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22d75f47293672abaf64be8fbe527927 | 102 928 | 7 Transport of UDI | The IP-based network should also be capable to carry the 64 kbit/s transparent data service described in Recommendation ITU-T I.231.1 [i.18], also known as "64 k clear-mode". The considerations of the objective here are based on the Recommendation ITU-T G.826 [i.19], a standard for synchronous digital networks. While t... |
22d75f47293672abaf64be8fbe527927 | 102 928 | 8 Synchronization of endpoints | To ensure the synchronization of the endpoints (e.g. MSAN, GW; AGW), they should be synchronized with Synchronous Ethernet (SyncE) based on the Recommendations ITU-T G.8261 [i.12], G.8262 [i.13] and G.8264 [i.14]. Additionally, PTP (IEEE 1588 v2 [i.15]) and NTPv4 may be used as mean for synchronization of endpoints. A ... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 1 Scope | The present document provides speech & audio transmission performance requirements and measurement methods for handsfree functions of super-wideband/fullband terminals, including conferencing terminals. The present document provides requirements in order to optimize the end to end quality perceived by users. Users beco... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 2 References | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 2.1 Normative references | References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the referenced document (including any amendments) applies. Referenced documents which a... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 2.2 Informative references | References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the referenced document (including any amendments) applies. NOTE: While any hyperlinks i... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 3 Definitions of terms and abbreviations | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 3.1 Terms | For the purposes of the present document, the following terms apply: binaural listening: both ears are involved for the perception of sound dichotic: relating to or involving the presentation of a stimulus to one ear that differs in some respect (as pitch, loudness, frequency or energy) from a stimulus presented to the... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 3.2 Abbreviations | For the purposes of the present document, the following abbreviations apply: AM-FM Amplitude Modulation - Frequency Modulation CSS Composite Source Signal DRP ear Drum Reference Point DUT Device Under Test EC Echo Cancellation EL Echo Loss EVS Enhanced Voice Services FB FullBand FFT Fast Fourier Transform GAT Group Aud... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 4 Applications and Codec considerations | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 4.1 Applications | The following applications are within the scope of the present document: • Speech and audio communication, including conferencing using high quality handsfree systems, for which super-wideband/fullband coding can better reproduce the audio environment and provide an improved sound quality, user's experience and audio i... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 4.2 Codec considerations | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 4.2.0 Introduction | As indicated in the scope only coders supporting conversational SWB and FB services are applicable to the present document. ETSI ETSI TS 102 925 V1.2.1 (2018-10) 11 |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 4.2.1 Super-wideband (SWB) | Table 4.2.1-1: List of super-wideband codecs covered by the present document Coder Reference Speech Other signals Stereo Remark ETSI TS 126 441 [25] X X Music (X) EVS codec. Stereo supported in a dual mono configuration Recommendation ITU-T G.722.1 [7] Annex C X X Music For low frame loss Recommendation ITU-T G.729.1 [... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 4.2.2 Fullband (FB) | The following codecs are recommended for fullband: • Recommendation ITU-T G.719 [10] Low-complexity, full-band audio coding for high-quality, conversational applications. - "Recommendation ITU-T G.719 [10] describes the G.719 coding algorithm for low-complexity full-band conversational speech and audio, operating from ... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5 Test equipment and associated considerations | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.0 Introduction | The terminals within the scope of the present document are not only dedicated to speech communication but are also mixing speech and audio contents and may implement stereo and multichannel transmissions. As a consequence there is a need to define new parameters, such as: • Loudness: Loudness Rating is determined only ... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1 Test Set-up | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.0 Introduction | Recommendation ITU-T P.58 [3] indicates: "The artificial ears ... support super-wideband as well as full-band applications. It should be noted that the acoustical impedance of the artificial ears has some limitations in realistically simulating human ears". "The artificial mouth supports super-wideband applications, ho... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.1 Setup for terminals | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.1.0 Introduction | As the scope of the present document includes all the potential types of handsfree terminals this clause defines the set up for each type of terminal. |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.1.1 Desktop operated handsfree terminal | The desktop operated handsfree terminal is intended to be placed on a table and the user is located close to the edge of this tables. When HATS is used in the test equipment, the setups can be found in Recommendation ITU-T P.581 [4], and is placed according to figures 5.1.1.1-1 and 5.1.1.1-2. When HATS is not used, it ... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.1.2 Handheld handsfree terminal | This kind of terminal could implement SWB or FB; The test configuration is defined on figure 5.1.1.2-1. ETSI ETSI TS 102 925 V1.2.1 (2018-10) 16 Figure 5.1.1.2-1: Configuration of Hand-Held loudspeaker relative to the HATS side view NOTE: For a hand-held terminal using external microphone(s) the test set-up defined in ... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.1.3 Softphone (computer-based terminals) | When a manufacturer gives conditions of use, they will apply for test. If no other requirement is given by a manufacturer, the softphone will be positioned according to the following conditions: Softphone including loudspeakers and microphone Two types of softphones are to be considered: • Type 1 is to be used as a des... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.1.4 Group audio terminal (GAT) | The Group audio terminal as defined in the present document is considered as a "one-piece" terminal including loudspeaker/microphone in the same "box". When supplementary microphones/loudspeakers may be added to the Group Audio Terminal, the test set-up "teleconference" should be used; as defined below. When manufactur... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.1.5 Teleconference systems | Teleconference systems may implement video and currently use multi-microphone systems and/or multi-loudspeaker systems. For SWB teleconference systems, HATS may be used for some tests. For FB teleconference systems and for other tests of SWB teleconference systems, additional tests are conducted using freefield microph... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.1.6 Void | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.2 Test signals | The test signals are defined according to Recommendation ITU-T P.501 [1] for tests made with speech signals. For some parameters it is necessary to combine speech signals with other types of signals (e.g. music, background noise) or the test signal may be an audio signal mixing any type of materials. Such signals are d... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.3 Test signal levels | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.3.0 General | The level dependency should be considered and consequently tests should also be done with signal levels lower and higher than the reference level defined in the following clauses. |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.3.1 Send | Unless specified otherwise, the test signal level shall be -4,7 dBPa at the MRP. When using HATS it is positioned according to figure 5.1.3.1-1. ETSI ETSI TS 102 925 V1.2.1 (2018-10) 22 When using a reference loudspeaker its centre is positioned at the lip ring position defined in figure 5.1.3.1. The loudspeaker is int... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.3.2 Receive | Unless specified otherwise, the applied test signal level at the digital input shall be -16 dBm0. |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.4 Setup of background noise simulation | A setup for simulating realistic background noises in a lab-type environment is described in ETSI TS 103 224 [28]. The signals attached to ETSI TS 103 224 [28] are fullband signals and should be used for background noise simulation. ETSI ETSI TS 102 925 V1.2.1 (2018-10) 23 The following noises of ETSI TS 103 224 [28] s... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.5 Acoustic environment | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.5.1 Measurement environment | NOTE: The acoustic environment may influence more significantly the results in low and high frequencies. It should be adapted to the terminal bandwidth. In general two possible approaches need to be taken into account: either room noise and background noise are an inherent part of the test environment or room noise and... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.5.2 Acoustic environment for the rooms where systems are implemented | The acoustic environment may have an important influence on the quality, in particular for group audio terminals and conference systems. Information is available in Annex A. |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.1.6 Influence of terminal delay issue on measurements | As delay is introduced by the terminal, care shall be taken for all measurements where exact position of the analysis window is required. It shall be checked that the test is performed on the test signal and not on any other signal. ETSI ETSI TS 102 925 V1.2.1 (2018-10) 24 |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.2 Environmental conditions for tests | The following conditions shall apply for the testing environment: a) Ambient temperature: 15 °C to 35 °C (inclusive). b) Relative humidity: 5 % to 85 %. c) Air pressure: 86 kPa to 106 kPa (860 mbar to 1 060 mbar). d) Unless specified otherwise, the background noise level shall be less than -64 dBPa(A) in conjunction wi... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.3 Accuracy of measurements and test signal generation | Unless specified otherwise, the accuracy of measurements made by test equipment shall be equal to or better than: Table 5.3-1: Measurement Accuracy Item Accuracy Electrical signal level ±0,2 dB for levels ≥ -50 dBV ±0,4 dB for levels < -50 dBV Sound pressure ±0,7 dB Frequency ±0,2 % Time ±0,2 % The values in table 5.3-... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.4 Specific test considerations | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.4.0 Introduction | Even if the present document is dedicated to conversational services, the signals that are transmitted may combine speech and audio. |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.4.1 Loudness Rating and Loudness | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.4.1.1 Loudness Rating | Loudness Rating, as defined in Recommendation ITU-T P.79 [5], applies for narrowband and wideband and is specific to telecommunications transmission systems. So, when a terminal implements wideband speech in addition with Super- wideband or fullband functions, or is intended to communicate with wideband terminals, the ... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.4.1.2 Loudness | Loudness quantifies the level as perceived by the user and should be more relevant when the signal combines speech and audio sequences for Super-wideband and fullband. ISO 532 [i.3] method B defines a standardized way to determine the loudness of a steady-state complex signal. This assessment method takes into account ... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.4.2 Binaural listening | The scope of the present document includes terminals that may have two or more microphones and two or more loudspeakers. The terminal may also provide stereo listening or binaural rendering built from MCU. NOTE: Loudness calculation should be based on binaural listening. |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.4.3 Subjective considerations | Recommendation ITU-T P.1301 [16] defines the subjective quality evaluation of audio and audiovisual multiparty telemeetings: "This recommendation concerns subjective quality assessment of telemeeting systems that provide multiparty communication between distant locations, using audio-only, video-only, audiovisual, text... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.4.4 Setup of variable echo path | Test setup for desktop hands free terminals: A notebook is positioned at least 20 cm in front of the device (or devices) with the transducers, as shown in figure 5.4.4-1. The notebook lid is moved during the measurement. > 20cm Figure 5.4.4-1: Positioning of DUT ETSI ETSI TS 102 925 V1.2.1 (2018-10) 27 Test setup for s... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.5 Network impairment simulation | At least one set of requirements is based on the assumption of an error free packet network, and at least one other set of requirements is based on a defined simulated malperformance of the packet network. An appropriate network simulator has to be used, for example NIST NetTM [i.5] (https://www- x.antd.nist.gov/itg/ni... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 5.6 Verification of the environmental conditions | This test is not a mandatory test. This test is intended to be used in order to verify the environmental conditions as defined in clause 5.2. For the measurements no test signal is used. A free-field measurement microphone is positioned in the test room. The room noise is measured in the frequency range between 20 Hz a... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.0 Considerations | When possible, parameter requirements will be derived from requirements defined for the wideband terminals. The recommended test method is also provided in the same clause as requirements. NOTE: Due to the time variant nature of IP connections, delay variation may impair the measurements. In such cases the measurement ... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.1 Send | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.1.0 Introduction | All the types of terminals within the scope of the present document shall fulfill the requirements of this clause. Even if these terminals are rather different, the intention of the present document is to guarantee that all the terminals effectively transmit Super-wideband and/or fullband bandwidths. |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.1.1 Frequency response | Requirements The objective is to define a flat frequency curve over the whole bandwidth. The frequency response for Super-wideband shall fulfill the mask as defined in table 6.1.1-1 and figure 6.1.1-1. ETSI ETSI TS 102 925 V1.2.1 (2018-10) 29 Table 6.1.1-1: Frequency mask for Super-wideband terminals - Send Frequency U... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.1.2 Send Loudness rating (SLR) | Requirements To ensure the compatibility with other terminals or systems a reference SLR needs to be defined. The requirements refer to wideband handsfree terminals, ETSI TS 103 740 [12]. Nominal value: +13dB ± 3 dB. There is no specific requirement for SWB or FB bandwidth. Measurement method (of Wideband Loudness rati... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.1.3 Void | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.1.4 Send Noise | Requirements The limit for the send noise is the following: • send noise level maximum -64 dBm(A). No peaks in the frequency domain higher than 10 dB above the average noise spectrum shall occur. NOTE 1: Softphones with cooling devices (fans) can produce a rather high level of noise; largely dependent of the activity o... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.1.5 Send Distortion | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.1.5.1 Signal to harmonic distortion versus frequency | Requirements The ratio of signal to harmonic distortion shall be above the following masks. The following draft requirements are defined for all the terminals within the scope of the present document, as it is needed to ensure that any terminal intended to be used in Super-wideband and fullband sends good quality signa... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.1.5.2 Signal to harmonic distortion for higher input level | Requirement For the signal defined in the measurement method, the signal to harmonic distortion ratio shall be ≥ 30 dB. Measurement method The terminal is set according to clause 5.1.1. For Super-wideband and fullband terminal, the signal used is an activation signal followed by a series sine wave signal with a frequen... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.1.6 Microphone mute | Requirement The SLR (Send Loudness Rating) with microphone mute on shall be at least 50 dB higher than with mic mute off. Measurement method The terminal will be positioned as described in clause 5.1. For a correct activation of the system, the test signal to be used for the measurements shall be the British-English si... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.2 Receive | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.2.0 Introduction | The scope of the present document includes a lot of different types of handsfree terminals. The receive performance may significantly depend on the size and on the application of the terminal. In the following clause the requirements are defined for the different types of terminals within the scope of the present docum... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.2.1 Equalization | This type of terminal may be used for reproduction of signals other than pure speech (e.g. music) for which user's preference may be different in term of sound signature. So, the terminals may implement an equalization function adjusting frequency response according to user's preference. ETSI ETSI TS 102 925 V1.2.1 (20... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.2.2 Frequency response | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.2.2.0 General | When using HATS (with the restrictions defined in clause 5) HATS shall be equalized according to Recommendation ITU-T P.581 [4]. However, at least for fullband terminals, it is recommended to use free-field microphones instead of the HATS. |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.2.2.1 Handheld terminal | Requirements Superwideband Table 6.2.2.1-1: Frequency mask for Superwideband handheld terminals - Receive Frequency Upper Limit Lower Limit 50 Hz 5 dB 400 Hz 5 dB -5 dB 12 500 Hz 5 dB -5 dB 14 000 Hz 5 dB -10 dB 16 000 Hz 5 dB NOTE: The limits for intermediate frequencies lie on a straight line drawn between the given ... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.2.2.2 Desktop terminal | Requirements Super-wideband Table 6.2.2.2-1: Frequency mask for Super-wideband desktop terminals - Receive Frequency (Hz) Upper limit (dB) Lower limit (dB) 75 5 -15 150 5 -5 12 500 5 -5 14 000 5 -10 NOTE: All sensitivity values are expressed in dB on an arbitrary scale. Figure 6.2.2.2-1: Frequency mask for Super-wideba... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.2.2.3 Terminals intended to be used simultaneously by several users | Additional requirements to be defined: • when the terminal is intended to be used by several users; ETSI ETSI TS 102 925 V1.2.1 (2018-10) 38 • when stereo features are made available. For all the testing positions the frequency curve shall fulfil the requirements defined for desktop terminals. |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.2.3 Receive Loudness Rating (RLR) and Loudness | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.2.3.1 Receive Loudness Rating | Requirements When terminal implements wideband speech functions or when the super-wideband/fullband functions may interact with wideband terminals, the handsfree terminal shall fulfill the requirements on RLR as defined in ETSI TS 103 740 [12], clause 7.1.7: • Desktop terminal: - Nominal value of RLR will be 5 dB ± 3 d... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.2.3.2 Loudness | The implementation of loudness measurements is very important for the receive part of the terminal. So, for the super-wideband and fullband transmissions it should be relevant to determine the loudness of the signals delivered by the terminal. When the terminal provides Super-wideband or fullband in addition with wideb... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.2.4 Receive Noise | Requirements • A-weighted The noise level measured until 10 kHz shall not exceed -54 dBPa(A) at nominal setting of the volume control. • Third-octave band spectrum. For SWB: The level in any 1/3-octave band, between 50 Hz and 12,5 kHz shall not exceed a value of -64 dBPa. For FB: The level in any 1/3-octave band, betwe... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.2.5 Receive Distortion | Requirements The ratio of signal to harmonic distortion shall be above the following mask. Table 6.2.5-1: Receive distortion for super-wideband and fullband Frequency Signal to distortion ratio limit, receive for desktop terminal (SWB) Signal to distortion ratio limit, receive for desktop terminal (FB) 100 Hz 20 dB 200... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3 Other parameters | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.0 Introduction | The interest of such types of terminals is to provide a very high quality. The parameters to be defined in this clause are intended to guarantee that this expected quality is effectively offered to the user(s). |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.1 Round-trip Delay | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.1.1 Round-trip Delay for VoIP terminals | The roundtrip delay of a VoIP-terminal is defined as the sum of send and receive delays. In the following clauses the calculation of the requirements for send and receive delay are explained. For a telecommunication connection, only the roundtrip delay can be experienced. For this reason, also the requirement for VoIP-... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.1.2 Quality of jitter buffer adjustment | Requirements The speech quality during and after inserted IP delay variation shall be as follows: Table 6.3.1.2-1: Requirements for variant network impairments Codec MOS-LQOf ETSI TS 126 441 [25] TBD Recommendation ITU-T G.722.1 [7] Annex C TBD Recommendation ITU-T G.729.1 [8] Annex E (extension SWB) TBD Recommendation... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.2 Terminal Echo Loss (TCL) | Requirement: The TCL measured as unweighted Echo Loss shall be ≥ 46 dB for all positions of the volume control (if supplied). Measurement method: The handsfree terminal is set-up as described in clause 5.1. For hands-free measurement, HATS is positioned but not used. For loudspeaking measurement, handset is positioned ... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.3 Objective listening quality | Requirement For further study. Measurement method Objective listening speech quality is measured using Recommendation ITU-T P.863 [14] in fullband mode. ETSI ETSI TS 102 925 V1.2.1 (2018-10) 45 The test signal to be used for the measurements shall be 4 sentence pairs (male/female) fulfilling the requirements of Recomme... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.4 Double talk performance | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.4.1 General | During double talk the speech is mainly determined by 2 parameters: impairment caused by echo during double talk and level variation between single and double talk (attenuation range). In order to guarantee sufficient quality under double talk conditions the Talker Echo Loudness Rating should be high and the attenuatio... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.4.2 Attenuation range in send direction during double talk AH,S,dt | Requirement Based on the level variation in send direction during double talk AH,S,dt the behaviour of the terminal can be classified according to table 6.3.4.2-1. ETSI ETSI TS 102 925 V1.2.1 (2018-10) 46 Table 6.3.4.2-1 Category (according to Recommendation ITU-T P.340 [6]) 1 2a 2b 2c 3 Full Duplex Capability Partial ... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.4.3 Attenuation range in receive direction during double talk AH,R,dt | Requirement Based on the level variation in receive direction during double talk AH,R,dt the behaviour of the terminal can be classified according to table 6.3.4.3-1. Table 6.3.4.3-1 Category (according to Recommendation ITU-T P.340 [6]) 1 2a 2b 2c 3 Full Duplex Capability Partial Duplex Capability No Duplex Capability... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.4.4 Detection of echo components during double talk | Requirement "Echo Loss" (EL) is the echo suppression provided by the terminal measured at the electrical reference point. Under these conditions the requirements given in table 6.3.4.4-1 are applicable (more information can be found in Annex A of Recommendation ITU-T P.340 [6]. ETSI ETSI TS 102 925 V1.2.1 (2018-10) 48 ... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.4.5 Minimum activation level and sensitivity of double talk detection | For further study. ETSI ETSI TS 102 925 V1.2.1 (2018-10) 50 |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.5 Speech and audio quality in presence of noise | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.5.1 Performance in send in the presence of background noise | Requirement The level of comfort noise shall be within in a range of +2 dB to -5 dB compared to the original (transmitted) background noise. The noise level is calculated with psophometric weighting. NOTE 1: It is advisable that the comfort noise matches the original signal as good as possible (from a perceptional poin... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.5.2 Speech quality in the presence of background noise | Requirement Speech Quality for super-wideband and fullband systems can be tested based on ETSI TS 103 281 [26]. For the background noises defined in clause 5.1.4 the following requirements apply: • N-MOS-LQOf ≥ 2.7. ETSI ETSI TS 102 925 V1.2.1 (2018-10) 51 • S-MOS-LQOf ≥ 3.3. • G-MOS-LQOf ≥ 2.7. NOTE: It is recommended... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.5.3 Quality of background noise transmission (with far end speech) | Requirement The test is carried out applying a speech signal in receive direction. During and after the end of the speech signal the signal level in send direction should not vary more than 10 dB (during transition to transmission of background noise without far end speech). The measurement is conducted for all types o... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.6 Potential other quality features | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.6.1 Sound localization and binaural performance | For further study. |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.6.2 Dereverberation performance | This feature is intended to reduce the reverberant signals due to the room where the terminal is installed. For further study. |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.6.3 Switching characteristics between transducers | For further study. |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.7 Quality of echo cancellation | |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.7.1 Temporal echo effects | Requirements This test is intended to verify that the system will maintain sufficient echo attenuation during single talk. The measured echo attenuation during single talk should not decrease by more than 6 dB from the maximum measured echo attenuation. Measurement method The test setup is described in clause 5.1. The ... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.7.2 Spectral echo attenuation | Requirements The echo attenuation vs. frequency shall be below the tolerance mask given in table 6.3.7.2-1. Table 6.3.7.2-1: Spectral echo loss limits Frequency Limit 100 Hz -41 dB 1 300 Hz -41 dB 3 450 Hz -46 dB 5 200 Hz -46 dB 7 500 Hz -37 dB 8 000 Hz -37 dB NOTE: The limit at intermediate frequencies lies on a strai... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.7.3 Occurrence of artefacts | For further study. |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.7.4 Variable echo path | Requirement This test is intended to verify that the system will maintain sufficient echo attenuation during single talk with dynamic changing echo paths. The measured echo level over time during single talk should not be more than 10 dB above the minimum noise level during the measurement. Measurement method The test ... |
548bdcc0533dcbd4ed60848bf1c006d9 | 102 925 | 6.3.8 Switching characteristics |
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