TECHNICAL FIELD

The aspects of the present disclosure relate generally to mobile communication devices and more particularly to reducing wind noise interference with a microphone of a mobile communication device.

BACKGROUND

Microphones operate by sensing sound, i.e. changes in air pressure. A movable membrane in the microphone is displaced by the changing air pressure. The position of the membrane is read electronically and converted into a digital or analog audio signal. In practice, the membrane is not directly linked with the outside chassis of the device containing the microphone in order to avoid the user touching the membrane, for example. Instead, the chassis of the device will include a “microphone hole” or cavity and the membrane is located within this hole. The small air volume inside the microphone hole is typically called the front cavity of the microphone. In windy conditions, wind will often pressurizes the front cavity too much and drive the membrane outside its operating range. This can result in, among other things, in clipping distortion which sounds bad and decreases speech intelligibility.

Existing solutions for reducing wind noise can include using a foam-like structure inside or on top of the front cavity. This often increases the size of the microphone unit and does not look aesthetically pleasing. Furthermore, this type of solution does not always adapt to windy conditions and these same disadvantages are present even in non-windy conditions.

There are also software -based solutions which aim to alleviate the distortion effects caused by wind. However, the effect of these software -based solutions is modest as they do not solve the root cause of the distortion, which is pressure overload at the microphone.

Accordingly, it would be desirable to be able to a microphone solution that addresses at least some of the problems identified above.

SUMMARY It is an object of the disclosed embodiments to reduce wind noise interference with a microphone in an apparatus such as a mobile communication device. This object is solved by the subject matter of the independent claims. Further advantageous modifications can be found in the dependent claims.

According to a first aspect the above and further objects and advantages are obtained by a microphone assembly. In one embodiment, the microphone assembly includes a housing defining a cavity, a microphone disposed in the cavity and a valve disposed in the housing proximate to the microphone. The valve is configured to be actuated when an air pressure level in the cavity exceeds a pre-determined threshold level and enables air to pass from the cavity and into the surrounding environment. Wind-caused excess pressure in the microphone front cavity, or negative pressure in the microphone front cavity, is released release via an active or passive valve. The valve will open when a desired pressure level is exceeded and connect the front cavity to the surrounding air allow for improved operation in windy conditions.

In a possible implementation form of the microphone assembly the valve is disposed in the housing between an opening in the cavity and an external environment. The valve will open when a desired pressure level is exceeded and connect the front cavity to the surrounding air allow for improved operation in windy conditions.

In a possible implementation form of the microphone assembly a channel is disposed in the housing. The channel is connected between the valve and an external environment. The channel allows air to travel from the cavity through the valve and to an outlet of the channel. Wind-caused excess pressure in the microphone front cavity is released release via the valve. The valve will open when a desired pressure level is exceeded and connect the front cavity to the surrounding air allowing for improved operation in windy conditions.

In a possible implementation form of the microphone assembly a controller is connected to the valve. The controller is configured to detect the air pressure level in the cavity and actuate the valve when the detected air pressure level exceeds the pre-determined threshold level. The valve is configured to be actuated when an air pressure level in the cavity exceeds a pre-determined threshold level and enables air to pass or flow from the cavity into the surrounding environment. The valve will open when a desired pressure level is exceeded and connect the front cavity to the surrounding air allow for improved operation in windy conditions. In a possible implementation form of the microphone assembly the controller includes one or more of a wind noise detector or a pressure sensor. The controller is configured to detect the air pressure level in the cavity and actuate the valve when the detected air pressure level exceeds the pre- determined threshold level to enable air to pass or flow from the cavity into the surrounding environment and reduce the air pressure.

In a possible implementation form of the microphone assembly, the microphone assembly is disposed in an ear bud. The aspects of the disclosed embodiments provide a valve-based pressure release from the microphone front cavity of an ear bud into the surrounding air for reducing acoustic overloading typically caused by wind.

In a possible implementation form of the microphone assembly, the microphone assembly is disposed in a mobile communication device. The aspects of the disclosed embodiments provide a valve-based pressure release from the microphone front cavity of a mobile communication device into the surrounding air for reducing acoustic overloading typically caused by wind.

According to a second aspect the above and further objects and advantages are obtained by a method. In one embodiment, a signal is obtained from the front cavity of a microphone assembly. Is determined from the obtained signal whether there is wind noise affecting the microphone. If it is determined that the obtained signal indicates wind noise, a valve is opened. When opened, the valve enables air to pass from the cavity and into the surrounding environment. Wind-caused excess pressure in the microphone front cavity, or negative pressure in the microphone front cavity, is released release via an active or passive valve. The valve will open when a desired pressure level is reached or exceeded, which can include negative pressure values, and connect the front cavity to the surrounding air allow for improved operation in windy conditions. In a possible implementation form of the method, the method includes detecting from the obtained signal whether a detected air pressure level in a front cavity of a microphone level is at or exceeds a predetermined threshold level. The valve is opened if the pressure level is at or exceeds the predetermined threshold level. The valve when opened enables air to pass from the cavity and into the surrounding environment. Wind-caused excess pressure in the microphone front cavity, or negative pressure in the microphone front cavity, is released release via an active or passive valve. The valve will open when a desired pressure level is reached or exceeded, which can include negative pressure values, and connect the front cavity to the surrounding air allow for improved operation in windy conditions.

In a possible implementation form of the method, the method further includes starting a timer when the valve is opened and closing the valve when the timer expires. The valve -based pressure release from the microphone front cavity into surrounding air for a period to time to reduce acoustic overloading typically caused by wind. These and other aspects, implementation forms, and advantages of the exemplary embodiments will become apparent from the embodiments described herein considered in conjunction with the accompanying drawings. It is to be understood, however, that the description and drawings are designed solely for purposes of illustration and not as a definition of the limits of the disclosed invention, for which reference should be made to the appended claims. Additional aspects and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. Moreover, the aspects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present disclosure, the invention will be explained in more detail with reference to the example embodiments shown in the drawings, in which:

Figures 1 illustrates a schematic block diagram of an exemplary apparatus incorporating aspects of the disclosed embodiments.

Figure 2 illustrates a schematic block diagram of an exemplary apparatus incorporating aspects of the disclosed embodiments.

Figure 3 illustrates a schematic block diagram of an exemplary apparatus incorporating aspects of the disclosed embodiments. Figure 4 illustrates aspects of an exemplary method incorporating aspects of the disclosed embodiments.

Figure 5 illustrates aspects of an exemplary method incorporating aspects of the disclosed embodiments.

Figure 6 illustrates aspects of an exemplary method incorporating aspects of the disclosed embodiments.

DETAIFED DESCRIPTION OF THE DISCFOSED EMBODIMENTS

Referring to Figure 1, a schematic block diagram of an exemplary apparatus 100 incorporating aspects of the disclosed embodiments is illustrated. The aspects of the disclosed embodiments are directed to releasing wind-caused excess pressure in the microphone front cavity via an active or passive valve. As illustrated in Figure 1, a valve 104 is disposed between the cavity 108 and surrounding air. This valve 104 will be opened or actuated when a desired pressure level is exceeded. The opening or actuation of the valve 104 allows air to flow through the valve 104. In one embodiment, the valve 104 can be mechanically tuned to open when desired pressure is reached (passive solution). Alternatively, the valve or valves 104 can be controlled by an external control to open when the desired pressure reached (active solution). The valve 104 connecting the cavity 108 to the surrounding air allows for improved operation in windy conditions.

As is illustrated in Figure 1, the exemplary apparatus 100 includes a housing 102 defining a cavity 108. In one embodiment, the cavity 108 is a microphone front cavity. A valve 104 is disposed in the housing 102. The valve 104 is configured to release air pressure from the microphone front cavity 104 and into the surrounding environment. In this manner, the valve 104 reduces acoustic overloading of the microphone 110, that is typically caused by wind.

In the example of Figure 1, the valve 104 is disposed proximate to the microphone 110. The valve 104 needs to be positioned within the housing 102 in a manner that enables air pressure from the microphone front cavity 108 to be received by the valve 104.

As shown in Figure 1, an air channel 112 is disposed within the housing 102. The air channel 112 can comprise an exhaust or ventilation path, for example. In one embodiment, the air channel 112 is a tubular structure that is configured to allow air to pass through it from one end to the other end. The air channel 112 of Figure 1 includes an opening 114 and an opening 116. In one embodiment, the opening 114 is disposed in a manner to receive air or air pressure from the microphone front cavity 108 and allow the air to travel into and through the channel 112 and into the surrounding environment. In this example, the opening 116 allows the air or air pressure in the channel 112 to exit into the surrounding air. In an alternate embodiment, wind can cause a negative pressure to the cavity 108. This can also cause interference, such a microphone clipping, for example. In this embodiment, the air flow could be from the opening 116 into the front cavity 108 via the air channel 112 and opening 114. Although only one channel 112, opening or aperture 114 and opening or aperture 116 are described herein, the aspects of the disclosed embodiments are not so limited. In alternate embodiments, the housing 102 can include any number of channels, opening, inlets, outlets and valves that will enable air pressure to be diverted from the microphone 110 to prevent acoustic overload of the microphone 110.

In one embodiment, the valve 104 is disposed within the air channel 112 proximate to the opening 114. In alternate embodiments, the valve 104 can be disposed at any suitable location with respect to the air channel 112 and the opening 114. For example, in one embodiment, the valve 104 could be disposed at or comprise the opening 114 of the channel 112. Referring to Figure 3, in one embodiment, the apparatus 300 comprises an earbud, eartip or headphone device. The apparatus 300 in this example includes an ear tip 120. When the valve 104 is closed, wind can cause overpressure on the top surface of the microphone 108. This overpressure can lead to clipping, for example. When the valve 104 is opened, air can travel through the channel or exhaust path 112 leading to pressure release. This results in less pressure to the microphone and less audio clipping.

The valve 104 can be an active valve or a passive valve. For example, an electrically-controlled active valve can be implemented using for example a miniaturized solenoid valve. A passive valve can be implemented as an overpressure vent.

Referring to Figure 1, in one embodiment, the apparatus 100 includes a controller 106. The controller 106 generally comprises a processor and memory. The processor is generally configured to execute non-transitory machine readable instructions, which when execute, are configured to carry out the processes described herein. When the valve 104 is an active valve, the controller 106 can control the operation of the valve 104 and switch the state of the valve between the open and closed positions.

In one embodiment referring to Figure 2, the apparatus 200 includes one or more sensors 118. In this example, when the valve 104 is an active valve, the valve 104 can be controlled by a sensor 118. For example, the sensor 118 can be a wind noise detector (WND) that is configured to read the microphone signal and use digital signal processing (DSP) to determine the limit of microphone clipping. Alternatively, the sensor 118 can be a pressure sensor.

The sensor 118 shown in Figure 2 can be a standalone device that is connected to and controls the valve 104 between the open and closed states. In an alternate embodiment, the sensor 118 is coupled to or part of the controller 106 illustrated in Figure 1. In one embodiment, signals from the sensor 118 can be sent to the controller 106 of Figure 1, which controls the state of the valve 104.

Referring to Figure 1, in one embodiment, the apparatus 100 optionally includes a timer 122. The timer 122 can be a standalone device connected to the controller 106, or part of the controller 106. The timer 122 is used to determine the minimum “open time” for the valve 104, in order to avoid rapid opening and closing the valve 104, which may create audio artefacts. The suitable value for timing of the timer 122 depends on the acoustic and mechanical structures, and can be experimentally found in a practical implementation.

Figure 4 illustrates an exemplary process flow 400 incorporating aspects of the disclosed embodiments. In this example, a signal from the front cavity of the microphone is obtained 402. The signal can include for example, an air pressure signal, a nois detector or such other suitable signal that can be used to detect wind noise. It is determined 404 if the signal indicates the presence of wind noise. If wind noise is detected, a valve 104 is opened 406 to allow air to flow through the valve.

Referring to Figure 5, in one embodiment, the signal is an air pressure signal. In this example, the air pressure in the microphone cavity is detected 408 from the obtained signal. It is determined 410 whether the detected air pressure reaches or exceeds a predetermined threshold value. If the predetermined threshold is not reached or exceeded, the process continues to detect or measure 408 the air pressure. If the predetermined threshold value is exceeded, the valve 104 is opened 406. The predetermined threshold value can include both positive and negative pressure values. In one embodiment, the release of air pressure through the valve reduces the pressure on the microphone 110 and reduces the acoustic noise. In the case of negative pressure on in the front cavity 108 of the microphone, the opening of the valve 104 releases the negative pressure.

In one embodiment, referring to Figure 6, once the valve opened 406, a timer 122 is started 414. The timer 122 is monitored 416 for an expiration of a predetermined time period. When the time period expires, the valve 104 is closed 418. The timer 122 can be reset 420. The timer 122 is used to determine the minimum “open time” for the valve 104. By using a minimum open time for the valve 104, rapid opening and closing of the valve 104 is avoided, which may otherwise create audio artefacts.

The aspects of the disclosed embodiments are directed to a venting structure for a microphone assembly. A microphone front cavity is connected to the surrounding air via a controllable valve. The wind-caused excess pressure in the microphone front cavity is released via the valve. The valve connects the front cavity to the surrounding air allow for improved operation in windy conditions, and tunable microphone sensitivity, respectively.

Valves, such as miniature valves are disposed between the front cavity and surrounding air. These valves will open when a desired pressure level is reached or exceeded. In a passive valve solution, the valves are mechanically tuned to open when the desired pressure is reached or exceeded. In an active valve solution, the valves are controlled by external control to open when desired pressure is reached or exceeded.

Thus, while there have been shown, described and pointed out, fundamental novel features of the invention as applied to the exemplary embodiments thereof, it will be understood that various omissions, substitutions and changes in the form and details of devices and methods illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit and scope of the presently disclosed invention. Further, it is expressly intended that all combinations of those elements, which perform substantially the same function in substantially the same way to achieve the same results, are within the scope of the invention. Moreover, it should be recognized that structures and/or elements shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.