1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T P.581 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (02/2014) SERIES P: TERMINALS AND SUBJECTIVE AND OBJECTIVE ASSESSMENT METHODS Objective measuring apparatus Use of head and torso simulator for hands-free and handset te
2、rminal testing Recommendation ITU-T P.581 ITU-T P-SERIES RECOMMENDATIONS TERMINALS AND SUBJECTIVE AND OBJECTIVE ASSESSMENT METHODS Vocabulary and effects of transmission parameters on customer opinion of transmission quality Series P.10 Voice terminal characteristics Series P.30 P.300 Reference syst
3、ems Series P.40 Objective measuring apparatus Series P.50 P.500 Objective electro-acoustical measurements Series P.60 Measurements related to speech loudness Series P.70 Methods for objective and subjective assessment of speech quality Series P.80 P.800 Audiovisual quality in multimedia services Ser
4、ies P.900 Transmission performance and QoS aspects of IP end-points Series P.1000 Communications involving vehicles Series P.1100 Models and tools for quality assessment of streamed media Series P.1200 Telemeeting assessment Series P.1300 Statistical analysis, evaluation and reporting guidelines of
5、quality measurements Series P.1400 Methods for objective and subjective assessment of quality of services other than voice services Series P.1500 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T P.581 (02/2014) i Recommendation ITU-T P.581 Use of head and torso simu
6、lator for hands-free and handset terminal testing Summary This revised version of Recommendation ITU-T P.581 covers hands-free (including speakerphone, loudspeaking and headset) and handset terminals and includes clauses for the calibration and use of the head and torso simulator (HATS) for handset
7、and headset terminals. This Recommendation specifies the use of the HATS for speakerphone terminal subjective and objective evaluations (e.g., Recommendation ITU-T P.340). It defines the test arrangements, the mouth calibration, the binaural equalization and loudness summation, as well as the method
8、 for headphone calibration to be applied for subjective third-party listening tests as described in Recommendation ITU-T P.832. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T P.581 2000-05-18 12 11.1002/1000/5085 2.0 ITU-T P.581 2009-12-14 12 11.1002/1000/10658 3.0 ITU-T P.
9、581 2014-02-13 12 11.1002/1000/12127 _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T P.581 (02/2014) FOREWORD The Internati
10、onal Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operat
11、ing and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, pro
12、duce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In th
13、is Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., i
14、nteroperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not sugges
15、t that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidenc
16、e, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may
17、be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2014 All rights reserved. No part of this publication may be r
18、eproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T P.581 (02/2014) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 3 5 Test arrange
19、ment 4 5.1 General . 4 5.2 Positioning of the HATS 4 6 Acoustic characteristics 6 6.1 Sound pick-up . 6 6.2 Calibration of the artificial mouth of the HATS 6 6.3 Equalization of HATS for test of receive characteristics . 6 6.4 Combination of left and right ear receive sensitivity . 7 7 Application o
20、f HATS for calibration of headphones used for subjective evaluation procedures . 8 Rec. ITU-T P.581 (02/2014) 1 Recommendation ITU-T P.581 Use of head and torso simulator for hands-free and handset terminal testing 1 Scope This Recommendation specifies the use of the head and torso simulator (HATS)
21、for hands-free (including speakerphone, loudspeaking and headset functions) and handset terminal testing. It applies for subjective tests, e.g., as described in ITU-T P.832 or for objective measurements as described in, for example, ITU-T P.340. The test positions, equalizations and calibration are
22、specified. The binaural test conditions are also considered. Test methods for both send and receive characteristics testing are specified. For the applications described in this Recommendation, the HATS consists of a head mounted on a torso that extends to the waist. The head is equipped with two ar
23、tificial ears according to ITU-T P.57 and with a mouth simulator. The HATS is specified physically as well as acoustically, in ITU-T P.58. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Rec
24、ommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other refe
25、rences listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T P.57 Recommendation ITU-T P.57 (2009), Artificial ears. ITU-T P.5
26、8 Recommendation ITU-T P.58 (1996), Head and torso simulator for telephonometry. ITU-T P.79 Recommendation ITU-T P.79 (2007), Calculation of loudness ratings for telephone sets. ITU-T P.340 Recommendation ITU-T P.340 (2000), Transmission characteristics and speech quality parameters of hands-free te
27、rminals. ITU-T P.832 Recommendation ITU-T P.832 (2000), Subjective performance evaluation of hands-free terminals. ITU-T P.1100 Recommendation ITU-T P.1100 (2008), Narrow-band hands-free communication in motor vehicles. ISO 4869 ISO 4869-1:1990, Acoustics hearing protectors Part 1: Subjective method
28、 for the measurement of sound attenuation. ISO 4869-2:1994, Acoustics hearing protectors Part 2: Estimation of effective A-weighted sound pressure levels when hearing protectors are worn. ISO 4869-3:2007, Acoustics hearing protectors Part 3: Measurement of insertion loss of ear-muff type protectors
29、using an acoustic test fixture. 2 Rec. ITU-T P.581 (02/2014) 3 Definitions 3.1 Terms defined elsewhere None. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 artificial ear: A device for the calibration of earphones incorporating an acoustic coupler and
30、 a calibrated microphone for the measurement of the sound pressure and having an overall acoustic impedance similar to that of the median adult human ear over a given frequency band. 3.2.2 diffuse field equalization: Equalization of the HATS sound pick-up, equalization of the difference, in dB, betw
31、een the spectrum level of the acoustic pressure at the ear-drum reference point (DRP) and the spectrum level of the acoustic pressure at the HATS reference point (HRP) in a diffuse sound field with the HATS absent using the reverse nominal curve given in Table 3 of ITU-T P.58. 3.2.3 ear canal entran
32、ce point (EEP): A point located at the centre of the ear canal opening. 3.2.4 ear-drum reference point (DRP): Point located at the end of the ear canal, corresponding to the ear-drum position. 3.2.5 ear reference point (ERP): A virtual point for geometric reference located at the entrance to the lis
33、teners ear, traditionally used for calculating telephonometric loudness ratings. 3.2.6 free-field frequency response of HATS (sound pick-up): Difference, in dB, between the third-octave spectrum level of the acoustic pressure at the ear-drum reference point (DRP) and the third-octave spectrum level
34、of the acoustic pressure at the HATS reference point (HRP) in a free sound field with the HATS absent (test point). 3.2.7 free-field plane wave diffraction at mouth reference point (MRP): Difference, in dB, between the third-octave spectrum level of the acoustic pressure at the mouth reference point
35、 (MRP) and the third-octave spectrum level of the acoustic pressure at the same point in a free sound field with the HATS absent. The characteristic is measured for a frontal sound incidence, with a propagation direction parallel to the reference axis. 3.2.8 free-field reference point: Point located
36、 in the free sound field, at least 1.5 m from a sound source radiating in free air (in case of a head and torso simulator (HATS) in the centre of the artificial head with no artificial head present). 3.2.9 hands-free terminal: A telephone set that does not require the use of hands during the communi
37、cations session; examples are headset, speakerphone and group-audio terminal. 3.2.10 HATS hands-free reference point (HATS HFRP): Corresponds to a reference point “n“ from ITU-T P.58: “n“ shall be one of the points numbered from 11 to 17 and defined in Table 6a of ITU-T P.58 (coordinates of far-fiel
38、d front point). The HATS HFRP depends on the location(s) of the microphones of the terminal under test: the appropriate axis lip-ring/HATS HFRP shall be as close as possible to the axis lip-ring/speakerphone microphone under test. NOTE As an example, if the manufacturer indicates that the speakerpho
39、ne microphone should be located in front of the HATS, but with an elevation angle of 40 from the horizontal plane, the HATS HFRP, for this test configuration, shall be chosen as point 13 (Table 6a of ITU-T P.58). In such a case, the transfer function between the HATS HFRP and MRP amounts to: 25.0 dB
40、 +3/4 dB in the third-octave bands centred on 200 Hz; 24 dB 3 dB in the third-octave bands centred on 250 Hz, 315 Hz, 400 Hz, 500 Hz and 2 kHz; Rec. ITU-T P.581 (02/2014) 3 24 dB +3/4 dB in the third-octave bands centred on 1.25 kHz and 1.6 kHz; 25.5 dB +3/4 dB in the third-octave bands centred on 6
41、30 Hz and 1 kHz; and 27 dB +3/4 dB in the third-octave band centred on 800 Hz. 3.2.11 HATS reference point (HRP): The point bisecting the line joining the ear canal entrance points (EEPs). 3.2.12 head and torso simulator (HATS) for telephonometry: Manikin extending downward from the top of the head
42、to the waist, designed to simulate the sound pick-up characteristics and the acoustic diffraction produced by a median human adult and to reproduce the acoustic field generated by the human mouth. The HATS shall conform to ITU-T P.58. 3.2.13 horizontal plane of HATS: The plane containing the referen
43、ce axis, perpendicular to the vertical plane. It is horizontally oriented when the HATS is in the reference position. 3.2.14 lip plane: Outer plane of the lip-ring. When the HATS is in the reference position, the lip plane is vertically oriented. The lip plane of the HATS is normally different from
44、the plane of the mouth simulator orifice. 3.2.15 lip-ring: Circular ring of thin rigid rod, having a diameter of 25 mm and less than 2 mm thick. It shall be constructed of non-magnetic material and be solidly fixable to the HATS. The lip-ring defines both the reference axis of the mouth and the mout
45、h reference point. 3.2.16 loudspeaking function: The handset is used in the normal position. The incoming signal is simultaneously presented to the user(s) from loudspeaker(s). 3.2.17 mouth reference point (MRP): The point on the reference axis, 25 mm in front of the lip plane. 3.2.18 pinna simulato
46、r: A device which has the approximate shape and dimensions of a median adult human pinna. 3.2.19 reference axis: The line perpendicular to the lip plane containing the centre of the lip-ring. 3.2.20 reference position of HATS: The reference position of the HATS in the test space is intended to simul
47、ate a person in the upright position. The HATS is in the reference position when the following conditions are met: the reference point coincides with the test point; the HATS reference plane is horizontal. 3.2.21 speakerphone set: A telephone set using a loudspeaker as a telephone receiver with or w
48、ithout an embedded microphone as a telephone transmitter; it may be used without the handset. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: DRP ear-Drum Reference Point EEP Ear canal Entrance Point ERP Ear Reference Point HATS Head And Torso Simulato
49、r HATS HFRP Head And Torso Simulator Hands-Free Reference Point HFLE LE factor for hands-free terminal receiving loudness rating calculation HFT Hands-Free Terminal HRP Head and torso simulator Reference Point 4 Rec. ITU-T P.581 (02/2014) LE Earphone coupling Loss MRP Mouth Reference Point RLR Receiving Loudness Rating 5 Test arrangement 5.1 General Unless stated otherwise, the calibration of the artificial mouth refers to: the MRP for handset and headset; the HATS HFRP position
