1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 + TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU02/4%#4)/.G0G0!).34G0G0).4%22) temporary loss of function or performance which is self-recoverable;3) temporary loss of function or performance which requires operation intervention or system reset;4) loss of
2、 function which is not recoverable due to damage of equipment (components), or due to the continuousnature of the interference.Table 1/K.23 lists various noise sources that cause induced voltage on transmission lines. It also lists the categories1) to 4) above of degradation of equipment performance
3、 and transmission quality, and the interfaces to be considered foreach noise source.Volume IX - Rec. K.23 3TABLE 1/K.23Categorization of induced noise source, waveshape to be evaluated, interference to be evaluated and line interfaces involvedInduced noise sourceWave shape to beevaluatedCategory of
4、equipment performance(See 3.3)Interface to be considered(Note 1)ContinuousnoiseTransientnoise1 2 3 4 2-wire NT S and TRadio broadcast Mobil transceiver Power line(outdoors)External induced noiseCoupling into telecommunicationlines from radiating sourceElectric railway lightning Automotive engine ign
5、ition Electrostatic discharge (Note 2) (Note 2)Coupling into telecommunicationlines a.c. power mains withinContinuous operation ofelectrical apparatus (Note 3)(Note 3)buildingSwitching (Note 3)(Note 3)Induced noise source Impulsive noise from analogue telecommunication circuit in telecommunicationsy
6、stem11Contact noise (e.g. at splices) Note 1 Some of these noise sources are being studied under other questions in Study Group V.Note 2 Equipment test, not interface.Note 3 Test mains input to NT and TE.4 Volume IX - Rec. K.234 Induced noise voltage parameters that should be evaluatedEvaluation of
7、transmission quality and malfunction of the equipment using raw data from various induced noisevoltage waves is too inefficient. Therefore, it is useful to describe waveshapes using several parameters, which are found byanalyzing waveshape features, and to establish a standardized measurement method
8、 and a standardized test procedure. Thiswill enable an efficient evaluation of the effect which induced noise voltage has on the digital transmission quality and themalfunction of equipment.Continuous noise voltage should be evaluated using the amplitudes of the frequency spectrum as a basic paramet
9、ersince from these amplitudes the waveshapes can be reproduced. Transient noise voltage should be evaluated using amplitudeprobability distributions, and frequency spectrum as well as waveshape parameters in the time domain (for example, peakvalue, periodic time, decay time, duration time of burst,
10、etc.). These basic parameters can be used to design a transient noisesimulator.Table 2/K.23 lists some induced noise voltage parameters that should be evaluated.TABLE 2/K.23Induced noise voltage parameters that should be evaluatedFrequency domain Time domainType of induced noisewaveform (Note)Amplitude Frequency PeakvalueFronttimeTime tohalf valuePeriodictimeDecaytimeDurationtime ofburstAmplitudeprobabilitydistributionContinuousNarrow band , noisevoltageBroad band , Impul-sive noisevoltageType I, Type II, , , ,11Note The encircled numbers give the induced noise source from Table 1/K.23.
