Communication assembly, aircraft provided with a communication assembly, and method for preventing interference in communication

Abstract

A communication assembly (1) for avoiding interference due to oxygen flow noise comprising: a) a breathing mask (10) comprising: a main body (14) having a face shell (11) with a breathing cavity (12) and a regulator (16) delivering breathing gas, b) a microphone (22) configured to capture sound signals in said breathing cavity, c) a test button (8) for supplying breathing gas to said breathing cavity, d) an attenuation device (34); e) a sound monitoring system (25), f) a controller (32) configured to cause said attenuation device to operate in an active mode when detecting an airflow noise passing through said breathing cavity (12) during inhalation of said user and to operate in an inactive mode when detecting a human voice or an airflow noise in said breathing cavity (12) in a stowed configuration, g) a transmitter (38) for transmitting an output signal (58).

Description

Technical Field

[0001] The present disclosure relates to a communication assembly comprising a breathing mask equipped with a microphone, an aircraft equipped with the communication assembly, and a method, the assembly and the method being intended to avoid interference due to oxygen flow noise in communications between a user, in particular a pilot or a co-pilot, or between an aircraft user and a control tower. Background Art

[0002] Most aircraft are equipped with a breathing mask system to supply oxygen to the crew for use in emergency situations, such as during an oxygen-deficient environment during aircraft decompression. During these emergency maneuvers, the pilot, navigator, and other crew members on board may wear a breathing mask that includes a demand breathing regulator and a microphone. The breathing mask must include a microphone so that communication with other crew members or control tower personnel can be maintained during such an emergency.

[0003] In most microphone systems, a sound emitted by the user activates the microphone, which converts the received sound into an audio signal for transmission. The sound received by the microphone includes not only the user's voice, but also, disadvantageously, background noise. When the user inhales, the sound of the airflow from the regulator is often particularly loud and is emitted as a noise with a large component comparable in frequency and intensity to the sound emitted by the speaker. When a crew member (pilot or other person) wearing a breathing mask speaks, the noise generated by other crew members during the inhalation period can seriously interfere with hearing or understanding the speaking crew member's voice. In addition, when the crew member is exposed to a tense emergency situation, their breathing rate increases, which further intensifies the noise interference level. This interference poses a very serious problem because, in such an emergency situation, effective communication between the crew member and the tower is essential.

[0004] In practice, an audio button may be provided to enable the pilot to manually activate the microphone function only when speaking, and to switch off the microphone when the microphone is not active (not emitting an audio signal).

[0005] Furthermore, a communication assembly including a breathing mask is known, in particular from document WO2008081226A1. The breathing mask includes a regulator that delivers breathing gas during the crew member's inhalation. The oxygen content of the breathing gas depends on the pressure inside the cabin (passenger compartment). Reference is usually made to the cabin altitude, which is a "standard" altitude corresponding to the pressure in the cabin (the interior of the aircraft where the user is located). This breathing mask includes a face-mounted housing that is sealed and applied to the crew member's face in a sealed manner to prevent any gas other than the breathing gas (in particular, ambient air) from entering the interior of the housing. The breathing gas is supplied as needed and has a regulated oxygen content. This prevents any dilution with the cabin air and also protects the crew member from any smoke or potentially harmful gases.

[0006] Due to this sealed design, this communication assembly includes a microphone disposed inside the housing and transmits audio signals to the aircraft's audio system.

[0007] Furthermore, document WO2008081226A1 discloses a communication assembly equipped with a microphone that allows for reducing the noise of breathing gas being injected into a housing. When noise corresponding to the injection of oxygen into the housing is detected, the audio signal transmitted by the microphone is automatically reduced (attenuated). In the case of voice detection, the audio signal transmitted by the microphone is not reduced (attenuated).

[0008] A microphone known as an active switch microphone (ASM) incorporates both respiratory gas injection noise detection and speech detection. This works very satisfactorily. However, compared to an audio button that activates the microphone function, this communication assembly has the disadvantage of complicating verification of its proper operation. In practice, during verification, the breathing mask is typically stored in its storage case, and the practice is to simultaneously verify the proper operation of the housing's respiratory gas supply and the microphone by listening to the respiratory gas flow in the housing via the aircraft's audio system.

[0009] A solution allowing to overcome this problem is to provide an on / off button which suppresses the reduction (attenuation) of the audio signal, even in case a flow of breathing gas is detected. Summary of the Invention

[0010] An ergonomic, reliable and robust communication assembly is proposed which allows to overcome at least some of the aforementioned problems.

[0011] To this end, the communication assembly intended to avoid interference due to oxygen flow noise in communications between a user, a crew member and another crew member, or between the user and a control tower, comprises:

[0012] a) a breathing mask comprising:

[0013] a body having a face shell with a breathing cavity, the face shell being adapted to be applied on the user's face in a use configuration in which the breathing cavity is delimited by the face shell and by the user's face,

[0014] a regulator comprising an inlet aperture intended to be connected to an oxygen source and an outlet aperture delivering breathing gas containing oxygen, the outlet aperture being in flow communication with the breathing cavity for supplying the breathing gas to the user in a flow through the breathing cavity during inhalation by the user,

[0015] b) a test button for supplying breathing gas to the breathing cavity in the absence of inhalation by the user when the communication assembly is in a stowed configuration in which the breathing cavity is not in contact with the user's face,

[0016] c) a microphone mounted on the body of the breathing mask, the microphone being configured to capture a sound signal in the breathing cavity and to emit a first electrical signal corresponding to the captured sound signal,

[0017] d) an attenuation device configured to receive the first electrical signal and to operate in at least one first mode or one second mode and to emit a second electrical signal, wherein:

[0018] in the first mode, the attenuation device attenuates at least one central band of the first electrical signal, the central band corresponding to a frequency range of the sound signal extending between 500 Hz and 1,500 Hz, and

[0019] in the second mode, the attenuation device does not attenuate the central band of the first electrical signal;

[0020] e) a sound monitoring system comprising:

[0021] a first sound monitor configured to monitor the sound signal, to detect a first sound intensity in a first frequency range, and to analyze the first sound intensity to determine whether the first sound intensity is within a first determined level range to detect airflow noise through the breathing cavity during inhalation by the user in the use configuration, and

[0022] a second sound monitor configured to monitor the sound signal, to detect a second sound intensity in a second frequency range, and to analyze the second sound intensity to determine whether the second sound intensity is within a second determined level range to detect human voice, the second frequency range being different from the first frequency range; and

[0023] f) a controller configured to select an operating mode of the attenuation device so as to cause the attenuation device to:

[0024] (i) operate in the first mode when the first sound intensity analyzed by the first sound monitor is within the first determined level range and (ii) operate in the second mode when the second sound intensity analyzed by the second sound monitor is not within the second determined level range, and

[0025] operate in the second mode when the second sound intensity analyzed by the second sound monitor is within the second determined level range;

[0026] g) a transmitter disposed downstream of the attenuation device for transmitting an output signal to another crew member or a transmitting antenna,

[0027] wherein the communication assembly:

[0028] the sound monitoring system is configured to monitor the sound signal, detect a third sound intensity in a third frequency range, and analyze the third sound intensity to determine whether the third sound intensity is within a third determined level range to detect airflow noise in the breathing cavity in the stowed configuration, the third frequency range being different from the first frequency range, and

[0029] the controller is configured not to cause the attenuation device to operate in the first mode when the third sound intensity is within the third determined level range.

[0030] It was found that the flow of respiratory gases in a breathing cavity when the breathing cavity is not closed by a face can be distinguished from the airflow in a breathing cavity when the breathing cavity is closed by a face. This possibility of distinction appears to be due to the absorption of sound waves by the face.

[0031] This solution has the advantage of reducing the constraints on the user. On the one hand, this solution avoids requiring the pilot to press a button each time he speaks to be heard. On the other hand, this solution avoids the button that suppresses the reduction of the audio signal being in a false position that can generate a false detection of airflow noise that interferes with the communication or of a functional anomaly of the communication assembly. Indeed, if the noise reduction function is in action in the case where the test button is pressed to check the proper operation of the communication assembly, the airflow noise of the respiratory gases in the breathing cavity will not be felt, or almost heard via the audio system of the aircraft.

[0032] According to another feature, in the second mode, preferably, the attenuation device does not modify the first electrical signal.

[0033] Thus, the second electrical signal is identical to the first electrical signal. Since the sound signal is considered to correspond to a word, it is not necessary to modify the first electrical signal.

[0034] According to another feature, the controller is preferably configured to cause the attenuation device to operate in the second mode when the third sound intensity is within the third determined level range.

[0035] Since the sound signal is considered to correspond to the airflow noise in the respiratory cavity in the stowed configuration, the user should hear this noise, just as a word should be heard. Thus, the second mode can be selected when the second sound intensity analyzed by the second monitor is within a second determined level range and when the third sound intensity is within a third determined level range.

[0036] According to another feature, the third frequency range extends at least partially above 2,000 Hz, preferably at least partially above 2,500 Hz.

[0037] It was found that the third frequency range thus allows to detect the airflow noise in the respiratory cavity in the stowed configuration.

[0038] According to a complementary feature, the third frequency range preferably extends completely below 5 kHz, more preferably below 4.5 kHz.

[0039] It was found that the third frequency range thus allows to clearly distinguish the airflow noise in the respiratory cavity in the stowed configuration from the airflow noise in the respiratory cavity in the use configuration.

[0040] According to another feature, the communication assembly further comprises a storage case configured to receive the respiratory mask in the stowed configuration.

[0041] Thus, the airflow noise in the respiratory cavity in the stowed configuration has less variations due to the environment of the respiratory cavity, which improves the reliability of identifying that the sound signal corresponds to the respiratory gas flow in the respiratory cavity in the stowed configuration.

[0042] According to a complementary feature, preferably, the third frequency range is centered between (with the median value of the third frequency range positioned between) 2,500 Hz and 3,500 Hz.

[0043] It was found that positioning the median value of the third frequency range between 2,500 Hz and 3,500 Hz favors a good discrimination of the airflow noise of the respiratory gas in the respiratory cavity in the stowed configuration, on the one hand, with respect to the human voice and, on the other hand, with respect to the airflow noise of the respiratory gas in the respiratory cavity in the use configuration.

[0044] According to another feature, preferably, the third frequency range extends completely above 1,000 Hz, more preferably above 1.5 kHz.

[0045] It is found that the third frequency range thus allows a clear distinction between the airflow noise in the respiratory cavity in the stowed configuration and the human voice.

[0046] According to an alternative feature, the first frequency range and the third frequency range overlap.

[0047] This feature can be advantageous in the case where a distinction between the airflow noise in the respiratory cavity in the stowed configuration and the human voice is not essential.

[0048] According to a complementary feature, the first frequency range and the third frequency range are identical and the first determined level range and the third determined level range are identical.

[0049] The detection of the human voice and of the airflow noise of the respiratory gases in the respiratory cavity in the stowed configuration is thus performed simultaneously, indistinguishably. The communication assembly is thus simpler.

[0050] According to an alternative feature, preferably, the sound monitoring system comprises a third sound monitor distinct from the second sound monitor, the third sound monitor being configured to monitor the sound signal, to detect the third sound intensity in the third frequency range, distinct from the second frequency range, and to analyze the third sound intensity to determine whether the third sound intensity is within the determined third determined level range to detect the airflow noise in the respiratory cavity in the stowed configuration.

[0051] The detection of the human voice is thus distinct from the detection of the airflow noise in the respiratory cavity in the stowed configuration, which allows a better detection and a better distinction with respect to the airflow noise in the respiratory cavity in the use configuration.

[0052] According to a complementary feature, the third sound monitor is preferably housed on a microphone circuit board necessary for the operation of the microphone.

[0053] The characteristics of the third sound monitor can thus be modified by replacing a module comprising the microphone and the microphone circuit board.

[0054] Additionally and complementarily, the microphone circuit board carries the first sound monitor, the third sound monitor and part of the controller, the controller returning intermediate information on the selection of the operating mode of the attenuation device.

[0055] According to an alternative feature, the communication assembly comprises a microphone circuit board and the first sound monitor, the second sound monitor and the third sound monitor being housed on a monitoring circuit board distinct from the microphone circuit board.

[0056] Thus, the existing communication assembly can be improved by adding a monitoring circuit board to avoid interference due to oxygen flow noise in the communication, while allowing easy verification of proper operation.

[0057] According to another feature in accordance with the disclosure, preferably, the communication assembly further comprises a band-pass filter for filtering sound signals having frequencies outside the main speech band, the band-pass filter being disposed between the attenuation device and the transmitter.

[0058] Thus, the communication assembly allows to eliminate spurious noise captured simultaneously with the user's speech, without causing any serious adverse effect on the good understanding of the user's speech by the control tower or other air traffic personnel.

[0059] According to a complementary feature, preferably, the band-pass filter has a bandwidth comprising a (total) frequency range between 500 and 1,500 Hz, preferably, the band-pass filter has a bandwidth comprising a (total) frequency range between 300 and 3,000 Hz.

[0060] According to a complementary or alternative feature, the band-pass filter preferably cuts off frequencies below 100 Hz and at least cuts off frequencies above 5,000 Hz.

[0061] In various embodiments of the communication assembly, it is possible by means of any of the following arrangements:

[0062] In the first mode, the attenuation device cuts off the entire sound signal;

[0063] The controller is configured to always cause the attenuation device to operate in the second mode when the first sound intensity analyzed by the first sound monitor is not within the first determined level range;

[0064] The controller is configured to cause the attenuation device to operate in the second mode:

[0065] the second sound intensity analyzed by the second sound monitor is within the second determined level range, or when the third sound intensity is within the third determined level range;

[0066] The controller is configured to operate the attenuation device in the first mode only:

[0067] the first sound intensity analyzed by the first sound monitor is within the first determined level range,

[0068] the second sound intensity analyzed by the second sound monitor is not within the second determined level range, and

[0069] the third sound intensity is not within the third determined level range;

[0070] the first frequency range extends (completely) above 10 kHz, preferably (completely) above 30 kHz;

[0071] the second frequency range extends (completely) below 1,000 Hz, preferably (completely) below 500 Hz, more preferably below 300 Hz;

[0072] the second frequency range extends (completely) above 100 Hz, preferably (completely) above 130 Hz;

[0073] each of the first sound monitor, the second sound monitor and the third sound monitor monitors the first electrical signal to monitor the sound signal;

[0074] the respiratory mask further comprises a holding strap attached to the main body of the respiratory mask.

[0075] An aircraft equipped with a communication assembly is also provided.

[0076] A method for avoiding interference due to oxygen flow noise in a communication between a user, a crew member and another crew member or between the user and a tower control is presented. In this method, a communication assembly comprises a respiratory mask including a main body having a face shell with a breathing cavity and a regulator, the main body of the respiratory mask supplying the breathing cavity during inhalation by the user, a microphone mounted on the main body of the respiratory mask and configured to capture a sound signal in the breathing cavity and emit a first electrical signal corresponding to the captured sound signal, a test button allowing to supply breathing gas to the breathing cavity when the communication assembly is in a stowed configuration, in which the breathing cavity is not in contact with the face of the user, an attenuation device configured to receive the first electrical signal, the method comprising:

[0077] placing the respiratory mask in a use configuration in which the face shell is applied on the face of the user, the breathing cavity being delimited by the face shell and by the face of the user, or placing the face shell of the respiratory mask in the stowed configuration and actuating the test button,

[0078] monitoring a first sound intensity of the sound signal captured by the microphone in a first frequency range, analyzing the first sound intensity, and determining whether the first sound intensity is within a first determined level range to detect airflow noise through the breathing cavity during inhalation by the user in the use configuration;

[0079] monitoring a second sound intensity of the sound signal captured by the microphone in a second frequency range, the second frequency range being different from the first frequency range, analyzing the second sound intensity, and determining whether the second sound intensity is within a second determined level range to detect human voice,

[0080] monitoring a third sound intensity of the sound signal captured by the microphone in a third frequency range, the third frequency range being different from the first frequency range, and analyzing the third sound intensity to determine whether the third sound intensity is within a third determined level range to detect airflow noise in the breathing cavity in the stowed configuration,

[0081] attenuating at least one central frequency band of the first electrical signal to produce an output signal, the central frequency band of the first electrical signal corresponding to a frequency range of the sound signal extending between 500 Hz and 1,500 Hz when the first sound intensity analyzed by the first sound monitor is within the first determined level range and when the second sound intensity analyzed by the second sound monitor is not within the second determined level range and the third sound intensity is not within the third determined level range,

[0082] not attenuating the central frequency band of the first electrical signal to produce the output signal when the second sound intensity analyzed by the second sound monitor is within the second determined level range, and

[0083] transmitting the output signal to another crew member or a transmitting antenna. BRIEF DESCRIPTION OF DRAWINGS

[0084] Other features and advantages will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the application.

[0085] Figure 1 is a schematic view of a communication assembly in a use configuration, the communication device comprising a breathing mask, a storage box equipped with a test button, and a microphone assembly;

[0086] Figure 2 is a schematic view of a communication assembly in a stowed configuration;

[0087] Figure 3 schematically represents a microphone assembly comprising a microphone emitting a first electrical signal;

[0088] Figure 4 shows a spectrum analysis of a first electrical signal in a use configuration, and

[0089] Figure 5 Spectral analysis of the first electrical signal in the stowed configuration is shown. DETAILED DESCRIPTION

[0090] Figure 1 and 2 The communication assembly 1 is shown positioned in an aircraft cabin 5. The communication assembly 1 essentially comprises a breathing mask 10, an oxygen source 4, a storage box 40, a test button 8, and a microphone assembly 30. The microphone assembly 30 comprises a microphone 20, a sound monitoring system 28, a controller 32, an attenuation device 34, and a transmitter 38.

[0091] The breathing mask 10 is intended to be used by a user 2, who is typically a crew member flying an aircraft. The breathing mask 10 comprises a body 14, a strap 6, a visor 13 and a regulator 16. The body 14 comprises a face shell 11 having a breathing chamber 12. Figure 1 In the use configuration shown in FIG, the facial shell 11 has a peripheral edge that contacts the face of user 2 around the user's mouth and nose. The peripheral edge is typically covered with foam or a similar flexible material so as to be applied to the face of user 2 in a substantially sealed manner. In the use configuration, a breathing chamber 12 is generally defined by the facial shell 11 and the face of user 2. The user inhales and exhales into the breathing chamber 12.

[0092] In the illustrated embodiment, the facial shell 11 is of the oronasal type. The visor 13 is optional and removably mounted on the facial shell 11. The visor 13 includes a secondary shell extending around the eyes and a transparent screen positioned opposite the eyes. The secondary shell defines a secondary cavity. Alternatively, the facial shell may be of the so-called full-face type and extend around the mouth, nose, and eyes to form a single cavity.

[0093] The strap 6 is connected to the body 14 and extends around the head of the user 2. In the use configuration, the strap 6 holds the facial shell 11 applied to the face of the user 2. In the embodiment shown, the strap 6 is formed by two expandable tubes during its pressurization and inflation. The tubes are held on the body 14 at their ends.

[0094] A regulator 16 is rigidly mounted on the main body 14. The regulator has an inlet port 15 and an outlet port 17. The inlet port 15 is connected to the oxygen source 4 via a flexible hose 18. The outlet port 17 communicates with the breathing chamber 12. As is well known, regulators have several operating modes, including a so-called normal mode, a so-called 100% oxygen mode, and a so-called emergency mode. In the 100% oxygen mode, the regulator 16 supplies breathing gas to the breathing chamber 12 consisting solely of gas from the oxygen source 4. This supply is performed on demand. In other words, when the user 2 inhales, the user creates a slight decompression in the breathing chamber 12 relative to the ambient pressure in the cabin 5, and the regulator supplies the breathing chamber 12 until the pressure in the breathing chamber reaches ambient pressure. In the normal mode, the regulator 16 supplies breathing gas to the breathing chamber 12 consisting of a mixture of oxygen from the oxygen source and ambient air. As the ambient pressure decreases, the oxygen content of the breathing gas increases, maintaining the pressure in the breathing chamber 12 substantially equal to the ambient pressure. In emergency mode, the regulator 16 supplies breathing gas consisting of gas from the oxygen source 4 to the breathing chamber 12 and maintains a slight overpressure in the breathing chamber 12 relative to the ambient pressure. The oxygen is stored under pressure in the oxygen source 4 or is generated under pressure in the oxygen source 4. The gas supplied by the oxygen source 4 preferably comprises at least 95% oxygen, preferably at least 99% oxygen.

[0095] The breathing mask 10 also allows the escape of gases exhaled by the user 2 in the breathing chamber 12. Preferably, the regulator 16 comprises a valve that is opened by overpressure in the breathing chamber 12 to allow gases exhaled by the user 2 to escape into the ambient air.

[0096] The storage box 40 has a storage space 42 in which Figure 2 The stowed configuration shown in FIG. receives the respiratory mask 10. In the illustrated embodiment, the storage box 40 includes four side walls 44, a bottom wall 46, and a door 48 that define a storage space 42. The storage box 40 is made of metal. The storage box 40 has an access opening that allows the respiratory mask 10 to be inserted into the storage space 42, or conversely, removed from the storage box 42. The door 48 is positioned opposite the bottom wall 46. The door 48 substantially blocks the access opening when closed and opens it when open. In the stowed configuration, the regulator 16 is in an emergency mode that provides the most protection for the user. Typically, the storage box 40 is equipped with a supply valve (not shown) that closes when the door 48 is closed to prevent oxygen from escaping through the breathing chamber 12. The supply valve opens when the door 48 is opened, or a similar feature allows the supply valve to open automatically when the respiratory mask is removed from the storage box 40.

[0097] The test button 8 allows opening of the supply valve while keeping the communication assembly in the stowed configuration and the door 48 closed, in particular while keeping the breathing mask 10 in the storage space 42 (and the door 48 closed). In an embodiment, the test button 8 is mounted on the storage box 40 near the access opening.

[0098] The microphone 20 is mounted on the main body 14, captures a sound signal in the breathing cavity 12 and converts the sound signal into a first electrical signal 52.

[0099] The attenuation device 34 receives the first electrical signal 52 from the microphone and emits a second electrical signal 54. The attenuation device 34 comprises at least one first (operational) mode and one second (operational) mode. Preferably, the first mode is an active mode and the second mode is an inactive mode. Advantageously, the second mode is a "straight through" type, wherein the attenuation device 34 does not modify the first electrical signal 52 from the microphone 30, so that the second electrical signal 54 is identical to the first electrical signal 52. At least in the first mode, the central frequency band is not attenuated. The central frequency band extends between 500 Hz and 1,500 Hz. In the first mode, the attenuation device 34 reduces the sound intensity of the first electrical signal 52 by at least half, at least in the central frequency band. Preferably, the attenuation device 34 cuts off the first electrical signal 52, at least in the central frequency band. More preferably, in the first mode, the attenuation device 34 acts on the whole range of audible sound frequencies and cuts off the first electrical signal. In one embodiment, the attenuation device 34 can be a switch, the first mode consisting in cutting off the first electrical signal 52, and the second mode consisting in emitting the first electrical signal 52 without modifying it. In an alternative embodiment, the attenuation device 34 can comprise electronic components or software designed to reduce the intensity of the first electrical signal in the first mode.

[0100] In the embodiment shown, the second electrical signal 54 is received by a band-pass filter 36, which is optional. The band-pass filter 36 emits a third electrical signal 56 to the emitter 38. The band-pass filter 36 is thus arranged between the attenuation device 34 and the emitter 38. The band-pass filter 36 has a bandwidth preferably comprised in the main speech frequency range, which extends between 300 Hz and 3,500 Hz, preferably between 300 Hz and 3,000 Hz. Thus, when the attenuation device 34 is in the second mode, the parasitic noise outside the main speech frequency range is eliminated by the band-pass filter 36.

[0101] The frequency range of speech is substantially between 300 Hz and 3,000 Hz. In telephone communication, the emission frequency range usually extends between 300 Hz and 3,400 Hz. It is found that 99% of the speech power is at frequencies below 3,000 Hz. Thus, the band-pass filter 36 substantially excludes parasitic noise, not speech.

[0102] In the illustrated embodiment, the transmitter 38 transmits the output signal 58 preferably via the audio system of the aircraft towards other crew members and / or towards the control tower.

[0103] In the illustrated embodiment, the sound monitoring system 28 comprises a first sound monitor 22, a second sound monitor 24 and a third sound monitor 26. The first sound monitor 22, the second sound monitor 24 and the third sound monitor 26 are connected in parallel to the output of the microphone 20. More specifically, the first sound monitor 22, the second sound monitor 24 and the third sound monitor 26 receive the first electrical signal 52.

[0104] The first sound monitor 22 monitors a first frequency range in order to determine whether the first electrical signal 52 corresponds to the airflow noise through the breathing cavity 12 during inhalation by the user 2 when the breathing mask 10 is in the use configuration. In other words, the first frequency range is chosen in order to distinguish, inter alia, between on the one hand the airflow noise of the pressurized breathing gas in the breathing cavity 12 in the use configuration and on the other hand the human voice or the airflow noise of the pressurized breathing gas in the breathing cavity 12 in the stowed configuration. When the user exhales, the microphone 20 can capture other noises, inter alia, the airflow noise of the ambient air of the cabin 5 from the breathing cavity 12. However, in the illustrated embodiment, these other noises are not distinguished, provided that the total sound level of these other noises has become sufficiently low so as not to substantially interfere with a good understanding of the speech.

[0105] In the use configuration, the breathing cavity 12 is substantially closed (the breathing gas flows through the breathing cavity 12 towards the lungs of the user 2), delimited on the one hand by the face shell 11 and on the other hand by the face of the user 2. In the stowed configuration, the breathing cavity 12 is open, so that the breathing gas flowing in the breathing cavity 12 can escape into the ambient air of the cabin 5.

[0106] Figure 4 A first curve 62 is shown representing the sound intensity as a function of the frequency of the airflow noise through the breathing cavity 12 in the use configuration, captured by the microphone 20. In other words, the first curve 62 is a frequency representation of the first electrical signal 52 during inhalation by the user 2.

[0107] Figure 5 A second curve 64 is shown representing the sound intensity as a function of the frequency of the airflow noise through the breathing cavity 12 in the stowed configuration. In other words, the second curve 64 is a frequency representation of the first electrical signal 52 during testing of the breathing mask 10 inside the storage box 40.

[0108] Figure 4 The first curve 62 shown in Fig. 2A is different from the second curve 64 shown in Fig. 2B in that the first curve 62 has a first peak 66 at a first frequency f1 and a second peak 68 at a second frequency f2, whereas the second curve 64 has a third peak 70 at a third frequency f3. Figure 5The difference between the second curve 64 shown in the middle is due, inter alia, to the fact that the respiratory gas flows in the closed respiratory lumen 12 relative to the respiratory lumen 12 being open to ambient air, and to the fact that the user's face has absorption properties of the different sounds of the storage case 40 or of the ambient air.

[0109] The spectral analysis of the first curve 62 and the second curve 64 reveals that the airflow noise of the respiratory gas in the respiratory lumen 12 is close to white noise in the use configuration and in the stowed configuration, i.e. the airflow noise of the respiratory gas in the respiratory lumen 12 has approximately the same intensity over a wide frequency range. However, a difference occurs between the first curve 62 and the second curve 64. In particular, the analysis reveals a high intensity component of the first curve 62 above 10 kHz and more particularly 30 kHz.

[0110] When the first sound monitor 22 detects that the first electrical signal 52 has a first intensity in the first frequency range that is included in a first determined level range, the first sound monitor 22 sends a first message 23 to the controller 32, which corresponds to a detection of the airflow noise through the respiratory lumen 12 in the use configuration. Otherwise, the first message 23 sent by the first sound monitor 22 to the controller 32 corresponds to the absence of a detection of the airflow noise of the respiratory lumen 12 in the use configuration. The first message 23 sent to the controller 32 is therefore binary.

[0111] Thus, if the first sound monitor 22 detects a sound with a frequency above 10 kHz and an intensity in this frequency range above 60 dBa, it can be deduced that the first electrical signal 52 corresponds to the noise of the respiratory gas inhaled by the user 2 in the use configuration.

[0112] The second sound monitor 24 monitors a second frequency range in order to determine whether the first electrical signal 52 corresponds to a human voice. In other words, the second frequency range is chosen in order to distinguish, inter alia, a human voice from the airflow noise of the pressurized oxygen in the respiratory lumen 12 in the use configuration or in the stowed configuration. Also here, other noises can be captured by the microphone 20. By human voice, it is understood human speech, in particular the speech of the user 2.

[0113] When the second sound monitor 24 detects that the first electrical signal 52 has a second intensity in the second frequency range that is included in a second determined level range, the second sound monitor 24 sends a second message 25 to the controller 32, which corresponds to a detection of a human voice. Otherwise, the second message 25 sent by the second sound monitor 24 to the controller 32 corresponds to the absence of a detection of a human voice. The second message 25 sent to the controller 32 is also binary.

[0114] The second monitor 24 is configured to detect sounds in a second frequency range characteristic of human voice. Preferably, the second frequency range extends below 1,000 Hz, for example below 500 Hz, and more preferably between 130 Hz and 230 Hz. Alternatively, the second frequency range can be centered between 25 Hz and 180 Hz, and have an amplitude between 50 Hz and 250 Hz.

[0115] In the illustrated embodiment, the second intensity extends above a second level, for example above 60 dBa.

[0116] The third sound monitor 26 monitors a third frequency range in order to determine whether the first electrical signal 52 corresponds to the flow noise of the pressurized breathing gas through the breathing cavity 12 when the breathing mask 10 is in the stowed configuration. In other words, the third frequency range is chosen in order to distinguish, in particular satisfactorily, on the one hand the flow noise of the pressurized breathing gas in the breathing cavity 12 in the stowed configuration from, on the other hand, human voice or the flow noise of the pressurized breathing gas in the breathing cavity 12 in the use configuration. In the illustrated embodiment, other noises that can be captured by the microphone 20 are not distinguished.

[0117] It was found that, in order to perform a good distinction between human voice and breathing gas flow noise in the breathing cavity 12 in the stowed configuration, the third frequency range is preferably chosen above 1,000 Hz, more preferably above 1,500 Hz. Moreover, the third frequency range should preferably extend (at least partially) above 2,000 Hz, more preferably above 2,500 Hz.

[0118] Moreover, in order to perform a good distinction between breathing gas flow noise in the breathing cavity 12 in the stowed configuration and breathing gas flow noise in the breathing cavity 12 in the use configuration, the third frequency range is preferably chosen (completely) below 5,000 Hz, more preferably below 4,500 Hz.

[0119] Moreover, it was found that, when the breathing mask is in the storage box 40, the peak of the intensity is present in the range of about 2,500 Hz to 3,500 Hz, depending on the characteristics of the storage box 40. Therefore, the third frequency range is preferably centered between 2,500 Hz and 3,500 Hz, and the width of the second frequency range is preferably below 2,000 Hz, more preferably below 500 Hz.

[0120] In the illustrated embodiment, preferably, the third frequency range is centered at 2,800 Hz, and extends 200 Hz on both sides, in other words, the second frequency range extends between 2,600 Hz and 3,000 Hz.

[0121] Preferably, the third frequency range monitored by the third sound monitor 26 is determined by a filter having an order greater than or equal to 2, preferably greater than or equal to 4.

[0122] In the illustrated embodiment, the third intensity extends above the third level, for example above 60 dBa.

[0123] The controller 32 receives the first message 23 from the first sound monitor 22, the second message 25 from the second sound monitor 24, and the third message 27 from the third sound monitor 26.

[0124] When the second message 25 corresponds to a detection of human voice, the controller 32 sends a command message 33 to the attenuation device 34 to place it in the second mode, regardless of the first message 23 and the third message 27. In other words, the second message 25 takes precedence over the first message 23 and the third message 27.

[0125] When the third message 27 corresponds to a detection of respiratory gas flow noise in the respiratory lumen 12 in the stowed configuration, the controller 32 sends a command message 33 to the attenuation device 34 to place it in the second mode, regardless of the first message 23. In other words, the third message 27 takes precedence over the first message 23. Thus, the communication assembly 1 can be tested (the sound is not attenuated) even if the first sound monitor 22 detects respiratory gas flow noise in the respiratory lumen 12 in the flow configuration, while the communication assembly is actually in the stowed configuration. Alternatively, it can be provided that the first message 23 takes precedence over the third message 27, in other words, when the second message 25 corresponds to an absence of detection of human voice and the first message corresponds to a detection of respiratory gas flow noise in the respiratory lumen 12, the controller places the attenuation device 34 in the first mode, regardless of the third message 27.

[0126] When the first message 23 corresponds to a detection of respiratory gas flow noise in the respiratory lumen 12 in the use configuration and the second message 25 corresponds to an absence of detection of human voice and the third message corresponds to an absence of detection of respiratory gas flow noise in the respiratory lumen 12 in the stowed configuration, the controller 32 sends a command message 33 to the attenuation device 34 to place it in the first mode.

[0127] When the first message 23 corresponds to an absence of detection of respiratory gas flow noise in the respiratory lumen 12 in the use configuration, the second message 25 corresponds to an absence of detection of human voice and the third message corresponds to an absence of detection of respiratory gas flow noise in the respiratory lumen 12 in the stowed configuration, the controller 32 places the attenuation device 34 in the second mode. However, alternatively, if it is noted that this situation corresponds to another parasitic noise, for example an exhalation of the user 2 through the respiratory lumen 12, the controller 32 can send a command message 33 to the attenuation device 34 to place it in the first mode.

[0128] The controller 2 can be configured to carry out a logical test in pairs between the first message 23, the second message 25 and the third message 27, the command message 33 being the result of a different logical test.

[0129] The microphone assembly 30 comprises a microphone circuit board 21 and a monitoring circuit board 35 connected by a cable 19. The microphone circuit board 21 is disposed in the main body 14 of the breathing mask 10. The monitoring circuit board 35 is disposed away from the breathing mask 10, in particular in the storage box 40 or in another location in the cabin 5 of the aircraft. The attenuation device 34, the filter 36 and the transmitter 38 are disposed on the monitoring circuit board 35.

[0130] In one embodiment, the controller 32 comprises a first logic unit and a second logic unit. The first logic unit carries out a test between the first message 23 and the third message 27, the result of which is tested by the second logic unit by the second message 25 to obtain the command message 33 sent to the attenuation device 34 according to one of the logics explained above. On the other hand, the first sound monitor 22, the third sound monitor 26 and the first logic unit are preferably disposed on the microphone circuit board 21, while the second sound monitor 24 and the second logic unit are disposed on the monitoring circuit board 35. Alternatively, all of the first sound monitor 22, the second sound monitor 24, the third sound monitor 26, the first logic unit and the second logic unit can be disposed on the monitoring circuit board 35.

[0131] In another embodiment, the first logic unit carries out a test between the first message 23 and the second message 25, the result of which is tested by the second logic unit by the third message 27 to obtain the command message 33 sent to the attenuation device.

[0132] Although the disclosure has been illustrated and described in detail in the drawings and foregoing description, the illustration and the description are to be considered illustrative or exemplary and not restrictive. For example, the microphone emitting the first electrical signal 52 can be a second microphone to which the second sound monitor 24 is connected, the first sound monitor 22 being connected to a first microphone different from the second microphone, and / or the third sound monitor 26 can be connected to a third microphone different from the second microphone, the different microphones being able to have different acoustic responses. Thus, the first electrical signal 52 can in particular be different from the electrical signal received by the first sound monitor 22.

[0133] In particular, the second microphone can be chosen so as to be particularly sensitive to speech signals and to have little distortion in the speech bandwidth. The first microphone and / or the third microphone can be chosen so as to obtain a response with a greater bandwidth but with low distortion requirements.

[0134] The microphone circuit board 21 and / or the monitoring circuit board 35 can be in the form of a printed circuit board using discrete analog components, for example, filters, operational amplifiers for amplifying signals and comparing them to predetermined levels, and logic components for controlling board behavior.

[0135] The microphone circuit board 21 and / or the monitoring circuit board 35 can be in the form of a digital board or a hybrid analog / digital board that uses software and digital signal processors (DSPs) to embed the functionality described above. For example, an analog-to-digital converter can convert the signals emitted by the microphone 20 into a stream of integers representing the captured sound. Software manages the processor to process the stream of integers to analyze the characteristics of the captured sound and determine the attenuation to be applied as explained above.

Claims

1. A communication assembly (1) for avoiding interference due to oxygen flow noise in communications between a user (2), a crew member and another crew member, or between the user and a control tower, the communication assembly comprising: a) A breathing mask (10) comprising: a body (14) having a facial shell (11) with a breathing cavity (12), the facial shell (11) being adapted to be applied on the face of the user (2) in a use configuration, the breathing cavity (12) being defined by the facial shell (11) and by the face of the user (2), a regulator (16) comprising an inlet orifice (15) intended to be connected to an oxygen source (4) and an outlet orifice (17) for delivering breathing gas containing oxygen, said outlet orifice (17) being in flow communication with said breathing chamber (12) for supplying said breathing gas to said user (2) in a flow through said breathing chamber (12) during inhalation of said user (2), b) a test button (8) for supplying breathing gas to the breathing chamber when the communication assembly is in a stowed configuration in which the breathing chamber (12) is not in contact with the face of the user (2), c) a microphone (20) mounted on the body (14) of the respiratory mask (10), the microphone (20) being configured to capture a sound signal in the respiratory cavity (12) and to emit a first electrical signal (52) corresponding to the captured sound signal, d) an attenuation device (34) configured to receive the first electrical signal (52) and to operate in at least a first mode or a second mode and to transmit a second electrical signal (54), wherein: In the first mode, the attenuation device (34) attenuates at least one central frequency band of the first electrical signal (52), the central frequency band corresponding to a frequency range of the sound signal extending between 500 Hz and 1,500 Hz, and In the second mode, the attenuation device (34) does not attenuate the center frequency band of the first electrical signal (52); e) a sound monitoring system (28), comprising: a first sound monitor (22) configured to monitor the sound signal, detect a first sound intensity in a first frequency range, and analyze the first sound intensity to determine whether the first sound intensity is within a first determined level range to detect airflow noise through the breathing cavity (12) during inhalation by the user in the use configuration, and a second sound monitor (24) configured to monitor the sound signal, detect a second sound intensity in a second frequency range different from the first frequency range, and analyze the second sound intensity to determine whether the second sound intensity is within a second determined level range to detect a human voice; and f) a controller (32) configured to select an operating mode of the attenuation device so that the attenuation device: (i) operating in the first mode when the first sound intensity analyzed by the first sound monitor (22) is within the first determined level range and (ii) when the second sound intensity analyzed by the second sound monitor is not within the second determined level range, and operating in the second mode when the second sound intensity analyzed by the second sound monitor is within the second determined level range; g) a transmitter (38) arranged downstream of the attenuation device (34) for transmitting the output signal (58) to another crew member or a transmitter antenna, in: The sound monitoring system (28) is configured to monitor the sound signal, detect a third sound intensity in a third frequency range, and analyze the third sound intensity to determine whether the third sound intensity is within a third determined level range to detect airflow noise in the breathing chamber (12) in the stowed configuration, the third frequency range being different from the first frequency range, and The controller (32) is configured to not cause the attenuation device (34) to operate in the first mode when the third sound intensity is within the third determined level range.

2. The communication assembly according to claim 1, characterized in that The third frequency range extends at least partially above 2,000 Hz.

3. The communication assembly according to claim 1, wherein: The third frequency range extends at least partially above 2,500 Hz.

4. The communication assembly according to claim 1, wherein: The third frequency range extends entirely below 5 kHz.

5. The communication assembly according to claim 1, wherein: The third frequency range extends entirely below 4.5 kHz.

6. The communication assembly according to claim 1, wherein: The communication assembly further includes a storage box (40) configured to receive the respiratory mask (10) in the stowed configuration.

7. The communication assembly according to claim 6, characterized in that The third frequency range is centered between 2,500 Hz and 3,500 Hz.

8. The communication assembly according to claim 1, wherein: The third frequency range extends fully above 1,000 Hz.

9. The communication assembly according to claim 1, wherein: The third frequency range extends completely above 1.5 kHz.

10. The communication assembly according to claim 1, wherein: The sound monitoring system (28) includes a third sound monitor (26) different from the second sound monitor (22), the third sound monitor (26) being configured to monitor the sound signal, detect the third sound intensity in the third frequency range, and analyze the third sound intensity to determine whether the third sound intensity is within the third determined level range determined to detect airflow noise in the breathing chamber (12) in the stowed configuration. The third frequency range is different from the second frequency range.

11. The communication assembly according to claim 1, wherein: In the first mode, the attenuation device (34) mutes all of the sound signals.

12. The communication assembly according to claim 11, characterized in that The controller (32) is configured to cause the attenuation device (34) to operate in the first mode only when: the first sound intensity analyzed by the first sound monitor (22) is within the first determined level range, the second sound intensity analyzed by the second sound monitor (24) is not within the second determined level range, and The third sound intensity is not within the third determined level range.

13. An aircraft equipped with a communications assembly according to any one of claims 1 to 12.

14. A method for avoiding interference due to oxygen flow noise in communications between a user (2), a crew member and another crew member, or between the user and tower control, wherein a communication assembly (1) comprises a breathing mask (10), a microphone (20), and a test button (8), the breathing mask (10) comprising a body (14) and a regulator (16), the body (14) of the breathing mask (10) having a face shell (11), the face shell (11) having a breathing chamber (12), the regulator (16) supplying oxygen during inhalation of the user (2). The breathing chamber (12), the microphone (20) is mounted on the body (14) of the breathing mask (10) and is configured to capture sound signals in the breathing chamber (12) and emit a first electrical signal (52) corresponding to the captured sound signals, the test button (8) allows the supply of breathing gas to the breathing chamber (12) when the breathing mask (10) is in a stowed configuration, in which the breathing chamber (12) is not in contact with the face of the user (2), an attenuation device (34) is configured to receive the first electrical signal (52), and the method comprises: placing the breathing mask (10) in a use configuration in which the face shell (11) is applied to the face of the user (2), the breathing chamber (12) being defined by the face shell (11) and by the face of the user (2), or placing the face shell (11) of the breathing mask (12) in the stowed configuration and actuating the test button (8), monitoring a first sound intensity of the sound signal captured by the microphone (20) in a first frequency range, analyzing the first sound intensity, and determining whether the first sound intensity is within a first determined level range to detect airflow noise passing through the breathing cavity (12) during inhalation of the user (2) in the use configuration, monitoring a second sound intensity of the sound signal captured by the microphone (20) in a second frequency range, the second frequency range being different from the first frequency range, analyzing the second sound intensity, and determining whether the second sound intensity is within a second determined level range to detect a human voice, monitoring a third sound intensity of the sound signal captured by the microphone (20) in a third frequency range, the third frequency range being different from the first frequency range, and analyzing the third sound intensity to determine whether the third sound intensity is within a third determined level range to detect airflow noise in the breathing cavity (12) in the stowed configuration, attenuating at least a center frequency band of the first electrical signal (52) to produce an output signal (58), the center frequency band of the first electrical signal (52) corresponding to a frequency range of the sound signal extending between 500 Hz and 1,500 Hz when (i) the first sound intensity analyzed by the first sound monitor (22) is within the first determined level range and (ii) the second sound intensity analyzed by the second sound monitor (24) is not within the second determined level range and (iii) the third sound intensity is not within the third determined level range, when the second sound intensity analyzed by the second sound monitor (24) is within the second determined level range, not attenuating the center frequency band of the first electrical signal to generate the output signal (58), and The output signal is transmitted to another crew member or a transmitter antenna.

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