Microphone assembly having a reconfigurable geometry

Abstract

The disclosure relates to a microphone assembly (100) for acquiring a plurality of audio signals, wherein the microphone assembly (100) has a reconfigurable geometry so that the microphone assembly (100) may be configured to be embedded in or attached to a body. The microphone assembly (100) comprises: a plurality of digital microphones (101a-h) configured to convert the sound signal impinging on each digital microphone into a corresponding digital electrical signal, a digital signal processing unit (102) comprising a serial digital communication interface (102a) and a processor (102b), and a connecting and mounting structure configured to provide a flexible electrical connection and a flexible mechanical arrangement for the plurality of digital microphones (101a-h).

Claims

1. A microphone assembly for acquiring a plurality of audio signals, the microphone assembly having a reconfigurable geometry so that the microphone assembly may be configured to be embedded in or attached to a body, the microphone assembly comprising: a plurality of digital microphones configured to convert a sound signal impinging on each of the digital microphones into a corresponding digital electrical signal, wherein the digital electrical signal is a Pulse-Code-Modulation (PCM) or a Pulse-Density-Modulation (PDM) digital serial electrical signal; a digital signal processor comprising a serial digital communication interface and a processor, wherein the serial digital communication interface is configured to receive the digital electrical signals provided by the plurality of digital microphones, and wherein the processor is configured to store, transmit, and/or process the digital electrical signals provided by the plurality of digital microphones; and a connecting and mounting structure configured to provide a flexible electrical connection and a flexible mechanical arrangement for the plurality of digital microphones, wherein the connecting and mounting structure comprises a plurality of wired connections configured to connect the plurality of digital microphones with the serial digital communication interface in such a way that at least one of the plurality of digital microphones is moveable relative to other digital microphones of the plurality of digital microphones, wherein the plurality of wired connections comprise: a VCC wire for providing the voltage required to power electronics embedded inside the plurality of digital microphones; a GND wire for connecting the ground of the plurality of digital microphones to the ground of the digital signal processor; a Clock wire for carrying clock signals to the plurality of digital microphones; a Word-Select wire for carrying to the plurality of digital microphones a signal specifying a selection of a Left-Right channel of the serial digital communication interface; and a serial-data wire for carrying PCM or PDM digital serial data from the plurality of digital microphones to the digital signal processor; wherein each of the plurality of wires is connected to two or more of the plurality of digital microphones, and wherein the plurality of wired connections further comprise: a first digital buffer configured to buffer the clock signals for the plurality of digital microphones; a second digital buffer configured to buffer the word-select signals for the plurality of digital microphones; and a plurality of resistors configured to terminate the serial-data wire.

2. The microphone assembly of claim 1, wherein the plurality of wired connections comprise flexible flat cables connecting the digital microphones to the digital signal processor.

3. The microphone assembly of claim 1, wherein the digital signal processor comprises one or more of: a Digital Signal Processor (DSP) chip, a microcontroller, a Central Processing Unit (CPU) and/or a Field Programmable Gate Array (FPGA) chip.

4. The microphone assembly of claim 1, wherein the microphone assembly further comprises one or more motors, wherein each motor is configured to move at least one of the plurality of digital microphones.

5. The microphone assembly of claim 1, wherein the processor of the digital signal processor is configured for at least one of the plurality of digital microphones to estimate a target position of a respective digital microphone on the basis of the signals provided by the plurality of digital microphones.

6. The microphone assembly of claim 5, wherein the microphone assembly further comprises a controller configured to control the positions of one or more of the plurality of digital microphones and wherein the processor is configured to send information about target positions via the serial digital communication interface to the controller for moving the one or more of the plurality of digital microphones to their respective target positions.

7. The microphone assembly of claim 1, wherein the processor of the digital signal processor is configured to compute a set of digital filters and to process the electrical signals provided by the plurality of digital microphones using the set of digital filters, wherein the set of digital filters can be adaptive and time-variant according to changes in an acoustical field, and/or changes of positions of the plurality of digital microphones.

8. The microphone assembly of claim 7, wherein the digital signal processor is configured to compute the set of digital filters on the basis of an approximate matrix inversion scheme, so as to generate one or more processed microphone signals with improved signal-to-noise ratio and better directivity pattern in comparison with raw microphone signals provided by the plurality of digital microphones.

9. A microphone assembly for acquiring a plurality of audio signals, the microphone assembly having a reconfigurable geometry so that the microphone assembly may be configured to be embedded in or attached to a body, the microphone assembly comprising: a plurality of digital microphones configured to convert a sound signal impinging on each of the digital microphones into a corresponding digital electrical signal, wherein the digital electrical signal is a Pulse-Code-Modulation (PCM) or a Pulse-Density-Modulation (PDM) digital serial electrical signal; a digital signal processor comprising a serial digital communication interface and a processor, wherein the serial digital communication interface is configured to receive the digital electrical signals provided by the plurality of digital microphones, and wherein the processor is configured to store, transmit, and/or process the digital electrical signals provided by the plurality of digital microphones; and a connecting and mounting structure configured to provide a flexible electrical connection and a flexible mechanical arrangement for the plurality of digital microphones, wherein the connecting and mounting structure comprises a plurality of wired connections configured to connect the plurality of digital microphones with the serial digital communication interface in such a way that at least one of the plurality of digital microphones is moveable relative to other digital microphones of the plurality of digital microphones, wherein the connecting and mounting structure comprises a plurality of enclosures, each enclosure encasing a rigid Printed Circuit Board (PCB), wherein one or more digital microphones of the plurality of digital microphones are soldered on the rigid PCB and connected to one of the plurality of wired connections.

10. The microphone assembly of claim 9, wherein the connecting and mounting structure comprises a plurality of fixing devices for fixing the plurality of enclosures on a surface of the rigid or flexible body where the microphone array is installed.

11. The microphone assembly of claim 10, wherein the plurality of fixing devices comprise one or more of: suction cups, clips, pins, zips, buttons, adhesive pads, crocodile jaws, and/or LEGO compatible bricks.

12. A microphone assembly for acquiring a plurality of audio signals, the microphone assembly having a reconfigurable geometry so that the microphone assembly may be configured to be embedded in or attached to a body, the microphone assembly comprising: a plurality of digital microphones configured to convert a sound signal impinging on each of the digital microphones into a corresponding digital electrical signal, wherein the digital electrical signal is a Pulse-Code-Modulation (PCM) or a Pulse-Density-Modulation (PDM) digital serial electrical signal; a digital signal processor comprising a serial digital communication interface and a processor, wherein the serial digital communication interface is configured to receive the digital electrical signals provided by the plurality of digital microphones, and wherein the processor is configured to store, transmit, and/or process the digital electrical signals provided by the plurality of digital microphones; and a connecting and mounting structure configured to provide a flexible electrical connection and a flexible mechanical arrangement for the plurality of digital microphones, wherein the connecting and mounting structure comprises a plurality of wired connections configured to connect the plurality of digital microphones with the serial digital communication interface in such a way that at least one of the plurality of digital microphones is moveable relative to other digital microphones of the plurality of digital microphones, wherein the digital signal processor is configured to determine a position of at least one digital microphone of the plurality of digital microphones based on electrical signals provided by the plurality of digital microphones.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further embodiments of the disclosure will be described with respect to the following figures, wherein:

(2) FIG. 1 shows a schematic diagram of a flexible microphone assembly according to an embodiment;

(3) FIG. 2 shows a schematic diagram illustrating a typical pinout of a digital MEMS microphone with an I2S interface for a microphone assembly according to an embodiment;

(4) FIG. 3 shows a schematic diagram of a stripe array of digital microphones along a single flat cable of a microphone assembly according to an embodiment;

(5) FIG. 4 shows a schematic diagram of a chicken horse array of digital microphones of a microphone assembly according to an embodiment;

(6) FIG. 5 shows an example of mounting a flexible microphone assembly over a human head according to an embodiment;

(7) FIG. 6 shows an example of mounting a table-top planar microphone assembly on a LEGO compatible mounting system according to an embodiment;

(8) FIG. 7 shows an example of a passive microphone assembly according to an embodiment; and

(9) FIG. 8 shows an example of an active microphone assembly according to an embodiment.

(10) In the figures, identical reference signs will be used for identical or functionally equivalent features.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(11) In the following description, reference is made to the accompanying drawings, which form part of the disclosure, and in which are shown, by way of illustration, specific aspects in which the present disclosure may be placed. It will be appreciated that other aspects may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense, as the scope of the present disclosure is defined by the appended claims.

(12) For instance, it will be appreciated that a disclosure in connection with a described method may also hold true for a corresponding device or system configured to perform the method and vice versa. For example, if a specific method step is described, a corresponding device may include a unit to perform the described method step, even if such unit is not explicitly described or illustrated in the figures.

(13) Moreover, in the following detailed description as well as in the claims embodiments with different functional blocks or processing units are described, which are connected with each other or exchange signals. It will be appreciated that the present disclosure covers embodiments as well, which include additional functional blocks or processing units that are arranged between the functional blocks or processing units of the embodiments described below.

(14) Finally, it is understood that the features of the various exemplary aspects described herein may be combined with each other, unless specifically noted otherwise.

(15) FIG. 1 shows an embodiment of a flexible microphone assembly 100 comprising a plurality of digital MEMS microphones 101a-h (e.g., with an I2S serial data interface). The microphone assembly 100 has no pre-defined geometry and it can operate, with variable acoustical performances, no matter how the positions of the microphones 101a-h are changed.

(16) In the example of an embodiment in FIG. 1, the flexible microphone assembly 100 comprises eight digital MEMS microphones 101a-h and a digital signal processing unit 102. Each of the digital MEMS microphones 101a-h is connected to the digital signal processing unit 102 through a flexible flat cable 103a-h. Thus, each of the digital MEMS microphones 101a-h can be freely placed at any position, e.g., a position that is considered optimal for the acoustical performance of the microphone array.

(17) In an embodiment, the digital signal processing unit 102 can be a Digital Signal Processor (DSP) chip, a microcontroller, a Central Processing Unit (CPU) and/or a Field Programmable Gate Array (FPGA) chip.

(18) The plurality of digital MEMS microphones 101a-h are configured to convert the sound signal impinging on each microphone 101a-h into a corresponding digital electrical signal, in particular a Pulse-Code-Modulation (PCM) or a Pulse-Density-Modulation (PDM) digital serial electrical signal. The digital signal processing unit 102 comprises a serial digital communication interface 102a (e.g., an I2S interface) and a processor 102b, wherein the serial digital communication interface 102a is configured to receive the electrical signals provided by the plurality of digital MEMS microphones 101a-h. The processor 102b is configured to store, transmit, and/or process the digital electrical signals provided by the plurality of digital MEMS microphones 101a-h. As will be described in more detail below, the flexible flat cables 103a-h are part of a connecting and mounting structure configured to provide a flexible electrical connection and a flexible mechanical arrangement for the plurality of digital MEMS microphones 101a-h, wherein the connecting and mounting structure comprises a plurality of wired connections configured to connect the plurality of digital MEMS microphones 101a-h with the serial digital communication interface 102a in such a way that at least one of the plurality of digital MEMS microphones 101a-h is moveable relative to the others.

(19) In an embodiment, the connecting and mounting structure comprises a plurality of enclosures, each enclosure encasing a rigid Printed Circuit Board (PCB), wherein one or optionally two microphones of the plurality of digital MEMS microphones 101a-h are soldered on the rigid Printed PCB and connected to one of the plurality of wired connections.

(20) In an embodiment, the connecting and mounting structure comprises a plurality of fixing devices for fixing the plurality of enclosures on a surface of the rigid or flexible body where the microphone array is installed. In an embodiment, the plurality of fixing devices comprise suction cups, clips, pins, zips, buttons, adhesive pads, crocodile jaws, and/or LEGO compatible bricks.

(21) In an embodiment, the processor 102b of the digital signal processing unit 102 is configured to compute a set of digital filters and to process the electrical signals provided by the plurality of digital MEMS microphones 10l a-h using the set of digital filters, wherein the set of digital filters can be adaptive and time-variant according to changes in an acoustical field, and/or changes of positions of the plurality of microphones 101a-h.

(22) In an embodiment, the digital signal processing unit 102 is configured to compute the set of digital filters on the basis of an approximate matrix inversion scheme, so as to generate one or more processed microphone signals with improved signal-to-noise ratio and better directivity pattern in comparison with raw microphone signals provided by the microphones 101a-h, as disclosed in WO2011042823 (already referred to above).

(23) FIG. 2 schematically illustrates an example of a pinout of a digital MEMS microphone 101a-h (e.g., with a digital I2S interface) of the microphone assembly 100 according to an embodiment. The name and function of each pin are explained in the following:

(24) Pin 1 is called SCK with a function of Serial-Data Clock for the I2S Interface.

(25) Pin 2 is called SD with a function of Serial-Data Output for the I2S Interface. This pin is tri-stated when it is not actively driving the appropriate output channel. The SD trace can comprise a 100 k pulldown resistor to discharge the line during the time when all microphones 101a-h on the bus have tri-stated their outputs.

(26) Pin 3 is called WS with a function of Serial Data-Word Select for the I2S Interface.

(27) Pin 4 is called L/R and provides a function for Left/Right Channel Select. When it is set low, the microphone 101a-h outputs the signal in the left channel of the I2S frame. When it is set high, the microphone 101a-h outputs the signal in the right channel of the I2S frame.

(28) Pins 5, 6 and 9 are called GND, and they are connected to the ground on the Printed Circuit Board (PCB).

(29) Pin 7 is called VDD and is connected to the power with 1.8 V to 3.3 V. This VDD pin should be decoupled to pin 6 with a 0.1 F capacitor.

(30) Pin 8 is called CHIPEN and it can enable the microphone 101a-h. When pin 8 is set low (ground), the microphone 101a-h can be disabled and put in a power-down mode. When pin 8 is set high (VDD), the microphone 101a-h can thus be enabled.

(31) In an embodiment, the acoustical port of the digital MEMS microphone 101a-h is located in the center of pin 5, which is meant to be soldered on the Printed Circuit Board (PCB). A central hole with this circular pin enables a sound to come into the microphone by passing through the Printed Circuit Board (PCB) itself.

(32) Generally, each of the digital MEMS microphones 101a-h only needs five wires for connecting to the digital signal processing unit 102, as pin 4 (L/R) and pin 8 (CHIPEN) can be configured locally. According to an embodiment two of the digital MEMS microphones 101a-h can share the same five wires, as the Serial-Data output of the I2S interface allows two sources to be wired on the same cable. They can talk respectively according to the status of the WS line. In an embodiment, one of the two microphones can be configured as left and the other as right. When more than two microphones are employed, the minimum number of the required wires will increase, but a number of wires can be shared among the digital MEMS microphones 101a-h, as seen in FIG. 3.

(33) FIG. 3 illustrates an embodiment of the microphone assembly 100 with eight digital MEMS microphones 101a-h forming a stripe array along a single flat cable. This embodiment refers to the case in which all the eight digital MEMS microphones 10l a-h are daisy-chained on individual small PCBs and all are wired on a single, long flat cable with only eight wires.

(34) As can be seen in FIG. 3, all of these eight digital MEMS microphones 101a-h can be connected to the same VCC 301, GND 302, Clock 303, Word-Select 304 wires, and each pair of the microphones 101a-h can share a Serial-Data wire 305. Therefore, eight wires in total are required for wiring eight digital MEMS microphones 101a-h together. To increase flexibility in the way each digital MEMS microphone 101a-h can be connected to its own individual flat cable 103a-h, the microphone assembly 100 can be arranged in a different schematic, which is depicted in FIG. 4.

(35) FIG. 4 shows a schematic diagram of the microphone assembly 100 according to an embodiment, wherein the microphone assembly 100 comprises eight digital MEMS microphones 101a-h and forms a chicken horse array and wherein only 5 wires are used to connect with an end of the flat cable 103a-h of each digital MEMS microphone 101a-h. In this case, before the wires for individual microphones 101a-h are separated, it is advisable to buffer the Word-Select and Clock signals by means of a logic buffer 401, 402, such as the SN74HC541 8-channel, low-power logic buffer. The digital MEMS microphones 10l a-h are thus be provided with clean digital clock signals, avoiding artifacts caused by echoes. The echoes can occur if the split-out of the clock signals to several cables is done by simply wiring the cables together.

(36) For the same reason, the Serial-Data wires 305a-d should be terminated properly: according to an embodiment four high-impedance resistors 403, e.g., 100k Ohm resistors, can be employed to terminate the Serial-Data lines 305a-d close to the split-out, so that the data transmitted by the two microphones 101a-h of each pair can remain clean when arriving at the digital signal processing unit 102 of the microphone assembly 100.

(37) With the flexible electrical connection and mechanical arrangement for the digital MEMS microphones 101a-h shown in the above embodiment, a flexible microphone assembly is provided in which the digital MEMS microphones 101a-h can be individually placed in freely chosen positions.

(38) FIG. 5 shows a first example of how the flexible microphone assembly 100 can be used, wherein the flexible microphone assembly 100 is mounted over a human head according to an embodiment.

(39) FIG. 6 shows a second example of how the flexible microphone assembly 100 can be used, wherein a table-top planar microphone array is mounted on a LEGO compatible mounting system according to an embodiment.

(40) As can be seen in FIG. 6, the casing and mounting systems mimic Lego bricks. This enables the digital MEMS microphones 101a-h to be incorporated in an infinite number of possible Lego constructions. The compatibility with LEGO bricks allows for construction of microphone assemblies in any shape. Lego Technic components can be used for building structures with movable parts.

(41) FIG. 7 shows a third example of how the flexible microphone assembly 100 can be used, wherein the microphone assembly 100 is attached to a glove according to an embodiment. The microphone assembly 100 of FIG. 7 comprises several (e.g., eight) digital MEMS microphones 10l a-h and a user can change the positions of the digital MEMS microphones 101a-h at will by simply moving the fingers.

(42) FIG. 8 shows a fourth example of how the flexible microphone assembly 100 can be used. In the example, each microphone 101a-h of the microphone assembly 100 is placed on a rotating disk according to an embodiment. The rotating disks on which the digital MEMS microphones 101a-h are placed can form a robotized system under control of a digital microcontroller.

(43) In an embodiment, the digital signal processing unit 102 can be configured to determine the previously unknown position of at least one microphone of the digital MEMS microphones 101a-h on the basis of the digital serial electrical signals provided by the digital MEMS microphones 101a-h. Furthermore, the digital signal processing unit 102 can, for each or for at least one of the digital MEMS microphones 101a-h, estimate a target position of the respective microphone 101a-h on the basis of the digital serial electrical signals provided by the digital MEMS microphones 101a-h.

(44) The digital signal processing unit 102 can actively change the positions of the digital MEMS microphones 101a-h by instructing the digital microcontroller to move the microphones 101a-h into the target positions determined above. The target positions may be optimal positions to which the digital MEMS microphones 101a-h should be moved for improving the acoustical performance of the microphone array.

(45) In an embodiment, the microphone assembly 100 further comprises one or more motors, wherein each motor is configured to move at least one of the plurality of digital MEMS microphones 101a-h to its target or optimal position.

(46) While a particular feature or aspect of the disclosure may have been disclosed with respect to only one of several implementations or embodiments, such feature or aspect may be combined with one or more other features or aspects of the other implementations or embodiments as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the terms include, have, with, or other variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term comprise. Also, the terms exemplary, for example and e.g. are merely meant as an example, rather than the best or optimal. The terms coupled and connected, along with derivatives may have been used. It should be understood that these terms may have been used to indicate that two elements cooperate or interact with each other regardless whether they are in direct physical or electrical contact, or they are not in direct contact with each other.

(47) While specific aspects have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific aspects shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific aspects discussed herein.

(48) Although the elements in the following claims are recited in a particular sequence with corresponding labeling, unless the claim recitations otherwise imply a particular sequence for implementing some or all of those elements, those elements are not necessarily intended to be limited to being implemented in that particular sequence.

(49) Many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the above teachings. Of course, those skilled in the art readily recognize that there are numerous applications of the disclosure beyond those described herein. While the present disclosure has been described with reference to one or more particular embodiments, those skilled in the art recognize that many changes may be made thereto without departing from the scope of the present disclosure. It is therefore to be understood that within the scope of the appended claims and their equivalents, the disclosure may be practiced otherwise than as specifically described herein.