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1、 The Institute of Electrical and Electronics Engineers, Inc. 345 East 47th Street, New York, NY 10017-2394, USA Copyright 1994 by the Institute of Electrical and Electronics Engineers, Inc. All rights reserved. Published 1994. Printed in the United States of America. ISBN 1-55937-424-1 No part of th
2、is publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher. IEEE Std 1206-1994 IEEE Standard Methods for Measuring Transmission Performance of Telephone Handsets and Headsets Sponsor Transmission Systems Committ
3、ee of the IEEE Communications Society Approved March 23, 1994 IEEE Standards Board Abstract: Practical methods for measuring the transmission characteristics of a telephone handset or headset by means of using a test connection to obtain objective measurements are provided. The obtained test results
4、 may be used as a means of evaluating or specifying the transmission per- formance of a handset or headset on a standardized basis. Keywords: telephone handset, telephone headset, transmission performance Authorized licensed use limited to: Tsinghua University Library. Downloaded on December 25,2010
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15、r 25,2010 at 10:45:02 UTC from IEEE Xplore. Restrictions apply. iii Introduction (This introduction is not a part of IEEE Std 1206-1994, IEEE Standard Methods for Measuring Transmission Perfor- mance of Telephone Handsets and Headsets.) This standard has been developed in response to a widely expres
16、sed need by the telecommunications indus- try for a standard, comprehensive method for testing the transmission performance of telephone handsets and headsets. The testing of handsets and headsets using a continuous spectrum excitation signal in addition to a sinusoi- dal signal is introduced in thi
17、s standard. Changes have been made in the calibration procedure from past issues. These changes must be considered when comparing results. To bring this standard into agreement with the International Telecommunication Union (ITU) * test position, the use of the loudness rating guard- ring position (
18、LRGP) is being recommended in addition to the AEN position (AEN stands for Affaiblisse- ment Equivalent pour la Nettet or equivalent articulation loss). The IEEE will maintain this standard current with the state of the technology. Comments on this standard and suggestions for any additional materia
19、l that should be included are invited (see p. ii). This new standard, begun in 1986, was prepared by the Subcommittee on Telephone Instrument Testing of the Transmission Systems Committee of the IEEE Communications Society. At the time this standard was approved, the members of the subcommittee were
20、 as follows: John Bareham, Chair Glenn Hess, Vice Chair Fred Dekalb, Secretary Joel AdamsPaul CoverdaleHenry Mar Tom BurnsRobert EllingtonPeter May Chandru ButaniBarbara HedmanMike Watters Cliff ChamneyDwight LynnStephen Whitesell Thomas ChildersRon MagnusonRobert Young At the time it balloted this
21、standard, the Subcommittee on Telephone Instrument Testing of the Transmission Systems Committee had the following membership: Joel AdamsPaul CoverdaleRon Magnuson John BarehamFred DekalbHenry Mar Tom BurnsRobert EllingtonPeter May Chandru ButaniBarbara HedmanMike Watters Cliff ChamneyGlenn HessStep
22、hen Whitesell Thomas ChildersDwight LynnRobert Young * The ITU was formerly the International Telegraph and Telephone Consultative Committee (CCITT). The IEEE Communications Society was formerly the IEEE Communication Technology Group. Authorized licensed use limited to: Tsinghua University Library.
23、 Downloaded on December 25,2010 at 10:45:02 UTC from IEEE Xplore. Restrictions apply. iv The nal conditions for approval of this standard were met on March 23, 1994. This standard was condition- ally approved by the IEEE Standards Board on March 17, 1994, with the following membership: Wallace S. Re
24、ad, Chair Donald C. Loughry, Vice Chair Andrew G. Salem, Secretary Gilles A. BarilDonald N. HeirmanJoseph L. Koepnger Bruce B. BarrowRichard J. HollemanD. N. Jim Logothetis Jos A. Berrios de la PazJim IsaakL. Bruce McClung Clyde R. CampBen C. JohnsonMarco W. Migliaro James CostantinoSonny KasturiMar
25、y Lou Padgett Stephen L. DiamondLorraine C. KevraArthur K. Reilly Donald C. FleckensteinE. G. Al KienerRonald H. Reimer Jay Forster Ivor N. KnightGary S. Robinson Ramiro GarciaLeonard L. Tripp Member Emeritus Also included are the following nonvoting IEEE Standards Board liaisons: Satish K. Aggarwal
26、 James Beall Richard B. Engelman David E. Soffrin Stanley I. Warshaw Stephen J. Huffman IEEE Standards Project Editor Authorized licensed use limited to: Tsinghua University Library. Downloaded on December 25,2010 at 10:45:02 UTC from IEEE Xplore. Restrictions apply. v Contents CLAUSEPAGE 1.Overview
27、 1 1.1 Scope 2 1.2 Purpose. 2 2.References 3 3.Definitions 4 4.Test equipment. 6 4.1 General. 6 4.2 Artificial ears . 6 4.3 Artificial mouth 6 4.4 Standard circuits. 6 5.Test procedures 9 5.1 General. 9 5.2 Transmit. 9 5.3 Receive. 11 ANNEXES A(normative) Procedure for subjectively determining recei
28、ver leakage 14 B(normative) Loudness balance subjective test procedure. 16 Authorized licensed use limited to: Tsinghua University Library. Downloaded on December 25,2010 at 10:45:02 UTC from IEEE Xplore. Restrictions apply. Authorized licensed use limited to: Tsinghua University Library. Downloaded
29、 on December 25,2010 at 10:45:02 UTC from IEEE Xplore. Restrictions apply. This page is intentionally blank. 1 IEEE Standard Methods for Measuring Transmission Performance of Telephone Handsets and Headsets 1. Overview This standard extends the telephone set transmission measurement methodology of I
30、EEE Std 269-1992 1 to handsets and headsets. It also draws heavily on ITUT Recommendation P.51: 1993 and ITUT Recommenda- tion P.57: 1993 for denition of suitable articial mouths and articial ears. Handsets and headsets are tele- communication devices having electroacoustic transducers for convertin
31、g sound energy into electrical energy (transmitters) and electrical energy into sound energy (receivers). They may also contain ampliers and other circuitry, but are distinguished from conventional telephones in that they maintain separate speech paths for the transmitted and received signals. Heads
32、ets differ from handsets in that they are hands-free devices typically worn on the head of the user. While handsets have xed physical relationships between the transmitter and receiver sound ports, headsets generally allow the user to adjust the location of the transmitter sound port relative to tha
33、t of the receiver. And while handsets usually have supra-aural (on-ear) receivers, headsets use a variety of techniques for cou- pling the sound energy from the receiver to the ear. The methods used to measure handset and headset transmission performance may be divided into two classes: objective me
34、thods and subjective methods. The objective methods, discussed in this standard, utilize a sound source with acoustic characteristics resembling those of the human mouth to drive the transmitter, and a cou- pler with acoustic characteristics resembling those of the human ear as a termination for the
35、 receiver. The sound source comprises a source of electrical energy and a loudspeaker unit having supplementary elec- trical and acoustical components that produce a sound eld simulating that of a typical human voice. This special loudspeaker is referred to as an articial mouth. The acoustic coupler
36、 comprises a microphone and a terminating air volume having supplementary acoustic components that produce a load on the receiver simu- lating that of a typical human ear. This coupler is referred to as an articial ear. The articial mouth and arti- cial ear are useful in comparing the performance of
37、 handsets and headsets at frequencies in the signicant portion of the speech range. The subjective measurements particularly applicable for rating overall communication connections include real-voice and real-ear calibrations. These types of calibrations are based on the ratio of the sensations of 1
38、 Information on references can be found in clause 2. Authorized licensed use limited to: Tsinghua University Library. Downloaded on December 25,2010 at 10:45:02 UTC from IEEE Xplore. Restrictions apply. IEEE Std 1206-1994IEEE STANDARD METHODS FOR MEASURING TRANSMISSION 2 loudness and clarity, percei
39、ved when a real ear is in the sound eld produced by a real voice, to those per- ceived when a telephone connection intervenes between the real voice and real ear. Other subjective methods include articulation tests, repetition counts, and judgment tests. The disadvantages of subjective methods are t
40、hat they involve human subjects and necessitate a large number of tests for the results to have signicance. When agreements, on the basis of subjective methods, are reached as to the desirability of particular perfor- mance characteristics for a given type of handset or headset, the control of the c
41、haracteristics can be main- tained by purely objective methods using the articial mouth and ear. The relationships established between subjective and objective measurements vary with the physical con- stants of the handset or headset design (such as size and shape) and the sound leakage between the
42、receiver and the users ear. Therefore, correlation between subjective and objective measurements should be estab- lished separately for each handset or headset design before measurements obtained using the techniques covered in this standard can be interpreted to reect performance under conditions o
43、f actual use. 1.1 Scope This standard covers handsets and headsets whose receive performance can be measured using standardized articial ears, as dened in ITUT Recommendation P.57: 1993 and ANSI S3.36-1985. The standard also covers handsets and headsets whose transmit performance can be measured wit
44、h the center of the transmitter sound port in front of the articial mouth lip plane. Other types of handsets or headsets, having transmitters whose sound ports fall behind the lip plane in nor- mal use, are not covered by this standard. However, the general methods described in this standard may be
45、used as guidelines for testing such handsets or headsets. This standard covers measurements on four-wire handsets and headsets having separate transmit and receive speech paths. This standard also applies to three-wire handsets and headsets in which a common lead is shared between the transmit and r
46、eceive circuitry. When handsets and headsets are connected to hybrid speech networks performing four-wire to two-wire conversion, their transmission performance may be mea- sured using the methods of IEEE Std 269-1992, with due consideration given to the relevant transmitter positioning and receiver
47、 coupling issues discussed in this standard. 1.2 Purpose This standard describes practical methods for measuring the transmission characteristics of a telephone handset or headset by means of using a test connection to obtain objective measurements. Although the vari- ous methods generally produce s
48、imilar results, some deviations can be expected depending on handset or headset characteristics. Measurement conditions should be noted when reporting results. The obtained test results may be used as a means of evaluating or specifying the transmission performance of a handset or headset on a stand
49、ardized basis. This standard is intended for measuring the transmission performance over the frequency range most useful for speech, 1005000 Hz. It is to be used for both single-frequency and varying-frequency measurements (such as continuous slow sweeps or equivalent, e.g., closely-spaced discrete steps). Continuous spectrum signals with one- or two-channel spectrum analysis methods, to the extent that they are equivalent to or bet- ter than the methods described herein, may also be used. These two types of signals (sinusoidal and continu- ous spectr