1、* INUTREOEILN TELECOMMUNICATION STANDARD I-ETS 300 245-2 February 1996 Second Edition Source: ETSI TC-TE Reference: RImE-04041 ICs: 33.080 Key words: ISDN, telephony terminals, handset function Integrated Services Digital Network (ISDN); Technical characteristics of telephony terminals; Part 2: PCM
2、A-law handset telephony ETSI European Telecommunications Standards institute ETSI Secretariat Postal address: F-O6921 Sophia Antipolis CEDEX - FRANCE Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: secretariatetsi.
3、fr Tel.: +33 92 94 42 O0 - Fax: +33 93 65 47 16 Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. Q European Telecommunications Standards Institute 1996. All rights reserved.
4、ETSI I-ETS*300 245-2 96 W 3400855 0080298 359 Page 2 LETS 300 245-2: February 1996 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 Editi
5、ng and Committee Support Dept.“ at the address shown on the title page. ETSI I-ETSU300 245-2 7b = 3400855 0080279 275 Page 3 I-ETS 300 245-2: February 1996 Contents Foreword . 5 6 7 Scope 7 Normative references 7 Definitions and abbreviations 8 3.1 Definitions 8 3.2 Abbreviations . 9 Call control fu
6、nctions . 9 5.2.5 5.2.6 5.2.7 5.2.8 5.2.3 5.2.4 Transmission aspects . 9 5.1 General . 9 Encoding . 9 5.1.1 5.1.2 Relative level . 9 5.1.3 Volume control 9 Speech performance characteristics . 9 5.2.1 Frequency response and sensitivity 9 5.2.1.2 Receiving . 10 5.2.2 Loudness rating . 11 5.2.2.1 Nomi
7、nal values 11 5.2.2.2 Volume control (optional) . 11 Sidetone 12 5.2.3.1 Talkers sidetone 12 5.2.3.2 Listeners sidetone 12 5.2.4.1 5.2.4.2 Stability loss . 12 Distortion . 12 5.2.5.1 Sending 12 Method 1 (Pseudo random noise) 13 Method 2 (Sinusoidal signal) . 13 5.2.5.2 Receiving . 13 Method 1 (Pseud
8、o random noise) 13 Method 2 (Sinusoidal signal) . 14 5.2.5.3 Sidetone . 14 Variation of gain with input level 14 5.2.6.1 Sending 14 5.2.6.2 Receiving . 14 Spurious out-of-band signals (Receiving) 15 5.2 5.2.1.1 Sending 9 Terminal Coupling Loss (TCL) 12 Weighted Terminal Coupling Loss (TCLw) 12 5.2.5
9、.1.1 5.2.5.1.2 5.2.5.2.1 5.2.5.2.2 Out-of-band signals . 15 5.2.7.1 Discrimination against out-of-band input signals (Sending) 15 5.2.7.2 Noise . 16 5.2.8.1 Sending 16 5.2.8.2 Receiving . 16 5.2.8.3 Level of sampling frequency (Receiving) . 16 5.2.9 Acoustic shock 16 5.2.1 O Delay . 16 5.3 Non-linea
10、r devices . 16 Power feeding . 17 Physical modules 17 7.1 Handset 17 7.2 Alerting module 17 Page 4 I-ETS 300 245-2: February 1996 Annex A (normative): Test specifications . 18 A . 1 A.2 General conditions for testing . 18 Test equipment requirements . 18 Codec approach and specification 18 Alternati
11、ve test methods 19 A.l.l A.1.2 Environment for test 18 A.1.2.1 Electro-acoustic equipment 18 A.1.2.2 Test equipment for digital telephone sets . 18 A.1.2.2.1 A.1.2.2.2 Direct digital processing approach 19 A.1.3 A.1.4 Accuracy of calibration 20 A.1.5 Bandwidth 20 Speech transmission requirements tes
12、ting . 20 A12.1 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-frequency response . 20 A.2.1.1 Sending . 20 A.2.1.2 Receiving 20 Loudness rating . 20 A.2.2.1 Sending loudness rating . 20 A.2.2.2 Receiving loudness rating . 21 Sidetone 21 A.2.3.1 Talker sidetone . 21 A.2.3.2 Listener sid
13、etone 21 Terminal coupling loss 22 A.2.4.1 Weighted terminal coupling loss . 22 A.2.4.2 Stability loss 22 Distortion . 23 A.2.5.1 Sending . 23 A.2.5.1.1 Method 1 . 23 A.2.5.1.2 Method 2 . 23 A.2.5.2 Receiving 24 A.2.5.2.1 Method 1 . 24 A.2.5.2.2 Method 2 . 24 A.2.5.3 Sidetone 24 Variation of gain wi
14、th input level 24 A.2.6.1 Sending . 24 A.2.6.2 Receiving 24 A.2.7.1 Discrimination against out-of-band input signals 25 A.2.7.2 Spurious out-of-band signals 25 Noise . 25 A.2.8.1 Sending . 25 A.2.8.2 Receiving 25 A.2.8.3 Level of sampling frequency (receiving) . 25 Delay . 25 Out-of-band signals . 2
15、5 Annex B (informative): Acoustic shock requirements . 28 B.l Continuous signal . 28 6.2 Peak signal . 28 Annex C (informative): Bibliography . 29 History . 30 ETSI I-ETS*300 245-2 96 3400855 0080301 773 = Page 5 I-ETS 300 245-2: February 1996 Foreword This second edition of Part 2 of this Interim E
16、uropean Telecommunication Standard (I-ETS) 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 provisional solution ahead of a more advanced standa
17、rd, 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. Part 2 of this I-ETS specifies technical characterist
18、ics for Integrated Services Digital Network (ISDN) telephony terminals as described in the scope of this I-ETS. The characteristics are additional to type approval requirements to which the terminal equipment is subject. The additional characteristics are meant to give improved performance. This sec
19、ond edition of Part 2 to this I-ETS is the second Part of an I-ETS comprising eight Parts. Part 1: General. Part 2: PCM A-law, handset telephony. Part 3: Pulse Code Modulation (PCM) A-law, loudspeaking and handsfree telephony. Part 4: Interface for additional equipment to an ISDN telephony terminal.
20、 Part 5: Wideband (7 kHz) handset telephony. Part 6: Wideband (7 kHz) handsfree telephony. Part 7: Locally generated information tones. Part 8: Speech transmission characteristics when using low-delay code-excited linear prediction coding at 16 kbit/s. Proposed announcement date Date of adoption of
21、this I-ETS: Date of latest announcement of this I-ETS (doa): 29 February 1996 31 May 1996 ETSI I-ETS*300 245-2 96 W 3400855 0080302 hOT Page 6 I-ETS 300 245-2: February 1996 Blank page Page 7 I-ETS 300 245-2: February 1996 1 Scope This second edition of Part 2 of this Interim European Telecommunicat
22、ion Standard (I-ETS) specifies the technical characteristics for Pulse Code Modulation (PCM) A-law 3,l kHz handset telephony terminals to be used at the basic access for the coincident S and T reference point of the Integrated Services Digital Network (ISDN). This Part applies in conjunction with LE
23、TS 300 245-1 l and the characteristics specified in this Patt are additional to those of I-ETS 300 245-1 l. The present version of this Part does not cover measurements on receivers (in handsets) with low acoustic output impedance. 2 Normative references Part 2 of this LETS incorporates by dated or
24、undated reference, provision from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this Part of this I-ETS only w
25、hen incorporated in it by amendment or revision. For undated references the latest edition of the publication referenced to applies. 111 31 41 I-ETS 300 245-1 : “Integrated Services Digital Network (ISDN); Technical characteristics of telephony terminals; Part 1 : General“. CCITT Recommendation P.l
26、O (1 988): “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“. CCITT Recommendation G.122 (1 988): “Influence of national systems on stability, ta
27、lker echo and listener echo in international connections“. CCITT Recommendation G.711 (1 988): “Pulse code modulation (PCM) of voice frequencies“. 161 CCIT Recommendation G.lO1 (1 988): “The transmission plan“ 71 CCIlT Recommendation G.223 (1 988): “Assumptions for the calculation of noise on hypoth
28、etical reference circuits for telephony“. Pl ITU-T Recommendation P.51 (1 993): “Artificial mouth“. 91 ITU-T Recommendation P.57 (1 993): “Artificial ears“. 1 o1 IEC Publication 651 : “Sound level meters“. i 41 i 51 CCIlT Recommendation 0.133 (1 988): “Equipment for measuring the performance of PCM
29、encoders and decoders“. CCIlT Recommendation G.712 (1 992): “Transmission performance characteristics of pulse code modulation“. ITU-T Recommendation P.64 (1 993): “Determination of sensitivity/frequency characteristics of local telephone systems“. ITU-T Recommendation P.64 (1 988): “Determination o
30、f sensitivity/frequency characteristics of local telephone systems to permit calculation of their loudness ratings“. IS0 3 (1973): “Preferred numbers - Series of preferred numbers“. ETSI I-ETSx300 245-2 96 = 3400855 0080304 482 Page 8 I-ETC 300 245-2: February 1996 ITU-T Recommendation P.79 (1 993):
31、 “Calculation of loudness ratings for telephone sets“. IEC 225: “Octave, half-octave and third-octave band filters intended for the analysis of sound and vibrations“. CCITT Recommendation 0.1 31 (1 988): “Quantizing distortion measuring equipment using a pseudo-random noise“. CCITT Recommendation 0.
32、1 32 (1 988): “Quantizing distortion measuring equipment using a sinusoidal test signal“. Definitions and abbreviations Definitions For the purposes of this LETS, the relevant definitions given in CCITT Recommendations P.10 2 and G.701 3 apply along with the following: Acoustic Reference Level (ARL)
33、: The acoustic level which gives - 1 O dBmO at the digital interface. digital interface: The 9-channels available at the coincident S and T reference point at an ISDN basic access. handsfree telephony terminal: A telephony terminal using a loudspeaker associated with an amplifier as a telephone rece
34、iver and which can be used without a handset based on CCITT Recommendation P.10 211. loudspeaking telephony terminal: A handset telephony terminal using a loudspeaker associated with an amplifier as a telephone receiver based on in CCITT Recommendation P.10 2. telephony 3,l kHz teleservice: A telese
35、rvice providing speech transmission at an audio bandwidth of 3,l kHz. The communication is bi-directional, with both directions active during the speech phase. User information is provided over a B-channel, signalling is provided over the D-channel based on ETS 300 11 1, clause 51. Terminal Coupling
36、 Loss (TCL): The frequency dependent coupling loss between the receiving port and sending port of a terminal due to: - - - acoustic coupling at the user interface; electrical coupling due to crosstalk in the handset cord or within the electrical circuits; seismic coupling through the mechanical part
37、s 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 will depend on the conditions of use. Weighted Terminal Coupling Loss (TCLW): The weighted TCL using the weighting of CCITT Recommendation G.12
38、2 4. Page 9 LETS 300 245-2: February 1996 3.2 Abbreviations For the purposes of this I-ETS, the following abbreviations, plus the relevant abbreviations in CCITT Recommendations P.10 2 and G.701 3 apply: ARL ERP ISDN LRGP MRP PCM RLR SLR STMR TCL TCLw Acoustic Reference Level Ear Reference Point Int
39、egrated Services Digital Network Loudness Rating Guard-ring Position Mouth Reference Point Pulse Code Modulation Receiving Loudness Rating Sending Loudness Rating SideTone Masking Rating Terminal Coupling Loss Weighted Terminal Coupling Loss 4 Call control functions The requirements of LETS 300 245-
40、1 l shall be met. 5 Transmission aspects 5.1 General Recommendations and requirements for PCM A-law handset terminals are given in this second Part of the I-ETS. For loudspeaking or handsfree terminals or when using other coding algorithms other Parts of this LETS may apply. 5.1.1 Encoding The defau
41、lt speech encoding algorithm for all telephony terminals shall be the A-law encoding at 64 kbis as defined in CCITT Recommendation G.711 5. Any possible other encoding algorithm will be additional. For some encoding algorithms recommendations are given in other Parts of this I-ETS. 5.1.2 Relative le
42、vel The digital interface is defined as a O dBr point according to CCIlT Recommendation G.lO1 6. 5.1.3 Volume control Unless stated otherwise, the requirements apply for all positions of the user-controlled receiving volume control, if provided. 5.2 Speech performance characteristics 5.2.1 Frequency
43、 response and sensitivity 5.2.1.1 Sending The sending sensitivity-frequency response (from Mouth Reference Point (MRP) to digital interface) shall be within the limits restricted by the fully drawn lines in figure 1. In figure 1, a response is given which is considered to give good quality (naturaln
44、ess and intelligibility). The response is drawn on a logarithmic (frequency) - linear (dB sensitivity) scale. ETSI I-ETS*300 245-2 76 3400855 O080306 255 Page 10 I-ETS 300 245-2: February 1996 dB 4 +5 O -5 -10 -15 -20 -25 *I II II II r- _ I O0 200 500 1 O00 2000 4000 Frequency (Hq Figure 1 : Sending
45、 sensitivity/frequency response The sensitivity values are dB on an arbitrary scale. Conformance shall be checked by the tests described in annex A, subclauses A.2.1 and A.2.1.1. 5.2.1.2 Receiving The receiving sensitivity-frequency response (from digital interface to Ear Reference Point (ERP) shall
46、 be within the limits restricted by the fully drawn lines in figure 2. In figure 2, a response is given which is considered to give good quality (naturalness and intelligibility). The response is drawn on a logarithmic (frequency) - linear (dB sensitivity) scale. +5 O -5 -1 o -1 5 -20 -25 Page 11 LE
47、TS 300 245-2: February 1996 dB II - I : ;,/ /: : ,I I r - - 7- - - _ II 1 O0 200 500 I O00 2000 4000 Frequency Hz) Figure 2: Receiving sensitivityff requency response The sensitivity values are dB on an arbitrary scale. Conformance shall be checked by the tests described in annex A, subclauses A.2.1
48、 and A.2.1.2. 5.2.2 Loudness rating 5.2.2.1 Nominal values The nominal values are: SLR = 7 dB RLR = 3 dB A manufacturing tolerance for both Sending Loudness Rating (SLR) and Receiving Loudness Rating (RLR) of I 3 dB is allowed. The nominal value of RLR shall be met for at least one setting of the (o
49、ptional) volume control. Conformance shall be checked by measurement of SLR and RLR as described in annex A, subclause A.2.2. 5.2.2.2 Volume control (optional) If provided, the volume control shall fulfil the following requirements. When the volume control is set to its maximum position, or an automatic gain control is present, the RLR shall not be less than (louder than) - 8 dB. With the volume control set to its minimum position, the RLR shall not be greater than (quieter than) 18 dB. Conformance shall be che
