7 ISDN user.part Q.860 ISDN and B-ISDN Generic Addressing and TransportGAnProtocol Q.920 DSS 1- ISDN user-network interface data link layer, general aspects Q.92 I ISDN user-network inte
Trang 1Fiber Optics Illustrated Dictionary
toward the radiant energy source The four beams of
light exiting from the pyramid are re-imaged with a
display system to yield four images The pyramid acts
like a knife-edge test system, revealing optical
aber-rations carried by the light electromagnetic beam The
system has been tested in astronomical applications
See knife-edge focusing
pyrheliometerAn instrument for measuring infrared
radiation which borders the visible spectrum on one
side and radio waves on the other
pyroelectric detectorAdetector that takes advantage
ofthe characteristic of a pyroelectric material to build
up a charge when exposed to pulsed or modulation
radiant energy Due to the quick response times of
pyroelectric detectors, they are more useful for some
types of applications and environments than other
types of thermal detectors that have difficulty
sepa-rating the impulse heat from ambient heat due to
slower response times See photodetector,
pyroelec-tric, thermocouple
pyroelectricA usually crystalline substance having
polarized molecular properties in the absence of
ap-plied voltage When stimulated by heat, the molecules
become more active, expanding and altering the
po-larization of the material enough to build up an
elec-trical charge on opposite surfaces of the material
Thus, a subtle electromagnetic impulse flows between
the surfaces
pyroelectricityElectromagnetic charges created
through a change in temperature Pyroelectricity
re-fers to the means of generating the charge, not the
nature of the charge itself, which is the same as
oth-ers Crystals have valuable osci llating characteristics
and are commonly used in timing mechanisms and
radio electronics and some have interesting
pyroelec-tric activity when exposed to heat See pyroelecpyroelec-tric,
pyroelectric detector
pyromagnetic effectThe combined effect ofheat and
magnetism in a material or circuit
pyrometerAn instrument for determining
tempera-ture, that is, a heat sensor for detecting and
option-ally quantifying thermal radiation A pyrometer is
generally used in situations hotter than those
mea-sured by a traditional mercury thermometer,
espe-cially where non-contact temperature is assessed
Temperature can be measured in a number of ways
by electrical resistance, optical, or other radiant
en-ergy emissions Thermal radiation may be assessed
by measuring the brightness (intensity) ofradiant
en-ergy within a narrow portion of the thermal spectrum
Another means is by evaluating data collected in two
different wavelengths (usually red and green) to
in-fer temperatures in the higher ranges (picture the way
an electric stove element changes color as it heats)
Infrared heat detectors (spectral radiation pyrometers)
have traditionally been combined with optical lenses and reflectors to make pyrometers Initially, fiber optic cables were not seen as good infrared lightguides, but improvements in fiber optic technolo-gies and control ofspectral characteristics have made
it practical to develop new fiber-based pyrometers
A fiber-based probe can be quite tiny and enables placement of the rest of the electronics at some dis-tance from the probe, which is very useful for medi-cal and industrial applications, especially those that involve insertion into constrained spaces or where there is high electrical activity that could interfere with electronic probes
The temperature range to be sensed with a fiber-based probe and the length of the fiber are related, with lower temperatures having lower limits on the length
of the fiber cable The angle of acceptance of the fi-ber endfaces (or a lens associated with the fifi-ber endfaces) determines the breadth of the sensing area and how closely the device must be held to the heat source for accurate readings By combining fibers with lens focusing geometries, it is possible to design heat probes with very precise tolerances suitable for medical evaluation or industrial applications such as quality assurance and microfabrication Unfocused fibers are suitable for general purpose applications where specificity of individual temperature regions
is not critical Where practical, backlighting the tar-get object can provide a visual guide for aligning the probe
Pythagorean Theorem
TheSUIllofthe squares ofthe sides (A, B) ofa right angle triangle equals the square ofthe hypotenuse (C).
Pythagoras' theorem, Pythagorean theorem A mathematical rule that states that, in a right-angled triangle, the sum of the squares of the sides is equal
to the square of the hypotenuse (the longest side) This theorem is widely used in mathematics for calculat-ing distances and other measures It is named for the Pythagoreans, a philosophical group connected with Pythagoras
Trang 2tity in coulombs See coulomb.
Q 1.abbrev. quality See Q factor 2.abbrev.queue
See queue 3 Amerit indicator for a capacitor or
in-ductor equal to the reactance divided by the
resis-tance 4 Ina resonant circuit, an indicator of the
sharpness or resolution of the resonance It is
calcu-lated by taking the resonant frequency and dividing
it by the resonant bandwidth See Q-switch
QaddressA storage location for data, from which
the information can be accessed and retrieved
QantennaAtype ofdipole antenna in which the feed
line impedance is made to match the radiometer
cen-ter impedance by the incen-terposition of a vertical
sec-tion, consisting of parallel bars between the two
QbitInan X.25 network, the Q bit is a binary
indi-cator located at the beginning of a data packet,
im-mediately preceding the D bit TheQbit signals the
existence ofuser data or qualified data in the form of
control information Protocols in higher layers can
set this bit to one (1) to indicate control packets,
oth-erwise a value ofzero (0) indicates data packets See
D bit, M bit
Qchannell.InNTSC color television
broadcast-ing, a frequency band in which green-magenta color
information is transmitted 2 In ISDN Basic Rate
Interface (BRI)SITinterface implementations, an
800-bps maintenance channel 3 In data
transmis-sions, a channel associated with an I channel in
modu-lated transmissions (e.g., phase-shift keying) See Q
signal
Q demodulation Demodulation of an incoming
broadcast signal in a color television receiver to
com-bine the chrominance signal and the color-burst
os-cillator signal in order to recover theQsignal
Qfactor(symb - Q) quality factor 1.Inelectronic
circuits, a means ofdescribing the desired
character-istics of a system The terms of the Q factor vary
de-pending upon what is described (capacitance,
induc-tance, etc.).In a digital circuit, for example, the Q
factor may be used to characterize the signal-to-noise
ratios of the two digital states The concept has
tra-ditionally been associated with electrical voltages and
wired communications, but can be generalized to
optical communications Generally, a higher number
ponent.Inlasers, for example, a maximal Q-factor may be associated with a filled laser resonance cav-ity, where the signal-to-noise ratio is high and switch-ing may be triggered The Q factor may be used as a figure ofmerit (e.g., for assessing bit error rates) See bit error rate 2 See Q-factor
QmultiplierA circuit used to enhance the selectiv-ity ofa component by feeding the signal back through the resonant network This was used in early super-heterodyne receivers, but various types offilters have, for the most part, superseded it
QoutputThe reference output of an electronic flip-flop state, which may be one or zero
QSeries RecommendationsA set ofITU-T recom-mended guidelines for switching and signaling These are available for purchase from the ITU-T Some of the related general categories and specific Qcategory recommendations are included in charts on the fol-lowing pages to give a sense ofthe breadth and scope ofthe topics listed here A full list of general catego-ries is listed in Appendix C and specific secatego-ries topics are listed under individual entries in this dictionary See also I, V, and X Series Recommendations
Qsignal1 In various data transmission schemes,it
is common to split a signal and to alter the character-istics of one or both of the two data streams so that they can be transmitted together without excessive interference or crosstalk A Q signal or quadrature-phase signal is one oftwo common streams; the other
is the in-phase signal or I signal, into which data are commonly split in various modulation systems See quadrature amplitude modulation See I signal 2 A telegraph code shorthand signal consisting oftwo let-ters prefaced by a"Q"that is still well known to ama-teur radio operators For example, QST is a general call preceding a message addressed to all members and amateurs As such, it is also the name ofthe jour-nal of the American Relay Radio League (ARRL) SeeQBF
QspoilingA technique used with lasers in which a more powerful burst or pulse is attained by inhibit-ing the action of the laser for a few moments, to al-Iowan increase in the number of ions, and then Q switching to allow the extra burst oflight to be emitted
Trang 3Fiber Optics Illustrated Dictionary
ITU-l'QSerlesReeommendations
Q.721 Signaling System No 7 functional description of the Signaling System No
7 TelephoneUserPart (TUP) In band andout~band
Q.20 Comparativeaqvantages of 44in-band" and "out-band"systems
Q.21 Systems recommended forout-band signaling
Q.22 Frequenciestobe· usedform-band
si~~Jin9:
Q.25 Splitting arrangementsand signal recogniti9Ptin1~s in"in~b~net"·signaling systems
:Splittingarrangemellts and signal recognitiQQ times in"in-band" signaling systems:
BhQne·featuresandsi nals Q.23 Tecl1nicalfeaturesofpusll-buUOD
telephone:sets Q.24 Multifrequencypush-button··signal
reception
Q.27 Transmissionoftheanswersignal Q.~8 Petennirmtionoftbemoment ofthe calledsubscriber'sanswer in the
automaticservice
Q.35 Technical characteristics oftonesforthe telel'honeservice
Q~1()9!raI1SDlis~ion<?ftheanswersignal in international·exchanges
Networkaceess
Q.33 Q.44
Q.26< ··Directacpesstothe~temational
networkfrom#lenationalnetwork
Quality of transmissions; interference and noise
Q.32
Q.29 :·@ausesornoise.andwaysofreducing
noise in telephone exchanges 0.30 Improving thereliability ofcontacts in spe~cpcir.cuits
Q.31 Noiseinanational4-WireautoIllatic excljang~
Reduction of therisk of instability by s'Vitchingm~Mls
Protc:ctiopaga.ipsteffeetsQf faulty tratl.slllissiolt·Ofl.grOUpS··ofcircuits Attenuati(}n etistortion
Q.4 Automatic s:witchillg futlctions for lisein
national···netWorks
Q.5 J\dvan~~es(lfs~jaut()matieservice ·~tl
theintemationalteleph()neservice
Q.6 ~ A.dvant~ge.s~fjll~J;natj@11aI. t!1.1tomatic
working
Signalingsystems
Q.7 Signalmg systemstcrbe'usedfor
imemiti9~~J.•·.•.~~ff'Wtltif;·.••~:p.<i
semiautomatic·telephoite.working
Q.8 Slgtlalit1gsY§telll~~t(l"euseqfor
mtemationalmantialandautomatic
workirIgontplalogtle leasedcircqits
Q.48 Dematldassi~Dlc;ntsigpalin~ systems
Q.SO Signalingbetweencircuit multiplication
~quip~ent.(GMJ;l'and.~t~m~ol1~l
sWitching·centers(ISC)
Q.55 Signalipg bet,weeqsignalproc:essing
networkequipmerit andinternational
~witchijlg c.m~~
Q.698 Inte1Workin~ofsigna1iJlgsystemNo 7
ISUP,TUP,and signa1mg system No 6
usingarrowcliagrams
Q.700 ·Introdtictiol'f<td·C€ITTSignalirig··System
No.7
Q.701·FlUlctionaldescriptionhfthe'message
trllll~ferpart(MTr)o(~~gnaling§ysterJ1
No.7
Voc~bu1a1"yof s\Vitc\Ung and signaling
Tel~IJlJ11uni~~~on~pplications ~or
'switches~d ~Jl1PUters (TA.SC)~
gen~J:81~~~rvi~~
Q.1302 Tel~IJPtlunic1\ti(')napplicationsfor··
:switches·· ~dc2tnPHt~
(f?\SC).-TASefunCtionalservices
Q.1303 Teleqo111II1lJ11ip,~ion.~pp1icatiot)~for
switches and computers (TASC)
-TASG~~g~~l.lt:archjtectur~,
.methodology.and requirements
Q.1290 :Glossat"}'Qftertpsus~ i!l~he
definitionof intelligent networks
Q.120llI~312~ncipJesofintenigetltnetwork
architecture
Q.12021I.328lliteIIigentNet\Vork·· >service
~lanellrchi~~~~
Q.12031I.329 IntelligentNetwork -global
f)JncHQPaJpla.n~~cJJi~tlJr~
Automatic and semiautomatic switchin
Trang 4Q.71 ISDN circuit mode.switchedbearer
services
Q.80 • Introduction to Stage 2 service
descriptions for supplementary services
Q.81 Number identificatio11
Q.82 Call offering
Q.83 Call completion
Q.84 Multiparty
Q.85 COl1lttluttlty ofinterest
Q.86 Charging
Q.87 Additional infotmation transfer
Q.761 Functional description of the ISDN
user-part ofSignaling System No.7
Q.762 General function ofmessages and
signals oftheISDN user part of
Signaling SystemNo.7
Q.763 Fonnatsand codes ofthe ISDN user part
of Signaling System No.7
Q.764 Signaling System No.7ISDN user part
signaling procedures
Q.767 Application of the ISDN user part of
CCITTSignaling SystemNo 7for
internationalISDNinterconnections
Q.768 Signaling interface between an
international switching centre (ISC) and
an ISDN satellite subnetwork
Q.850 Usage of cause and location in the
digital subscriber signaling system no 1
and the Signaling System No 7 ISDN
user.part
Q.860 ISDN and B-ISDN Generic Addressing
and Transport(GAnProtocol
Q.920 DSS 1- ISDN user-network interface
data link layer, general aspects
Q.92 I ISDN user-network interface,datalink
layer specification
Q.922 ISDN data link layer specification for
frame mode bearer services
Q.923 Specification ofa synchronization and
coordination function for the provision
of theOSIconnection-mode network
service in an ISDN environment
Q.930 DSS I-ISDN user-network interface
layer 3, general aspects
Q.931 DSS1 - ISDN user-network interface
layer3 specification for basic call
control
Q.932 DSSI-genericprocedures for the
control ofISDN supplementary services
Q.933 ISDN DSSI - signaling specification for
frame mode basic call control
Q.939 TypicalOSS1 service indicator codings
for ISDN telecommunications services
Q.940ISDN user-netWork interface protocol for management, general aspects Q.950 ISDN suppletnentaryservices protocols, structure, and general principles Q.9SI··.•·Numberidentificatiol1
Q.9S2 Stage 3 description for call offering supplementary services.using DSS 1 -diversion supplementary services Q.953 CalLcompletiQJ1
Q.954 •Multiparty
Q.955 Community ofinterest Q.956 Charging
Q.967.·.•.Additional.• information transfer Q.l901 Bearer-Inde}lendentCaIlControl
Protocol Q.1950 Bearer-Independent CallControl
Protocol Q.1970 Bearer-IndependentCallContr()lIP
Bearer Control· Protocol Q.1990 Bearer-Independent Call Control
Tunneling frotocol Q.2010 Broadband mtegrateclserVicesdigital
network overview - signaling Capability Set 1 (CS-l) Q.2100 B-ISDN signaling ATMadaptation
layer(S~)ovetviewdescription Q.2110 B-ISDN
ATM.adaptationJayer-service specified connection oriented protocol (SSCOP)
Q.2111 Service~SpecificCol1nection Orientetf
Protocolina multilink and connectionless environment (SSCOPMCE)
Q.2119
B-ISDNA.TMadaptati()111ayer-:-convergence functionforSSCOP above the.framerelay core service Q.2120 B-ISDNmeta-signalingprotocol Q.2130 B~ISDN siitJ.aling~TMadaptation
layer - service-speciticcoordinatiort function for support ofsignaling at the user network interface (SSFC AtUNI) Q.2140 B-ISDN ATM adaptation
layer-servicespecifjc coordination function for signaling at the network node interface (SSCF at NNI) Q.2144 B-ISDNSignalingATMadaptation
l~yer(SAAB)-larerln~agementfor the SAALatthe netvvork:node interface(NNI)
Q.2150 AAL2 signaling transport converter Q.2210 Messagetnmsfer partl~vel3
functions and messages Itsingthe services ofITU-T Recommendation Q.2140
Trang 5Fiber Optics Illustrated Dictionary
ITU-TQSeries Recommendations,cont
ISDN and B-ISDN cont
Q.2610 B-ISDNusage of cause andlocationin
B-ISDN user part and DSS-2
Q.2650 B-ISDN- intemetwQrking between
Signaling System No.7 B-ISDNUser
Part(B~ISUP)and digital subscriber
Signaling System No.2 (OSS-2)
Q.2660 B-ISDN- intemetworking between
signaling System No 7 B-ISDNUser
Part (B-ISUP) and N-ISDN User Part
(N-ISUP)
Q.2723 Extensions to SS7 B-ISDN User Part
(B-1SUP)
Q.2725 B-ISDNUser Part CS-2.l See Q.2761
throughQ.2764
Q.2726 B-ISDN UserPart eS-2.I See Q.2761
through Q.2764
Q.2727 B-ISDNUserPart(B-1SUP) support of
Frame Relay
Q.2730 B-ISDN- S87B-ISDN User Part
(B-ISUP) supplementary services
Q.2735 Stage 3 description ()fCommunity of
Interesfsupplementary services for
B-ISON using SS7
Q.2761 B-ISDN - functional description of the
B-ISDNUserPart.{B-ISUP)ofSS7
Q.2762 B-ISDN- general functions of
messagesandsignals of theB-1SUP of
S87
Q.2763 B-ISDN - SS7 B-ISDN User Part
(B-ISUP)-Formats and codes
Q.2764 B-ISDN- 8S7 B-ISDN UserPart
(B-ISUP) -Basic call procedures
Q.2765 B-ISDN S87 B-ISUP-Application
Transport Mechanism (APM)
Q.2931 B-ISDN- Digital Subscriber Signaling
SystemNo.2 (OS8 2) - User Network
Interface(UNI)Layer3specification
for basic call/connection control
Q.2934 B-ISDN DSS-2switched virtualpath
capability
Q.2941 B-ISDNDSS 2extensions
Q.2951 B-ISDN - Stage3description for
number identificati9n supplementary
servicesusingB-I8DN D88-2- basic
call
Q.2955 B-ISDN DSS-2 - stage 3 description
for community of interest
supplementary services- basic call
Q.2957 B-ISD~DSS-2 - stage 3 description
for additional infotnlation transfer
supplementary services - basic call
Q.2959 B-ISDNDSS-2-(;all priority
Q.2961 B-ISDNDSS-2 -support of additional
parameters
Q.2962 B-ISDN DSS-2 - connection
characteristics negotiation duringcaUl
connection establishment phase Q.2963 B-ISDN DSS-2 - extensions forATM
Q.2964 B-ISDNDSS-2 - basic look-ahead and
other clauses
Q.296S B-ISDN DSS-2 - Quality of Service
(QoS) issues Q.2971 B-ISDN - digital subscn"ber
DSS-2-user network interface Layer 3 specification for point-to-multipoint calVconnection control
Q.2981 B-ISDN and B-PISN - call control
protocol Q.2982 B-ISDN DSS-2 - Q.293 I-based
separated call control protocol Q.2983 B-ISDN DSS-2 - Q.2931-based bearer
control protocol Q.2984 B-ISDN and B-PISN - prenegotiation
for multiconnection Q.2991 Abstract test suite for the network
integration testing for B-ISDN and B-ISDNIN-ISDN
Modeling, Intelligent Networks Q.76 UPT functional modeling and
information flow Q.1200 Intelligent Networks (INs)
recommendation structure Q.1201 Principles of Intelligent Networks
architecture Q.1202 Intelligent Networks - service plane
architecture Q.1203 Intelligent Networks - global
functional plane architecture Q.1204 Intelligent Networks - distributed
functional plan architecture Q.120S Intelligent Networks - physical plane architecture
Q.1208 General aspects of the Intelligent
Networks application protocol Q.1210 Q l2xxseriesstructure for Intelligent
Networks Q.1211 Introduction tg IntelligentNetworks
Capability Set 1 (CS-l) Q.1213 Global functional plane for Intelligent Networks·CS-1
Q.1214 Distributed functionalplanefor
Intelligent Networks CS-]
Q.1215 Physical plane for Intelligent Networks
CS-l Q.1218 Interface recommendation· for
Intelligent Networks CS 1 Q.1219 Intelligent Networksuserguidefor CS-l Q.l220 Q.l22x series Intelligent Networks
Capability Set 2 (C8-2) recommendation structure Q.1221 Instruction tolntelligent Networks CS-2
Trang 6Q.t711 Functional modelfor 1MT 2000
networks Q.1721 Information flows forIMt~2000CS-l Q.1731 Radio technology independent :requirements for 1MT-2000Layer 2 radio interface.··.\i :/:) .>:
Q.17S1 Internetwork signaling requirements for
1MT-2000CS"1
Wireless communications
CS-2
Q.1223 G10tial functional plane for Intelligent
Networks CS-2
Q.1224 Distributed functionalplane for
Intelligent Networks CS-2
Q.1225 Physicalplane forJl1telligentNetworks
CS-2
Q.1228 Interface recommendation for
IntelligentNetworks CS-2
Q.l229 IntelligentNetworksuser's guidefor
CS-2
Q.1231 Introduction to Intelligent Networks
CapabilitySet 3 (CS-3)
Q.1236 Intelligent Networks CS-3
Management Information ModeJ
requirementsand methodology
Q.1237 ExtensionstoIntelligent Network CS-3
in supportofB-ISDN
Q.1238 Interface recommendation for
Intelligerit NetWorkCS-3
Q.1241 Introduction to Intelligent Networks
Capability Set 4 (CS-4)
Q.1244 Distributedfunctionalplane for
IntelligentNetworks eS-4
Q.1248 Interface recommendation foI'
Intelligent NetworkCS-3
Q.1290 Glossaryof tenns for Intelligent
Networks (included inQ.9)
Q.1300 Telecom applications for switches and
computers (TASC) general overview
Q.1301 TASe - architecture
Q.1302 TASe - functional services
Q.1303 TA8C management, architecture,
methodology, andrequirements
Q.1400 Architecture framework for the
development ofsignaling and
organization, administration, and
maintenance protocols tlsing·OSI
concepts
Q.1521 Requirements on· underlying networks
and signaling protocols to support UPT
Q.1531 UP!security requirementsfor Service
Set1(8S-1)
Q.1541 UP!Stage 2 for 8S-1 on SC-t-1995:
procedures for UPT functional
modeling and infonnation flows
Q.1542 UPTStage 2 forSS-l on
CS-2-procedures for universal personal
telecommunication functional
modeling and information flows
Q.1551 Applieation·of IntelligentNetwork
application protocols (INAP) CS-l for
UP! SS-1
Q.1600 Signaling System No.7 interaction
between ISIUP atIdINAP
Q.1601 Signaling System No 7 interaction
between N-ISDN and INAP CS-2
Q.14
Q.lOOO
Q.1001 Q.I002 Q.1003 Q.l004 Q.lOOS Q.1032 Q.lOSl Q.I100
Q.l101
Q.ll11
Q.1112
Q.l1S1
152
Q.l231
Means tocontroltbenumbel"of satellite links in an international telephone connection
Structure of the QJOOOseries fecommenda~ons forpubJicJand mobile networks
Generalaspects ofpublicland mobile
networks Network functions (or publicland mobile networks
Locationregistratioh prdceduresfor
public land mobile networks Location register restoration procedures
forpublic'landmobile.networks Handover procedures for public land mobile networks
Signaling requirements relating to routing ofcaUs to mobile subscribers Mobile application part for publiclart(f mobile networks
Interworking with Standard A ThfMARS~l'.systell1- structure ofthe Recommendations ontheINMARSA1
mobilesat~llitesystems General requirements for the interworking of the terrestrialtelephone
networkand INMARSATStandardA system
Interfacesbetween theINMARSAT standard B system and the international publicswitched telephone networkl ISDN
ProceduresforihtetWorkmgbetween INMARSAT standard-B.system and the international public switched telephone networklISDN
Interfaces·for iIlterworkil1g between the INMARSATaeronautical mobile-satellitesystemandtheinternational public switched telephone network! ISDN
Proceduresforintenvorking between INMARSAT aeronautical mobile satellitesystem and the international public switched telephonenetwork!
ISDN
Extensionsto··ttltetligent.NetworkCS-3
insupport ofB-ISDN
Trang 7Fiber Optics Illustrated Dictionary
Q-bandA microwave frequency spectrum ranging
from 36 to 46 GHz, between the Ka-band and the
V-band Frequencies in this range tend to be used for
radar and small aperture satellite transmissions See
band allocations for a chart ofdesignated frequencies
Q-factorA measure of frequency selectivity, or the
"sharpness" ofresonance in a resonant vibratory
sys-tem which has one degree of mechanical or
electri-cal freedom See Q factor, Q-switch
Q-switchInlaser resonating cavities, a mechanism
for opening and closing the cavity to allow or block
the laser light to produce laser pulses rather than a
continuous wave This mechanism can be constructed
with acousto-optic or electro-optic devices (e.g.,
Pockels cells) The term comes from the high
signal-to-noise ratio (Q factor) that is characteristic of an
amplified signal in a filled laser resonating cavity
In acousto-optical switching, incident light from the
laser is deflected when it comes in contact with
acous-tical waves (e.g., in a modulating crystal) and is
scat-tered so that there isn't sufficient focused energy to
exit the resonating cavity
In electro-optical switching, incident light from the
laser hits a polarizing "shutter" such that the light will
pass or not pass Thus, Pockels cells, in conjunction
with a polarizer, act as a Q-switch to alternately
al-low the laser cavity to be filled or emptied in a
pro-cess sometimes called cavity dumping Pockels cells
may also be configured/assembled with other
com-ponents to allow a portion of the pulse to exit before
the cavity is fully filled (amplified) See pockels
ef-fect, Q, Q-factor
Q-TelecomAbusiness unit of Info-Quest providing
telecommunications services to Greece as one offour
GSM suppliers in the country In June 2002, it was
announced that Q-Telecom would deploy Harris
Cor-poration point-to-multipoint digital radio systems
throughout Greece
Q.SIGAglobal common channel signaling protocol
(CCS), based upon the ISDN signaling protocol, used
inthe digital transmission of voice over digital
net-works such as ATM In addition to the features in the
ISDN signaling protocol, Q.SIG includes private
branch exchange (PBX) features so a network of
PBXs can interact as a distributed system CCS
sys-tems are more prevalent in Europe than in the United
States See voice over ATM
QA 1 quality assurance 2 queued arbitrated In
DQDB, an information field segment used to
trans-fer slots when they arrive through a nonisochronous
transfer
QAM See quadrature amplitude modulation
QBESee query by example
QBF, fox messageQBF="quick brown fox." The
Q signal code to send a test sentence that includes all
the letters of the English alphabet A QBF message
is commonly used to verify whether all letters
avail-able to a device or contained within a coding system
are present and/or working correctly It is familiar to
most as "THE QUICK BROWN FOX JUMPS
OVER THE LAZY DOG" (which is then repeated
in lowercase, if needed) The idea is to convey the
entire alphabet in the shortest sentence that is com-fortably memorable as possible In wireline devices,
it is more often called a "fox message" since Q sig-nals are associated more specifically with radio fre-quency communications The phrase "fox message"
is used more generically to test alphabetic commu-nication signals and the physical integrity of type-writer or computer keyboard keys See Q signal, Z code
QCquality control
QC laserSee quantum cascade laser
QCELPSee Qualcomm Code Excited Linear Pre-dictive Coding
QCIFSee Quarter Common Intermediate Format
QCTQualcomm CDMA Technologies See Qual-comm Code Excited Linear Predictive Coding
QDSee queuing delay
QD-DOS, QDOSAhistoric microcomputer operat-ing system (Quick and Dirty Operatoperat-ing System) de-veloped by Tim Paterson, which was derived from a mid-1970s manual describing Gary Kildall's CP/M, and extremely similar in syntax and functionality At that time, ffiM was looking for an operating system for its line of microcomputers ffiM contacted Mi-crosoft about contracting their (computer language) products, thinking they had also purchased the rights
to CP/M When they found that Microsoft didn't have
an operating system, they went to visit Digital Re-search (originally Inter-Galactic ReRe-search), but the
DR representative was reluctant to sign ffiM's non-disclosure agreement on DR's behalf, especially when the attorney didn't like the terms ofthe contract ffiM went back to Microsoft and DR thought it would have a further opportunity to talk terms with ffiM, especially since Microsoft didn't have an operating system that could meet ffiM's needs at the time, as they had been concentrating their efforts on devel-oping computer languages Microsoft, however, promised one to ffiM in a very short time period, and delivered on the contract by purchasing the code for QDOS from Seattle Computing, the company for which Paterson was working They provided it to ffiM who released it as PC-DOS Microsoft subse-quently purchased the distribution rights for QDOS for $50,000 and later released a slightly altered ver-sion ofPC-DOS as MS-DOS (Microsoft Disk Oper-ating System) Microsoft managed to stipulate con-tractually that they could retain the rights to sell the product they had developed for ffiM, in competition with ffiM Thus, QDOS, derived from CP/M became IBM's product, rather than CP/M itself: and evolved into MS-DOS, and eventually Windows See CP/M, Microsoft Corporation, MS-DOS, Digital Research
QDUSee quantizing distortion units
QFASee Quick File Access
QFCSee Quantum Flow Control
QFM See quadrature frequency modulation
QICquarter inch cartridge See Quarter Inch Car-tridge Drive Standards
QICC1 See Quad Integrated Communications Con-troller 2 See Quad International Communications Corporation
Trang 8management software product from Quadritek (now
Lucent IPGSP) that facilitates the central
manage-ment of network databases In March 2000, Lucent
announced that QIP had been ranked as the market
share leader for standalone Internet Protocol (IP)
ad-dress management products The product is used by
prominent companies such as MCI Worldcom's
UUNET, Discover Financial Services, Ford Motor
Company, and others See Quadritek
QJDPQIP/Windows 2000 Joint Developer Program
Lucent Technologies' initiative launched in
Decem-ber 1999 to foster development of design interfaces
and requirements between QIP 5.0 IP address
man-agement software and Windows 2000 See QIP,
Quadritek
QL See query language
QLLC See Qualified Logical Link Control
QMSQueue Management System See queue
man-agement
QoRSee Query on Release
QoSSee Quality of Service
QPLQualcomm PureVoice Library See Qualcomm
Code Excited Linear Predictive Coding
QPSK1 See quadrature phase shift keying 2 See
quaternary phase shift keying
QRqueuing requirements See queuing theory
QRPAdesignation for low-power amateur frequency
radio transmissions Low-power transmitters and
re-ceivers are an interesting subgroup ofhobbyist radio,
when used with respect for the privacy of
individu-als and within regulatory guidelines Regulations for
short distance, low-power transmissions are more
lenient than for other types ofbroadcasts QRP
trans-mitters can be used for short-distance broadcasting,
home security systems, door intercoms, climbing
communicators, baby and child monitors, and other
short-range projects
QRP ARCIThe QRP Amateur Radio Club
Interna-tional is a nonprofit organization dedicated to
ama-teur design, construction, and use ofQRP (low power)
transmitters See Amateur Radio Relay League, QRP
http://www.qrparci.org/
QSAMsee quadrature sideband amplitude
modula-tion
QSDGSee Quality of Service Development Group
QTAMSee Queued Telecommunications Access
Method
QTFSee quartz tuning fork
QTC QuickTime Conference See QuickTime
QTSSQuickTime Streaming Server See QuickTime
QTVR QuickTime Virtual Reality See QuickTime
QuADQuorum Associate Distributor See Quorum
International
quad-Prefix for four
quad antennaAtype ofarray antenna similar in
prin-ciple to a Yagi-Uda antenna, except that it uses
full-wavelength loops in the place of half-full-wavelength
straight elements, thus providing greater gain over a
similar Yagi-Uda antenna As with many antennas,
the feed is commonly 75-ohm coaxial cable A
two-element quad antenna is called aquagi.
with the elements mounted on a boom or radiating out like the support threads of a spider web In one common configuration, the prominent features in-clude simple straight-pole elements mounted in a horizontal plane at right angles to one another with a diamond-shaped configuration on one pole mounted
in the vertical plane There are variations on quad antennas including cubical quads (which can re-semble an open umbrella with the fabric missing) and hybrid quads
Mini-quads - compact quad antennas - have some advantages that are appealing to amateur radio en-thusiasts including reasonable cost, low wind load-ing, and small turning radius Quad/mini-quad anten-nas in the 15±5 m frequencies are readily available
Quad Integrated Communications Controller
QICC (pron qwik) Asingle-chip integrated CPU32+
microprocessor from Motorola designed for embed-ded telecommunications andinternetwor~ing appli-cations The MC68360 QICC is a next-generation MC68302 with four serial communications control-lers, two serial management controlcontrol-lers, and one se-rial peripheral interface that operates at 4.5 MIPS at
24MHz QICC is useful for controller applications
Quad International Communications Corpora-tionQICC ACalifornia-based international supplier
of telecommunications products including Frame Relay
quad wiringWiring bundles consisting offour indi-vidually sheathed, untwisted wires brought together (aggregated) within a single cover Quad wiring is
~:~~e~~~ir~rt~~e1~~~i~~i~~ri:~~~\1;°~~f:r~~:~~~ III
green and red (tip and ring) for the first line, and black and yellow for the second line This type ofwiring is not recommended for data transmission installations
Quad fiber cables consist of four individual fiber cables bundled together within a single cover
quadratureA state in which cyclic events are 90 degrees out of phase In signal transmission quadra-ture, phasing is a common technique used to distin-guish information in signals It is also used to vary a signal so crosstalk between two closely associated transmissions is reduced
quadrature amplitude modulationQAM Amodu-lation technique employing variations in signal am-plitude This modulation scheme is used in asymmet-ric digital subscriber line services, for example It is
a two-dimensional coding scheme that can be trans-mitted in a narrower spectrum, a combination ofam-plitude and phase-shift modulation The QAM spec-trum derives from the specspec-trum of the baseband sig-nals as they apply to the quadrature channels
QAM is similar to nonreturn-to-zero baseband trans-mission and multiphase phase shift keying (PSK), except that QAM does not have a constant envelope
as in PSK
QAM requires lower sampling frequencies and the spectral width can be optimized by keeping the baud rate lower, thus reducing the potential for crosstalk
See modulation
Trang 9Fiber Optics Illustrated Dictionary
quadrature/quadriphase phase-shift keying
QPSK A type of phase shift keying modulation
scheme in which four signals are used, each shifted
by 90°, with each phase representing two data bits
per symbol, in order to carry twice as much
informa-tion as binary phase shift keying (BPSK), which can
be seen as two independent binary phase shift key
(BPSK) systems
QPSK can be used to carry bit timing and can be
fil-tered using raised cosine filters for out-of-band
sup-pression Even more sophisticated systems exist that
employ differential encoding ofsymbol phases
Lin-ear power amplifiers are used with the various QPSK
schemes
Staggered quadrature/quadriphase phase shift keying
(SQPSK) is similar to QPSK except that the data
channels are offset to shift the carrier 90° The
stag-gering facilitates recovery of I and Q channels See
frequency modulation, frequency shift keying, on/off
keying, modulation, quadrature sideband amplitude
modulation
quadrature sideband amplitude modulation
QSAM A modulation encoding technique in which
different signal amplitude states represent data
Quadritek Systems Inc.A network products firm
founded in 1993 to provide server-related solutions
QIP is Quadritek's(IF)network address management
software product
InMarch 1998, ffiM and Quadritek announced a
col-laboration in which ffiM would make changes to its
Dynamic Host Configuration Protocol (DHCP) and
Domain Name Server (DNS) to enable Quadritek and
other vendors to use an open standard API to
man-age servers Thus, Quadritek's QIP product could be
used to manage multiple, distributed IBM DHCP/
DNS servers Quadritek is now Lucent Technologies
IPSPG
quadruplex circuitA circuit which is carrying two
bidirectional transmissions simultaneously to make
a total of four
Qualcomm Code Excited Linear Predictive
Cod-ing QCELP A proprietary algorithm from Qual
comm CDMA Technologies (QCT) that supports
digital voice coding/decoding through code division
multiple access (CDMA) methods QCELP
compres-sion supports fixed and variable encoding
In the mid-1990s, Qualcomm released the PureVoice
vocoder (voice coder), based on 13-kilobit QCELP
for useincellular and Personal Communications
Sys-tem (PCS) products The design goal ofthe PureVoice
vocoder was to provide voice quality approaching
that ofwireline while still keeping the bit rate as low
as possible to work within the capacity limitations of
mobile communications devices Since it is a
soft-ware solution, it can be integrated into a wide
vari-ety of desktop and mobile devices
In 1998, Qualcomm announced an agreement with
Apple Computer to integrate the PureVoice
QCELP-based audio codec technology into Apple's popular
QuickTime multimedia software The PureVoice
technology is popular because of its relatively high
quality and small file size, which is significantly
smaller than audio files stored in wav format, for example
PureVoice was also adapted for use in email in the late 1990s, so users could send actual voice messages through computer networks such as the Internet The excellent compression ratios inherent in the QCELP technology made this a practical application and en-abled greetings to be communicated without tradi-tional long-distance telephone charges The PureVoice Player/Recorder and the PureVoice Con-verter are available online as licensed, freely distrib-utable software from Qualcomm Incorporated
Qualified Logical Link ControlQLLC Adata link control protocol from IBM which works with the ffiM SNA systems to allow them to operate over X.25 packet switched data networks
quality1 Meeting subjective and/or objective stan-dards of excellence in operation, manufacture, aes-thetics, or a combination of these 2 In manufactur-ing, quality is more narrowly defined as conformance
to high objective standards ofappropriateness, func-tionality, and longevity within the context of related products 3 In service industries, quality is generally determined by adherence to operating and ethical standards of the industry and degree ofcustomer sat-isfaction See quality assurance
quality assuranceSystematic actions which seek to assure satisfactory levels of manufacture, service, functionality, and longevity
quality factorSee Q factor
quality of serviceQoS This has a general meaning across many industries and somewhat more specific meanings in telecommunications networks Quality
of service is a performance descriptor and reference for the provision of services on a network It includes parameters and values pertaining to data rates, accept-able delays, losses, errors, etc
As part ofthe QoS requirements for an ATM network, four class of service (CoS) traffic types have been specified:
CoS Characteristics
Class A Connection-oriented, constant bit rate
(CBR), with a strong timing relationship between source and destination Constant bit rate video and PCM encoded voice are included
in this category
Class B Connection-oriented; bit rate may
vary, with a strong timing relationship between source and destination
ClassC Connection-oriented; bit rate varies,
no timing relationship between source and destination TCPlIP andX.25are included in this category
Class D Connectionless; bit rate varies, no
timing relationship between source and destination Connectionless packet data are included in this category
Trang 10ceived in part determines how their quality is
evalu-ated Consequently, QoS requirements vary with the
type ofdata See cell rate, class of service
Quality of Service Development GroupQSDG A
Telecommunication Standardization Sector group of
the International Telecommunications Union
estab-lished in 1984 to help develop practical
implemen-tations ofinternational telecommunication quality of
service (QoS) standards It is funded primarily by
ad-ministrations and ROAs
quantizationAprocess in which a continuous range
of values, such as an incoming analog signal, is
sub-divided into ranges, with a discrete value assigned to
each subset This is a means ofconverting analog data
to digital data, and is used in musical sound sampling,
modem communications, voice over data networks,
radio wave modulation, and many other aspects of
telecommunications
Generally the frequency of the sampling influences
the quality and fidelity ofthe outgoing quantized
sig-nal, within certain limits set by the capabilities ofthe
equipment and the characteristics of the human
per-ceptual system Higher sampling rates tend to
pro-duce closer approximations to the original signal, but
also require greater transmission speeds and
band-width
Quantization is used in a number of modulation
schemes, including pulse code modulation (PCM),
which is commonly used in voice communications
See modulation, patches, pulse code modulation,
sampling, quantization error
quantization, vectorAvector version ofscalar
quan-tization, designed to reduce the volume of data files
or the bit rates of data transfers Vector quantization
has practical applications for image and speech coding
quantization errorA number of aspects can
intro-duce error into a quantized signal, including the
amount of noise and interference accompanying the
signal, the signal range or amplitude as it relates to
the capabilities of the quantizing mechanism, the
strength and complexity ofthe signal being quantized,
and the mathematics used to carry out the conversion
Quantization error is sometimes assessed after a
digi-tal signal is reconverted to analog fonnat, and the end
signal is compared to the original, with the differences
assessed subjectively (as in music systems) or
evalu-ated with various measuring instruments
quantizeTo convert a continuous range ofvalues into
discrete, nonoverlapping values or steps This is an
important means to convert analog to digital values
quantizing distortion unitsQDU Ameasure ofthe
degree of degradationina voice channel that occurs
as a result offormat and signal conversions (e.g.,
ana-log to digital to anaana-log) This is described in the
ITU-TG Series Recommendation G.tt3 (transmission
im-pairments)
quantometerAn instrument for the measurement of
magnetic flux
quantum(plural - quanta, symb - q) A relatively
recently discovered and investigated phenomenon
related to the movement ofelectrons Quantum theory
quantum is a discrete quantity of electromagnetic
energy (e.g., a photon of light energy), the smallest
possible amount of energy at any given frequencyv.
Quantum phenomena are of great interest to physi-cists, and researchers are now investigating ways of enlisting quantum behaviors in the manufacture and use of various industrial products such as lasers and
in operations associated with digital logic, with some surprising and provocative success See Einstein, Albert; Planck, Max; quantum cascade laser
quantum cascade laserQC laser A new type of ''NanoLaser'' developed by Frederico Capasso and Jerome Faist at Bell Laboratories in 1994 The QC laser is a continuously tunable, single-mode, distrib-uted-feedback device
To understand how a QC laser works, imagine an electric current stimulating a number of electrons to cascade over a series of steppes (a terraced organi-zation), squeezed through quantum wells in succes-sive layers, dropping off energy in the fonn of pho-tons (light pulses) as they contact and travel through each steppe At each steppe, the electrons perform a quantum jump between well-defined energy levels
The photons emitted as a result of their activity re-flect back and forth in an amplification process that stimulates other quantum jumps and emissions and results in a high output This process can be exploited
by creating a corrugated grating layer within a semi-conductor which acts as a filtering device for specific wavelengths according to the grating period and, to some extent, the operating temperature
~~~fsJi~d~a~:S:r~~~~d?:g~y;:g:;ti~:~r P~~~;.
and finer linewidth in terms of the specificity of the wavelengths emitted They can operate over a wide selection of wavelengths in the mid-infrared range from 3.4 - t7 J.lm QC lasers can be used in many ap-plications, including medical diagnostics, radar het-erodyne detectors, production process control, and remote sensing applications - particularly environ-mental monitoring in toxic environments due to gas-sensing capabilities
The wavelength of the laser is determined by quan-tum confinement Thus, it can be tuned selectively over a wide range of the infrared spectrum by vary-ing the layer thicknesses and spacvary-ing of the different materials used in its manufacture This differs from other technologies in that the output wavelength is not dependent upon the chemical composition of the semiconductors, but upon their thickness and posi-tioning These layers, created with a molecular beam epitaxy(MBE)materials-growth process, are some-times only a few atoms thick The QC laser also func-tions at higher temperatures than traditional diode lasers, making it practical for room temperature use
See Capasso, Frederico; distributed-feedback laser;
Fabry-Perot laser; quantum well; vertical-cavity sur-face-emitting laser
Quantum CorporationA prominent data storage device developer/distributor, founded in 1980.Quantum
became well-known for computer hard drives in the