1、ETSI I-ETS*300 245-3 95 3400855 001573L 293 ETSI ELECOMMUNICATION STANDARD I-ETS 300 245-3 February 1995 Source: ETSI TC-TE Reference: TTTE 10-07 (C) UDC: 621.395 Key words: ISDN, telephony terminals Integrated Services Digital Network (ISDN); Technical characteristics of telephony terminals Part 3:
2、 Pulse Code Modulation (PCM) A-law, loudspeaking and handsfree telephony ETSI European Telecommunications Standards Institute ETSI Secretariat Postal address: 06921 Sophia Antipolis Cedex - FRANCE Office address: Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE Tel.: + 33 92 94 42 O0 - Fax:
3、 t 33 93 65 47 16 European Telecommunications Standards Institute 1 995. All rights reserved. No part may be reproduced except as authorised by written permission. The copyright and the foregoing restriction on reproduction extend to all media in which the information may be embodied. ETSI I-ETSx300
4、 245-3 95 3400855 0035732 L2T Page 2 I-ETS 300 245-3: February 1995 Whilst every care has been taken in the preparation and publication of this document, errors in content, typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to “ETSI Editing and Standard
5、s Approval Dept.“ at the address shown on the title page. ETSI I-ETSx300 245-3 95 3400655 0035733 Ob6 Page 3 LETS 300 245-3: February 1995 Contents Foreword . 7 1 Scope . 9 2 Normative references 9 3 Definitions and abbreviations 10 3.1 Definitions . 10 3.2 Abbreviations 10 4 Call control functions
6、11 5 Transmission aspects 11 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 General . 11 5.1 . 1 Encoding 11 5.1.2 Relative level 11 5.1.3 Volume control . 11 5.1.4 Requirements applicable to Hands-Free Telephone, Loudspeaking Telephony and Call Progress Monitoring . 12 Sensitivity frequency response . 13 5.2.1 Se
7、nding . 13 5.2.2 Receiving . 13 5.3.1 Sending . 15 5.3.2.1 Maximum sensitivity . 15 5.3.2.2 Volume control range 15 Adaptive gain control (optional) . 15 Loudness ratings 15 5.3.2 Receiving . 15 5.3.3 Terminal Coupling Loss (TCL) . 16 5.4.1 Hands-free function . 16 5.4.2 Loudspeaking function . 16 5
8、.4.3 Call Progress Monitoring (CPM) . 17 Stability loss 17 5.5.1 Hands free function . 17 5.5.2 Loudspeaking function . 17 Distortion 17 5.6.1 Harmonic distortion (sinusoidal signal) 17 5.6.1.1 Sending 17 5.6.1.2 Receiving 18 Total distortion (pseudo-random noise signal) 18 5.6.2.1 Sending 18 5.6.2.
9、2 Receiving 18 5.7.2 Receiving . 19 5.6.2 Out-of-band signals 18 5.7.1 Sending . 18 Noise 19 5.8.1 Sending . 19 5.8.1.1 Idle mode 19 5.8.1.2 Noise during transition from active mode to idle mode . 19 5.8.2 Receiving . 20 5.8.2.1 Idle mode 20 5.8.2.1 . 1 A-weighted 20 5.8.2.1.2 Third-octave band spec
10、trum . 20 Noise during transition from active mode to idle mode . 20 5.8.2.2 ETSI I-ETS*300 245-3 95 3400855 OOL573Y TT2 Page 4 I-ETS 300 245-3: February 1995 5.9 Delay 20 5.1 O Switching characteristics . 20 5.1 1 5.12 Articulation 21 Acoustic Echo Controllers characteristics . 21 Annex A (normativ
11、e): Test specification 22 A . 1 Test considerations. . 22 A . 1.1 Test signals . 22 A.l . 1 . 1 Broadband signal . 22 A . 1 . 1 . 2 Test signal levels 23 A . 1.2.1 Sending 23 A . 1.2.2 Receiving 24 Test rooms 24 A . 1 . 3.1 Anechoic room 24 A.1 . 3.2 “Anechoic“ tests in a reverberant field 27 Test a
12、rrangement 27 A.l . 4.1 Hands-free function 27 A.l . 4.2 Loudspeaking function 27 Alternative test methods 28 Sinusoidal and narrow-band signals . -23 A . 1.2 A.l . 3 A . 1 . 4 A . 1 . 5 A.2 Transmission requirements testing . 28 A.2.1 A.2.2 A.2.3 A.2.4 A.2.5 A.2.6 A.2.7 A.2.8 A.2.9 Sensitivity/freq
13、uency response 28 Sending 28 Receiving 29 Loudness ratings . 29 Sending Loudness Rating (SLR) 29 Receiving Loudness Rating (RLR) 29 Terminal Coupling Loss. . 30 Stability loss 30 A.2.4.1 Hands-Free function . 30 A.2.4.2 Loudspeaking function 30 Distortion . -30 A.2.5.1 Harmonic distortion (sinusoida
14、l signal) 30 A.2.5.1.1 Sending . 30 Receiving . 30 Total distortion (pseudo-random noise signal) . 31 A.2.5.2.1 Sending $31 A.2.5.2.2 Receiving . 31 Out-of-band signals . 31 A.2.6.1 Sending 31 A.2.6.2 Receiving . -31 Noise 31 A.2.7.1 Sending 31 A.2.7.1 . 1 Idle mode 32 A.2.7.1.2 Noise during the tra
15、nsition active mode to idle mode 32 A.2.7.2 Receiving 32 A.2.7.2.1 Idle mode 32 A.2.7.2.2 Noise during transition from active mode to idle mode 32 Delay 32 Switching characteristics . 33 Test signal levels . 33 A.2.9.2 Build-up time . 33 A.2.9.3 Switching time 34 A.2.1 . 1 A.2.1 . 2 A.2.2.1 A.2.2.2
16、A.2.5.1 . 2 A.2.5.2 A.2.9.1 A.2.1 O Echo cancelling characteristics 34 A.2.1 1 Articulation . -34 Annex B (informative): Description of the Composite Source Signal (CSS) 35 B . 1 B.2 B.3 ETSI I-ETS*300 245-3 95 3400855 0035735 939 Page 5 LETS 300 245-3: February 1995 General presentation of the CSS
17、. 35 Use of the CSS . 41 B.2.1 Calculation and analysis 41 B.2.1 . 1 Principle of acoustical and electrical calibration - test signal levels 41 B.2.1 . 2 Analysis parameters 41 Principles of testing applied to annex A . 42 B.2.2.1 single talk conditions . 42 B.2.2.2 Distortion measurements 42 B.2.2.
18、3 Out-of-band measurements . 42 B.2.2.4 Noise measurements 42 B.2.2.5 Delay measurements 43 B.2.2.6 Switching characteristics 43 B.2.2.7 Echo cancelling characteristics 43 B.2.2 Measurements of frequency responses. TCL and Loudness Ratings, in Practical Composite Source Signal . 43 B.3.1 Voiced sign
19、al to simulate voice properties 43 B.3.2 B.3.3 Pause . 44 Pseudo noise signal 44 Annex C (informative): Bibliography . 45 History 46 ETSI I-ETS*3DO 245-3 95 3400855 0015736 75 Page 6 LETS 300 245-3: February 1995 Blank page ETSI I-ETS*300 245-3 95 H 3400855 0035737 703 Page 7 LETS 300 245-3: Februar
20、y 1995 Foreword Part three of this Interim European Telecommunication Standard (LETS) was produced by the Terminal Equipment (TE) Technical Committee of the European Telecommunications Standards Institute (ETSI). An ETSI standard may be given I-ETC status either because it is regarded as a provision
21、al solution ahead of a more advanced standard, or because it is immature and requires a “trial period“. The life of an LETS is limited to three years after which it can be converted into an ETS, have its life extended for a further two years, be replaced by a new version or, be withdrawn. This is th
22、e third Part of an LETS which is currently intended to comprise eight Parts: Part 1: “General (I-ETS 300 245-1 I I)“ Part 2: “PCM A-Law, handset telephony (I-ETS 300 245-2 21)“. Part 3: “Pulse Code Modulation (PCMI A-Law, Loudspeaking and handsfree telephony“. Part 4: Interface for additional equipm
23、ent. Part 5: Wideband (7 kHz) telephony. Part 6: Wideband (7 kHz) handsfree telephony Part 7: Locally generated information tones. Part 8: Terminal application of 16 kbit/s speech coding algorithms (TlE 10-07H). Proposed announcement date Date of latest announcement of this I-ETS (doa): 31 May 1995
24、ETSI I-ETSx300 245-3 95 = 3400855 OOL573 648 Page 8 LETS 300 245-3: February 1995 Blank page ETSI I-ETS*300 245-3 95 3400855 0035739 584 Page 9 LETS 300 245-3: February 1995 1 Scope Part 3 of this LETS specifies technical characteristics for Pulse Code Modulation (PCM) A-law, 3,l kHz loudspeaking an
25、d handsfree telephony terminals to be used at the basic access for the coincident S and T reference point of the Integrated Services Digital Network (ISDN). Such terminals are intended to be used by a single person. This Part of I-ETC 300 245 applies in conjunction with I-ETS 300 245-1 i11 and the c
26、haracteristics specified in this Part are additional to those of I-ETC 300 245-1 ill. 2 Normative references Part 3 of this LETS incorporates, by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publica
27、tions are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to Part 3 of this I-ETS only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to apply. i1 I i31 41 i51 i6
28、1 I-ETS 300 245-1 : “Integrated Services Digital Network (ISDN); Technical characteristics of telephony terminals, Part 1 : General“. I-ETC 300 245-2: “Integrated Services Digital Network (ISDN); Technical characteristics of telephony terminals, Part 2: PCM A-law handset telephony“. ITU-T Recommenda
29、tion P. 1 O (1 993): “Vocabulary of terms on telephone transmission quality and telephone sets“. CCITT Recommendation G.701 (1 988): “Vocabulary of digital transmission and multiplexing, and pulse code modulation (PCM) terms“. ETC 300 1 1 1 (1 992): “Integrated Services Digital Networks (ISDN); Tele
30、phony 3,l kHz teleservice, Service description“. CCITT Recommendation G.122 (1 988): “Influence of national systems on stability, talker echo, and listener echo in international connections“. 71 ITU-T Recommendation P.51 (1 993): “Artificial mouth“. 81 i91 i101 CCITT Recommendation G.71 1 (1 988): “
31、Pulse code modulation (PCM) of voice f r eq u en c i es “ . ITU-T Recommendation P.34 (1 993): “Transmission characteristics of hands-free telephones“. CCITT Recommendation O. 1 31 (1 988): “Quantizing distortion measuring equipment using a pseudo-random noise test signal“. I 11 IS0 266 (1 975): “Ac
32、oustics - Preferred frequencies for measurements“. i121 I 31 i141 ITU-T Recommendation P.79 (1 993): “Calculation of loudness ratings for telephone sets“. CCITT Recommendation G.223 (1 988 1: “Assumptions for the calculation of noise on hypothetical reference circuits for telephony“. CCITT Recommend
33、ation 0.41 (I 988): “Psophometer for use on telephone- type circuits“. ETSI I-ETS*300 245-3 95 m 3400855 0035740 2Tb Page 10 I-ETS 300 245-3: February 1995 151 IEC 651 (1 979): “Sound level meters“. 3 Definitions and abbreviations 3.1 Definitions For the purposes of this Part of the I-ETS, the relev
34、ant definitions given in ITU-T Recommendations P.10 31 and G.701 141 apply along with the following: Acoustic Reference Level (ARL): The acoustic level which gives - 1 O dBmO at the digital interface. telephony 3,l kHz teleservice: A description of telephony 3,l kHz teleservice is given in ETS 300 1
35、1 1 51, clause 5. loudspeaking function: The handset is used in the normal position. The incoming signal is simultaneously presented to the users) from loudspeaker(s). hands-free function: For free handling no handset or any other equipment with transducers is held to the ear of the user. If a hands
36、et is implemented then it is placed at a distance from the user. Normally, the handset is not active. The numbers, the implementation and the use of microphone(s) and loudspeaker(s1 are not limited. Call Progress Monitoring (CPM): The loudspeaker is used to monitor the received signals while the voi
37、ce transmission in the sending direction is disconnected. Terminal Coupling Loss (TCL): The frequency dependent coupling loss between the receiving port and sending port of a terminal due to: - - - acoustical coupling at the user interface; electrical coupling due to crosstalk in the handset cord or
38、 within the electrical circuits; seismic coupling through the mechanical parts of the terminal. NOTE 1: The receiving port and the sending port of a digital voice terminal is a O dBr point. NOTE 2: The coupling at the user interface depends on the conditions of use. weighted Terminal Coupling Loss (
39、TCLw): The Terminal Coupling Loss (TCL) calculated using the weighting of CCITT Recommendation G. 122 61. Hands-Free Reference Point (HFRP): A point located on the axis of the artificial mouth, at 50 cm from the lip ring, where the level calibration is made, in free field. It corresponds to the meas
40、urement point no 11, as defined in ITU-T Recommendation P.51 171. idle mode: Idle mode is when the terminal is not activated by an input signal (e.g. input signal level below implemented threshold level). active mode: Active mode is when the terminal is activated by an input signal (e.g. input signa
41、l level above implemented threshold level). single talk: An operation mode where only one user is speaking. double talk: An operation mode where two users are speaking simultaneously. 3.2 Abbreviations For the purposes of this Part of the I-ETS, the following abbreviations apply: AEC AGC Ardt Acoust
42、ic Echo Controller Automatic Gain Control Received speech attenuation during double talk ETSI I-ETSa300 245-3 95 3400855 OOL574L 132 Page 11 LETS 300 245-3: February 1995 ARL Asdt CPM css ETS ETSI ISDN FFT HATS HFRP H FT LRGP LST MRP PCM PN RLR SLR TCL TCLw TCLwdt TCLwst Tondt Tonst TR TS I-ETS Acou
43、stic Reference Level Sent speech attenuation during double talk Call Progress Monitoring Composite Source Signal European Telecommunication Standard European Telecommunications Standards Institute Interim European Telecommunication Standard Integrated Services Digital Network Fast Fourier Transforma
44、tion Head And Torso Simulator Hands-Free Reference Point Hands-Free Telephony Terminal Loudness Rating Guard-ring Position Loudspeaking Telephony Terminal Mouth Reference Point Pulse Code Modulation Pseudo Noise Receiving Loudness Rating Sending Loudness Rating Terminal Coupling Loss Weighted Termin
45、al Coupling Loss Weighted Terminal Coupling Loss - double talk Weighted Terminal Coupling Loss - single talk Break in time - double talk Break in time - single talk Built up time Switching time 4 Call control functions The requirements of I-ETS 300 245-1 11 shall be met. 5 Transmission aspects 5.1 G
46、eneral Requirements for PCM A-law terminals are given in this Part of the I-ETS. When using other coding algorithms other Parts of this I-ETS may apply. 5.1.1 Encoding The default speech encoding algorithm for all speech terminals shall be the A-law encoding at 64 kbit/s, as defined in CCITT Recomme
47、ndation (3.71 1 181. Any other possible encoding algorithm are additional. For some encoding algorithms, requirements are given in other Parts of this I-ETC. 5.1.2 Relative level The digital interface is a O dBr point according to CCITT Recommendation G.101, 5.1.3 Volume control Unless stated otherw
48、ise, the requirements apply for all positions of the user-controlled receiving volume control, if the volume control is manually operated. ETSI I-ETS*300 245-3 3400855 0015742 o79 Page 12 LETS 300 245-3: February 1995 5.1.4 Requirements applicable to Hands-Free Telephone, Loudspeaking Telephony and
49、Progress Monitoring Call Table 1 presents the requirements that shall be applicable to Hands-Free Telephony, Loudspeaking Telephony and Call Progress Monitoring. The applicability is indicated by an “X“ in the corresponding column. The characteristics indicated by “(XI“ are for further study. For Loudspeaking Telephony Terminals (LSTs), the requirements for handset telephony can be found in LETS 300 245-2 i21. Table 1 : Applicability of requirements ETSI I-ETS*300 245-3 75 3400855 0035743 TO5 Page 13 I-ETS 300 245-3: February 1995 5.2 Sensitivity frequency response 5.2.1 S
