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3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 1 Scope | The present document describes auditory and instrumental testing methodologies, which can be used to evaluate the perceived listening effort in the following speech communication scenarios at acoustical interfaces in the presence of acoustical near-end ambient noise. Similar to other instrumental quality prediction met... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 2 References | |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 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 that ar... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 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... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 3 Definition of terms, symbols and abbreviations | |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 3.1 Terms | Void. |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 3.2 Symbols | For the purposes of the present document, the following symbols apply: ACT Frames in the signal(s) containing active speech dBPa Sound Pressure Level in dB, referenced to 1 Pa dBSPL Sound Pressure Level in dB, referenced to 20 µPa FN Noise flag, indicating if the prediction algorithm uses a noise-only reference or not ... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 3.3 Abbreviations | For the purposes of the present document, the following abbreviations apply: ACR Absolute Category Rating AMR Adaptive Multi-Rate codec (NarrowBand) AMR-WB Adaptive Multi-Rate codec-WideBand ANC Active Noise Cancellation ASL Active Speech Level BGN BackGround Noise ETSI ETSI TS 103 558 V1.3.1 (2021-07) 11 BW BandWidth ... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 4 Introduction | Communication in noisy environments may be extremely stressful for the person located at the near-end side. Since the background noise is originated from the natural environment, it can usually not be reduced for the listener. In addition, the perceived signal may be disturbed by other linear or non-linear signal proce... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 5 Auditory test design | |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 5.1 Overview | The basis of any perceptually based measure, which models the behaviour of human test persons, are auditory tests. In general, these tests are carried out with naïve test persons, who are asked to rate a certain quality aspect of a presented speech sample. For the assessment of listening effort, a test design related t... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 5.2 Speech material | The source speech database (far end signal) to be used for data collection and listening tests needs to consist of at least eight samples (2 male and 2 female talkers, 2 samples per talker). Appropriate test signals for multiple languages and in fullband bandwidth can be found in Recommendation ITU-T P.501 [5] or in an... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 5.3 Background noise simulation | The presence of ambient noise is the most influencing aspect on listening effort. In order to provide an accurate sound field reproduction at the DUT and/or at the listener position, the method according to ETSI TS 103 224 [i.4] shall be used for the recording of samples. The present document includes two recording/pla... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 5.4 Recording procedure | |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 5.4.1 Acoustic recordings (receiving) | The test setup is motivated by the requirement that all signals can be measured outside the device. For capturing the signals, a HATS according to Recommendation ITU-T P.58 [7] is used. The specific setup may vary from one application to another. However, the recording procedure shall always follow the guidelines descr... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 5.4.2 Electrical recordings (sending) | The measurement setup records the degraded signal at the electrical POI. Either acoustical (via HATS and terminal) or electrical insertion (via e.g. gateways or SPNF devices) are possible. ETSI ETSI TS 103 558 V1.3.1 (2021-07) 14 |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 5.5 Sample presentation | |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 5.5.1 General considerations | Besides varying background noise levels, speech signals at different levels are an included use case and can be used in the listening test. To avoid any hearing impairment in the tests, the minimum health and safety requirements regarding noise exposure according to Directive 2003/10/EC [10] shall be met. Additional gu... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 5.5.2 Monaural signals | If only monaural degraded signals are available (e.g. in case of single-channel electrical recordings), diotic presentation shall be used. Similar to the case of binaural recordings, diffuse-field equalized headphones shall be used for the playback of the samples. No further listening filter shall be used. The calibrat... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 5.6 Anchor/Reference Conditions | Reference conditions are a well-established method for conducting meaningful comparisons of auditory test results from different laboratories or from the same laboratory at different times. These conditions always include a best possible (also often denoted as clean or direct) condition, as well as conditions where kno... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 5.7 Attributes and test methodology | The instructions to the test subjects shall be presented in written form in the mother tongue of the test subjects. For presentation, e.g. text printed on paper, assessment terminal/PC or projected slides may be used. Examples for listening test instructions in different languages are given in annex A. The listening te... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 5.8 Requirements for the listening laboratory | The listening laboratory facilities need to comply with the recommendations provided in Recommendation ITU-T P.800 [1] and the ITU-T Handbook of subjective testing practical procedures [8]. |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 5.9 Listening test structure | Beside the 12 reference conditions, between 12 and 60 test conditions shall be included per auditory database. This reflects a reference to overall condition ratio between 17 % and 50 %. The recommended ratio equals to 20 %, i.e. referring to 48 test conditions. At least four different samples shall be used per conditi... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 5.10 Reporting of results | All titles of the samples used in an auditory database shall be reported as rows in a table. As a second column, the information about the corresponding condition number (e.g. C01, C02, etc.) should be included (if applicable). All per-sample and per-condition MOS values shall be rounded to two digits for the report. T... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6 Instrumental Assessment | |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.1 Overview | In general, the listening effort prediction algorithm requires several input signals: • Degraded input signal (): By default, this signal is a diffuse-field equalized binaural recording of noisy speech. In several applications, only a single-channel signal is available or of interest, see also clause 6.8 for monaural... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.2 Pre-processing | |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.2.1 Overview | Before performing any metric calculation and predicting listening effort scores, the input signals of the algorithm have to be prepared for the following stages. The pre-processing of the inputs , and is conducted in order to compensate differences regarding temporal alignment, level offsets and spectral s... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.2.2 Compensation of Delay | Similar as in speech quality prediction models like e.g. ETSI TS 103 281 [4] or Recommendation ITU-T P.863 [i.2], the reference signal shall be compensated for possible delays introduced by e.g. terminals, network or signal processing. This is indispensable for a valid comparison towards the reference signal at a later... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.2.3 Reference Scaling | Comparisons between degraded and reference signal in later stages of the prediction algorithm are carried out based on realistic listening levels. The reference signal is intended to provide an optimum regarding clear pronunciation, frequency shaping, etc., but also regarding best-possible speech level. According to th... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.2.4 Speech Part Detection | In order to determine the time ranges of active speech, the classification algorithm according to Appendix II of Recommendation ITU-T G.160 [11] is applied on the reference signal Opt(). The first step is to classify energy frames of 10 ms (block-wise, no overlap) according to the method described in [11]. The thresh... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.2.5 Determination of Processed Signal | In order to analyse the impact of the possibly disturbed speech components on perceived listening effort, the influence of the noise has to be cancelled out. In case of acoustic recordings with near-end noise (i.e. not transmitted or processed), the processed but noise-free signal () can be easily determined accordin... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.2.6 Transfer Function | In order to characterize the transmission system of the degraded signal in the frequency domain, the complex transfer function f is utilized in later stages. Similar as for the determination of delay, the high amount of noise in the degraded signal requires some more computational effort. Again, the calculation shall... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.3 Spectral transformation | The hearing model according to Sottek [12] is calculated for the signals degraded (), noise-only () (if applicable) and clean speech reference Opt(). The transformation includes an auditory filter bank representation of the signal and a hearing-adequate envelope determination. ETSI ETSI TS 103 558 V1.3.1 (2021-07)... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.4 Compensated Reference | Based on the transfer function and the hearing model spectrum opt(, ) of the optimum reference, a so-called compensated reference Comp(, ) spectrum vs time is determined. First, a linearly interpolated version is calculated from the transfer function , which uses the same frequency resolution as the... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.5 Separation of Speech and Noise Component | In case no noise-only signal () is provided, in consequence also no processed signal () is available. Thus, the corresponding hearing model spectra (, ) and , are estimated based on the available inputs. Equation (14) shows the basic assumption of the composition: , = , + (, ) (14) For the de... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.6 Binaural processing | In order to address the capability of human hearing to improve SNR compared to monaural listening, a binaural processing stage is included in the prediction model. The spectral components for left and right ears are combined by a short-term equalization-cancellation (STEC) model according to [14]. This extension of the... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.7 Instrumental Assessment | |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.7.1 Metrics | |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.7.1.1 Level Metrics | Since the hearing model spectra for processed speech and noise component are individually available, level metrics can be calculated in the frequency domain. The active speech level act is calculated according to equation (21) on the processed signal across all frequencies. Only active time frames (ACT) according to cl... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.7.1.2 Spectral Distance Metric | In order to investigate the relation and possible masking effects of the processed ( , ) and noise ( , ) spectra vs time, a similar index metric as in the calculation method according to ANSI/ASA S3.5 [18] is described in the following paragraphs. The method of [18] provides a speech intelligibility index (SI... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.7.1.3 Correlation Metrics | Similar as the intelligibility metric introduced in e.g. [i.9], a spectral cross-correlation is carried out in four different ways. Instead of the clipping procedure described in [i.9], the threshold of hearing according to ISO 389-7 [17] is applied to the spectra. After this step, the non-linear loudness transfo... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.7.2 Regression | In order to combine all metrics described in the previous clauses, a random forest regression according to [24] is used. Table 6.4 provides a summary of all metrics used for the regression. Beside the eight parameters directly related to the perceptual model, additional flags are used in the regression: • FN is a flag ... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.7.3 Post-processing | The MOS calculated in the previous clause does not take into account too loud speech levels. It is obvious that in general an increasing speech level correlates with improvement in listening effort. However, in contrast to a prediction algorithm, extremely high speech levels would not be presented to test subjects in a... |
3dc0b53cce535ec6161a3fb2f0f2a7d8 | 103 558 | 6.8 Model modes for monaural signals | For the introduced model, one or two binaural inputs (noisy speech and optionally noise-only) and one single-channel reference signal are needed. In several applications, only one ear signal is available or is of interest. In this case, the model can be run with the following simplifications: 1) Monaural mode: For term... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 1 Scope | The present document describes a methodology for recording and reproducing different room characteristics and realistic reverberation under conditions that are well-defined and tailored for a calibrated setup in a lab environment. The individual aspects of the description are: • Measurement of room impulse responses. •... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 2 References | |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 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... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 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... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 3 Definition of terms, symbols and abbreviations | |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 3.1 Terms | Void. |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 3.2 Symbols | For the purposes of the present document, the following symbols apply: Clarity with cut-off time Sampling frequency Reverberant components of the impulse response to microphone ℎ Impulse response to microphone ℎ Impulse response to the microphone closest to the HATS ℎ, Direct path com... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 3.3 Abbreviations | For the purposes of the present document, the following abbreviations apply: DRR Direct-to-Reverberant energy Ratio DUT Device Under Test FFT Fast Fourier Transform HATS Head And Torso Simulator LRC Lip Ring Centre MLS Maximum Length Sequence MM Measurement Microphone(s) MRP Mouth Reference Point MSA Microphone Sound A... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 4 Rationale | Including reverberation in a realistic manner is of paramount importance for accurate testing of, e.g. phones in hands- free mode, group-audio terminals or smart speakers with speech recognition capabilities. While it is possible to test this simply by using the device in a reverberant room, the present document introd... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5 Room simulation in Sending | |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.1 Impulse Response Measurement | |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.1.1 Microphone setup | |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.1.1.1 Fixed Microphone setup | A fixed microphone setup should be used for DUTs with smaller form factors (e.g. mobile phones in hands-free operation). The microphone setup shall consist of = 8 microphones and conform to the description in ETSI TS 103 224 [1], clause 5. Since this setup is device-independent, no new impulse response measurements are... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.1.1.2 Flexible Microphone setup | For larger DUTs, a flexible microphone setup with a use-case dependent number of microphones shall be used. The microphone setup shall conform to the description in ETSI TS 103 224 [1], clause 7. Since this setup is device- dependent, testing a new device requires new impulse response measurements. |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.1.2 Sound source | Since the testing scenario consists of a human talker in a reverberant environment, a HATS with an equalized artificial mouth according to Recommendation ITU-T P.58 [2] shall be used for sound generation. This applies to measurement of impulse responses as well as to recording of reverberant speech signals. ETSI ETSI T... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.1.3 Measurement procedure | There exist different possibilities for measuring impulse responses, e.g. using Maximum Length Sequences (MLS) or using swept-sines (sweeps). The advantage of sweeps is that non-linearities can easily be observed and that the SNR in lower frequencies is higher than with MLS. Using logarithmic sweeps is therefore recomm... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.2.1 Introduction and System Overview | In order to correctly reproduce the sound field in a reverberant room, the setup described in ETSI TS 103 224 [1] is not sufficient. Direct sound as well as the reverberant components shall be considered. A combination of the multi-channel loudspeaker setup with the artificial mouth of a HATS is used for the reproducti... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.2.2 Preparations | |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.2.2.1 Separation of impulse responses | The reproduction system needs two signal parts: the direct sound (single channel that is played over the HATS) and the reverberant components (eight target signals that are fed into the reproduction system according to ETSI TS 103 224 [1]). An example impulse response ℎ is shown in Figure 2 with the direct path com... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.2.2.2 Delay and level adjustment | For the aforementioned level and delay compensation, the signal from the artificial mouth needs to be adjusted to the signal from the reproduction system. This shall be achieved by comparing the level of and the delay between two signals. A linear or logarithmic sweep signal of at least 2 s covering a frequency range f... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.2.3 Test room requirements | The requirements are identical to the requirements in ETSI TS 103 224 [1]. In addition, the reverberation time of the measurement chamber that is used for the reproduction imposes a lower bound on the range of rooms that can be reproduced. Thus, an anechoic room is recommended. If semi-anechoic rooms or measurement cha... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.2.4 Equalization and calibration | The calibration of the microphone array and the equalization of the loudspeaker system are identical to ETSI TS 103 224 [1]. The artificial mouth of the HATS shall conform to Recommendation ITU-T P.58 [2], no additional equalization is needed. ETSI ETSI TS 103 557 V1.3.1 (2020-03) 12 |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.2.5 Accuracy of the reproduction arrangement | |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.2.5.1 Evaluation parameters | The accuracy of the reproduction shall be verified by measuring the following four parameters and asserting that they are within the given tolerance range around the true value for each dataset. The first three parameters are based on the impulse response h(k) of the entire reproduction system. The impulse response of ... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.2.5.2 Reverberation time | Probably the most widely used parameter to characterize the acoustic behaviour of a room is its reverberation time , the required time for a level decay of 60 dB. Several methods for estimating are available, but even the most common standard ISO 3382-1 [i.3] only provides guidelines instead of a robust and clear c... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.2.5.3 Clarity | The clarity is a measure that is applied in room acoustics to quantify the usability of a room for a certain class of signals. It is a logarithmic ratio between the energy in the early part of the room impulse response (direct sound and early reflections) and the energy in the late reverberation up to the length K of t... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.2.5.4 Direct-to-Reverberant energy Ratio | The DRR is conceptually fairly similar to the aforementioned clarity; it is a ratio between the energy of the direct sound (without the early reflections) and the energy of all reverberant components. This corresponds to a value of 5 ms for the cut-off time. An overall ratio is then determined by averaging the individu... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.2.5.5 Coherence | In contrast to the other three parameters (which can all be calculated individually for each channel), the coherence describes the relation between original source (S) and reproduced (R) sound pressure at a given microphone channel i. It is usually given in the form of the magnitude-squared coherence, which is calculat... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.4 Impulse response database and signal generation | An impulse response database is provided in Annex A. The corresponding files are available separately from the present document. |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.5 Validation and examples | |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.5.1 Reproduction of room acoustical parameters | Room impulse responses were recorded in six different rooms according to Table 1. Table 1: Investigated rooms Label Room Approximate volume Room 1 Meeting room with additional damping panels 120 m3 Room 2 Listening laboratory 107 m3 Room 3 Office room 54 m3 Room 4 Meeting room 120 m3 Room 5 Small workshop 172 m3 Room 6... |
74645ace5556dce86741d88057c1b6d4 | 103 557 | 5.5.2 Application examples | As an example, for the use and the performance of the reproduction system, different hands-free telephones were positioned on a table in room 1 from the impulse response database at the group-audio terminal position. Speech utterances from a HATS were recorded. The speech signals used were a sequence of six male and si... |
a6afe51320dace98232cafb04d55714c | 103 553-3 | 1 Scope | The present document provides an overview of available SuperCapacitor (SC) technology, with details of SC characteristics (electrical, mechanical, thermal) and applicability in the Telecommunication/Information and Communication Technology (TLC/ICT) domain [i.1]. A general overview of the evolution of energy storage te... |
a6afe51320dace98232cafb04d55714c | 103 553-3 | 2 References | |
a6afe51320dace98232cafb04d55714c | 103 553-3 | 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... |
a6afe51320dace98232cafb04d55714c | 103 553-3 | 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... |
a6afe51320dace98232cafb04d55714c | 103 553-3 | 3 Definition of terms, symbols and abbreviations | |
a6afe51320dace98232cafb04d55714c | 103 553-3 | 3.1 Terms | For the purposes of the present document, the terms given in IEC 60050-114 [i.2] and the following apply: electrochemical capacitor; supercapacitor: device that stores energy using a double layer in an electrochemical cell |
a6afe51320dace98232cafb04d55714c | 103 553-3 | 3.2 Symbols | Void. |
a6afe51320dace98232cafb04d55714c | 103 553-3 | 3.3 Abbreviations | For the purposes of the present document, the following abbreviations apply: AC Alternating Current CO Central Office DC Direct Current ELDC Electric Double Layer Capacitor FTTCab Fibre To The Cabinet FTTx Fibre To The x (x:= E = Exchange; B = Building; dP = distribution Point; H = Home) ICT Information Communication T... |
a6afe51320dace98232cafb04d55714c | 103 553-3 | 4 General introduction to supercapacitors | SCs store electrical energy in the form of electrical charges in two electrodes and an electric field between them. They have very low internal impedance and can be recharged in seconds. They are characterized by very high values of specific power (watts per kilogram) and are particularly suitable for peak power applic... |
a6afe51320dace98232cafb04d55714c | 103 553-3 | 5 Working principle | SCs are devices that are able to store more electrical energy than equivalent electrostatic capacitors. They use positive and negative metallic plates (generally cylindrically shaped) with very large active surface and very short distance between the plates (e.g. 0,1 nm). A SC consists of two electrodes, placed on alum... |
a6afe51320dace98232cafb04d55714c | 103 553-3 | 6 Supercapacitor technology and performance | Table 1 provides data on the main SC performance parameters. The nominal voltage of an SC cell is dependent on its construction and the type of electrolyte (higher for organic electrolytes and lower for aqueous ones). SC specific energy is very low in general, since these devices are mainly intended to be used against ... |
a6afe51320dace98232cafb04d55714c | 103 553-3 | 7 Applications | Applications for SC technology are related to Next Generation Access Networks (NGANs), using active loads spread outside traditional Central Offices (COs). In such a scenario, a TLC active load is generally supplied from the local public mains (in some cases, TLC loads are remotely powered from COs, with power backup p... |
a6afe51320dace98232cafb04d55714c | 103 553-3 | 8 Economic and environmental topics | Taking into account their expected long lifetime, SC represent a very low cost for complete cycles of charge and discharge compared with traditional electrochemical storage systems that are more commonly defined in cost per kilowatt hour. The most evident limit of SC is their very low autonomy (up to a few seconds, as ... |
6fe5939738939a1aa6c0db3e5ea25ae3 | 103 553-2 | 1 Scope | The present document contains the main requirements for evaluating appropriate innovative batteries for stationary use for powering ICT equipment in telecom sites, active network units and data centres or customer premises with standardized power interfaces in -48 V, up to 400 VDC or 12 V. Based on the general selectio... |
6fe5939738939a1aa6c0db3e5ea25ae3 | 103 553-2 | 2 References | |
6fe5939738939a1aa6c0db3e5ea25ae3 | 103 553-2 | 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... |
6fe5939738939a1aa6c0db3e5ea25ae3 | 103 553-2 | 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... |
6fe5939738939a1aa6c0db3e5ea25ae3 | 103 553-2 | 3 Definition of terms, symbols and abbreviations | |
6fe5939738939a1aa6c0db3e5ea25ae3 | 103 553-2 | 3.1 Terms | For the purposes of the present document, the following terms apply: Battery Management System or Unit (BMS, BMU): electronic system associated with a battery which monitors and/or manages its state, calculates secondary data, reports that data and/or controls its environment to influence the battery's performance and ... |
6fe5939738939a1aa6c0db3e5ea25ae3 | 103 553-2 | 3.2 Symbols | For the purposes of the present document, the following symbols apply: A ICT equipment power feeding interface of -48 VDC A3 ICT equipment power feeding interface of up to 400 VDC NOTE: As defined in Recommendation ITU-T L.1200 [i.2]. Cn Battery capacity in Ah in n hours discharge rate In Battery discharge current in n... |
6fe5939738939a1aa6c0db3e5ea25ae3 | 103 553-2 | 3.3 Abbreviations | For the purposes of the present document, the following abbreviations apply: AC Alternating Current AGM Absorbent Glass Mat Ah Ampere hour B Battery Block BMS Battery Management System BMU Battery Management Unit BMU (B) Battery Management Unit (Block) BMU (M) Battery Management Unit (Module) BMU (S) Battery Management... |
6fe5939738939a1aa6c0db3e5ea25ae3 | 103 553-2 | 4 Battery configurations and stationary applications | A battery is an assembly of cells contained in a more or less sealed jar made of: • negative and positive electrodes having active material on electric collectors; • separator between the electrode making galvanic insulation and containing ionic electrolyte; • electrolyte allowing the movement of ions making the electr... |
6fe5939738939a1aa6c0db3e5ea25ae3 | 103 553-2 | 5 Overview of battery technologies |
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