Noise reduction device and method for fan in terminal

Abstract

Embodiments of the present application relate to a noise reduction device and method for a fan in a terminal. The noise reduction device includes: a first air duct, at least one noise reduction air duct, and a switch assembly; one end of the first air duct is connected to a fan air outlet, and the other end of the first air duct is connected to a terminal air outlet; one end of the noise reduction air duct is connected to the fan air outlet, and the other end of the noise reduction air duct is connected to the terminal air outlet; switches in the switch assembly are located at an air inlet of the noise reduction air duct and an air outlet of the noise reduction air duct, and the switch assembly is configured to control opening or closing of the noise reduction air duct; and an air duct length difference between the first air duct and the noise reduction air duct is nL+L / 2, where n is a natural number and L is a wind noise wavelength at the fan air outlet.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Chinese Patent Application No. 202311142344.1, filed on September 5, 2023. The disclosure of the above-mentioned application is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present application relates to the field of terminals, and more particularly to a noise reduction device for a fan in a terminal and a noise reduction method for a fan in a terminal.BACKGROUND

[0003] Currently, products such as mobile phones, customer premise equipment (CPEs), tablets, and laptops generate heat during use, so it is necessary to cool down the terminals.

[0004] The current cooling method used is to install a fan inside the terminal, however the wind generated by the fan will produce noise during the transmission to the terminal air outlet, which affects the user experience.SUMMARY

[0005] The present application provides a noise reduction device for the fan in the terminal and a method thereof.

[0006] In a first aspect, embodiments of the present application provide a noise reduction device for a fan in a terminal including: a first air duct, at least one noise reduction air duct, and a switch assembly; one end of the first air duct is connected to a fan air outlet, and the other end of the first air duct is connected to a terminal air outlet; one end of the noise reduction air duct is connected to the fan air outlet, and the other end of the noise reduction air duct is connected to the terminal air outlet; switches in the switch assembly are located at an air inlet of the noise reduction air duct and an air outlet of the noise reduction air duct, and the switch assembly is configured to control opening or closing of the noise reduction air duct; and an air duct length difference between the first air duct and the noise reduction air duct is nL+L / 2, where n is a natural number and L is a wind noise wavelength at the fan air outlet.

[0007] In a second aspect, embodiments of the present application provide a noise reduction method for a fan in a terminal including: obtaining a current speed setting at a fan air outlet, different speed settings correspond to different wind speeds; opening a target noise reduction air duct corresponding to the current speed setting by controlling a switch based on a preset mapping relationship, the preset mapping relationship indicates that different speed settings correspond to different lengths of noise reduction air ducts; and delivering an airflow at the fan air outlet to a terminal air outlet via a first air duct of fixed length and the target noise reduction air duct, to ensure that waveforms of wind noise generated by the first air duct and the target noise reduction air duct at the terminal air outlet are consistent, and that a waveform phase difference is m * 180°.

[0008] In a third aspect, embodiments of the present application provides an electronic device, including: at least one communication interface; at least one bus connected to the at least one communication interface; at least one processor connected to the at least one bus; and at least one memory connected to the at least one bus, and the processor is configured for: obtaining a current speed setting at a fan air outlet, different speed settings correspond to different wind speeds; opening a target noise reduction air duct corresponding to the current speed setting by controlling a switch based on a preset mapping relationship, the preset mapping relationship indicates that different speed settings correspond to different lengths of noise reduction air ducts; and delivering an airflow at the fan air outlet to a terminal air outlet via a first air duct of fixed length and the target noise reduction air duct, to ensure that waveforms of wind noise generated by the first air duct and the target noise reduction air duct at the terminal air outlet are consistent, and that a waveform phase difference is m * 180°.

[0009] In a fourth aspect, embodiments of the present application further provide a computer-readable storage medium, the computer-readable storage medium stores a computer program, and the computer program implements the method as described in any of the preceding items of the present application when executed by a processor.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings, incorporated in and forming part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0011] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0012] One or more embodiments are illustrated by way of example through the corresponding images in the accompanying drawings. These exemplary descriptions do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings represent similar elements. Unless otherwise stated, the figures in the drawings do not constitute a limitation on scale. FIG. 1 is a schematic view of a noise reduction device for a fan in a terminal according to an embodiment of the present application. FIG. 2 is a flowchart of a noise reduction method for a fan in a terminal according to an embodiment of the present application. FIG. 3 is a schematic view of an air duct opening control process for three fan speed settings according to an embodiment of the present application. FIG. 4 is a structural schematic view of a noise reduction apparatus for a fan in a terminal according to an embodiment of the present application. FIG. 5 is a structural schematic view of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0013] To make the purposes, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort are within the scope of protection of the present application.

[0014] The following disclosure provides many different embodiments or examples to implement different structures of the embodiments of the present application. To simplify the disclosure of the embodiments of the present application, the components and settings of specific examples are described below. Certainly, these are merely examples and are not intended to limit the embodiments of the present application. Furthermore, reference numerals and / or letters may be repeated in different examples of the embodiments of the present application. This repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed.

[0015] The embodiments of the present application provide a noise reduction device for the fan in the terminal, as shown in FIG. 1. The noise reduction device includes: a first air duct, at least one noise reduction air duct, and a switch assembly.

[0016] One end of the first air duct is connected to a fan air outlet, and the other end of the first air duct is connected to a terminal air outlet, which is configured to direct airflow from the fan to the terminal air outlet. The first air duct is an air duct that follows the normal airflow direction from the fan, as shown in FIG. 1. The first air duct is the leftmost air duct.

[0017] One end of the noise reduction air duct is connected to the fan air outlet, and the other end of the noise reduction air duct is connected to the terminal air outlet. There can be one or multiple noise reduction air ducts. The air duct length difference between each noise reduction air duct and the first air duct is nL + L / 2, where n is a natural number and L is a wind noise wavelength at the fan air outlet, as shown in FIG. 1. The noise reduction air ducts include noise reduction air duct ①, noise reduction air duct ②, and noise reduction air duct ③ on the right.

[0018] Switches in the switch assembly are located at an air inlet of the noise reduction air duct and an air outlet of the noise reduction air duct, and the switch assembly is configured to control opening or closing of the noise reduction air duct; that is, the first air duct can be turned on simultaneously with one noise reduction air duct, or the first air duct can be turned on simultaneously with multiple noise reduction air ducts.

[0019] Because the air duct length difference between the first air duct and the noise reduction air duct is nL+L / 2, the time for the wind of the fan air outlet from the noise reduction air duct to the terminal air outlet is nT+T / 2 later than the time from the first air duct to the terminal air outlet, where T is the waveform period. That is, at the terminal air outlet shown on the waveform diagram, the waveform of the wind in the first air duct and the waveform of the wind in the noise reduction air duct are consistent and have a phase difference of m * 180°. The wind noise formed by the two winds cancels each other out, achieving the function of reducing wind noise. Where m is a positive integer.

[0020] Whether one noise reduction air duct or multiple noise reduction air ducts are turned on, the air duct length difference between each noise reduction air duct and the first air duct is nL + L / 2. Therefore, the phase difference between the waveform of the wind of the noise reduction air duct and the waveform of the wind of the first air duct is m * 180°.

[0021] The embodiment of the present application provides multiple switches, and the switches are configured in at least the following two ways.

[0022] In an embodiment, the air inlet of each noise reduction air duct or the air outlet of each noise reduction air duct is provided with a switch, and the switch is configured to open or close the noise reduction air duct.

[0023] In another embodiment, a common switch is provided between the air inlets or the air outlets of two adjacent noise reduction air ducts, and the switch is configured to simultaneously open one noise reduction air duct and close the other noise reduction air duct.

[0024] Example, the noise reduction device includes a first noise reduction duct, a second noise reduction duct, and a third noise reduction duct with sequentially increasing air duct lengths; the first noise reduction duct, the second noise reduction duct, and the third noise reduction duct are provided in parallel in sequence.

[0025] A switch is provided between an air inlet of the first noise reduction duct and an air inlet of the second noise reduction duct, and a switch is provided between an air outlet of the first noise reduction duct and an air outlet of the second noise reduction duct. By toggling the switch between the first noise reduction air duct and the second noise reduction air duct to cause only the first noise reduction air duct to close, and the second noise reduction air duct is open, achieving airflow to pass through the second noise reduction air duct; or by toggling the switch between the first noise reduction air duct and the second noise reduction air duct to cause only the second noise reduction air duct to close, and the first noise reduction air duct is open, achieving airflow to pass through the first noise reduction air duct.

[0026] A switch is provided between the air inlet of the second noise reduction duct and an air inlet of the third noise reduction duct, and a switch is provided between the air outlet of the second noise reduction duct and an air outlet of the third noise reduction duct. By toggling the switch between the second noise reduction air duct and the third noise reduction air duct to cause only the second noise reduction air duct to close, while the third noise reduction air duct is open, achieving airflow to pass through the third noise reduction air duct; or by toggling the switch between the second noise reduction air duct and the third noise reduction air duct to cause only the third noise reduction air duct to close, while the second noise reduction air duct is open, achieving airflow to pass through the second noise reduction air duct.

[0027] In an embodiment, a shape of the first duct is any one of a straight line, an arc, or a bend; a shape of the noise reduction duct is any one of a straight line, an arc, or a bend. The specific shape of the air duct is designed according to the internal structure of the terminal device, and the embodiment of the present application does not limit it.

[0028] Based on the same technical concept, the embodiment of the present application also proposes a noise reduction method for a fan in a terminal, as shown in FIG. 2. The method includes: Step 201: obtaining a current speed setting at a fan air outlet.

[0029] Where different speed settings correspond to different wind speeds.

[0030] The terminal is equipped with a fan for heat dissipation, and different speed settings of the fan correspond to different wind speeds. The terminal obtains the current speed setting at the fan air outlet.

[0031] Step 202: opening a target noise reduction air duct corresponding to the current speed setting by controlling a switch based on a preset mapping relationship.

[0032] Where the preset mapping relationship indicates that different speed settings correspond to different lengths of noise reduction air ducts.

[0033] The terminal obtains the wind noise frequency at the current speed setting corresponding to the wind speed at the fan air outlet. Then, based on a preset coefficient u and the wind noise frequency, the wind noise wavelength of the wind speed is determined. The formula for calculating the wind noise wavelength is λ = u / f, where λ is the wind noise wavelength, u is the wave speed, and f is the wind noise frequency.

[0034] Since the first air duct and the noise reduction air duct flow through the same airflow at the fan air outlet, the wind noise frequency of the first air duct and the wind noise frequency of the noise reduction air duct are the same, and the wind noise wavelength of the first air duct and the wind noise wavelength of the noise reduction air duct are the same.

[0035] The terminal determines the air duct length of the noise reduction air duct based on the wind noise wavelength and the air duct length of the first air duct, thereby ensuring that the difference between the air duct length of the noise reduction air duct and the air duct length of the first air duct is nL + L / 2, where n is a natural number and L is the wind noise wavelength.

[0036] In this way, the terminal obtains the air duct length of the noise reduction air duct corresponding to the current speed setting. Performing the above operation for each speed setting of the fan can obtain the air duct length of the noise reduction air duct corresponding to each speed setting, thus establishing a mapping relationship between the fan speed setting and the air duct length of the noise reduction air duct, and saving this mapping relationship.

[0037] After the fan is opened, the terminal determines the target noise reduction air duct corresponding to the fan's current speed setting based on the preset mapping relationship, and opens the target noise reduction air duct via a control switch. This ensures that only the first air duct and the target noise reduction air duct are open, while the other noise reduction air ducts are closed.

[0038] Step 203: delivering an airflow at the fan air outlet to a terminal air outlet via a first air duct of fixed length and the target noise reduction air duct, to ensure that waveforms of wind noise generated by the first air duct and the target noise reduction air duct at the terminal air outlet are consistent, and that a waveform phase difference is m * 180°, where m is a positive integer.

[0039] The air output of the fan is divided into two paths. One path passes through a fixed length first air duct from the fan air outlet to the terminal air outlet, while the other path passes through a target noise reduction air duct from the fan air outlet to the terminal air outlet. The waveform of the wind noise generated by the two paths at the terminal air outlet is consistent and has a phase difference of m * 180°. The wind noise cancels each other out, and the wind noise heard at the terminal air outlet position is reduced.

[0040] This embodiment of the application sets up noise reduction air ducts of different lengths corresponding to each fan speed setting, the target noise reduction air duct can be opened according to the current speed setting, thus splitting the same airflow into two paths. The airflow travels from the first air duct and the target noise reduction air duct to the terminal air outlet, respectively. At the terminal air outlet, a waveform with consistent waveforms and a phase difference of m * 180° is formed, thereby canceling out wind noise and reducing overall wind noise.

[0041] Exemplary, the speed settings include a first speed setting, a second speed setting, and a third speed setting corresponding to the wind speed decreasing in sequence, and the noise reduction duct includes a first noise reduction duct, a second noise reduction duct, and a third noise reduction duct with sequentially increasing air duct lengths. The opening the target noise reduction air duct corresponding to the current speed setting by controlling the switch based on the preset mapping relationship includes the following three embodiments.

[0042] In a first embodiment, in response to detecting that the current speed setting is a first speed setting, closing the second noise reduction air duct and the third noise reduction duct, and opening the first noise reduction duct by controlling the switch.

[0043] In a second embodiment, in response to detecting that the current speed setting is a second speed setting, closing the first noise reduction air duct and the third noise reduction duct, and opening the second noise reduction duct by controlling the switch.

[0044] In a third embodiment, in response to detecting that the current speed setting is a third speed setting, closing the first noise reduction air duct and the second noise reduction duct, and opening the third noise reduction duct by controlling the switch.

[0045] The embodiments of the present application will be explained in detail below with reference to FIG. 1.

[0046] The fan includes three speed settings: high, medium, and low. Enclosed by an external structure, the fan's wind originates from the fan air outlet and flows in a fixed direction via the air ducts to the terminal air outlet. Below the fan, on the left, is the first air duct with normal wind; on the right are noise reduction air duct ①, noise reduction air duct ②, and noise reduction air duct ③. At the noise reduction air ducts, there are two switches on top and bottom that can be turned horizontally and vertically to close and open different noise reduction channels.

[0047] When the fan is rotating at high speed, the corresponding wind speed is A1, the generated wind noise frequency is the highest, which is f1, the wavelength of the wind noise waveform is L1, the wavelength is the shortest, and the period is T1. Therefore, the noise reduction flows through the shortest noise reduction air duct ① to the terminal air outlet. At this time, the air duct switch 1 needs to be turned to the vertical upward direction, the air duct switch 4 needs to be turned to the vertical downward direction to close the noise reduction air duct ③, the air duct switch 2 needs to be turned to the vertical upward direction, the air duct switch 3 needs to be turned to the vertical downward direction to close the noise reduction air duct ②, ensuring that the wind flows from the noise reduction air duct ① to the terminal air outlet position. The wind flows from the noise reduction air duct ① to the terminal air outlet, and reaches the terminal air outlet position later than the wind in the first air duct to nT1+T1 / 2. Therefore, the wind noise waveforms from both air ducts reaching the air outlet position are essentially the same, with a phase difference of m * 180°. The wind noise from the two winds cancels each other out, achieving the function of reducing wind noise.

[0048] When the fan is operating at medium speed, the corresponding wind speed is A2, the generated wind noise frequency is f2, the wind noise waveform wavelength is L2, the wavelength is medium, and the period is T2. Therefore, the noise reduction flows through the medium-length noise reduction air duct ② to the terminal air outlet. At this time, the air duct switch 1 needs to be turned to the vertical upward direction, the air duct switch 4 needs to be turned to the vertical downward direction to close the noise reduction air duct ③, the air duct switch 2 needs to be turned to the horizontal left direction, and the air duct switch 3 needs to be turned to the horizontal left direction to close the noise reduction air duct ①, ensuring that the wind flows from the noise reduction air duct ② to the terminal air outlet position. The wind from the noise reduction air duct ② to the terminal air outlet, and reaches the terminal air outlet position later than the normal flow of wind to the air duct by nT2+T2 / 2. Therefore, the wind noise waveforms reaching the terminal air outlet through the two air ducts are essentially the same, with a phase difference of m * 180°. The wind noise from the two winds cancels each other out, achieving noise reduction.

[0049] When the fan is operating at a low speed, the corresponding wind speed is A3, the generated wind noise frequency is f3, the waveform wavelength is L3, the wavelength is the maximum, and the period is T3. Therefore, the noise reduction flows through the longest noise reduction air duct ③ to the terminal outlet. At this time, the air duct switch 1 and the air duct switch 4 should be turned to the left to close the noise reduction air duct ②, ensuring that the wind is from the noise reduction air duct ③ to the terminal air outlet. The wind from the noise reduction air duct ③ to the terminal air outlet, and reaches the terminal air outlet position later than the normal flow of wind to the air duct by nT3+T3 / 2. Therefore, the wind noise waveforms reaching the terminal outlet through the two air ducts are essentially the same, with a phase difference of m * 180°. The wind noise from the two winds cancels each other out, achieving noise reduction.

[0050] FIG. 3 is a schematic view of an air duct opening control process for three fan speed settings according to an embodiment of the present application.

[0051] Compared to existing technologies, this embodiment of the present application does not use a microphone or speaker for active noise reduction. It eliminates the need for adding microphones, speakers, and other auxiliary circuits, thus not significantly increasing costs. Furthermore, since no microphone or speaker is added inside the phone, it does not interfere with antenna and radio frequency indicators, and does not increase design complexity.

[0052] Based on the same technical concept, the present application provides a noise reduction apparatus for a fan in a terminal, as shown in FIG. 4. The apparatus includes: an acquisition module 401, configured for obtaining a current speed setting at a fan air outlet, different speed settings correspond to different wind speeds; an activation module 402, configured for opening a target noise reduction air duct corresponding to the current speed setting by controlling a switch based on a preset mapping relationship, the preset mapping relationship indicates that different speed settings correspond to different lengths of noise reduction air ducts; and a delivery module 403, configured for delivering an airflow at the fan air outlet to a terminal air outlet via a first air duct of fixed length and the target noise reduction air duct, to ensure that waveforms of wind noise generated by the first air duct and the target noise reduction air duct at the terminal air outlet are consistent, and that a waveform phase difference is m * 180°, where m is a positive integer.

[0053] In an embodiment, the activation module 402 is configured for determining a wind noise frequency of the wind speed corresponding to the current speed setting at the fan air outlet; determining a wind noise wavelength of the wind speed according to a preset coefficient and the wind noise frequency; determining an air duct length of a noise reduction air duct according to the wind noise wavelength and an air duct length of the first air duct, an air duct length difference between the air duct length of the noise reduction air duct and the air duct length of the first air duct is nL+L / 2, where n is a natural number and L is a wind noise wavelength at the fan air outlet; and establishing a mapping relationship between the speed setting and the air duct length of the noise reduction air duct.

[0054] In an embodiment, the speed settings include a first speed setting, a second speed setting, and a third speed setting corresponding to the wind speed decreasing in sequence, and the noise reduction duct includes a first noise reduction duct, a second noise reduction duct, and a third noise reduction duct with sequentially increasing air duct lengths. The activation module 402 is configured for: in response to detecting that the current speed setting is a first speed setting, closing the second noise reduction air duct and the third noise reduction duct, and opening the first noise reduction duct by controlling the switch; or, in response to detecting that the current speed setting is a second speed setting, closing the first noise reduction air duct and the third noise reduction duct, and opening the second noise reduction duct by controlling the switch; or, in response to detecting that the current speed setting is a third speed setting, closing the first noise reduction air duct and the second noise reduction duct, and opening the third noise reduction duct by controlling the switch.

[0055] As shown in FIG. 5, the embodiment of the present application provides an air conditioner control device, including a processor 501, a communication interface 502, a memory 503, and a communication bus 504. The processor 501, the communication interface 502, and the memory 503 communicate with each other via the communication bus 504.

[0056] The memory 503 is used to store computer programs.

[0057] In an embodiment of the present application, the processor 501 is configured to implement the noise reduction method for the fan in the terminal provided in any of the aforementioned method embodiments when executing the program stored in the memory 503.

[0058] The embodiment of the present application also provides a computer-readable storage medium, the computer-readable storage medium stores a computer program, and the computer program implements the noise reduction method for the fan in the terminal as provided in any of the aforementioned method embodiments when executed by a processor.

[0059] The apparatus embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0060] By the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented using software plus a general-purpose hardware platform, or certainly, using hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or certain parts of the embodiments.

[0061] It should be understood that the terminology used herein is for the purpose of describing specific exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "a", "an" and "said" as used herein may also include the plural forms. The terms "comprising", "including", "containing" and "having" are inclusive and therefore specify the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a specific order described or illustrated unless explicitly stated otherwise. It should also be understood that additional or alternative steps may be used.

[0062] The above descriptions are merely specific implementations of embodiments of the present application, enabling those skilled in the art to understand or implement the embodiments of the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the embodiments of the present application. Therefore, the present application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A noise reduction device for a fan in a terminal, <b>characterized by comprising: a first air duct, at least one noise reduction air duct, and a switch assembly; wherein: one end of the first air duct is connected to a fan air outlet, and the other end of the first air duct is connected to a terminal air outlet; one end of the noise reduction air duct is connected to the fan air outlet, and the other end of the noise reduction air duct is connected to the terminal air outlet; switches in the switch assembly are located at an air inlet of the noise reduction air duct and an air outlet of the noise reduction air duct, and the switch assembly is configured to control opening or closing of the noise reduction air duct; and an air duct length difference between the first air duct and the noise reduction air duct is nL+L / 2, where n is a natural number and L is a wind noise wavelength at the fan air outlet.

2. The noise reduction device according to claim 1, wherein a common switch is provided between the air inlets or the air outlets of two adjacent noise reduction air ducts, and the switch is configured to simultaneously open one noise reduction air duct and close the other noise reduction air duct.

3. The noise reduction device according to claim 1, wherein the air inlet of each noise reduction air duct or the air outlet of each noise reduction air duct is provided with a switch, and the switch is configured to open or close the noise reduction air duct.

4. The noise reduction device according to claim 2, wherein the noise reduction device comprises a first noise reduction duct, a second noise reduction duct, and a third noise reduction duct with sequentially increasing air duct lengths; the first noise reduction duct, the second noise reduction duct, and the third noise reduction duct are provided in parallel in sequence; a switch is provided between an air inlet of the first noise reduction duct and an air inlet of the second noise reduction duct, and a switch is provided between the air inlet of the second noise reduction duct and an air inlet of the third noise reduction duct; and a switch is provided between an air outlet of the first noise reduction duct and an air outlet of the second noise reduction duct, and a switch is provided between the air outlet of the second noise reduction duct and an air outlet of the third noise reduction duct.

5. The noise reduction device according to claim 1, wherein a shape of the first duct and / or a shape of the noise reduction duct is a straight line, an arc, or a bend.

6. A noise reduction method for a fan in a terminal, <b>characterized by comprising: obtaining a current speed setting at a fan air outlet, wherein different speed settings correspond to different wind speeds; opening a target noise reduction air duct corresponding to the current speed setting by controlling a switch based on a preset mapping relationship, wherein the preset mapping relationship indicates that different speed settings correspond to different lengths of noise reduction air ducts; and delivering an airflow at the fan air outlet to a terminal air outlet via a first air duct of fixed length and the target noise reduction air duct, to ensure that waveforms of wind noise generated by the first air duct and the target noise reduction air duct at the terminal air outlet are consistent, and that a waveform phase difference is m * 180°, where m is a positive integer.

7. The method according to claim 6, wherein the opening the target noise reduction air duct corresponding to the current speed setting by controlling the switch based on the preset mapping relationship, the method further comprises: determining a wind noise frequency of the wind speed corresponding to the current speed setting at the fan air outlet; determining a wind noise wavelength of the wind speed according to a preset coefficient and the wind noise frequency; determining an air duct length of a noise reduction air duct according to the wind noise wavelength and an air duct length of the first air duct, wherein an air duct length difference between the air duct length of the noise reduction air duct and the air duct length of the first air duct is nL+L / 2, where n is a natural number and L is a wind noise wavelength at the fan air outlet; and establishing a mapping relationship between the speed setting and the air duct length of the noise reduction air duct.

8. The method according to claim 6, wherein the speed settings comprise a first speed setting, a second speed setting, and a third speed setting corresponding to the wind speed decreasing in sequence, and the noise reduction duct comprises a first noise reduction duct, a second noise reduction duct, and a third noise reduction duct with sequentially increasing air duct lengths; the opening the target noise reduction air duct corresponding to the current speed setting by controlling the switch based on the preset mapping relationship comprises: in response to detecting that the current speed setting is a first speed setting, closing the second noise reduction air duct and the third noise reduction duct, and opening the first noise reduction duct by controlling the switch; or in response to detecting that the current speed setting is a second speed setting, closing the first noise reduction air duct and the third noise reduction duct, and opening the second noise reduction duct by controlling the switch; or in response to detecting that the current speed setting is a third speed setting, closing the first noise reduction air duct and the second noise reduction duct, and opening the third noise reduction duct by controlling the switch.

9. An electronic device, <b>characterized by comprising: a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory are configured to communicate with each other via the communication bus; the memory is configured to store a computer program; and the processor is configured to implement the method according to any one of claims 6 to 8 when executing the program stored in the memory.

10. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, and the computer program implements the method according to any one of claims 6 to 8 when executed by a processor.

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