1、 Recognized as anAmerican National Standard (ANSI)The Institute of Electrical and Electronics Engineers, Inc.345 East 47th Street, New York, NY 10017-2394, USACopyright 1996 by the Institute of Electrical and Electronics Engineers, Inc.All rights reserved. Published 1996. Printed in the United State
2、s of AmericaISBN 1-55937-714-3No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher.IEEE Std 743-1995(Revision of IEEE Std 743-1984)IEEE Standard Equipment Requirements and Measurement Techniqu
3、es for Analog Transmission Parameters for TelecommunicationsSponsorTransmission Systems and Access Committeeof theIEEE Communications SocietyApproved 12 December 1995IEEE Standards BoardApproved 16 July 1996American National Standards InstituteAbstract:Performance requirements for test equipment tha
4、t measures the analog transmission pa-rameters of subscriber loops, message trunks, PBX trunks, and ties lines are specified. Require-ments for these measurements with DS1 bit stream access are also provided. The measurementof loss, noise, and impulse noise on non-loaded cable pairs used for digital
5、 subscriber lines isaddressed.Keywords:active speech level, ADSL, amplitude jitter, digital bit stream access, digital subscriberlines, dropouts, echo canceller and suppressor disabling, echo path loss and delay, envelope delaydistortion, frequency shift, gain hits, HDSL, impulse noise, intermodulat
6、ion distortion, ISDN, loss,network impulse response, noise, phase hits, phase jitter, return loss, round trip delay, signal-to-total-distortion ratio, timing offset, twenty-three-tone measurementsIEEE Standardsdocuments are developed within the IEEE Societies and the Standards Coordinating Com-mitte
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17、re use of subject matter covered by patent rights. By publication of this standard,no position is taken with respect to the existence or validity of any patent rights inconnection therewith. The IEEE shall not be responsible for identifying all patents forwhich a license may be required by an IEEE s
18、tandard or for conducting inquiries intothe legal validity or scope of those patents that are brought to its attention.iiiIntroduction(This introduction is not part of IEEE Std 743-1995, IEEE Standard Equipment Requirements and Measurement Techniques for AnalogTransmission Parameters for Telecommuni
19、cations.)The provision of standard technical requirements for analog transmission measuring equipment is intendedto assure comparable measurement results and proper interworking between different test equipments. It isnot necessary that all the measurements specied be provided in one piece of test e
20、quipment; a manufacturermay choose to provide only a subset of the measurements specied in this standard.The purpose of this standard is to provide technical requirements for the generation and measurement ofanalog transmission signals used to characterize the telecommunications network. Such charac
21、terizationincludes measurement of various impairments to voiceband (204000 Hz) signals (speech and data) at bothanalog and PCM access points.This standard also provides lters for the extended frequency range of signals now carried on a traditionalanalog twisted copper cable pair between the central
22、ofce and the customer premises. These lters permitlevel, noise and impulse noise measurements on lines providing digital transmission for the Integrated Ser-vices Digital Network (ISDN), the High-bit-rate Digital Subscriber Line (HDSL), and the Asymmetric Digi-tal Subscriber Line (ADSL). The traditi
23、onal C-Message weighting is intended to be used only for voice-related measurements, and a new data lter (D Filter) is intended to be used for voice-frequency digitally-related measurements. Other lters that have been replaced or deleted are listed.The initial issue of this standard, IEEE Std 743-19
24、84, IEEE Standard Methods and Equipment for Measur-ing the Transmission Characteristics of Analog Voice Frequency Circuits, was based on AT or that a certain course of action is preferred but not necessarily required; or that (in thenegative form) a certain course of action is deprecated but not pro
25、hibited (shouldequals is recommendedthat).The word mayis used to indicate a course of action is permissible within the limits of the standard(mayequals is permitted).1.5 AnnexesAll of the annexes to this standard are informative, and are included in the standard for informationpurposes only.1.6 Refe
26、rencesThis standard shall be used in conjunction with the following published standards. When the following stan-dards are superseded by an approved revision, the revision shall apply.ANSI/EIA/TIA 232-E-1991, Interface between Data Terminal Equipment and Data CircuitTerminatingEquipment Employing Se
27、rial Binary Data Interchange, July 1991.1ANSI/EIA/TIA 530-A-1992, High-Speed 25-Position Interface for Data Terminal Equipment and Data Cir-cuit-Terminating Equipment, Including Alternative 26-Position Connector.ANSI T1.102-1993, American National Standard for TelecommunicationsDigital HierarchyElec
28、tricalInterfaces.ANSI T1.221-1995, American National Standard for TelecommunicationsOperations, Administration,Maintenance, and Provisioning (OAM those sourcesbeing the timing basis from which signals and sampling are derived and analyzed (usually expressed propor-tionally in parts per million). Tim
29、ing offset will cause a uniform percentage change in signal frequencies.2.1.39 tone-to-C-Notched noise ratio: The ratio in dB of the incoming holding tone power to the C-Notched noise power at the point of measurement. The incoming holding tone power is reduced in power byat least 50 dB by the 1010
30、Hz Notch. 2.1.40 tone-to-D-Notched noise ratio:The ratio in dB of the incoming holding tone power to the D-Notchednoise power at the point of measurement. The incoming holding tone power is reduced in power by at least 50dB by the 1010 Hz Notch.2.1.41 total distortion: The summation of noise and dis
31、tortion resulting from the application of a test signal(quantizing noise, phase jitter, intermodulation distortion, etc.), and the noise not related to the application ofa test signal (background noise).2.1.42 transmission level point (TLP):a point in a transmission system at which the ratio is spec
32、ied in dBof the power of a test signal at that point to the power of a signal at a reference point. The reference level point,called the zero transmission level point (0 TLP), is an arbitrary established point relative to which transmissionlevels at all other points are specied. A signal level of X
33、dBm at the 0 TLP is designated X dBm0.2.1.43 1 kHz envelope delay:The envelope delay at a carrier frequency of 1020 Hz.2.2 Abbreviations and acronymsThe following abbreviations and acronyms, commonly used in the communications eld, are used in thisstandard. Some are dened in 2.1. Listed with each ab
34、breviation and acronym is the subclause in the remain-der of this standard where it is introduced.ADPCM Adaptive differential pulse code modulation (8.2.1)A/D Analog-to-digital converter (8.7.3.3)ADSL Asymmetric Digital Subscriber Line (3.2.2)AFIR Adaptive nite impulse response lter (3.4.8)CRC Cycli
35、c redundancy check (4.2.2.5)D/A Digital-to-analog converter (8.7.3.3)dBm Decibels relative to 1 mW (6.1)dBm0 Decibels relative to 1 mW, referred to a zero transmission level point (6.1)dBrn Decibels relative to 1 pW reference noise level (6.2)dBrnC Decibels relative to 1 pW reference noise level, me
36、asured with a C-Message or C-Notch fre-quency weighting (6.2)dBrnD Decibels relative to 1 pW reference noise level, measured with a D Filter or D-Notch Filter(6.2)DFT Discrete Fourier transform (8.6.1)DSL Digital subscriber line (3.2.2)DSP Digital signal processor (8.7.3.7)DRS Digital reference sequ
37、ence for a 1013.8-Hz sine wave (5.3.3)EDD Envelope delay distortion (3.4.1)IEEEStd 743-1995 IEEE STANDARD EQUIPMENT REQUIREMENTS AND MEASUREMENT TECHNIQUES8ELEPL Equal level echo path loss (8.3)EPD Echo path delay (3.4.7)EPL Echo path loss (3.4.7)ERL Echo return loss(8.3)ESF Extended superframe form
38、at (4.2.2.2)HDSL High-bit-rate Digital Subscriber Line (3.2.2)IMD Intermodulation distortion (3.4.5)ISDN Integrated Services Digital Network (3.2.2)ITU-T International Telecommunications UnionTelecommunications Standardization Sector (theformer name is the CCITT) (3.2.2)LMS Least mean squares algori
39、thm (8.7.2)LSB Least signicant bit (4.2.2.2)NIR Network impulse response (3.4.8)P/AR Peak-to-average ratio (3.4.10)PCM Pulse code modulation (4.2.1)RL Return loss (8.3)S/N Signal-to-noise ratio (4.2.2.4)SRL Singing return loss (8.3)S/TD Signal-to-total-distortion ratio (3.2.3)TLP Transmission level
40、point (4.2.2.2)T/TD Tone-to-total-distortion ratio (3.2.3)2nd IMD Second-order intermodulation distortion (8.6.5)3rd IMD Third-order intermodulation distortion (8.6.5)3. General descriptions of measurements3.1 Digitally-encoded measurementsThe scope of this standard includes measurement of analog si
41、gnals that have been sampled, quantized, andencoded in digital bit streams. Measurements of such signals will be accomplished by mathematically pro-cessing the train of sampled signal values represented by the digital bit stream. The formats and characteris-tics of the digital signals treated by thi
42、s standard are specied in 4.2.3.2 Steady-state measurements using a tone or quiet termination3.2.1 Level and attenuation distortionThis is a measurement of signal power at an access point of nominal impedance in a circuit. The impedancemay range from 100 W to 900 W, with 600 W most commonly used. Th
43、e expected signal levels at the accesspoints usually range from 40 dBm to +15 dBm.The frequency range of interest for normal speech and voiceband data services may extend from below60 Hz to above 4 kHz. Wide-band data circuits further extend this range. The requirements for level mea-surement with a
44、 sinusoidal tone are given in 6.1. The requirements for frequency response (or attenuationdistortion) measurements with a 23-tone test signal are given in 8.6.2.IEEEFOR ANALOG TRANSMISSION PARAMETERS FOR TELECOMMUNICATIONS Std 743-199593.2.2 Noise Noise measurements can be made with the channel or c
45、able pair terminated in its nominal impedance and notest signal on the channel. These noise measurements are made using one of several frequency weightingnetworks/lters (see clause 9). These include:a) C-Message. A frequency weighting that weights the noise according to its perceived annoyance to at
46、ypical listener, of standard telephone service.b) C-Notch. C-Message weighting with the addition of a narrow stop-band or notch lter centered at1010 Hz. This measurement is used to make a dynamic evaluation of the effects of noise on voice-grade services.c) 3.4 kHz Flat. When used on voice frequency
47、 circuits, this lter permits the investigation of the pres-ence of low-frequency noise (power induction, etc.).d) D Filter. A lter composed of a 300 Hz high-pass lter and a 3.4 kHz low-pass lter connected intandem. The 300 Hz high-pass lter may be used separately as a low-frequency (power line) hump
48、rotection lter. The 3.4 kHz low pass lter may be used for all functions where the 3 kHz Flat lterhad been used previously. The 3.4 kHz low-pass lter is designated as 3.4 kHz Flat.NOTEThe analog and digital pole and zero specications are provided in clause 9 to assure proper transient perfor-mance.e)
49、 15 kHz Flat. A lter used when making unweighted measurements of noise on program circuits. It isa 15 kHz low-pass lter of Butterworth shape rolling off at 12 dB per octave. It is not ordinarily usedon voice message circuits.f) Psophometric. Psophometric weighting is specied by the ITU-T in ITU Recommendation O.41(01/95) for use in measuring noise on telephone circuits in countries that recognize the ITU-T Rec-ommendations. It differs from the C-Message weighting.g) E Filter. A lter with a 150kHz pass band used for testing the Integrated Servic
