Marco teórico sobre menores infractores
4. Investigaciones sobre violencia infanto-juvenil
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A
Abbssoorrppttiioonn
The attenuation (loss) of radiation as it passes through mate- rial. A portion of the radiated energy of light is converted e.g. to heat.
A
Alliiggnnmmeenntt
Optimal positioning of the ends of the ➜ optical fiber for ➜ splice joints. In the case of fusion splicing of single-mode fibers, alignment of optical fibers can be carried out with the ➜ LID-System.
A
Arrmmoorriinngg
Protective element (usually of steel wires or strips) used in cables for special service conditions, as in undersea and mining applications, rodent protection etc. It is applied over the ➜ cable sheath.
A
Atttteennuuaattiioonn
Reduction in the signal power between two cross-sections of a fiber. It is dependent on the wavelength. Main causes: scat- tering, absorption. It is expressed in "dB“, defined as: -10 log P(L1) / P(L2).
B
Baacckkssccaatttteerriinngg TTeecchhnniiqquuee
Measures the reflectance of lines and their connections along the entire path by means of an OTDR.
B
Baannddwwiiddtthh
Apart from attenuation the bandwidth is the second parame- ter characterizing the properties of an optical fiber. The band- width is a measure of the ➜ dispersion of an ➜ optical fiber.
B
Baannddwwiiddtthh lleennggtthh pprroodduucctt
This product describes the effect that the bandwidth of a given fiber is inversely proportional to the length of the fiber. The bandwidth length product is usually expressed in MHz x km or GHz x km.
B
Buutttt CCoouupplliinngg ((bbuutttt jjooiinntt,, bbuutttteedd ffiibbeerrss))
Signal transmission across fibers joined together end to end.
C
Caabbllee SShheeaatthh
Sheath or jacket usually of polyethylene (PE) or poly-vinyl- chloride (PVC) which protects the core from environmental influences.
C
CAATTVV ((CCaabbllee TTVV))
CATV networks are analog distribution networks in which the various television programs are transmitted over tree-confi- gured coaxial cables and large amplifier cascades to the sub- scriber.
C
Cllaaddddiinngg
The glass surrounding the core of an optical fiber; the clad- ding has a lower refractive index than core glass.
C
Cooaattiinngg
A plastic coating applied for mechanical protection to the surface of the fiber cladding.
C
Coommppoossiittee BBuuffffeerreedd FFiibbeerr
Combination of single-fiber loose buffer and tight buffered fiber. The slight gap between fiber and buffer tube is filled with a gliding layer.
C
Coonnnneeccttoorr
A means of providing a readily separable plug-in connection between two optical fibers. As a rule the ➜ insertion loss of a connector is higher than the transmission loss of a ➜ splice.
C
Coorree GGllaassss
Core of an optical fiber with a refractive index higher than that of the cladding glass.
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Fiber Optics Glossary
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C
Crriimmppiinngg
Compression of a sleeve around a fiber to provide mechanical protection.
C
Crroossssttaallkk
Unwanted transfer of energy, e.g. between two adjacent fibers of a cable.
D
Diissppeerrssiioonn
Dispersion causes light pulses in a fiber to spread in time. A distinction is made between modal, material and waveguide dispersion.
D
Duupplleexx CCoonnnneeccttoorr
Two fiber optic connectors held together by a clip or by design usually to provide go and return paths.
D
Duupplleexx OOppeerraattiioonn ((ttwwoo-ppaatthh ttrraannssmmiissssiioonn))
Information transmission in both directions on one fiber.
F
FDDDDII ((FFiibbeerr DDiissttrriibbuutteedd DDaattaa IInntteerrffaaccee))
Fiber optic network with dual, counter-rotating ring topology and 100-Mbit/s data transfer rate. The FDDI provides a fault- tolerant response to cable breaks and node failures.
F
Fiibbeerr
See Optical waveguide
F
Fiibbeerr MMuullttiipplleexxiinngg
Transmission method in which each transmission channel is assigned a fiber.
F
FIITTLL ((FFiibbeerr IInn TThhee LLoooopp))::
Depending on where the fiber terminates, it may be referred to as:
FTTB - Fiber to the building FTTC - Fiber to the curb FTTH - Fiber to the home FTTD - Fiber to the desk
G
Grraaddeedd-IInnddeexx FFiibbeerr
The graded-index fiber is an optical waveguide with a ➜ gra- ded-index profile.
G
Grraaddeedd-IInnddeexx PPrrooffiillee
Refractive index of a fiber that decreases in a parabolic curve with increasing distance from the center of the fiber core cross section.
G
GRRPP EElleemmeenntt
Support and tensile strength member made from glass fila- ments (GRP glass fiber reinforced plastic).
I
Innddoooorr CCaabbllee
Cables for applications inside buildings. They are not general- ly suitable for installation outdoors.
I
Innsseerrttiioonn LLoossss
The transmission quality of a connector is judged by referen- ce to its insertion loss, i.e. by determining the extent to which the attenuation of an optical transmission path increases when a connector is inserted in this path.
I
ISSDDNN ((IInntteeggrraatteedd SSeerrvviicceess DDiiggiittaall NNeettwwoorrkk))
Data, voice and images are switched and transmitted across the digital network via a single connection.
L
LAANN ((LLooccaall AArreeaa NNeettwwoorrkk))
A local network for serial transmission between inde-pen- dent terminal equipments.
L
L-PPAASS™™
The video image evaluation system L-PAS (Lens-Profile Align- ment System) is used for splice process control. The fiber ends to be fused together are imaged by one or more CCD came- ras. The video signal is used not only to display the fibers on the monitor and to control fiber alignment but also to evalu- ate the splice loss.
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L
Laauunncchh AAnnggllee
Angle between the direction of propagation of the inci-dent light and the optical axis of an optical fiber. For the incident light to be launched, this angle must be between zero and a maximum value which is depend-ent on the point of inciden- ce at the fiber endface and on the difference in refractive index at that point and at the cladding.
L
LIIDD-SSyysstteemm™™
The LID-System (Local Injection and Detection) is used for pre- cision alignment of the fibers in the x/y and z axes. It com- prises two bend couplers (transmitter and receiver). The light on the transmit side is injected into the fiber. The transmitted optical power is received and measured on the receive side. The criterion for optimum alignment of the fibers is attained when the optical power transmitted via the splice reaches maximum.
L
Liigghhtt WWaavveess
Electromagnetic waves in the region of optical frequencies. The term light originally referred merely to the radiation visi- ble to the human eye with a wavelength between 400 and 800 nm. It is however usual to call radiation in the bordering spectral ranges (e.g. infrared) light also.
M
MAANN ((MMeettrrooppoolliittaann AArreeaa NNeettwwoorrkk))
Data network system permitting data and voice transmis- sion. Links ➜ LANs in cities to provide better performance than is possible with ➜ WANs.
M
Miiccrroobbeennddiinngg
Bends in a fiber causing light losses and hence increased attenuation.
M
Mooddeess
All the optical waves that can propagate in an optical fiber.
M
Muullttiiffiibbeerr BBuuffffeerr
M
Muullttiimmooddee ffiibbeerr
Optical fiber whose core diameter is large relative to the ➜ wavelength of the light, thus allowing two or more ➜ modes to propagate.
O
Oppttiiccaall WWaavveegguuiiddee
Transparent dielectric waveguide for the transmission of elec- tromagnetic waves in the region of visible light.
O
Ouuttddoooorr CCaabbllee
Cables which are designed to meet all the requirements encountered in buried and ducted cable systems.
P
Piiggttaaiill
Short length of optical fiber for interconnecting components, one end being provided with a connector, theother end being connected by fusion splicing.
P
POONN ((PPaassssiivvee OOppttiiccaall NNeettwwoorrkk))
A passive network for ➜ FITL with passive components such as ➜ couplers, ➜ splitters and ➜ connectors.
R
Reecceeiivveerr
Component for converting optical signals to electrical form. It comprises a photodiode which converts the in-coming optical signal to a photocurrent which is then amplified in a (low- noise) amplifier. It may incorporate further electronic circuits, e.g. decoders, for signal processing.
R
Reefflleeccttiioonn
Return of rays (waves) from interfaces between two different materials.
R
Reeffrraaccttiioonn
Change in direction which an electromagnetic wave (e.g. light) undergoes when it passes from one material to anot- her and the ➜ refractive index of the two materials is of dif- fering magnitude.
Additional
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R
Riibbbboonn FFiibbeerr
The fibers are arranged parallel to each other and joined together equally spaced in a flat plane (e.g. bonded directly or between two adhesive films); several ribbons can be grou- ped into stacks inside a cable.
S
Seellff-CCeenntteerriinngg EEffffeecctt
The self-centering effect is the tendency of the fiber to form a homogeneous joint which is consequently free of misalign- ment as a result of the surface tension of the molten glass during the fusion bonding process.
S
Siinnggllee FFiibbeerr LLoooossee BBuuffffeerr
Comprises a fiber surrounded by a loose buffer tube.
S
Siinnggllee-MMooddee FFiibbeerr
Optical fiber whose core diameter is so small relative to the ➜ wavelength of the light that only a single ➜ mode is pro- pagated.
S
Sllootttteedd CCoorree CCaabbllee
Cable in which the fibers are located in slots formed in the surface of the cable's central member.
S
Spplliiccee
Permanent joint made between two optical fibers by fusion or adhesive bonding.
S
Spplliitttteerr
Optical component for distributing the optical power from one fiber to several other fibers.
S
Sttaarr CCoouupplleerr
Active or passive component providing a uniform distribution of optical power between equal numbers of incoming and outgoing fibers.
S
Stteepp-IInnddeexx PPrrooffiillee
Fiber with the refractive index declining abruptly between core and cladding but staying constant within the core and cladding themselves.
T
Tiigghhtt BBuuffffeerreedd FFiibbeerr
A fiber having a plastic buffer jacket applied directly over its protective coating.
T
Tiimmee DDiivviissiioonn MMuullttiipplleexxiinngg
Transmission method in which several digital signals arriving in parallel are transmitted as a serial data stream over the same fiber.
T
Trraannssmmiissssiioonn BBaannddwwiitthh
The frequency at which the magnitude of the transfer func- tion of an optical fiber has fallen to a specified value. The transmission bandwidth of an optical fiber is approximately reciprocal to its length.
W
WAANN ((WWiiddee AArreeaa NNeettwwoorrkk))
A network which encompasses interconnectivity between devices over a wide geographic area.
W
Waavveelleennggtthh
Length of a complete cycle (period) of a wave. Optical com- munications usually employ three wavelength ranges. These lie at 850 nm, 1310 nm and 1550 nm.
W
Waavveelleennggtthh MMuullttiipplleexxiinngg
Transmission method in which several signals are transmit- ted simultaneously at different wavelengths over the same fiber.