TWI845785B - Earphone system with microelectromechanical system (mems) microphone with noise cancellation function and operation method thereof - Google Patents

Abstract

An earphone system with microelectromechanical system (MEMS) microphone with noise cancellation function and operation method thereof is disclosed. By providing two wires to connect a host and an earphone device, wherein, at least one of the wires to transmit a music signal, the other one of the wires is a ground wire, and then driving the earphone device through a differential voltage or an offset voltage. The MEMS microphone within the earphone device with active noise cancellation (ANC) does not need to transmit a received environmental noise to the host through additional wires for calculating. The mechanism is help to reduce the line losses, costs and signal delay of the earphone device.

Description

Micro-electromechanical microphone headset system with noise reduction function and its operation method

The present invention relates to an active anti-noise system and its operating method, in particular to a micro-electromechanical microphone headset system with noise reduction function and its operating method.

In recent years, with the popularization and rapid development of semiconductor technology, the miniaturization of various electronic components has become a problem. At the same time, it also enables portable devices or mobile devices to achieve the purpose of being thin and light without sacrificing functionality, or enables electronic products that originally have space limitations to accommodate more electronic components to provide more functions, such as headphones.

Generally speaking, traditional headphones receive sound signals from the sound source in order to play them through the sound unit. However, due to the presence of various environmental noises in the living environment, it is easy for the listener to feel that the sound is not clear enough. Therefore, some manufacturers have proposed using a microphone independent of the headphones or a micro-electromechanical microphone installed in the headphones to receive environmental noise, and transmit the environmental noise to the sound source host through a wire to generate a sound wave signal with a phase opposite to the environmental noise, so that the anti-noise signal can be used to offset the environmental noise while playing music. However, under such a structure, there are problems of (1) line loss, (2) high cost and (3) signal delay. The following is a further explanation of these three problems:

(1) The first-stage output of sound after passing through a micro-electromechanical microphone is often much less than 1 volt. If it does not pass through any amplifier or signal format conversion, such a small voltage will be distorted during the wire transmission process. We call this line loss (or simply "line loss"). Line loss will cause the sound signal to be unable to be completely restored, and thus unable to effectively eliminate environmental noise.

(2) Connecting the microphone and the sound source host through a wire is an inevitable cost in terms of structure. In addition, in order to avoid wire loss, additional amplifiers or signal format converters added to the system will also increase manufacturing costs. In addition, the aforementioned MEMS microphone requires power supply, so the current method requires not only a wire to transmit environmental noise, but also an independent power line from the sound source host to the headphone device to power the MEMS microphone.

(3) Environmental noise is transmitted through the air, and the time it takes for the earphone housing to reach the human ear is very short. The so-called noise reduction technology is to collect noise from the microphone as quickly as possible within this limited time, then generate an anti-phase signal through circuit calculation, and finally the sound device emits a sound wave to cancel the noise. However, in the aforementioned architecture, when the sound signal is transmitted, the packet format conversion and signal processing will produce delays, which will make it impossible to eliminate high-frequency noise in real time, thereby affecting the user experience.

In summary, it can be seen that the previous technology has long been plagued by problems such as line loss, high cost, and signal delay. Therefore, it is necessary to propose improved technical means to solve this problem.

The present invention discloses a micro-electromechanical microphone headset system with noise reduction function and its operation method.

First, the present invention discloses a micro-electromechanical microphone headset system with noise reduction function, which includes: a sound source host and a headset device. The sound source host is used to provide at most two wires, wherein one of the two wires transmits a music signal, and the other of the two wires is a ground wire. Then, in the headset device, it includes: a micro-electromechanical microphone and a sound module. The micro-electromechanical microphone includes: a noise receiving module and an active anti-noise module. The noise receiving module is electrically connected to the wire and continuously receives ambient noise through the sound receiving element to generate ambient sound wave signals corresponding to the ambient noise; the active anti-noise module is electrically connected to the noise receiving module and the wire to receive the music signal from the wire that transmits the music signal, and to generate an inverted sound wave signal with a phase opposite to the ambient sound wave signal, and transmit the inverted sound wave signal and the music signal together; and the sound module is electrically connected to the active anti-noise module to receive the inverted sound wave signal and the music signal, and simultaneously plays the received inverted sound wave signal and the music signal through the sound unit, so that the played inverted sound wave signal offsets the ambient noise.

In addition, the present invention also discloses a method for operating a micro-electromechanical microphone headset with a noise reduction function, which is applied in an environment with a sound source host and a headset device, and the steps include: the sound source host provides at most two wires, wherein one of the two wires transmits a music signal, and the other of the two wires is a ground wire; the headset device is electrically connected to the sound source host through the two wires to receive the music signal from the sound source host; the headset device continuously transmits the music signal through the sound source host. The micro-electromechanical microphone with noise reduction function collects ambient noise and generates an ambient sound wave signal corresponding to the ambient noise; the micro-electromechanical microphone generates an anti-phase sound wave signal with a phase opposite to the ambient sound wave signal, and transmits the anti-phase sound wave signal and the music signal to the sound unit installed in the headphone device; the headphone device simultaneously plays the received anti-phase sound wave signal and the music signal through the sound unit, so that the played anti-phase sound wave signal offsets the ambient noise.

The system and method disclosed in the present invention are as described above. The difference from the prior art is that the present invention provides a maximum of two wires to connect the audio source host and the headphone device, one of which is used to transmit the music signal, and the other of which is a ground wire, and drives the headphone device in a differential voltage or offset voltage manner. The micro-electromechanical microphone in the headphone device has active anti-noise processing capabilities, and does not need to transmit the received environmental noise to the audio source host for calculation through an additional line.

Through the above-mentioned technical means, the present invention can achieve the technical effect of reducing line loss, cost and signal delay.

110: Audio source host

120: Headphones

121: Micro-electromechanical microphone

121a: The first micro-electromechanical microphone

121b: Second micro-electromechanical microphone

122: Voice module

131: Noise collecting module

132: Active anti-noise module

311,411,511,611: First lead

312,412,512,612: Second conductor

313,513: The third conductor

Step 210: The audio source host provides at most two wires, one of which transmits a music signal, and the other of which is a ground wire.

Step 220: The headphone device is electrically connected to the audio source host via the two wires to receive the music signal from the audio source host.

Step 230: The headphone device continuously collects ambient noise through at least one micro-electromechanical microphone with noise reduction function, and generates an ambient sound wave signal corresponding to the ambient noise.

Step 240: The micro-electromechanical microphone generates an anti-phase sound wave signal that is opposite in phase to the ambient sound wave signal, and transmits the anti-phase sound wave signal and the music signal to a sound unit disposed in the headphone device.

Step 250: The earphone device simultaneously plays the received inverse sound wave signal and the music signal through the sound unit, so that the played inverse sound wave signal cancels out the ambient noise.

Figure 1 is a system block diagram of the micro-electromechanical microphone headset system with noise reduction function of the present invention.

Figure 2 is a flow chart of the method for operating the micro-electromechanical microphone headset with noise reduction function of the present invention.

Figure 3 is a schematic diagram of the first embodiment of the present invention.

Figure 4 is a schematic diagram of the second embodiment of the present invention.

Figure 5 is a schematic diagram of the third embodiment of the present invention.

Figure 6 is a schematic diagram of the fourth embodiment of the present invention.

The following will be used in conjunction with diagrams and examples to explain in detail the implementation of the present invention, so that the process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

First, before explaining the MEMS microphone headset system with noise reduction function and its operation method disclosed in the present invention, the environment in which the present invention is applied is explained. The present invention is applied to a headset device, and only two wires are used to connect the headset device and the sound source host. The improved power supply method realizes active noise reduction and reduces line loss, cost and signal delay.

The following diagrams are used to further explain the MEMS microphone headset system with noise reduction function and its operation method of the present invention. Please refer to "Figure 1" first. "Figure 1" is a system block diagram of the MEMS microphone headset system with noise reduction function of the present invention. This system includes: a sound source host 110 and a headset device 120. The sound source host 110 provides a maximum of two wires, one of which transmits a music signal, and the other of which is a ground wire. In actual implementation, the wires only include a first wire and a second wire, wherein the first wire transmits a music signal with a DC offset and drives the headset device 120 with an offset voltage, and the second wire is a ground wire.

Next, the earphone device 120 includes a micro-electromechanical microphone 121 and a sound module 122. The micro-electromechanical microphone 121 includes a noise receiving module 131 and an active anti-noise module 132. The noise receiving module 131 is electrically connected to the wire, and continuously receives the ambient noise through the sound receiving element to generate an ambient sound wave signal corresponding to the ambient noise. In actual implementation, the sound receiving element is electrically connected to the analog front end circuit (Analog Front End, AFE), the analog-to-digital converter (Analog-to-digital converter, ADC), the active anti-noise module 132 and the amplifier in sequence. It should be particularly noted that the earphone device 120 may further include another MEMS microphone, which is electrically connected to the MEMS microphone 121 and the wire, and continuously receives residual noise to generate a corresponding error signal, and transmits the error signal to the MEMS microphone 121 for delay compensation processing by the active anti-noise module 132.

The active anti-noise module 132 is electrically connected to the noise receiving module 131 and the wire, and is used to receive the music signal from the wire that transmits the music signal, and to generate an anti-phase sound wave signal that is opposite in phase to the ambient sound wave signal, and transmit the anti-phase sound wave signal and the music signal together. In other words, the generated anti-phase sound wave signal has a phase difference of 180 degrees from the ambient sound wave signal. In actual implementation, the active anti-noise module 132 may include: anti-phase, delay, gain, time control, equalization, signal superposition, format conversion and filtering, etc., for noise processing and music signal processing.

The sound module 122 is electrically connected to the active anti-noise module 132 to receive the reverse phase sound wave signal and the music signal, and simultaneously play the received reverse phase sound wave signal and the music signal through the sound unit, so that the played reverse phase sound wave signal offsets the environmental noise. In actual implementation, the sound unit may include: electromagnetic, piezoelectric, electrostatic, plasma, etc.

It should be particularly noted that in actual implementation, the modules described in the present invention can be implemented in various ways, including software, hardware or any combination thereof. For example, in some embodiments, each module can be implemented using software and hardware or one of them. In addition, the present invention can also be implemented partially or completely based on hardware. For example, one or more modules in the system can be implemented through integrated circuit chips, system on chip (SoC), complex programmable logic device (CPLD), field programmable gate array (FPGA), etc. The present invention can be a system, method and/or computer program. The computer program may include a computer-readable storage medium that carries computer-readable program instructions for causing a processor to implement various aspects of the present invention. The computer-readable storage medium may be a tangible device that can hold and store instructions for use by an instruction execution device. Computer-readable storage media may be, but are not limited to, electric storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: hard drive, random access memory, read-only memory, flash memory, optical disk, floppy disk, and any suitable combination of the above. As used herein, computer-readable storage media is not to be interpreted as a transient signal per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., optical signals through optical fiber cables), or electrical signals transmitted through wires. In addition, the computer-readable program instructions described herein may be downloaded from the computer-readable storage media to various computing/processing devices, or downloaded to external computer devices or external storage devices through a network, such as the Internet, a local area network, a wide area network, and/or a wireless network. The network may include copper transmission cables, optical fiber transmission, wireless transmission, routers, firewalls, switches, hubs, and/or gateways. The network card or network interface in each computing/processing device receives computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing/processing device. The computer program instructions for executing the operation of the present invention can be assembly language instructions, instruction set architecture instructions, machine instructions, machine-related instructions, microinstructions, firmware instructions, or source code or object code (Object Code) written in any combination of one or more programming languages, wherein the programming language includes object-oriented programming languages, such as Common Lisp, Python, C++, Objective-C, Smalltalk, Delphi, Java, Swift, C#, Perl, Ruby and PHP, as well as conventional procedural programming languages, such as C language or similar programming languages. The computer program instructions may be executed entirely on the computer, partially on the computer, as a separate piece of software, partially on the client computer and partially on the remote computer, or entirely on the remote computer or server.

Please refer to "Figure 2", which is a method flow chart of the operation method of the micro-electromechanical microphone headset with noise reduction function of the present invention, which is applied in an environment with a sound source host 110 and a headset device 120. The steps include: the sound source host 110 provides at most two wires, wherein one of the two wires transmits a music signal and the other of the two wires is a ground wire (step 210); the headset device 120 is electrically connected to the sound source host 110 through the two wires to receive the music signal from the sound source host 110 (step 220); the headset device The device 120 continuously collects the ambient noise through the micro-electromechanical microphone with noise reduction function, and generates an ambient sound wave signal corresponding to the ambient noise (step 230); the micro-electromechanical microphone 121 generates an anti-phase sound wave signal with a phase opposite to the ambient sound wave signal, and transmits the anti-phase sound wave signal and the music signal to the sound unit disposed in the earphone device 120 (step 240); the earphone device 120 simultaneously plays the received anti-phase sound wave signal and the music signal through the sound unit, so that the played anti-phase sound wave signal offsets the ambient noise (step 250). Through the above steps, the audio source host 110 and the headphone device 120 can be connected by providing at most two wires, one of which is used to transmit the music signal, and the other of which is a ground wire, and the headphone device 120 is driven by a differential voltage or an offset voltage. The micro-electromechanical microphone in the headphone device 120 has active anti-noise processing capabilities, and does not need to transmit the received environmental noise to the audio source host 110 for calculation through an additional line.

The following is explained in the form of an embodiment in conjunction with "Figure 3" to "Figure 6". As shown in "Figure 3", "Figure 3" is a schematic diagram of the first embodiment of the present invention. In this first embodiment, the audio source host 110 and the headphone device 120 are electrically connected by three wires (i.e., the first wire 311, the second wire 312 and the third wire 313). Among them, the first wire 311 is used to transmit the music signal, the second wire 312 is used to transmit VDD, and the third wire 313 is a ground wire. In addition, when the music signal is a differential signal, since two wires are required to transmit the music signal, the first wire 311 and the second wire 312 can be used for transmission, and the third wire 313 is also a ground wire. For example, the first wire 311 can transmit a positive signal, and the second wire 312 can transmit a negative signal. In actual implementation, the first wire 311 and the second wire 312 are parallel and equal-length lines, and transmit the same music signal with a phase difference of 180 degrees. In this way, the transmission rate and anti-interference ability can be improved. Next, the noise receiving module 131 receives the environmental noise through the sound receiving element, and generates an environmental sound wave signal corresponding to the received environmental noise. Next, the ambient sound wave signal is transmitted to the active anti-noise module 132, which generates an anti-phase sound wave signal with a phase opposite to the ambient sound wave signal. The active anti-noise module 132 then transmits the music signal received from the first wire 311 and the second wire 312, as well as the anti-phase sound wave signal generated by itself, to the sound module 122 so that the music signal can be played through the sound unit, so that the played anti-phase sound wave signal can offset the ambient noise, thereby achieving the effect of active anti-noise.

Please refer to "Figure 4", which is a schematic diagram of the second embodiment of the present invention. In this second embodiment, the audio source host 110 and the headphone device 120 are electrically connected by two wires (i.e., a first wire 411 and a second wire 412), wherein the first wire 411 is used to transmit a music signal with a DC offset, and the second wire 412 is a ground wire. Compared with the first embodiment, the number of wires between the audio source host 110 and the headphone device 120 is less, so it has a greater cost advantage. Afterwards, as in the first embodiment, the noise receiving module 131 will also receive environmental noise through the sound receiving element, and generate an environmental sound wave signal corresponding to the received environmental noise. Next, the ambient sound wave signal is transmitted to the active anti-noise module 132, which generates an anti-phase sound wave signal with a phase opposite to the ambient sound wave signal, and then transmits the music signal received from the first wire 411 and the anti-phase sound wave signal generated by itself to the sound module 122, so that they can be played through the sound unit, so that the played anti-phase sound wave signal offsets the ambient noise, thereby achieving the effect of active anti-noise.

As shown in FIG. 5, FIG. 5 is a schematic diagram of the third embodiment of the present invention. In this third embodiment, the difference between it and the first embodiment of FIG. 3 is only the number of micro-electromechanical microphones. In the third embodiment, the earphone device 120 includes a first micro-electromechanical microphone 121a and a second micro-electromechanical microphone 121b, and the two are electrically connected to each other. The second micro-electromechanical microphone 121b can receive residual noise, and generate a corresponding error signal according to the residual noise to be fed back to the first micro-electromechanical microphone 121a, so that the active anti-noise module of the first micro-electromechanical microphone 121a can compensate for the anti-noise effect affected by the delay. For example, when residual noise is received, an error signal is generated to make the first MEMS microphone 121a control the output time of the reverse phase sound wave signal to shorten the delay, or adjust the reverse phase sound wave signal according to the error signal, etc. In addition, due to the different number of MEMS microphones, the electrical connection method of the wires is slightly different. For the third embodiment, as shown in "Figure 5", the first wire 511 and the second wire 512 are both electrically connected to the first MEMS microphone 121a and the second MEMS microphone 121b, and the third wire 513 as the ground wire is electrically connected to the sound module 123, the first MEMS microphone 121a and the second MEMS microphone 121b at the same time.

In addition, as shown in FIG. 6 , FIG. 6 is a schematic diagram of the fourth embodiment of the present invention. In this fourth embodiment, the difference from the third embodiment is only the number of wires. In the fourth embodiment, there are only two wires between the audio source host 110 and the earphone device 120, namely the first wire 611 and the second wire 612. The first wire 611 is electrically connected to the first micro-electromechanical microphone 121a and the second micro-electromechanical microphone 121b at the same time, and the second wire 612, which is a ground wire, is electrically connected to the first micro-electromechanical microphone 121a, the second micro-electromechanical microphone 121b and the sound module 123 at the same time. In this example, it can be clearly seen that even in the case of multiple MEMS microphones, only two wires (i.e., the first wire 611 and the second wire 612) are required between the audio source host 110 and the headphone device 120. In other words, the active anti-noise processing is directly processed in the MEMS microphone inside the headphone device 120, and the sound signal does not need to be transmitted between the audio source host 110 and the headphone device 120 through additional wires, so it can effectively reduce line loss, cost and signal delay.

In summary, the difference between the present invention and the prior art is that the present invention provides at most two wires to connect the audio source host and the headphone device, one of which is used to transmit the music signal, and the other of which is a ground wire, and drives the headphone device in a differential voltage or offset voltage manner. The micro-electromechanical microphone in the headphone device has active anti-noise processing capabilities, and does not need to transmit the received environmental noise to the audio source host for calculation through an additional line. This technical means can solve the problems existing in the prior art, thereby achieving the technical effect of reducing line loss, cost and signal delay.

Although the present invention is disclosed as above by the aforementioned embodiments, it is not intended to limit the present invention. Anyone familiar with similar techniques can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of patent protection of the present invention shall be subject to the scope of the patent application attached to this specification.

110: Audio source host

120: Headphones

121: Micro-electromechanical microphone

122: Voice module

131: Noise collecting module

132: Active anti-noise module

Claims (8)

A micro-electromechanical microphone headset system with noise reduction function, the system comprises: a sound source end host, used to provide at most two wires, wherein one of the two wires transmits a music signal, and the other of the two wires is a ground wire; and an earphone device, electrically connected to the sound source end host through the two wires, the earphone device comprises: a micro-electromechanical microphone, which comprises: a noise receiving module, which is electrically connected to the two wires and continuously receives an environmental noise through at least one sound receiving element, so as to generate an environmental sound wave signal corresponding to the environmental noise signal; and an active anti-noise module electrically connected to the noise receiving module and the two wires, used to receive the music signal from the two wires transmitting the music signal, and generate an anti-phase sound wave signal with a phase opposite to the ambient sound wave signal, and transmit the anti-phase sound wave signal and the music signal together; and a sound module electrically connected to the active anti-noise module, used to receive the anti-phase sound wave signal and the music signal, and simultaneously play the received anti-phase sound wave signal and the music signal through a sound unit, so that the played anti-phase sound wave signal offsets the ambient noise. The micro-electromechanical microphone headphone system with noise reduction function as claimed in claim 1, wherein the two wires include a first wire and a second wire, the first wire is used to transmit the music signal with a DC offset and drive the headphone device with an offset voltage, and the second wire is the ground wire. As in claim 1, the micro-electromechanical microphone headset system with noise reduction function, wherein the sound receiving element is electrically connected to an analog front end circuit (AFE), an analog-to-digital converter (ADC), the active noise reduction module and an amplifier in sequence, and the active noise reduction module includes inversion, delay, gain, time control, equalization, signal superposition, format conversion and filtering operations for noise processing and audio processing. As in claim 1, the headphone device further comprises another micro-electromechanical microphone, the other micro-electromechanical microphone is electrically connected to the micro-electromechanical microphone and the two wires, and continuously receives a residual noise to generate a corresponding error signal, and transmits the error signal to the micro-electromechanical microphone for the active anti-noise module to perform delay compensation processing. A method for operating a micro-electromechanical microphone headset with a noise reduction function is applied in an environment having a sound source end host and a headset device, and the steps include: the sound source end host provides at most two wires, wherein one of the two wires transmits a music signal, and the other of the two wires is a ground wire; the headset device is electrically connected to the sound source end host through the two wires to receive the music signal from the sound source end host; the headset device continuously transmits the music signal through at least one micro-electromechanical microphone headset with a noise reduction function. The electric microphone collects an environmental noise and generates an environmental sound wave signal corresponding to the environmental noise; The microcomputer electric microphone generates an anti-phase sound wave signal with a phase opposite to the environmental sound wave signal, and transmits the anti-phase sound wave signal and the music signal to a sound unit disposed in the earphone device; and the earphone device simultaneously plays the received anti-phase sound wave signal and the music signal through the sound unit, so that the played anti-phase sound wave signal offsets the environmental noise. As in claim 5, the operating method of a micro-electromechanical microphone headset with noise reduction function, wherein the two wires include a first wire and a second wire, the first wire is used to transmit the music signal with a DC offset and drive the headset device with an offset voltage, and the second wire is the ground wire. The method for operating a MEMS microphone headset with noise reduction function as claimed in claim 5, wherein the MEMS microphone is electrically connected to an analog front end circuit (AFE), an analog-to-digital converter (ADC), an active anti-noise module and an amplifier in sequence to amplify and output the inverted sound wave signal, and the active anti-noise module includes inversion, delay, gain, time control, equalization, signal superposition, format conversion and filtering operations to perform noise processing and audio processing. As in claim 5, the method for operating a MEMS microphone headset with noise reduction function, wherein the headset device further includes another MEMS microphone, the other MEMS microphone is electrically connected to the MEMS microphone and the two wires, and continuously receives a residual noise to generate a corresponding error signal, and transmits the error signal to the MEMS microphone for the MEMS microphone to perform delay compensation processing.

Images