Iec 60645 5 2004

NORME INTERNATIONALE CEI IEC INTERNATIONAL STANDARD 60645 5 Première édition First edition 2004 11 Electroacoustique – Appareillage audiométrique – Partie 5 Instruments pour la mesure de l''''impédance o[.]

Système de mesure

Instruments can be designed to measure one or more components of ear impedance or admittance The International System of Units or its derived units should be utilized Measurement units must be clearly displayed on the front of the instrument.

A sinusoidal test signal with a frequency of 226 Hz is required for instruments in classes 1, 2, and 3 The actual frequency must deviate from its nominal value by no more than ±1% for class 1 instruments and by no more than ±2% for classes 2 and 3 instruments.

Total harmonic distortion must be less than 1% for Class 1 instruments and less than 3% for Class 2 and 3 instruments, as measured according to Article 6 If sinusoidal signals at frequencies other than 226 Hz are available, the same accuracy requirements for frequency and harmonic distortion apply.

When conducting tests that require frequency accuracy better than 1%, such as multi-frequency tympanometry, it is essential for the manufacturer to specify the frequency accuracy used for the test.

5.1.3 Niveau du signal de sonde

The levels of probe signals, whether sinusoidal at any frequency, wideband stationary, or non-stationary, should be set to ensure a relatively low probability of eliciting the stapedius reflex For a sinusoidal probe signal at 226 Hz, the acoustic pressure level, as measured in accordance with Article 6, must not exceed 90 dB.

This condition requires that the level be below the mean value, reduced by twice the standard deviation, of the threshold for the stapedius reflex in a sufficiently large population of young adults with normal otological status when the probe signal is used as the excitation signal for the stapedius reflex.

A population of 25 individuals is considered sufficient for the study According to ISO 389-1, a "normally hearing person" is defined as someone in good health, without any signs or symptoms of auditory impairment, free of earwax in the auditory canal, and who has not been excessively exposed to noise, ototoxic medications, or hereditary hearing loss in the past.

Pour un signal de sonde sinusọdal à 226 Hz, les étendues de mesure minimales, exprimées en volume équivalent d'air, doivent être: pour la tympanométrie dans le plan de mesure, de

0,2 cm 3 à 5 cm 3 ; pour la tympanométrie compensée, de 0 cm 3 à 2 cm 3 pour les instruments des classes 1 et 2, et de 0 cm 3 à 1,2 cm 3 pour les instruments de classe 3

The manufacturer must specify the sensitivity of the acoustic reflex measurement system and the stimulus level at which unexpected changes may occur in the display system, synchronized with the presentation of the stimulus that triggers the reflex.

The measurement of artifacts in a rigid-walled cavity does not necessarily reflect the actual conditions of the human ear Therefore, no specific method for measuring artifacts in human ears is defined.

LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU.

Instruments are designed to measure various components of aural impedance and admittance, utilizing SI units or derived SI units for accuracy The measurement units must be clearly displayed on the instrument's front panel.

Instruments of Types 1, 2, and 3 must provide a probe signal as a pure tone at a frequency of 226 Hz, with Type 1 instruments maintaining a frequency accuracy of less than ±1% and Types 2 and 3 less than ±2% Additionally, the total harmonic distortion should be under 1% for Type 1 and under 3% for Types 2 and 3, as specified in Clause 6 These requirements for frequency accuracy and harmonic distortion also apply to pure tones of frequencies other than 226 Hz.

When conducting tests like multi-frequency tympanometry that demand frequency accuracy exceeding 1%, it is essential for the manufacturer to specify the accuracy of the frequency utilized for that particular test.

For pure tones of any frequency, as well as stationary broadband and non-stationary probe signals, the sound level must be maintained at a level that minimizes the likelihood of triggering the middle ear muscle reflex Specifically, for a 226 Hz pure tone probe signal, the sound pressure level should not exceed 90 dB, in accordance with Clause 6.

The threshold level for the acoustic middle ear reflex should be set below the mean value minus two standard deviations, based on a sufficiently large population of otologically normal young adults, defined as at least 25 individuals According to ISO 389-1, an "otologically normal person" is someone in good health, free from any signs of ear disease, earwax obstruction, and without a history of excessive noise exposure, ototoxic drug use, or familial hearing loss.

For a 226 Hz probe tone, the minimum volume ranges for tympanometry measurements are as follows: measurement plane tympanometry ranges from 0.2 cm³ to 5 cm³, while meatus compensated tympanometry ranges from 0 cm³ to 2 cm³ for Types 1 and 2 instruments, and from 0 cm³ to 1.2 cm³ for Type 3 instruments.

Système pneumatique

Pour les instruments de classe 1, le domaine de pression relative doit être compris au minimum entre +200 daPa et −600 daPa

Pour les instruments de classe 2 et 3, le domaine de pression relative doit être compris au minimum entre +200 daPa et –200 daPa

The relative pressure limits measured in a 0.5 cm³ cavity must range between -800 daPa and +600 daPa, applicable to all instrument classes All instruments are required to have an automatic system that prevents sudden breaches of these limits.

5.2.3 Exactitude de l'indicateur de pression relative

For Class 1 instruments, the actual relative pressure produced in cavities ranging from 0.5 cm³ to 5 cm³ must not deviate from the indicated value by more than ±10 daPa or ±10%, taking the higher of these two values into account.

For Class 2 and 3 instruments, the actual relative pressure produced by the instrument in cavities ranging from 0.5 cm³ to 2 cm³ must not differ from the indicated value by more than ±10 daPa or ±15%, taking the higher of these two values into account.

Ces spécifications doivent être respectées pour les diverses vitesses disponibles de variation de la pression

5.2.4 Vitesse de variation de la pression

Class 1 instruments must provide the capability to adjust relative pressure (either increasing or decreasing) at a calibrated rate of 50 daPa/s ± 10 daPa/s, with measurements taken in cavities ranging from 0.5 cm³ to 5 cm³.

NOTE D'autres vitesses de variation peuvent également être offertes et spécifiées par le fabricant Cela s'applique également aux instruments des classes 2 et 3

The indicated and actual impedance/admittance values must differ by no more than ±5% or ±0.1 cm³ of the equivalent volume, or ±10⁻⁹ m³/Pa⋅s, depending on which is greater Additionally, the manufacturer is required to specify the deviation between static and dynamic modes of operation, along with the measurement method used.

The various temporal response parameters as defined in 10.1.6, measured in accordance with the procedure described in Annex C, shall not exceed 50 ms and overshoot and undershoot shall not exceed 10 %

NOTE At probe tone frequencies higher than 226 Hz, shorter response times are desirable

For instruments of Type 1, the range of relative pressure shall be at least from +200 daPa to

For Types 2 and 3, the range shall be at least from +200 daPa to –200 daPa

The relative pressure limits are set at -800 daPa and +600 daPa within a 0.5 cm³ cavity, applicable to all instrument types Each instrument must include a mechanism to prevent sudden pressure fluctuations that could breach these limits.

5.2.3 Accuracy of the relative pressure indicator

For Type 1 instruments, the actual relative pressure in cavities ranging from 0.5 cm³ to 5 cm³ must not deviate from the indicated relative pressure by more than ± 10 daPa or ± 10%, depending on which value is greater.

For Types 2 and 3 instruments, the relative pressure in cavities ranging from 0.5 cm³ to 2 cm³ must not deviate from the indicated relative pressure by more than ±10 daPa or ±15%, whichever is greater.

These specifications shall be met for the rates of changes of pressure provided

Instruments of Type 1 shall at least provide the possibility of changing the relative pressure

(increasing and/or decreasing) at a calibrated rate of 50 daPa/s ± 10 daPa/s, measured in cavities from 0,5 cm 3 to 5 cm 3

NOTE Other rates may also be provided and specified by the manufacturer This applies also to Types 2 and 3 instruments

Système d'excitation du réflexe acoustique

Les spécifications concernant le système d'excitation du réflexe acoustique sont celles qui figurent aux Articles 6, 8 et 10 de la CEI 60645-1:2001, aux exceptions près données ci- dessous

NOTE Si I'instrument est conỗu pour effectuer des mesures de seuil d'audition, il convient d'appliquer le texte intégral de la CEI 60645-1

When selecting sinusoidal signal frequencies for audiometry, it is essential to choose from standardized frequencies Class 1 instruments must provide excitation signals at 500 Hz, 1,000 Hz, 2,000 Hz, and 4,000 Hz for both contralateral and ipsilateral acoustic reflex measurements In contrast, Class 2 instruments are required to offer at least one of the frequencies 500 Hz, 1,000 Hz, or 2,000 Hz for ipsilateral acoustic reflex measurements Additionally, frequency deviations must not exceed +1% for Class 1 instruments and +3% for Class 2 instruments.

5.3.2.2 Distorsion harmonique des signaux sinusọdaux

For the specified frequencies and excitation levels in Table 2, the total harmonic distortion of the test signal must not exceed 2.5% for over-ear headphones and 5% for in-ear headphones at sound levels up to 110 dB within the frequency range of 500 Hz to 4,000 Hz At higher sound levels, the total harmonic distortion should not exceed 5% for over-ear headphones and 10% for in-ear or intra-ear headphones.

NOTE Si la sortie maximale d'un instrument correspond à un niveau d'audition inférieur à 110 dB, il convient d'appliquer l’exigence donnée aux niveaux maximaux de sortie de l'instrument

Si un signal de bruit aléatoire à large bande existe, son niveau spectral de pression acoustique, mesuré acoustiquement, doit être constant à ±5 dB près, par rapport au niveau à

Headphones should maintain a frequency response of 1,000 Hz within the range of 500 Hz to 4,000 Hz for over-ear models, with a tolerance of ±10 dB For in-ear or earbud headphones, this frequency response must also remain consistent within the same range.

S'il existe d'autres types de signaux d'excitation, le fabricant doit en décrire les caractéristiques

Instruments calibrated according to the specified standard must feature identification on the front face or excitation control The signal level control should be marked with the designation "Hearing Level" (HL) or an equivalent national designation The "zero" mark on the hearing level control must correspond to a transducer output signal that aligns with the reference values provided in the relevant sections of ISO 389 If different transducers or reference levels not indicated in ISO 389 are utilized, the manufacturer must specify the origins and bases of the reference signals, as well as the procedures and ear simulators or couplers to be used for calibration.

Les réglages de niveau maximaux doivent être indiqués pour chaque fréquence et pour le bruit à large bande

5.3 Acoustic reflex activating stimulus system

Specifications for the acoustic reflex activating stimulus system are as given in Clauses 6, 8 and 10 of IEC 60645-1:2001, with the exceptions specified below

NOTE If the instrument is designed to make hearing threshold measurements, the full text of IEC 60645-1 should apply

When fixed frequencies are provided, they shall be selected from the standard audiometric frequencies Type 1 instruments shall provide at least 500 Hz, 1 000 Hz, 2 000 Hz and

4 000 Hz stimuli for both contralateral and ipsilateral acoustic reflex stimulation and measurements; Type 2 instruments shall provide at least one of the frequencies 500 Hz,

1 000 Hz or 2 000 Hz stimuli for ipsilateral acoustic reflex stimulation and measurements The frequency shall not deviate by more than ±1 % for Type 1 instruments and ±3 % for Type 2 instruments

For the specified frequencies and stimulus levels in Table 2, total harmonic distortion must remain below 2.5% for supra-aural earphones and 5% for probe-type earphones at hearing levels up to 110 dB within the 500 Hz to 4,000 Hz frequency range At higher levels, the maximum allowable harmonic distortion increases to 5% for supra-aural earphones and 10% for insert or probe-type earphones.

NOTE If the maximum output for an instrument corresponds to a hearing level of less than 110 dB, the requirement given should apply to the maximum output levels of the instruments

A broad band random noise should exhibit a uniform spectrum pressure level, measured acoustically, within ±5 dB relative to the 1,000 Hz level for supra-aural earphones across the frequency range of 500 Hz to 4,000 Hz For insert or probe-type earphones, this uniformity should be maintained within ±10 dB over the same frequency range.

If other types of stimuli are provided, the manufacturer shall describe the characteristics of such stimuli

Instruments calibrated to this standard must be clearly marked on the front panel or the stimulus level control The signal level control should be labeled with the designation "Hearing."

The zero marking on the hearing level control must align with the output from the transducer that corresponds to the reference equivalent values specified in ISO 389 If different transducers or reference levels are utilized, the manufacturer must provide details on the origins and basis of these reference levels, along with the calibration procedures and the ear simulators or couplers employed Additionally, the maximum level setting for each frequency and for broad-band noise should be clearly indicated.

5.3.3.2 Domaines et intervalles de variation minimaux

For Class 1 instruments, the excitation level control must encompass at least the ranges specified in Table 2 The graduation steps for the excitation level should correspond to intervals of 5 dB or less.

Pour les instruments de classe 2, le niveau d'excitation peut être constant et doit être spécifié par le fabricant

Tableau 2 – Domaines minimaux de niveaux d'audition concernant les différents signaux d'excitation pour les instruments de classe 1

Domaine de niveau a d'audition pour les écouteurs supra-auraux en dB

Domaine de niveaux a d'audition pour les écouteurs à embouts ou intra-auriculaires en dB

50 – 100 50 – 80 50 – 90 a Dans le cas du bruit, les domaines peuvent également être spécifiés en tant que niveaux de pression acoustique

NOTE Chez les enfants, les niveaux des signaux d'excitation peuvent être supérieurs à ceux qui sont indiqués

5.3.3.3 Exactitude de la commande de niveau du signal d'excitation

The acoustic pressure level generated by the transducer must not deviate from the specified value by more than ±3 dB, regardless of the stimulus control position and for frequencies ranging from 500 Hz.

For supra-aural headphones, the frequency response should be within ±5 dB at 4,000 Hz for noise stimuli In the case of in-ear or earbud headphones, the variation must not exceed ±5 dB within the frequency range of 500 Hz.

5.3.4 Commande de présentation du signal d'excitation

Instruments must be equipped with a manual or automatic switch to present excitation signals The switch and associated circuits should be designed to ensure a response to the excitation signal rather than to transients or other noise.

5.3.4.2 Rapport signal sur bruit et rapport ôộmission-coupureằ

The signal-to-noise ratio for both switch positions must be at least 70 dB Additionally, the residual sound pressure level, measured with A-weighting when the switch is open, should not fall below 25 dB.

For instruments of Type 1, the stimulus level control shall cover at least the range listed in

Table 2 Readings of stimulus level shall be indicated in intervals of 5 dB or less

For instruments of Type 2, the stimulus level may be fixed and shall be specified by the manufacturer

Table 2 – Minimum hearing level ranges for different stimuli for Type 1 instruments

Stimulus 500 Hz to 2 000 Hz 4 000 Hz Noise

Hearing level range a for supra-aural earphones in dB 50 – 120 50 – 120 50 – 115

Hearing level range a for insert or probe-type earphones in dB 50 – 100 50 – 80 50 – 90 a In case of noise the range may alternatively be specified in terms of sound pressure levels

NOTE In children, stimulus levels in the ear canal may be higher than indicated on the stimulus level control

The sound pressure level generated by the stimulus transducer must remain within ±3 dB of the specified values across all settings of the stimulus level control for frequencies between 500 Hz and 4,000 Hz For noise stimuli, this variation should not exceed ±5 dB when using supra-aural earphones Additionally, for insert or probe-type earphones, the sound pressure level should not differ by more than ±5 dB within the 500 Hz to 2,000 Hz range and ±10 dB at 4,000 Hz.

Instruments must include a manual or automatic switch to deliver stimulus signals, ensuring that the switch and its circuit are designed to respond specifically to the stimulus rather than to transients or background noise.

5.3.4.2 On-off and signal-to-noise ratios

Généralités

Les procédures suivantes doivent être utilisées pour s'assurer que les instruments sont conformes aux spécifications données dans la présente norme On donne à l'Annexe A des indications concernant l'étalonnage périodique.

Système de mesure de l'impédance ou de l'admittance

The probe must be sequentially connected to a series of rigid-walled cavities in a sealed manner The quantity, shapes, and cavities must adhere to the specifications outlined in Article 7 Testing should be conducted at a probe frequency of 226 Hz.

The measurement of impedance or admittance should be conducted at ambient pressure, taking into account a correction for the test cavity based on temperature and atmospheric pressure, as outlined in formula 3.10.

For other types of probe signals, it is the manufacturer's responsibility to specify appropriate measuring devices that represent the extreme values of the measurement range, as well as at least one intermediate value.

Signal de sonde

6.3.1 Spectre du signal de sonde

The frequency of a sinusoidal probe signal must be measured either acoustically or electrically The measurement uncertainty should be less than ±1 Hz or ±0.5%, taking the higher of these two values into account.

For non-sinusoidal probe signals, their spectrum must be measured by securely coupling the probe to a coupler compliant with IEC 60126, ensuring that the connector is installed according to the manufacturer's instructions.

5.3.4.3 Rise-fall times a) On-condition

When the stimulus presentation control is set to the ON condition, the sound pressure level generated by the transducer must reach –1 dB relative to its final steady state level within 100 ms Additionally, the transition of the sound pressure level from –20 dB to –1 dB must occur progressively and should not take less than the specified time.

The sound pressure level generated by the transducer must not exceed 1 dB above its steady state level in the ON position during the rise or decay of the tone, specifically within a duration of 5 ms.

When the stimulus presentation control is switched to the OFF position, the sound pressure level produced by the transducer must decrease to –20 dB relative to its steady state level in the ON position within 100 ms Additionally, the transition from –1 dB to –20 dB must occur progressively and take no less than 5 ms.

If a pulsed stimulus signal is used, the manufacturer shall specify the temporal characteristics of the signal

6 Demonstration of conformity with specifications

The following procedures are to be used for ensuring that the instruments meet the specifications given in this standard Guidelines for routine calibration are described in

The probe shall be connected in turn to a set of hard-walled cavities, making an air-tight seal

The number, shapes and cavities shall be as specified in Clause 7 Tests shall be carried out at a probe frequency of 226 Hz

The impedance/admittance indicator must be read with the pressure adjusted to ambient levels, and the test cavity should be corrected for temperature and barometric air pressure according to the formula specified in section 3.10.

NOTE For other types of probe signal the manufacturer should specify suitable test objects, which represent the extreme parts of the measurement range and at least one intermediate value

The frequency of a pure tone probe signal shall be measured acoustically or electrically; the measuring instrument uncertainty shall be less than ±1 Hz or ±0,5 %, whichever is greater

For non-pure tone probe signals, the spectrum must be measured by applying the probe with an air-tight seal on an acoustic coupler, following IEC 60126 standards, and positioning the ear tip as per the manufacturer's instructions.

6.3.2 Niveau du signal de sonde et distorsion harmonique

The level and harmonic distortion of the probe signal must be measured by securely coupling the probe to a coupler that complies with IEC 60126 standards, with the connector positioned according to the provided instructions (see 6.3.1).

6.4.1 Exactitude de l'indicateur de la pression de l'air

Air pressure must be checked by securely coupling the probe to a manometric measurement system with an uncertainty not exceeding ±2% or ±3 daPa, considering the higher of the two values Additionally, the volume displacement of the membrane should be less than 0.2 cm³ for the measured range At ambient pressure, the manometric measurement system should contain an air volume of 0.5 cm³ for measuring the specified maximum values according to section 5.2.2, and a volume of 5 cm³ for measuring the minimum pressure values in compliance with section 5.2.1.

NOTE 1 Un déplacement en volume de la membrane de 0,2 cm 3 correspond au changement de volume moyen du conduit auditif pendant une tympanométrie

NOTE 2 La petite cavité d'un volume de 0,5 cm 3 peut être obtenue par exemple en utilisant des transducteurs de pression pouvant être remplis partiellement d'un fluide (huile, eau)

The rate of change of air pressure must be measured by securely connecting the probe to a manometric measurement system, ensuring that the uncertainty does not exceed ±2% or ±3 daPa, with the higher value being considered Additionally, the membrane should have a volume displacement of less than 0.2 cm³.

La réponse de l'instrument de mesure doit être au moins trois fois plus rapide que les vitesses de changement de pression disponibles sur l'instrument à vérifier

Les mesures doivent être effectuées avec des volumes de 0,5 cm 3 et de 2 cm 3 remplis d'air et couplés au système de mesure manométrique

6.4.3 Exactitude de l'indicateur de pression de l'air ou du signal de sortie électrique analogique et/ou de l'enregistreur

The accuracy of the air pressure indicator or the analog electrical output signal, as well as the recorder, must be verified using the same pressure measurement system specified in sections 6.4.1 and 6.4.2 Measurements should be conducted with volumes of 0.5 cm³ and 2 cm³, utilizing the rate of change provided by the testing instrument.

Signaux d'excitation du réflexe acoustique

Harmonic distortion measurements, signal excitation level accuracy, and the emission-to-cutoff ratio must be conducted for supra-aural headphones using an acoustic coupler or an artificial ear For in-ear headphones, these measurements should be performed by coupling the probe to a coupler.

(CEI 60126), l'embout de la sonde étant placé conformément aux instructions (voir 6.3.1)

NOTE Lorsque l'étalonnage des signaux d'excitation ipsilatéraux est effectué à l'aide d'un coupleur de 2 cm3

According to CEI 60126, it is important to note that nominal levels (sound pressure level and/or hearing level based on the signal excitation control device) may vary depending on the volume of the ear canal being tested Manufacturers should specify these variations for all frequencies of the provided sinusoidal sounds, particularly for equivalent volume readings of 0.5 cm³ and 1.0 cm³.

6.3.2 Probe signal level and harmonic distortion

The probe signal level and harmonic distortion of the probe tone must be measured using an acoustic coupler in accordance with IEC 60126 The probe should be securely coupled with an airtight seal, and the ear tip must be positioned as per the provided instructions (refer to section 6.3.1).

6.4.1 Accuracy of air pressure indicator

To ensure accurate air pressure measurements, the probe must be applied with an air-tight seal to a pressure measuring system that has a maximum measurement uncertainty of ±2% or ±3 daPa, whichever is greater Additionally, the system should feature a membrane volume displacement of less than 0.2 cm³ within the measured range At ambient pressure, the pressure measuring system is required to have an air-filled volume of 0.5 cm³ to effectively measure the maximum pressure limits specified.

5.2.2 and a volume of 5 cm 3 for the measurement of the minimum pressure limits according to 5.2.1

NOTE 1 A membrane volume displacement of 0,2 cm 3 corresponds to the average volume change of the external auditory meatus during tympanometry

NOTE 2 The small cavity volume of 0,5 cm 3 can be attained, for example, by using pressure transducers which can be partly filled with fluid (oil, water)

6.4.2 Rate of change of pressure

To measure the rate of change in air pressure, a probe with an air-tight seal must be applied to a pressure measuring system that has a maximum measurement uncertainty of ±2% or ±3 daPa, whichever is greater, and a membrane volume displacement of less than 0.2 cm³.

The response of the measuring instrument shall be at least three times faster than the rate provided on the instrument to be tested

Measurements shall be made with air-filled volumes of 0,5 cm 3 and 2 cm 3 coupled to the pressure measuring system

6.4.3 Accuracy of air pressure indicator or analogue electrical output and/or recorder

The accuracy of the air pressure indicator and recorder must be verified using the same pressure measuring system outlined in sections 6.4.1 and 6.4.2 This verification involves conducting measurements with air-filled volumes of 0.5 cm³ and 2 cm³ at the rates specified by the tested instrument.

6.5 Acoustic reflex activating stimulus signals

Measurements of harmonic distortion, stimulus level control accuracy, and ON/OFF ratio for supra-aural earphones will be conducted using an acoustic coupler or an artificial ear as suitable For probe earphones, these measurements will be taken with the probe connected to an acoustic coupler (IEC 60126), ensuring the probe tip is positioned according to specified instructions.

When calibrating ipsilateral stimuli on a 2 cm³ coupler (IEC 60126), it is important to recognize that nominal levels, such as sound pressure level (SPL) and hearing level (HL), may differ based on the volume of the ear canal being tested Manufacturers should provide specifications for these variations across all pure tone frequencies, particularly for equivalent volume readings of 0.5 cm³ and 1.0 cm³.

Valeurs maximales autorisées des incertitudes élargies de mesure

Table 3 outlines the maximum allowable values for expanded measurement uncertainties at a 95% confidence level, corresponding to an expansion factor of k = 2, for measurements conducted in accordance with this standard, as stated in the publication.

ISO/CEI Guide pour l'expression de l’incertitude de mesure On donne une série de valeurs pour U max concernant les mesures fondamentales pour l'approbation du modèle

The expanded measurement uncertainties listed in Table 3 represent the maximum allowable values for ensuring compliance with the requirements of this international standard If the actual expanded uncertainty of a measurement conducted by the testing laboratory exceeds the maximum allowable value specified in Table 3, that measurement must not be used to verify compliance with the standard's requirements.

Tableau 3 – Valeurs maximales tolérées des incertitudes élargies de mesure U max pour les mesures fondamentales

Niveau de pression acoustique bruit à large bande

Linéarité de la commande du niveau d'audition

Temps de montée et de descente (ms) 5.3.4.3, 10.3.3 1 ms

Pression de l'air 5.2.1, 5.2.2, 5.2.3, 6.4.1, 6.4.3 2 % ou 3 daPa

Vitesse de variation de la pression de l’air

6.6 Maximum permitted expanded uncertainty of measurements

Table 3 outlines the maximum allowable expanded uncertainty for a 95% probability, corresponding to a coverage factor of k = 2, in relation to the measurements conducted under this standard, as per the ISO/IEC Guide for expressing measurement uncertainty.

One set of values for U max is given for basic type approval measurements

The maximum permitted expanded uncertainties for measurements, as outlined in Table 3, are essential for demonstrating compliance with this International Standard If a test laboratory's actual expanded uncertainty surpasses the values specified in Table 3, the measurement cannot be utilized to prove adherence to the standard's requirements.

Table 3 – Values of U max for basic measurements

Sound pressure level, 226 Hz to 4 000 Hz 5.1.3, 6.3.2, 10.1.4.2, 10.3.2 0,7 dB

Sound pressure level, broad band noise 5.3.2.3, 10.3.2 1,2 dB

Linearity of hearing level control 5.3.3.2, 5.3.3.3, 6.5, 10.3.2 0,1 dB

Rise and fall time (ms) 5.3.4.3, 10.3.3 1 ms

Rate of air pressure change 5.2.4, 6.4.2 2 % or 3 daPa

Généralités

For the calibration of instruments measuring equivalent volume and relative pressure, the manufacturer must provide at least three calibration cavities for class 1 instruments and two calibration cavities for classes 2 and 3 instruments This standard does not recommend a calibration method for other components of acoustic impedance or admittance The manufacturer is required to specify the method used for calibrating such components.

Dimensions des cavités d'étalonnage

Les cavités d'étalonnage doivent avoir une forme cylindrique dont la hauteur est d'environ une à trois fois le diamètre Pour la classe 1, les trois cavités doivent avoir des volumes de

For classes 2 and 3, the two cavities must have volumes of 0.5 cm³ and either 1.0 cm³ or a volume close to the maximum measurement limit of the instrument If additional cavities are provided, their volumes should be selected from the following values: 1.0 cm³, 1.5 cm³, 2.5 cm³, 3.0 cm³, or 3.5 cm³.

4,0 cm 3 ; 4,5 cm 3 Les tolérances sur les volumes doivent être de ±2 % ou 0,05 cm 3 , en considérant la plus élevée de ces deux valeurs.

Matériau des parois des cavités d'étalonnage

Les cavités d'étalonnage doivent présenter des surfaces dures et non poreuses, et être fabriquées de préférence en métal ou dans une matière plastique suffisamment dure et stable.

Couplage de la sonde à une cavité d'étalonnage

Les cavitộs et la sonde doivent ờtre conỗues de telle sorte que, lorsqu'elles sont couplộes de faỗon ộtanche, le volume de la cavitộ corresponde à la valeur indiquộe

Marquage

L'instrument doit comporter les marquages suivants: nom du fabricant, classe (conformément à l'Article 4), modèle, numéro de série et identification du ou des transducteurs utilisés.

Notice d'emploi

An instruction manual must accompany each instrument, detailing all characteristics and specifications in accordance with the current standard The manufacturer should specifically reference Articles 5, 6, and 10 to ensure proper calibration of the instrument.

Exigences concernant la sécurité

Les instruments doivent satisfaire aux exigences de la CEI concernant la sécurité spécifiées dans la CEI 60601-1 et dans la CEI 60601-1-4

To ensure accurate calibration of equivalent volume and pressure instruments, manufacturers must provide a minimum of three calibration cavities for Type 1 instruments and two for Types 2 and 3 This standard does not outline calibration procedures for other components related to acoustic impedance or admittance, and manufacturers are required to specify the calibration techniques used for these components.

Calibration cavities must be cylindrical, with a length-to-diameter ratio between one and three For Type 1, the three cavities should have volumes of 0.5 cm³, 2.0 cm³, and 5.0 cm³ Types 2 and 3 require two cavities with volumes of 0.5 cm³ and an additional specified volume.

1,0 cm 3 or a volume near the maximum limit of the measurement range of the instrument

Additional cavities, when provided, shall have volumes from: 1,0 cm 3 ; 1,5 cm 3 ; 2,5 cm 3 ;

3,0 cm 3 ; 3,5 cm 3 ; 4,0 cm 3 ; 4,5 cm 3 Volume tolerances shall be ±2 % or 0,05 cm 3 , whichever is greater

7.3 Material of calibration cavity walls

The calibration cavities shall have hard, non-porous surfaces, preferably of metal or sufficiently hard and stable plastic

7.4 Connection of probe to a calibration cavity

The cavities and the probe shall be designed in such a way that, when connected with an air- tight fit, the indicated volume of the cavity shall be obtained

The instrument must display the manufacturer's name, the type specified in Clause 4, the model, serial number, and the identification of the transducer(s) used.

An instruction manual shall be supplied with each instrument In this manual the manufacturer shall specify all characteristics as required by this standard, with special reference to

Clauses 5, 6 and 10 to ensure proper calibration of the instrument

Instruments shall conform to IEC safety requirements specified in IEC 60601-1 and

8.3.2 Immunité aux perturbations conduites et aux champs radioélectriques

8.3.2.1 Les instruments doivent satisfaire aux exigences de la CEI 60601-1-2 pour la compatibilité électromagnétique (CEM)

8.3.2.2 Pendant tout essai d’immunité concernant la compatibilité électromagnétique et à la suite de ces essais, les conditions suivantes doivent être remplies:

In electromagnetic compatibility testing conditions, unwanted sounds emitted by any airborne transducer must not exceed an auditory level of 80 dB The IEC 60645-1:2001, section 13.3, outlines the methods for verifying compliance.

Durée de préchauffage

The maximum preheating duration must be specified by the manufacturer and should not exceed 10 minutes when the instrument has been stored at room temperature The requirements for the characteristics outlined in this standard must be met after the specified preheating time and any adjustments made according to the manufacturer's instructions.

Variation de la tension d'alimentation et conditions d'environnement

Specifications must be met for any long-term variation under the most unfavorable combination of supply voltage and frequency, within limits of ±10% for voltage or ±5% for frequency In the event of a rapid fluctuation in the power supply that impacts the instrument's performance, it must revert to a safe operating mode that does not endanger the subject being examined.

The manufacturer must define the battery voltage limits within which the specifications must be met, and an appropriate indicator should be in place to ensure that the battery voltages remain within the specified limits.

8.5.3 Domaines de fonctionnement pour la température et l'humidité

The specifications must be met for any combination of temperatures ranging from +15 °C to +35 °C and relative humidity levels between 30% and 90% Additionally, for the test cavity, adjustments for temperature and atmospheric pressure should be considered as outlined in section 10.1.1.

Rayonnements et signaux acoustiques indésirables

8.6.1 Sons indésirables émis par la sonde

Unwanted sounds, regardless of their source, such as noise from the pneumatic system, should not impact the accuracy of measurements This must be verified using a 0.5 cm³ test cavity under both dynamic and static conditions.

When the excitation signal for the acoustic reflex is removed, the acoustic pressure level of the noise emitted by the devices, including the necessary recording equipment provided by the manufacturer, must not exceed 50 dB when measured at a distance of 1 meter from any part of the equipment, using A-weighting and S-time weighting characteristics during the measurements.

8.3.2 Immunity to power and radio frequency fields

8.3.2.1 Instruments shall meet the requirements of IEC 60601-1-2 for electromagnetic compatibility (EMC)

8.3.2.2 During, and as a result of any EMC immunity testing, the following condition shall be met:

– under the EMC test conditions, the unwanted sound from any air conduction transducer shall not exceed a hearing level corresponding to 80 dB Subclause 13.3 of

IEC 60645-1:2001, gives methods for showing conformity

The maximum warm-up time shall be specified by the manufacturer and shall not exceed

After a warm-up period of 10 minutes at room temperature, the unit must meet the performance requirements outlined in the standard, following any necessary setup adjustments as specified by the manufacturer.

8.5 Supply variation and environmental conditions

The specifications require that any long-term deviation in supply voltage or mains frequency remains within ±10% for voltage and ±5% for frequency In the event of short-term line variations that impact instrument performance, the instrument must switch to a safe mode to protect the subject being tested.

The manufacturer must specify the acceptable battery voltage limits to ensure compliance with the specifications, and an appropriate indicator should be included to verify that the battery voltages remain within these defined limits.

8.5.3 Temperature and humidity operating range

The specifications shall be met for all combinations of values of temperature within the range

+15 °C to +35 °C and relative humidity within the range 30 % to 90 %, with the test cavity corrected for temperature and barometric air pressure as stated in 10.1.1

8.6 Unwanted acoustic signals and radiation

Extraneous sounds, including noise from the pneumatic system, must not interfere with measurement accuracy Verification of this requirement is essential.

0,5 cm 3 test cavity under dynamic as well as static conditions

When the acoustic reflex activation stimulus is turned off, the sound pressure level, frequency-weighted A, and time-weighted S of the noise emitted from the instrumentation, including essential recording devices supplied by the manufacturer, were measured at a specified distance.

1 m from any part of the instrumentation, shall not exceed 50 dB during measurement

9 Symboles utilisés et présentation des données concernant l'impédance ou l'admittance acoustique

Symboles pour l'indication des grandeurs mesurées

Représentation d'un tympanogramme

L'axe horizontal doit indiquer la pression relative en daPa L'échelle doit être linéaire La valeur 0 daPa doit correspondre à la pression atmosphérique

For the representation of admittance, conductance, susceptance, or equivalent volume, a linear scale is required In contrast, for impedance, resistance, or reactance, a nonlinear scale may be employed, necessitating the inversion of the increasing magnitude axis compared to the linear scale.

For a probe signal frequency of 226 Hz, the scale ratio should be such that 300 daPa on the relative pressure scale (horizontal axis) is represented by a length of 1 cm on the equivalent volume scale (vertical axis), or by the corresponding value related to acoustic impedance Additional scale ratios can be provided.

On doit spécifier l'oreille dans laquelle la sonde a été introduite.

Représentation de l'essai de réflexe acoustique

9.3.1 Présentation des données analogiques ou numériques

La présentation des données analogiques ou numériques doit être exprimée en unités de volume équivalent, ou comme il est spécifié en 5.1.1

9 Symbols, forms and formats for acoustic impedance/admittance data

9.1 Symbols for indicating measured quantities

The horizontal axis shall indicate the relative pressure in daPa The scale on this axis shall be linear A scale value of 0 daPa shall represent atmospheric pressure

For admittance, conductance, susceptance or equivalent volume, the scale shall be linear

For measuring impedance, resistance, or reactance, it is advisable to utilize a non-linear scale, with the direction of the scale inverted compared to a linear scale to reflect increasing magnitude.

For a probe tone frequency of 226 Hz, the scale should be adjusted so that 300 daPa on the relative pressure scale corresponds to a length of 1 cm³ on the equivalent volume scale, reflecting the related value for acoustic impedance.

Additional scale proportions may be provided

Provision shall be made for specifying into which ear the probe was inserted

The analogue or digital readout shall be calibrated in equivalent volume units or as specified in 5.1.1

9.3.2.1 L'échelle horizontale doit indiquer le temps en secondes

9.3.2.2 L'échelle verticale doit être graduée en unités de volume équivalent ou en valeurs d'impédance ou d'admittance acoustiques, selon la grandeur mesurée

9.3.3 Oreille soumise au signal d'excitation

On doit spécifier dans quelle oreille la sonde a été introduite et à quelle oreille le signal d'excitation acoustique a été appliqué (c'est-à-dire excitation ipsilatérale ou contro-latérale).

Représentation des essais concernant la trompe d'Eustache

Certain instruments can be utilized to gain insights into the functioning of the Eustachian tube, whether the eardrum is intact or perforated It is advisable to adopt the following representation for these tests.

L'axe horizontal doit indiquer le temps en secondes

L'axe vertical doit indiquer la pression d'air en daPa L'échelle doit être linéaire et doit permettre de représenter des pressions relatives positives ou négatives par rapport à la pression atmosphérique

NOTE Si l'on dispose de documents pré-imprimés, il convient que leur exactitude satisfasse aux exigences de la présente norme

10 Caractéristiques complémentaires à spécifier par le fabricant

Système de mesure de l'impédance ou de l'admittance aurale

10.1.1 Influence de la température ambiante et de la pression atmosphérique

The influence of ambient temperature and atmospheric pressure is a critical factor for impedance measurements Manufacturers must provide users with data that enables proper calibration of the device using the appropriate test cavities, as specified in Article 7.

Le fabricant doit fournir des informations particulières concernant les dimensions de la sonde et des canalisations associées qui peuvent être utilisées entre la sonde et l'instrument

NOTE Il serait souhaitable de disposer de sondes de caractéristiques et de dimensions normalisées; cependant, la recherche actuelle n'impose pas d'exigences spécifiques sur les dimensions

The manufacturer must provide information on the recommended procedures for cleaning, maintaining, and replacing the probe, associated piping, and probe tips Additionally, they should specify the frequency at which these procedures should be repeated.

9.3.2.1 The horizontal scale shall indicate time in seconds

9.3.2.2 The vertical scale shall be calibrated in equivalent volume units or acoustic impedance/ admittance quantities as measured

Provision shall be made for specifying into which ear the probe was inserted and to which ear the acoustic stimuli were applied (i.e ipsilateral or contralateral)

9.4 Eustachian tube function test format

To assess the function of the Eustachian tube, instruments can be utilized regardless of whether the tympanic membrane is intact or perforated It is advisable to follow a specific format for these tests to ensure accurate results.

The horizontal axis shall indicate time in seconds

The vertical axis shall indicate air pressure in daPa The scale on this axis shall be linear, with provision for both positive and negative pressures relative to atmospheric pressure

NOTE Where printouts are available, their accuracy should meet the requirements of the standard

10 Additional characteristics to be specified by the manufacturer

10.1 Aural impedance/admittance measurement system

10.1.1 Influence of ambient temperature and atmospheric pressure

Ambient temperature and atmospheric pressure significantly impact impedance measurements It is essential for manufacturers to supply data that allows users to achieve accurate calibration using the specified test cavities outlined in Clause 7.

The manufacturer shall provide specific information regarding the dimensions of the probe and any associated tubing that might be used between the probe and the instrument

NOTE It would be desirable to have probes of standardised features and dimensions; however, current research does not support any specific dimension requirements

The manufacturer will supply information on the recommended cleaning, maintenance, and replacement procedures for the probe, ear tips, and associated tubing, along with guidance on the frequency of these procedures.

10.1.4 Caractéristiques du signal de sonde

Pour les instruments des classes 1 à 3, la fréquence du signal de sonde doit être de 226 Hz

Le fabricant peut fournir des fréquences supplémentaires pourvu que les tolérances spécifiées en 5.1.2 soient respectées

NOTE L'admittance acoustique d'une cavité de volume égal à 1 cm 3 , remplie d'air dans les conditions atmosphériques normalisées (pression atmosphérique de 101,3 kPa, température de 20 °C), est égale à

10 –8 m 3 /Pa ⋅ s pour une fréquence de 226 Hz

The manufacturer must specify the acoustic pressure level of the probe signals as outlined in section 5.1.3, including the tolerances and variations of this level based on the load volume, as well as the conditions under which these measurements were taken.

10.1.4.3 Signaux de sonde non stationnaires ou impulsionnels

For non-stationary probe signals, the manufacturer must specify their temporal and spectral characteristics Additionally, the manufacturer should outline the measurement procedures for these temporal and spectral characteristics, along with their tolerances.

10.1.5 Indicateur d'impédance ou d'admittance acoustiques

Le fabricant doit spécifier les unités SI affichées, les étendues de mesure et leurs tolérances, ainsi que leur variation en fonction de la pression atmosphérique

For instruments measuring the temporal characteristics of the acoustic reflex, key parameters such as initial latency, rise time, terminal latency, fall time, and overshoots (both positive and negative) are essential for accurate measurements Manufacturers must specify the electrical output signal or any corresponding recording system related to these characteristics for all classes of impedance or admittance measurement instruments Additionally, tolerances for each of these characteristics should be provided, following the procedures outlined in Annex C.

10.2.1 Système de commande de la pression

The range of pressure variation relative to atmospheric pressure must be clearly defined Additionally, if an automatic pressure variation system is in place, the rates of variation should also be specified.

The pressure in the ear canal should be displayed either in analog or digital format It is essential to specify the accuracy of the display device, along with its limitations related to atmospheric pressure and altitude above sea level.

For instruments of Types 1 to 3 the probe signal frequency shall be 226 Hz The manufacturer may supply any additional probe tone frequency provided that tolerances stated in 5.1.2 are met

NOTE The acoustic admittance of an air-filled cavity of volume 1 cm 3 at standard atmospheric conditions

(atmospheric pressure 101,3 kPa, temperature 20 °C) is 10 –8 m 3 /Pa ⋅ s at a frequency of 226 Hz

The manufacturer must define the sound pressure level for the probe signals according to section 5.1.3, including its tolerances and variations based on loading volume, along with the conditions under which these measurements were conducted.

10.1.4.3 Non-stationary/pulsed probe signals

Manufacturers must provide the temporal and spectral characteristics of non-stationary probe signals, along with the procedures for measuring these characteristics and their associated tolerances.

The manufacturer shall specify the SI units displayed, the ranges and their tolerances as well as their dependence on barometric pressure

To accurately measure the temporal characteristics of the acoustic reflex, it is essential to consider initial latency, rise time, terminal latency, fall time, and overshoot-undershoot Manufacturers must specify these characteristics for the electrical output and recording systems of all impedance/admittance instruments Additionally, tolerances for each characteristic should be provided by the manufacturer, following the procedures detailed in Annex C.

The range of pressure variation relative to atmospheric (ambient) pressure shall be specified

When automatic change of pressure is provided, the rates of change shall also be specified

The pressure in the external acoustic meatus shall be indicated by analogue or digital display

The accuracy of the display shall be specified as well as its limitations with regard to atmospheric pressure and altitude above sea level

Système d'excitation du réflexe acoustique

Le fabricant doit spécifier les types de signaux d'excitation disponibles

For acoustic excitation signals, the manufacturer must specify the frequencies of the sinusoidal signals, their tolerances, and the maximum harmonic distortion, as well as the types of noise used, along with their characteristics and tolerances.

Pour les signaux d'excitation non acoustiques, le fabricant doit spécifier les types de stimuli et décrire leurs caractéristiques et leurs tolérances

10.3.2 Commande de niveau du signal d'excitation

The manufacturer must specify the accuracy, range of variation, and steps for the stimulus level control, as well as the maximum output levels for each available acoustic signal and any other relevant features.

10.3.3 Commande de présentation du signal d'excitation

For acoustic excitation signals, the manufacturer must specify the level ratios for the "emission" and "cut-off" positions, the rise and fall times, and the A-weighted residual sound pressure level in the "off" position If a pulse signal is utilized, the manufacturer must detail its temporal characteristics along with their tolerances.

Pour les signaux d'excitation non acoustiques, le fabricant doit spécifier d'une manière similaire les caractéristiques de la commande de présentation du stimulus, selon leur applicabilité.

Measuring system

Instruments are designed to measure various components of aural impedance and admittance, utilizing SI units or derived SI units for accuracy The measurement units must be clearly displayed on the instrument's front panel.

Instruments of Types 1, 2, and 3 will provide a probe signal as a pure tone at a frequency of 226 Hz, with Type 1 instruments maintaining an actual frequency within ±1% of the nominal frequency, while Types 2 and 3 must remain within ±2% Additionally, the total harmonic distortion must be less than 1% for Type 1 instruments and under 3% for Types 2 and 3, as specified in Clause 6 These requirements for frequency accuracy and harmonic distortion also apply to pure tones of frequencies other than 226 Hz.

When conducting tests like multi-frequency tympanometry that demand frequency accuracy exceeding 1%, it is essential for the manufacturer to specify the accuracy of the frequency utilized in the test.

For pure tones of any frequency, as well as stationary broadband and non-stationary probe signals, the sound level must be maintained at a level that minimizes the likelihood of triggering the middle ear muscle reflex Specifically, for a 226 Hz pure tone probe signal, the sound pressure level should not exceed 90 dB, in accordance with Clause 6.

To establish the threshold level for the acoustic middle ear reflex, it is necessary to use a value that is less than the mean minus two standard deviations, based on a sufficiently large population of otologically normal young adults A sample size of 25 individuals is deemed adequate for this purpose According to ISO 389-1, an "otologically normal person" is defined as someone in good health, free from any signs or symptoms of ear disease, without obstructing earwax, and lacking a history of excessive noise exposure, ototoxic drug use, or familial hearing loss.

For a 226 Hz probe tone, the minimum volume ranges for tympanometry measurements are as follows: measurement plane tympanometry ranges from 0.2 cm³ to 5 cm³, while meatus compensated tympanometry ranges from 0 cm³ to 2 cm³ for Types 1 and 2 instruments, and from 0 cm³ to 1.2 cm³ for Type 3 instruments.

The manufacturer must specify the sensitivity of the acoustic reflex measuring system and identify the stimulus level at which potential artefactual changes may occur in the measurement display, coinciding with the presentation of the reflex-eliciting stimulus.

The measurement of artifacts in hard-walled cavities may not accurately reflect the conditions found in human ears Consequently, there is no established method for measuring artifacts specifically within human ears.

The difference between the indicated and actual values of impedance or admittance must not exceed ±5% or ±0.1 cm³ for equivalent volume, or ±10⁻⁹ m³/Pa⋅s, considering the higher of these values The manufacturer is required to specify the difference between static and dynamic operating modes, as well as the measurement method used.

The various parameters of the time response, as defined in section 10.1.6 and measured according to the procedure outlined in Appendix C, must not exceed 50 ms, with deviations above or below this threshold not exceeding 10%.

NOTE Pour des signaux de sonde de fréquence supérieure à 226 Hz, des temps de réponse plus courts sont souhaitables

Pour les instruments de classe 1, le domaine de pression relative doit être compris au minimum entre +200 daPa et −600 daPa

Pour les instruments de classe 2 et 3, le domaine de pression relative doit être compris au minimum entre +200 daPa et –200 daPa

The relative pressure limits measured in a 0.5 cm³ cavity must range between -800 daPa and +600 daPa, applicable to all instrument classes All instruments are required to have an automatic system that prevents sudden changes or exceedance of these limits.

5.2.3 Exactitude de l'indicateur de pression relative

For Class 1 instruments, the actual relative pressure generated within cavities ranging from 0.5 cm³ to 5 cm³ must not deviate from the indicated value by more than ±10 daPa or ±10%, taking the higher of these two values into account.

For Class 2 and 3 instruments, the actual relative pressure produced by the instrument in cavities ranging from 0.5 cm³ to 2 cm³ must not differ from the indicated value by more than ±10 daPa or ±15%, taking the higher of these two values into account.

Ces spécifications doivent être respectées pour les diverses vitesses disponibles de variation de la pression

Class 1 instruments must provide the capability to adjust relative pressure (either increasing or decreasing) at a calibrated rate of 50 daPa/s ± 10 daPa/s, with measurements taken in cavities ranging from 0.5 cm³ to 5 cm³.

NOTE D'autres vitesses de variation peuvent également être offertes et spécifiées par le fabricant Cela s'applique également aux instruments des classes 2 et 3

The discrepancy between indicated and actual impedance or admittance values must not surpass ±5% or ±0.1 cm³ of the equivalent volume, or ±10⁻⁹ m³/Pa⋅s, depending on which is greater Additionally, the manufacturer is required to specify the deviation between static and dynamic modes of operation, along with the measurement method used.

The various temporal response parameters as defined in 10.1.6, measured in accordance with the procedure described in Annex C, shall not exceed 50 ms and overshoot and undershoot shall not exceed 10 %

NOTE At probe tone frequencies higher than 226 Hz, shorter response times are desirable.

Tiêu đề	Part 5: Instruments for the measurement of aural acoustic impedance/admittance
Chuyên ngành	Electroacoustics
Thể loại	Standards document
Năm xuất bản	2004

Định dạng
Số trang	66
Dung lượng	0,92 MB