TDMM Chapter 11 Flashcards
ACR-F
Attenuation to Crosstalk Ratio - Far End
Performance parameter based on a crosstalk measured on a disturbed pair at the opposite end from which the disturbing signal is transmitted and normalized by the attenuation loss of the disturbed wire pair
ACR-N
Attenuation to Crosstalk Ratio - Near End
The ratio between the signal strength arriving at the end of a link and the disturbance casued by the NEXT coupling from a disturbing wire pair
Attenuation
Decrease in magnitude of power of a transmitted signal between two points
Expresses the loss of optical fiber cabling
CP
Consolidation Point
Interconnection for cables for horizontal cabling to furniture pathways
Delay Skew
Difference in propagation delay between fastest and slowest pairs in same cable sheath
EMI
Electromagnetic Interference
Energy that has an undesirable effect on signal or transmission
Fresnel Reflection
Whenever light travelling in material encounters a different density material, some is reflected back to source
Insertion Loss
Loss in signal from insertion of a component, link or channel
Insertion Loss Deviation
Difference between expected and actual insertion loss
MUTOA
Multi User Teelcom Outlet Assembly
A grouping in one location of serveral telecom outlets
NEXT
Near End Crosstalk
A measure of the signal coupling between any two pairs along the entire length of a balanced twisted pair cable
NVP
Nominal Velocity of Propagation
Determines speed of transmission along a cable relative to speed of light
OTDR
Optical Time Domain Reflectometer
Tool that measures transmission characteristics of opetical fiber
PSAACRF
Power Sum Attenuation to Alien Crosstalk Ratio at Far End
A ratio in decibels that subtracts attenuation from PSAFEXT betweeen close cables
PSAACRN
Power Sum Attenuation to Alien Crosstalk Ratio at Near End
A ratio in decibels that subtracts attenuation from PSANEXT betweeen close cables
PSACR
Power Sum Attenuation to Crosstalk Ratio
A ratio in decibels that subtracts attenuation from PSNEXT loss
PSACRF
Power Sum Attenuation to Crosstalk Ratio Far End
A computation of unwated signal coupling from multiple transmitters at the near end into a pair measured at the far end
PSANEXT
Power Sum Alien Near End Crosstalk
The power sum of unwanted signal coupling from multiple disturbing end crosstalk pairs
Propagation Delay
Measurement of the time required for signal to travel from one end of the transmission path of the other end
Rayleigh Scattering
Scattering of light as it travels along an optical fiber
Return Loss
Measurement of the reflection of signal power resulting from the insertion of a device in a transmission line
SNR
Signal to Noise Ratio
The ratio between the amount of signal and noise
TDR
Time Domain Reflectometer
A testing device to measure length of cable and locate faults
What is required to perform field testing?
- Set of measurable transmission performance parameters
- necessary field test instruments
What should you do in situations where there are no predefined testing requirements for field testing?
Use the most applicable standard
What does a wire map test determine?
If the individual conductors in the cabling are connected correctly
Name seven errors that can be detected during a wire map test
- Continuity
- Shorts between conductors
- Transposed pairs
- Reversed pairs
- Split pairs
- Shield continuity
- Grounded conductor
True or False
Direct current loop resistance is required as an acceptance test for balanced twisted pair cabling
False
True or False
Characteristic impedance is not required as an acceptance test for balanced twisted pair cabling
True
What method is used to calculate the length of a balanced twisted pair cable?
The TDR method
What formula is used to calculate the maximum permissible length for a channel or permanent link?
(NVP x (round trip delay) x c x 110%) / 2
Name three variations in balanced twisted pair cable that can result in different propagation delays in the cable pairs
- Different twist rates
- Slightly different electrical characteristics
- Different dielectric materials
True or False
If a field test instrument uses the same NVP for all pairs in a balanced twisted pair cable, the reported length will be the same for each pair
False
What term refers to the time required for a signal to travel from one end of the transmission path to the other end?
Propagation Delay
What term describes the difference in propagation delay between the fastest and slowest pairs within the same cable sheath?
Delay Skew
What is the relationship between insertion loss in decibels and system performance?
The smaller the loss in decibels, the better the performance