Device and method for calibrating sensitivity of built-in microphone of mobile phone

Abstract

The present invention discloses a device and method for calibrating the sensitivity of a built-in microphone of a mobile phone. The device includes: a protective sound inlet cover, an electret microphone, a sealing gasket, a main body housing, a circuit board, a mobile phone interface, and a sealing bottom ring; wherein, the inside of the main body housing is hollow and both ends are open; one end of the housing is a tapered opening from thick to thin, and a sealing gasket and an electret microphone are sequentially installed at the outer edge of the tapered opening; the protective sound inlet cover is open at one end and has a hollow cavity inside, and is sleeved on the tapered opening; the circuit board and the mobile phone interface are sequentially placed inside the main body housing, and one end of the circuit board is welded to the mobile phone interface; the other end of the mobile phone interface protrudes partially from the main body housing; the sealing bottom ring covers the other end of the mobile phone interface and seals the other end opening of the main body housing. The present invention measures the sensitivity of the built-in microphone of the mobile phone through synchronous measurement by an external calibration device, and the measurement data is accurate, the operation is simple, and the performance is stable.

Description

Technical Field

[0001] The present invention relates to the technical field of signal acquisition, and more specifically to a device and method for calibrating the sensitivity of a built-in microphone of a mobile phone. Background Art

[0002] A microphone, also known as a mic, is an energy conversion device that can convert sound signals into electrical signals. Its application scenarios are very rich, including mobile phones, walkie-talkies, landline phones, microphones, etc., all relying on the existence of the microphone. Especially for a mobile phone to make a normal call, the microphone is essential.

[0003] Currently, the microphone functions of different products in different usage scenarios are different, and there are countless microphone models on the market. However, in some scenarios where it is necessary to accurately test the sound volume using the built-in microphone of a mobile phone, the test data obtained is often not accurate.

[0004] There are many software on the market that can perform noise tests through the mobile phone microphone. Some of them have calibration functions. Currently, there are mainly several calibration methods. One is that the mobile phone user needs to compare and measure with a professional sound level meter, measure the same sound source, and correct the result of the mobile phone according to the reading shown on the sound level meter to make the readings consistent, thus completing the calibration of the mobile phone microphone. Generally speaking, ordinary users do not have the above measurement conditions. The second is to complete the above calibration process in a laboratory environment in advance, and recommend calibration values for each type of mobile phone. The mobile phone test software app automatically obtains the mobile phone model information and performs calibration according to the calibration value corresponding to the mobile phone model. The disadvantage of this method is that it is necessary to comprehensively measure and calibrate a wide variety of mobile phone models in advance, and the providers of mobile phone measurement software generally do not have this condition. In addition, the state of the mobile phone microphone will also change with use at any time, and this method cannot recognize the gradual change of the mobile phone sensitivity. The existing technologies all have defects, resulting in that mobile phone users cannot obtain relatively accurate test results and cannot meet specific test requirements.

[0005] Therefore, enabling mobile phone users to obtain relatively accurate test results and meet specific test requirements is an urgent problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides a device and method for calibrating the sensitivity of a built-in microphone of a mobile phone, and measures the sensitivity of the built-in microphone of the mobile phone by an external calibration device.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a device for calibrating the sensitivity of a built-in microphone of a mobile phone, comprising: a protective sound inlet cover, an electret microphone, a sealing gasket, a main body housing, a circuit board, a mobile phone interface, and a sealing bottom ring;

[0009] Wherein, the interior of the main body housing is hollow and open at both ends;

[0010] One end of the main body housing is a tapered opening from thick to thin, and the sealing gasket and the electret microphone are sequentially installed at the outer edge of the tapered opening;

[0011] The protective sound inlet cover is open at one end, has a hollow cavity inside, and is sleeved on the tapered opening, with the electret microphone and the sealing gasket built inside the hollow cavity;

[0012] The circuit board and the mobile phone interface are sequentially placed inside the main body housing, and one end of the mobile phone interface is welded to the circuit board; the other end of the mobile phone interface protrudes partially from the main body housing;

[0013] The sealing bottom ring covers the other end of the mobile phone interface and seals the opening at the other end of the main body housing.

[0014] Further, the sealing gasket is an O-ring with a hole in the middle and is adaptively installed with the tapered opening.

[0015] Further, the circuit board includes a constant current source rectification module, an analog signal acquisition module, an analog-to-digital conversion module, and a signal transmission module;

[0016] The constant current source rectification module provides a driving power supply for the electret microphone, the analog signal acquisition module continuously acquires the analog electrical signals output by the electret microphone, the analog-to-digital conversion module converts the analog electrical signals into a digital signal stream, and the signal transmission module transmits the digital signal stream into the mobile phone to be calibrated through the mobile phone interface.

[0017] Further, the mobile phone interface is a Micro-USB interface, a Type-C interface, or a Lightning interface.

[0018] In a second aspect, the present invention provides a method for calibrating the sensitivity of a built-in microphone of a mobile phone, using the device for calibrating the sensitivity of a built-in microphone of a mobile phone as described in the first aspect, comprising the following steps:

[0019] S1. Obtain and control the mobile phone to play a standard sound source;

[0020] S2. Obtain a first signal value measured by the built-in microphone of the mobile phone and a second signal value measured by the device; wherein, the device is pre-connected to the mobile phone to be calibrated;

[0021] S3. Analyze and process the first signal value and the second signal value to obtain the sensitivity and compensation value of the built-in microphone of the mobile phone;

[0022] S4. Use the compensation value as the calibration value to calibrate the built-in microphone of the mobile phone.

[0023] Furthermore, the following steps are also included:

[0024] S5. Obtain multiple standard sound sources with different frequencies; use each standard sound source with a different frequency as the input, and sequentially execute steps S1 - S4;

[0025] S6. Connect the obtained corresponding multiple calibration value data into a curve in the spectrogram, and use the algorithm of the digital filter to access the mobile phone sound signal acquisition path to achieve the calibration of the frequency response.

[0026] Furthermore, the standard sound source includes white noise, pink noise or a single - frequency sound representing a frequency.

[0027] Furthermore, in step S3, the formula for obtaining the sensitivity of the built - in microphone of the mobile phone is:

[0028] Lsi = Lpi - Lpo+Lso

[0029] where Lpo is the sound pressure level measured by the device; Lso is the sensitivity of the device; Lpi is the sound pressure level measured by the built - in microphone of the mobile phone; Lsi is the sensitivity of the built - in microphone of the mobile phone;

[0030] In step S3, the formula for obtaining the compensation value of the built - in microphone of the mobile phone is:

[0031] Ld = Lpo - Lpi

[0032] where Ld is the compensation value of the built - in microphone of the mobile phone.

[0033] It can be seen from the above - mentioned technical solutions that, compared with the prior art, the present invention discloses a device and method for calibrating the sensitivity of a built - in microphone of a mobile phone. By using an external calibration device to measure the sensitivity of the built - in microphone of the mobile phone, the following beneficial effects are achieved:

[0034] 1. Optimize the sound acquisition environment: The combination of the protective sound inlet cover and the tapered port provides a good sound acquisition environment for the electret microphone; the protective sound inlet cover can effectively block the interference of external noise and dust, while the tapered port helps to reduce the reflection and distortion of sound during transmission, thereby improving the purity and clarity of the sound signal.

[0035] 2. Enhance calibration accuracy: The electret microphone, as the core component, directly determines the calibration accuracy with its sensitivity and accuracy. The circuit board in the device further improves the calibration accuracy by amplifying and filtering the sound signals through precise circuit design. Meanwhile, the protective sound inlet cover with a standard diameter also provides flexibility for the metrological calibration requirements of the device.

[0036] 3. Simplify installation and operation: The compact and reasonable structural design of the device makes the installation and operation processes simple and fast. Just connect the device to the mobile phone through the mobile phone interface to complete the calibration work, without complex settings or adjustments. This not only saves time but also reduces the operation difficulty and improves the user experience.

[0037] The present invention uses an external calibration device and the built-in microphone of the mobile phone for synchronous measurement, where the sensitivity of the external calibration device is known in advance. Then, the measured difference between the two is used to correct the value of the built-in microphone of the mobile phone. The calibration process can be achieved simply and quickly, only requiring an external calibration device. It realizes accurate measurement data, fully automated calibration process, convenient operation process, low cost and stable performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0039] Figure 1 It is an exploded view of the external calibration device provided by the present invention.

[0040] Figure 2 It is a structural diagram of the external calibration device provided by the present invention.

[0041] Figure 3 It is a sectional view of the external calibration device provided by the present invention.

[0042] Figure 4 It is a perspective view of the external calibration device provided by the present invention.

[0043] Figure 5 It is an installation schematic diagram of the external calibration device provided by the present invention.

[0044] Figure 6 It is a functional schematic diagram of the external calibration device provided by the present invention.

[0045] Figure 7 It is a flowchart of the method for calibrating the sensitivity using the external calibration device provided by the present invention.

[0046] In the drawings: 1 - protective sound inlet cover, 2 - electret microphone, 3 - sealing gasket, 4 - main body housing, 5 - circuit board, 6 - mobile phone interface, 7 - sealing bottom ring. Specific implementation manners

[0047] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] An embodiment of the present invention discloses a device for calibrating the sensitivity of a built-in microphone of a mobile phone, that is: an external calibration device; in the subsequent description process of the present invention, the external calibration device is partially used, and it has the same meaning as the device for calibrating the sensitivity of the built-in microphone of the mobile phone.

[0049] Referring to Figures 1-4 as shown, it includes: a protective sound inlet cover 1, an electret microphone 2, a sealing gasket 3, a main body housing 4, a circuit board 5, a mobile phone interface 6, and a sealing bottom ring 7;

[0050] Among them, the inside of the main body housing 4 is hollow and both ends are open;

[0051] One end of the main body housing 4 is a tapered opening from thick to thin, and a sealing gasket 3 and an electret microphone 2 are sequentially installed at the outer edge of the tapered opening;

[0052] The protective sound inlet cover 1 has an opening at one end, a hollow cavity inside, and is sleeved on the tapered opening, and the electret microphone 2 and the sealing gasket 3 are built in the hollow cavity;

[0053] The circuit board 5 and the mobile phone interface 6 are sequentially placed inside the main body housing 4, and one end of the circuit board 5 is welded to the mobile phone interface 6; the other end of the mobile phone interface 6 protrudes from the main body housing 4 partially;

[0054] The sealing bottom ring 7 covers the other end of the mobile phone interface 6 and seals the opening at the other end of the main body housing 4.

[0055] Among them,

[0056] The protective sound inlet cover 1 adopts standard sizes of 1 inch, ½ inch or ¼ inch for adapting to an acoustic calibrator for calibration.

[0057] The electret microphone 2 consists of two parts: sound-electric conversion and impedance transformation; the key component of sound-electric conversion is the electret diaphragm. When the electret diaphragm encounters sound wave vibration, it causes the electric field at both ends of the capacitor to change, thereby generating an alternating voltage that changes with the sound wave.

[0058] The sealing gasket 3 is made of metal or non-metal plate materials through processes such as cutting, stamping or cutting, and is used for sealed connection between devices; among them, non-metal ones include asbestos gaskets, non-asbestos gaskets, paper gaskets, rubber gaskets, etc.

[0059] One end of the main body housing 4 is a tapered opening from thick to thin, and its main body part can be adjusted according to actual design requirements, but the core is to provide a closed and stable internal environment to accommodate other components;

[0060] The mobile phone interface 6 can be a Micro-USB interface, a Type-C interface or a Lightning interface.

[0061] The Micro-USB interface is a serial bus standard for connecting a computer system to external devices and is used on some Android mobile phones.

[0062] The Type-C interface is the charging interface used by most Android mobile phones, which can be inserted from both sides, has a faster transmission speed, can support higher-power charging, and can also be used as a video output interface.

[0063] The Lightning interface is the dedicated charging interface for Apple products and is Apple's high-speed multi-functional I / O interface.

[0064] Embodiment 1

[0065] External calibration device reference Figures 1-4 As shown:

[0066] The sound protection inlet cover 1 is a cylindrical structure with one end open and hollow inside. There are 9 small round holes at the other end for collecting sound signals, and the diameter of its cylindrical surface is the standard size of 1 inch;

[0067] One end of the main body housing 4 is a tapered opening from thick to thin. After the sound protection inlet cover 1 is sleeved on the tapered opening and pressed tightly, it can fit tightly with it. At the same time, glue is brushed on the outside of the tapered opening to firmly fix the sound protection inlet cover 1 on the main body housing 4;

[0068] The electret microphone 2 and the sealing gasket 3 are located inside the sound protection inlet cover 1 on one side of the main body housing 4. At the same time, a small amount of glue is also brushed between the electret microphone 2 and the sealing gasket 3 and between the sealing gasket 3 and the main body housing 4. While fixing the electret microphone 2 and the sealing gasket 3, it can prevent water or dust from entering the inside of the main body housing 4, thus affecting the normal operation of the external calibration device;

[0069] The circuit board 5 and the mobile phone interface 6 are connected together by welding. Glue is applied to both the inner and outer rings of the sealing bottom ring 7. First, the mobile phone interface 6 is fixed to the inner side of the sealing bottom ring 7 with glue, and then the whole is fixed to the other side of the main body housing 4 with glue to form the overall external calibration device.

[0070] In this embodiment, both the protective sound inlet cover 1 and the main body housing 4 are made of metal materials, which are not only wear-resistant but also have good shock and drop resistance.

[0071] One end of the main body housing 4 is a circular tapered opening that gradually changes from thick to thin. The outer diameter of the thicker part of the tapered opening is close to 1 inch, which is used to fit the protective sound inlet cover 1; the outer diameter of the thinner part of the tapered opening is three-quarters of an inch, and the inner diameter is one-half of an inch.

[0072] The main body adopts a flat cuboid structure with two parallel middle sides and arc structures on both sides. It is integrally formed by metal die-casting technology.

[0073] The sealing gasket 3 is a rubber O-ring; the outer diameter of the sealing gasket 3 is three-quarters of an inch, and the inner diameter is one-half of an inch, which is adaptively installed with the tapered opening.

[0074] The electret microphone is a standard microphone with high measurement accuracy. The standard microphone has a specified size and a clearly marked accurate sensitivity.

[0075] The circuit board includes main modules such as a constant current source rectification module, an analog signal acquisition module, an analog-to-digital conversion module, and a signal transmission module. The constant current source rectification module provides a stable driving power supply for the electret microphone. The analog signal acquisition module continuously acquires the analog electrical signals output by the electret microphone. The analog-to-digital conversion module converts the analog electrical signals into a digital signal stream. The signal transmission module transmits the digital signal stream in real time through the interface into the mobile phone to be calibrated, and is received by the mobile phone calibration program and participates in the calibration.

[0076] The mobile phone interface 6 is of two Type-C interface models, which is convenient for the vast majority of mobile phones on the market to use.

[0077] This device combines a protective sound inlet cover and a tapered opening to provide a good sound acquisition environment for the electret microphone; the circuit board processes the sound signals such as amplification and filtering, improving the calibration accuracy; and the structure design of the device is compact and reasonable, and the installation and operation processes are simple and fast; just connect the device to the mobile phone through the mobile phone interface to complete the calibration work, which not only saves time but also reduces the operation difficulty and improves the user experience.

[0078] Embodiment 2

[0079] An embodiment of the present invention further provides a method for calibrating the sensitivity of a built-in microphone of a mobile phone. Using the calibration device as in Example 1, before the method is executed, it is first plugged into the socket of the mobile phone to be calibrated, and referring to Figures 5-6 as shown, it is used to convert the sound signal into a digital signal and transmit it to the mobile phone.

[0080] When this method is specifically implemented, it is loaded and implemented through a mobile application software. This software can synchronously identify the digital signals uploaded by the external calibration device and the built-in microphone of the mobile phone, and at the same time can drive the earpiece speaker of the mobile phone to play a standard sound source.

[0081] Referring to Figure 7 as shown, this method includes:

[0082] S1. Obtain and control the mobile phone to play a standard sound source;

[0083] S2. Obtain the first signal value measured by the built-in microphone of the mobile phone and the second signal value measured by the device; wherein, the device is pre-plugged into the mobile phone to be calibrated;

[0084] S3. Analyze and process the first signal value and the second signal value to obtain the sensitivity and compensation value of the built-in microphone of the mobile phone;

[0085] S4. Use the compensation value as the calibration value to calibrate the built-in microphone of the mobile phone.

[0086] During the calibration process of this method, the user can operate the mobile phone software to make the earpiece speaker of the mobile phone play a standard sound source (including white noise, pink noise, and single-frequency sounds of certain representative frequencies). At this time, the external calibration device and the built-in microphone of the mobile phone can collect the standard sound source played by the earpiece speaker and convert it into a digital signal at the same time; by comparing the differences between the digital signals converted from the sound signals collected by the built-in microphone of the mobile phone and the external microphone, the sensitivity difference between the built-in microphone of the mobile phone and the external microphone is determined. After the software recognizes this difference data, it can automatically calculate and remember the compensation value of the digital signal measured by the built-in microphone of the mobile phone, complete the calibration of the built-in microphone of the mobile phone, and finally enable the mobile phone to accurately measure the noise through the built-in microphone after disconnecting the external calibration device.

[0087] Specifically: when the earpiece speaker of the mobile phone plays a 1000 Hz sound, the sound pressure level measured by the external calibration device (mobile phone calibrator) is Lpo, and the sound pressure level obtained by the built-in microphone is Lpi.

[0088] The sensitivity of the external calibration device is Lso, including the comprehensive sensitivity of the electret microphone and the signal processing system. This sensitivity can be calibrated and obtained by another standardized acoustic calibrator; its formula is

[0089] Lso = 20 * log10(Som / 1000) + Loe

[0090] Som is the sensitivity of the electret microphone, with the unit of mV / Pa; Loe is the gain of the device circuit system, with the unit of dB;

[0091] Then, through the comparison method, the sensitivity of the built-in microphone and the signal link system can be obtained:

[0092] Lsi = Lpi - Lpo + Lso

[0093] When actually measuring with the sampling mobile phone, a compensation value should be added to the calculation result of the original sensitivity; according to the compensation principle, when using the built-in microphone, the compensation required in the software is:

[0094] Ld = Lpo - Lpi

[0095] Among them, the compensation value Ld is the calibration value that needs to be written into the storage memory.

[0096] The above is the calibration of the built-in microphone using a single sound. When it is necessary to further consider that the frequency response of the built-in microphone may be uneven and the overall frequency response of the built-in microphone needs to be calibrated, the mobile phone earpiece speaker can be made to play representative single-frequency sounds in sequence, such as 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, etc. For each single-frequency sound, a corrected sound pressure level, Ld250, Ld500, Ld1000, Ld2000, Ld4000, etc., is identified according to the above method. The data of each representative frequency point is connected into a curve in the spectrogram, and a digital filter with the above frequency characteristics is designed by using the method of digital filter design. Connecting the digital filter into the sound signal acquisition path realizes the calibration of the frequency response.

[0097] Among them, the digital filter is an algorithm or device composed of digital multipliers, adders, and delay units. The function of the digital filter is to perform arithmetic processing on the digital codes of the input discrete signal to achieve the purpose of changing the signal spectrum.

[0098] The above method can be implemented by programming in the software, enabling the entire calibration process to be automatically implemented.

[0099] The protective sound inlet cover of the external calibration device proposed by the present invention adopts standard dimensions. When the sensitivity of the external calibration device (or the new mobile phone calibrator) has an error due to long-term use or other reasons, it can be calibrated by a standard sound calibrator to ensure its accuracy. Generally speaking, a well-preserved microphone ages slowly, and its sensitivity can remain basically stable for a long time.

[0100] The mobile phone interface on the other side of the external calibration device can select the corresponding model of the external calibration device according to different mobile phone models, including two models: Type-C and Lighting interfaces, which is convenient for the vast majority of mobile phones on the market to use.

[0101] This method mainly synchronously measures by using an external calibration device and the built-in microphone of the mobile phone. The sensitivity of the external calibration device is known in advance. Then, the difference between the two is used to correct the value of the built-in microphone of the mobile phone. The sound source required for calibration can use the speaker of the mobile phone earpiece, that is, the speaker at the top of the mobile phone. The calibration process can be realized simply and quickly, only need to externally connect a calibration device, or it can be called a new mobile phone calibrator.

[0102] This method solves the problem of the accuracy of measurement data, ensures that the calibration process is fully automated, the operation process is very convenient, the cost of a single external calibration device is extremely cheap, and the performance is stable. This method makes the idea of accurately measuring the sound volume of the mobile phone come true and can play a role in many occasions.

[0103] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

[0104] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for calibrating the sensitivity of a built-in microphone of a mobile phone, characterized in that: include: Protective sound inlet cover, electret microphone, sealing gasket, main housing, circuit board, mobile phone interface and sealing bottom ring; The main body shell is hollow inside and open at both ends; One end of the main housing is a gradual change from thick to thin, and the sealing gasket and the electret microphone are sequentially installed at the outer edge of the gradual change; The protective sound inlet cover is open at one end and has a hollow cavity therein, which is sleeved on the gradient port, and the electret microphone and the sealing gasket are built into the hollow cavity; the protective sound inlet cover adopts a standard size of 1 inch, 1 / 2 inch or 1 / 4 inch, and is used for adapting to an acoustic calibrator for calibration; The circuit board and the mobile phone interface are placed in sequence inside the main body shell, and the circuit board is welded with one end of the mobile phone interface; the other end of the mobile phone interface partially protrudes from the main body shell; The sealing bottom ring cover is arranged at the other end of the mobile phone interface and blocks the opening at the other end of the main body shell; The circuit board includes a constant current source rectifier module, an analog signal acquisition module, an analog-to-digital conversion module and a signal transmission module; the constant current source rectifier module provides a driving power supply for the electret microphone; the analog signal acquisition module continuously acquires the analog electrical signal output by the electret microphone; the analog-to-digital conversion module converts the analog electrical signal into a digital signal stream; the signal transmission module transmits the digital signal stream into the mobile phone to be calibrated through the mobile phone interface; The calibration method of the device comprises the following steps: S1. Obtain and control the mobile phone to play standard sound source; S2, obtaining a first signal value measured by a built-in microphone of a mobile phone and a second signal value measured by the device; wherein the device is pre-plugged into the mobile phone to be calibrated; S3, analyzing and processing the first signal value and the second signal value to obtain the sensitivity and compensation value of the built-in microphone of the mobile phone; wherein, the sensitivity formula of the built-in microphone of the mobile phone is: Lsi=Lpi-Lpo+Lso; wherein Lpo is the sound pressure level tested by the device; Lso is the sensitivity of the device; Lpi is the sound pressure level tested by the built-in microphone of the mobile phone; Lsi is the sensitivity of the built-in microphone of the mobile phone; the compensation value formula of the built-in microphone of the mobile phone is: Ld=Lpo-Lpi; wherein Ld is the compensation value of the built-in microphone of the mobile phone; S4, using the compensation value as a calibration value to calibrate the built-in microphone of the mobile phone; S5, obtaining a plurality of standard sound sources of different frequencies; taking each standard sound source of different frequencies as input, executing steps S1-S4 in sequence; S6. Connect the corresponding multiple calibration value data into a curve in the spectrum diagram, and use a digital filter algorithm to connect it to the mobile phone sound signal acquisition path to achieve frequency response calibration.

2. A device for calibrating the sensitivity of a built-in microphone of a mobile phone as claimed in claim 1, characterized in that: The sealing gasket is an O-ring with a hole in the middle, and is adapted to be installed with the gradient port.

3. A device for calibrating the sensitivity of a built-in microphone of a mobile phone as claimed in claim 1, characterized in that: The mobile phone interface is a Micro-USB interface, a Type-C interface or a Lightning interface.

4. The device for calibrating the sensitivity of a built-in microphone of a mobile phone as claimed in claim 1, characterized in that: The standard sound source includes white noise, pink noise or a single-frequency sound representing a frequency.

Images