; ≤1 dB insertion loss increase @ 54 to 750 MHz
