Electronic system with heat dissipation and feedforward active noise control function

Abstract

An electronic system with heat dissipation and feed-forward active noise control function includes a fan module, an embedded controller, a reference microphone, a multi-channel speaker module, a beamforming control module and an active noise reduction controller. The beamforming control module controls the orientation of the multi-channel speaker module. The multi-channel speaker module provides anti-phase noise signals to cancel noise according to a speaker control signal. The reference microphone detects broadband noise generated by the fan module in operation to provide a corresponding broadband noise signal. A virtual microphone module of the active noise reduction controller provides a virtual error signal according to a transfer function between the reference microphone and a physical error microphone, a transfer function between the multi-channel speaker module and the physical error microphone and the broadband noise signal, and generates the speaker control signal according to a synchronization signal, the broadband noise signal and the virtual error signal.

Description

Technical Field

[0001] This invention provides an electronic system with heat dissipation and feedforward active noise control functions, particularly an electronic system that uses heat dissipation, virtual microphone signals, and beamforming technology to control a multi-channel speaker module to achieve feedforward active noise control. Background Technology

[0002] In today's information society, computer systems have become an indispensable information tool for most people. To prevent components from overheating and causing power reduction or damage, computer systems generally use fans to provide cooling, either to expel heat generated inside the device or to draw in cool air from outside.

[0003] The fan's speed and static pressure determine its airflow. The noise level of a fan is roughly proportional to the fifth root of its speed; the faster the speed, the stronger the heat dissipation, but the louder the noise. As central processing units become more powerful, the waste heat generated inside the device also increases. In addition, the trend of miniaturization reduces heat flow efficiency. How to balance heat dissipation and noise reduction is an important issue. Summary of the Invention

[0004] This invention provides an electronic system with heat dissipation and feedforward active noise control functions, comprising a fan module, an embedded controller, a reference microphone, a multi-channel speaker module, a beamforming control module, and an active noise cancellation controller. The fan module operates according to a fan control signal to provide heat dissipation. The embedded controller provides the fan control signal. The reference microphone detects broadband noise generated by the fan module during operation and provides a corresponding broadband noise signal. The multi-channel speaker module includes at least a first speaker and a second speaker, and provides an out-of-phase noise signal according to a speaker control signal. The beamforming control module provides a beamforming control signal to control the orientation of the multi-channel speaker module, aligning the sound output directions of the first and second speakers to a specific location. The active noise cancellation controller provides a virtual error signal based on a first transfer function, a second transfer function, and the broadband noise signal, and generates the speaker control signal based on a synchronization signal, the broadband noise signal, and the virtual error signal. The synchronization signal contains information about the structure and operation settings of the fan module. The first transfer function is the transfer function between the reference microphone and a physical error microphone when the multi-channel speaker module is not running. The second transfer function is the transfer function between the multi-channel speaker module and the physical error microphone when the fan module is not running. The inverted noise signal contains multiple noise cancellation waveforms to cancel the noise generated by the electronic system during operation. Attached Figure Description

[0005] Figure 1 This is a functional block diagram of an electronic system with heat dissipation and feedforward active noise control functions operating in offline mode, according to an embodiment of the present invention.

[0006] Figure 2 This is a functional block diagram of an electronic system with heat dissipation and feedforward active noise control functions operating in online mode, according to an embodiment of the present invention.

[0007] Figure 3 This is a schematic diagram illustrating the implementation of the active noise reduction controller in the electronic system according to an embodiment of the present invention.

[0008] Figure 4 This is a flowchart illustrating the operation of an electronic system with heat dissipation and feedforward active noise control functions in offline mode, as described in an embodiment of the present invention.

[0009] Figure 5 This is a schematic diagram of the transfer function between the multi-channel speaker module, reference microphone, and physical error microphone when the electronic system with heat dissipation and feedforward active noise control functions is running in offline mode according to an embodiment of the present invention.

[0010] Figure 6 This is a flowchart illustrating the operation of an electronic system with heat dissipation and feedforward active noise control functions in online mode, as described in an embodiment of the present invention.

[0011] The reference numerals in the attached figures are explained as follows:

[0012] 10: Processor

[0013] 20: Fan Module

[0014] 30: Embedded Controller

[0015] 40: Multi-channel speaker module

[0016] 50: Reference microphone

[0017] 60: Active noise cancellation controller

[0018] 62: Frequency Calculator

[0019] 64: Signal Generator

[0020] 66: Digital Filter

[0021] 68: Speaker module driver circuit

[0022] 70: Virtual microphone module

[0023] 71: First Path Compensation Transfer Function Module

[0024] 72: Second Path Compensation Transfer Function Module

[0025] 76: Adaptive Filter

[0026] 80: Physical Error Microphone

[0027] 90: Beamforming Control Module

[0028] 100: Electronic Systems

[0029] 410-440, 610-670: Steps

[0030] SPK_L: Left channel speaker

[0031] SPK_R: Right channel speaker

[0032] S1, S2: Position signals

[0033] S FG Fan control signal

[0034] S MIC Speaker control signal

[0035] S SYN Synchronization signal

[0036] y(n): Inverting noise signal

[0037] y'(n): Processed inverted noise signal

[0038] e(n): Error signal

[0039] e'(n): Virtual error signal

[0040] f(n): Wideband noise signal

[0041] d(n): Noise signal

[0042] x(n): Reference signal

[0043] x'(n): Processed reference signal

[0044] P(Z), P'(Z): Transfer functions between the reference microphone and the physical error microphone

[0045] D(Z), D'(Z): Transfer functions between the speaker module and the reference microphone

[0046] C(Z), C'(Z): Transfer functions between the speaker module and the physical error microphone

[0047] W(Z): Parameters of the digital filter Detailed Implementation

[0048] Figure 1 This is a functional block diagram of an electronic system 100 with heat dissipation and feedforward active noise control functions operating in offline mode according to an embodiment of the present invention. Figure 2 This is a functional block diagram of an electronic system 100 with heat dissipation and feedforward active noise control functions operating in online mode according to an embodiment of the present invention.

[0049] Electronic system 100 includes a processor 10, a fan module 20, an embedded controller (EC) 30, a multi-channel speaker module 40, a reference microphone 50, an active noise cancellation (ANC) controller 60, and a beamforming control module 90, wherein the active noise cancellation controller 60 includes a virtual microphone module 70. The multi-channel speaker module 40 includes at least a left channel speaker SPK_L and a right channel speaker SPK_R.

[0050] In this invention, the electronic system 100 can operate in both offline and online modes. For example... Figure 1 As shown, when the electronic system 100 is running in offline mode, the beamforming control module 70 provides a beamforming control signal S based on a position signal S1. BF The multi-channel speaker module 40 will follow the beamforming control signal S BF This adjusts the orientation (sound output direction) of the left channel speaker SPK_L and the right channel speaker SPK_R. Furthermore, the active noise cancellation controller 60 operates based on an error signal e(n) provided by a physical error microphone 80 to determine the transfer functions D'(Z) between the multi-channel speaker module 40 and the reference microphone 50, C'(Z) between the multi-channel speaker module 40 and the physical error microphone 80, and P'(Z) between the reference microphone 50 and the physical error microphone 80 at a specific fan speed.

[0051] like Figure 2 As shown, when the electronic system 100 is running in online mode, the beamforming control module 70 provides a beamforming control signal S based on a position signal S2. BF The multi-channel speaker module 40 will follow the beamforming control signal S BF This adjusts the orientation (sound output direction) of the left channel speaker SPK_L and the right channel speaker SPK_R. Furthermore, the virtual microphone module 70 of the active noise cancellation controller 60 calculates a virtual error signal e'(n) based on the transfer functions P'(Z) and C'(Z), and the active noise cancellation controller 60 uses the virtual error signal e'(n) and the synchronization signal S... SYNThe wideband noise signal f(n) and the associated inverse noise signal y(n) are used to provide the speaker control signal S. MIC This drives the multi-channel speaker module 40, enabling it to provide an inverse noise signal y(n) to cancel the virtual error signal e'(n), thereby performing feedforward active noise control. The detailed operation of the electronic system 100 in offline and online modes will be described later in the specification.

[0052] The processor 10 may be a central processing unit (CPU) or a graphics processing unit (GPU). It is the key computing engine in the electronic system 100, responsible for executing the instructions and programs required by the operating system, and is also the main source of waste heat in the electronic system 100.

[0053] The fan module 20 may have different structures depending on its type, but it mainly uses a motor to drive the fan blades to rotate, drawing cooler air into the chassis and expelling hotter air from inside, thereby achieving a heat dissipation effect. In this invention, the fan module 20 will operate according to a fan control signal S provided by the embedded controller 30. FG To run, fan control signal S FG The higher the value, the faster the motor speed in fan module 20, resulting in stronger heat dissipation, but also generating more noise. During the operation of electronic system 100, fan module 20 is typically the primary source of noise. In one embodiment, the fan control signal S... FG A square wave signal with pulse width modulation (PWM) can be used to adjust the motor speed in fan module 20 by changing its duty cycle. In one embodiment, fan module 20 may include one or more axial or centrifugal fans, typically located at the rear of electronic system 100 facing away from the user. However, the number of fans, fan type, fan drive method, and location of the fans included in fan module 20 do not limit the scope of this invention.

[0054] The embedded controller 30 stores the EC codes for various operations of the relevant electronic system 100 and the timing of important power-on signals. In the power-off state, the embedded controller 30 remains operational, awaiting user power-on notifications; in the power-on state, the embedded controller 30 controls the system's standby / sleep state, keyboard controller, charging indicator light, and motor speed in the fan module 20. The embedded controller 30 typically includes a temperature sensor (not shown). Figure 1 and Figure 2 This monitors the operating temperature of the processor 10 and outputs a fan control signal S accordingly. FGAs the operating temperature of processor 10 increases, the fan control signal S... FG The longer the working cycle, the faster the motor speed in fan module 20; the lower the operating temperature of processor 10, the faster the fan control signal S... FG The shorter the working cycle, the slower the motor speed in fan module 20.

[0055] The left channel speaker SPK_L and right channel speaker SPK_R of the multi-channel speaker module 40 are electronic components that convert electronic signals into sound signals. They typically include a diaphragm and a drive circuit consisting of an electromagnet and a voice coil. The multi-channel speaker module 40 can operate according to the beamforming control signal S provided by the beamforming control module 70. BF The speaker module 40 adjusts the orientation of the left channel speaker SPK_L and the right channel speaker SPK_R so that they can send sound signals in a specific direction. Furthermore, the speaker module 40 can adjust the speaker control signal S provided by the active noise cancellation controller 60. MIC To send an inverted noise signal y(n), when the speaker control signal S... MIC When current passes through the voice coil, the voice coil vibrates with the frequency of the current, and the diaphragm connected to the voice coil also vibrates, thereby pushing the surrounding air to vibrate and produce sound. The function of the multi-channel speaker module 40 is to provide relevant sound effects when the user operates the electronic system 100, and therefore it is usually located on the front side of the electronic system 100 facing the user.

[0056] A reference microphone 50 is positioned near the fan blades in the fan module 20 to capture the noise generated during the operation of the fan module 20 and transmit the measured broadband noise signal f(n) to the active noise cancellation controller 60. The broadband noise signal f(n) includes the broadband noise spectrum of the airflow noise d(n) generated by the fan module 20 and the inverse noise signal y(n) provided by the multi-channel speaker module 40. In one embodiment, the reference microphone 50 may be a digital microelectromechanical system (MEMS) microphone, possessing high heat resistance, high vibration resistance, and high resistance to radio frequency interference. However, the type of reference microphone 50 does not limit the scope of this invention.

[0057] Figure 3 This is a schematic diagram illustrating the implementation of the active noise cancellation controller 60 in an embodiment of the present invention. The active noise cancellation controller 60 includes a frequency calculator 62, a signal generator 64, a digital filter 66, a speaker module driver circuit 68, a first path compensation transfer function module 71, a second path compensation transfer function module 72, an adaptive filter 76, and a virtual microphone module 70.

[0058] When the electronic system 100 is running in offline mode, the active noise cancellation controller 60 can receive the synchronization signal S. SYN The system receives a broadband noise signal f(n) from the reference microphone 50, corresponding to the anti-phase noise signal y(n), and an error signal e(n) from the physical error microphone 80. Based on these, it calculates the transfer functions C'(Z) between the multi-channel speaker module 40 and the physical error microphone 80, D'(Z) between the multi-channel speaker module 40 and the reference microphone 50, and P'(Z) between the reference microphone 50 and the physical error microphone 80. The synchronization signal S... SYN This includes information about the structure of the relevant fan module 20 (e.g., the number of fan blades) and its operating settings (e.g., motor speed in different modes). Figure 1 and Figure 2 In the embodiment shown, the synchronization signal S SYN This can be provided by the embedded controller 30. In other embodiments of the invention, the synchronization signal S SYN It can be provided by processor 10 or other components.

[0059] When the electronic system 100 is running in online mode, the active noise cancellation controller 60 can receive the synchronization signal S. SYN The virtual microphone module 70 receives a broadband noise signal f(n) from the reference microphone 50, along with the related anti-phase noise signal y(n). The virtual microphone module 70 provides a virtual error signal e'(n) based on the transfer functions C'(Z) and P'(Z) derived in offline mode. This is based on the synchronization signal S. SYN The active noise cancellation controller 60 can calculate the broadband noise generated by the fan module 20 when it runs at a predetermined fan speed, based on the broadband noise signal f(n), the virtual error signal e'(n), and the transfer functions C'(Z) and D'(Z) obtained in offline mode, and then provide the speaker control signal S accordingly. MIC This drives the multi-channel speaker module 40 so that the inverse noise signal y(n) provided by the multi-channel speaker module 40 can effectively cancel the influence of the noise signal d(n), that is, to reduce the virtual error signal e'(n) to 0 as much as possible. Figure 1 and Figure 2 In the embodiment shown, the synchronization signal S SYN This can be provided by the embedded controller 30. In other embodiments of the invention, the synchronization signal S SYN It can be provided by processor 10 or other components.

[0060] Figure 4 The flowchart shown illustrates an electronic system 100 with heat dissipation and feedforward active noise control functions operating in offline mode according to an embodiment of the present invention, which includes the following steps:

[0061] Step 410: Set the physical error microphone 80 at a specific location.

[0062] Step 420: Align the sound output direction of all speakers in the multi-channel speaker module 40 with a specific position.

[0063] Step 430: With the multi-channel speaker module 40 not running, measure the transfer function P'(Z) between the reference microphone 50 and the physical error microphone 80.

[0064] Step 440: With the fan module 20 not running, measure the transfer function D'(Z) between the multi-channel speaker module 40 and the reference microphone 50, and the transfer function C'(Z) between the multi-channel speaker module 40 and the physical error microphone 80.

[0065] Figure 5 This diagram illustrates the transfer function of an electronic system 100 with heat dissipation and feedforward active noise control functions in an embodiment of the present invention during signal transmission between a multi-channel speaker module 40, a reference microphone 50, and a physical error microphone 80 when operating in offline mode. Figure 5 In this context, d(n) represents the noise signal to be eliminated during offline operation of the electronic system 100, f(n) represents the broadband noise signal measured by the reference microphone 50, e(n) represents the error signal output by the physical error microphone 80, y(n) represents the anti-phase noise signal provided by the multi-channel speaker module 40, and S MIC The active noise cancellation controller 60 outputs the speaker control signal, P(Z) represents the transfer function between the reference microphone 50 and the physical error microphone 80, D(Z) represents the transfer function between the multi-channel speaker module 40 and the reference microphone 50, and C(Z) represents the transfer function between the multi-channel speaker module 40 and the physical error microphone 70. When the fan module 20 operates at different fan speeds, the resulting air pressure will also be different, and the air pressure caused by the rotation of the fan blades will affect the transfer function between the multi-channel speaker module 40, the reference microphone 50, and the physical error microphone 80. Therefore, this invention can determine the transfer function corresponding to each fan speed in offline mode.

[0066] In step 410, the present invention places the physical error microphone 80 at a specific location, which may be the user's expected position when operating the electronic system 100. For example, when the electronic system 100 is a laptop, the user's head is usually located at a specific distance directly in front of the screen. Therefore, the physical error microphone 80 can be placed at the expected position of the user's head, for example, about 30 to 45 centimeters directly in front of the screen of the electronic system 100, but is not limited to this. The physical error microphone 80 is used to capture the overall noise of the electronic system 100 when it is running in offline mode and outputs a corresponding error signal e(n) to the active noise cancellation controller 60, where d(n) represents the noise signal to be eliminated during the operation of the electronic system 100 in offline mode. More specifically, the error signal e(n) output by the physical error microphone 80 is related to the difference between the noise signal d(n) and the captured inverse noise signal y(n). The smaller the value of the error signal e(n), the better the noise reduction effect.

[0067] In step 420, the beamforming control module 70 can provide a beamforming control signal S based on the position signal S1. BF This allows all speakers in the multi-channel speaker module 40 to be aligned with a specific position, where the position signal S1 is related to the user's expected position when operating the electronic system 100, and can be provided by the processor 10, the embedded controller 30, or other components, but is not limited to these.

[0068] In step 430, the adaptive filter 76 measures the transfer function P'(Z) between the reference microphone 50 and the physical error microphone 80 while the multi-channel speaker module 40 is not operating. More specifically, in step 430, the active noise cancellation controller 60 outputs a speaker control signal S. MIC With the multi-channel speaker module 40 turned off (y(n) value 0), the adaptive filter 76 adjusts the parameter W(Z) of the digital filter 66 based on the broadband noise signal f(n) measured by the reference microphone 50 and the error signal e(n) output by the physical error microphone 80. After a predetermined period of adaptive signal processing, the parameter W(Z) of the digital filter 66 converges to a predetermined stable state, at which point the parameter W(Z) of the digital filter 66 can be used as the transfer function P'(Z) between the reference microphone 50 and the physical error microphone 80.

[0069] In step 440, the present invention measures the transfer function D'(Z) between the multi-channel speaker module 40 and the reference microphone 50, and the transfer function C'(Z) between the multi-channel speaker module 40 and the physical error microphone 70 under no-pressure conditions. More specifically, in step 440, the embedded controller 30 outputs a fan control signal S.FG To shut down fan module 20, active noise cancellation controller 60 outputs speaker control signal S. MIC The multi-channel speaker module 40 provides an inverted noise signal y(n). In offline mode, the inverted noise signal y(n) is white noise used as the test signal, and the adaptive filter 76 adjusts the parameter W(Z) of the digital filter 66 based on the inverted noise signal y(n) provided by the multi-channel speaker module 40 and the error signal e(n) output by the physical error microphone 80. After a predetermined period of adaptive signal processing, the parameter W(Z) of the digital filter 66 converges to a predetermined stable state, at which point the parameter W(Z) of the digital filter 66 can be used as the transfer function D'(Z) between the multi-channel speaker module 40 and the reference microphone 50 under no-pressure conditions. Similarly, the adaptive filter 76 adjusts the parameter W(Z) of the digital filter 66 based on the inverted noise signal y(n) provided by the multi-channel speaker module 40 and the error signal e(n) output by the physical error microphone 80. After a predetermined period of adaptive signal processing, the parameter W(Z) of the digital filter 66 will converge to a predetermined stable state. At this point, the parameter W(Z) of the digital filter 66 can be used as the transfer function C'(Z) between the multi-channel speaker module 40 and the physical error microphone 80 under no-wind-pressure conditions.

[0070] Figure 6 This is a flowchart of the electronic system 100 with heat dissipation and feedforward active noise control functions operating in online mode according to an embodiment of the present invention, which includes the following steps:

[0071] Step 610: Determine the user's location when operating the electronic system 100.

[0072] Step 620: Align the sound output direction of all speakers in the multi-channel speaker module 40 with the user's position when operating the electronic system 100.

[0073] Step 630: The reference microphone 50 captures the noise generated by the fan module 20 during operation and provides the corresponding wideband noise signal f(n).

[0074] Step 640: The virtual microphone module 70 provides a virtual error signal e'(n) based on the transfer functions P'(Z) and C'(Z), the broadband noise signal f(n), and the phase-inverting noise signal y(n).

[0075] Step 650: The active noise cancellation controller 60, based on the synchronization signal S SYN The number of fan blades in fan module 20 and the motor speed in each mode are obtained, and the relevant speaker control signal S is calculated. MIC The reference signal x(n) is the reference power value.

[0076] Step 660: The active noise cancellation controller 60 calculates the actual single-blade fundamental frequency, actual single-blade harmonic frequency, actual blade passing frequency (BPF), and actual wideband noise spectrum of the fan module 20 based on the broadband noise signal f(n), the virtual error signal e'(n), and the reference signal x(n), and provides the speaker control signal S accordingly. MIC .

[0077] Step 670: The multi-channel speaker module 40 operates according to the speaker control signal S MIC Generate an inverted noise signal y(n); execute step 610.

[0078] In step 610, the present invention determines the user's location while operating the electronic system 100. In one embodiment, the user's location can be defined by the system itself, for example, located at a specific distance directly in front of the screen, wherein the specific distance may vary depending on the type of electronic system 100. In another embodiment, the electronic system 100 may have image recognition capabilities, thus enabling real-time detection of the user's location.

[0079] In step 620, the beamforming control module 70 can provide a beamforming control signal S based on the position signal S2. BF This ensures that the sound output direction of all speakers in the multi-channel speaker module 40 is aligned with the user's location when operating the electronic system 100. In one embodiment, the position signal S2 may be related to the user's expected position as defined by the system itself, and may be provided by the processor 10, the embedded controller 30, or other components. In another embodiment, the position signal S2 may be related to the user's actual position when operating the electronic system 100, and may be provided by the image recognition unit of the electronic system 100.

[0080] The noise source of the fan module 20 during operation originates from the airflow caused by the motor rotation. Narrow-frequency components may originate from thickness noise caused by volumetric displacement due to fan blade movement, or BPF noise caused by variable load forces on the fan blade surface (including axial lift and tension on the fan surface). Since BPF and related harmonics are related to pressure disturbances generated when each fan blade passes a fixed reference point, specific narrow-frequency noise is generated when periodic pressure waves are generated at the fan blade tip. On the other hand, when airflow passes over the fan blades, it peels away from the boundary layer or the sides of the blade tips, forming alternating vortices. This phenomenon is called vortex shedding. Vortex shedding causes the instantaneous velocity of the fluid on both sides of the fan blades to differ, resulting in different instantaneous pressures on both sides of the fan blades at different fluid velocities. This causes the fan blades to vibrate, generating specific broadband noise.

[0081] In step 630, the reference microphone 50 will capture the noise caused by the blades of the fan module 20 when it is running in online mode during the operation of the electronic system 100, and provide the corresponding wideband noise signal f(n).

[0082] In step 640, the virtual microphone module 70 provides a virtual error signal e'(n) based on the transfer functions P'(Z) and C'(Z) obtained in offline mode, the broadband noise signal f(n), and the anti-phase noise signal y(n), where e'(n) = P'(Z)*f(n) + C'(Z)*y(n). As mentioned above, P'(Z) is the transfer function between the reference microphone 50 and the physical error microphone 80 at a specific fan speed, C'(Z) is the transfer function between the multi-channel speaker module 40 and the physical error microphone 70 under no-pressure conditions, and D'(Z) is the transfer function between the multi-channel speaker module 40 and the reference microphone 50 under no-pressure conditions. In this invention, the virtual microphone module 70 can be implemented in software or firmware, but this is not limited to the scope of the invention.

[0083] In step 650, the frequency calculator 62 of the active noise cancellation controller 60 can use the synchronization signal S provided by the embedded controller 30. SYN The motor speed, single-blade frequency point, and number of blades of fan module 20 are known, where the value of BPF is the product of the motor speed and the number of blades of fan module 20. Assuming the number of blades in fan module 20 is 37, Table 1 below shows the data calculated by the frequency calculator 62, but this does not limit the scope of the invention. The unit of motor speed is rpm, and the unit of frequency is Hertz.

[0084] 500 8.3 16.6 24.9 33.2 37 307.1 614.2 921.3 1000 16.6 33.2 49.8 66.4 37 614.2 1228.4 1842.6 1500 25 50 75 100 37 925 1850 2775 2000 33.3 66.6 99.9 133.2 37 1232.1 2464.2 3696.3 2500 41.7 83.4 125.1 166.8 37 1542.9 3085.8 4628.7 3000 50 100 150 200 37 1850 3700 5550 3500 58.3 116.6 174.9 233.2 37 2157.1 4314.2 6471.3 4000 66.7 133.4 200.1 266.8 37 2467.9 4935.8 7403.7 4500 75 150 225 300 37 2775 5550 8325 5000 83.3 166.6 249.9 333.2 37 3082.1 6164.2 9246.3 5500 91.6 183.2 274.8 366.4 37 3389.2 6778.4 10167.6 5700 95 190 285 380 37 3515 7030 10545

[0085] Table 1

[0086] Next, the signal generator 64 of the active noise cancellation controller 60 generates a reference signal x(n) based on the data calculated by the frequency calculator 62. The reference signal x(n) includes information such as the estimated octave, estimated BPF, and sound pressure level spectrum (dBSPL) of the fan module 20 at different motor speeds, and thus determines the speaker control signal S. MIC The reference power value is obtained by adjusting the parameter W(Z) of the digital filter 66, which can change the speaker control signal S. MIC The power value.

[0087] In step 660, the active noise cancellation controller 60 calculates the actual single-blade fundamental frequency, actual single-blade harmonic frequency, actual BPF, and actual wideband noise spectrum of the fan module 20 based on the broadband noise signal f(n), the virtual error signal e'(n), and the reference signal x(n), and provides the speaker control signal S accordingly. MIC To drive the speaker module driver circuit 68 to output the speaker control signal S MIC The multi-channel speaker module 40 is then driven to provide an inverted noise signal y(n), where W(Z) represents the adjustable operating parameters of the digital filter 66. More specifically, the inverted noise signal y(n) comprises multiple noise cancellation waveforms, which are respectively inverse signals related to the actual single-blade fundamental frequency, the actual single-blade octave, the actual BPF fundamental frequency, the actual BPF octave, and the broadband noise spectrum.

[0088] In step 670, the active noise cancellation controller 60 adjusts the speaker control signal S based on the transfer function D'(Z) between the multi-channel speaker module 40 and the reference microphone 50, and the transfer function C'(Z) between the speaker module 40 and the physical error microphone 70. MIC The characteristics of the signal are as follows. More specifically, the first path compensation transfer function module 71 processes the inverted noise signal y(n) based on the transfer function D'(Z) between the speaker module 40 and the reference microphone 50, which obtains the relevant current fan speed in offline mode, and outputs the corresponding processed inverted noise signal y'(n) to the signal generator 64. The signal generator 64 subtracts the processed inverted noise signal y'(n) from the broadband noise signal f(n) and outputs the corresponding reference signal x(n) to the digital filter 66 and the second path compensation transfer function module 72. Then, the second path compensation transfer function module 72 processes the reference signal x(n) based on the transfer function C'(Z) between the multi-channel speaker module 40 and the physical error microphone 70, which obtains the relevant current fan speed in offline mode, and outputs the corresponding processed reference signal x'(n) to the adaptive filter 76.

[0089] The adaptive filter 76 can perform signal processing on the processed reference signal x'(n) and the virtual error signal e'(n) according to a specific algorithm, thereby adjusting the parameter W(Z) of the digital filter 66. More specifically, the processed reference signal x'(n) includes information such as the motor speed of the fan module 20, the estimated single-blade fundamental frequency, the estimated harmonic frequency, the estimated BPF, and the estimated wind pressure. The adaptive filter 76 then uses the error signal e(n) to calculate the actual single-blade fundamental frequency, the actual harmonic frequency, and the actual BPF, as well as other relevant narrow-band noise information, during the operation of the fan module 20, and adjusts the parameter W(Z) of the digital filter 66 accordingly. In this way, when the digital filter 66 drives the speaker module drive circuit 68 to output the speaker control signal S... MIC At this time, the inverted noise signal y(n) generated by the multi-channel speaker module 40 reflects the actual operating status of the fan module 20, the wind pressure effect caused by the current fan speed, and the current noise reduction level. More specifically, the inverted noise signal y(n) contains multiple noise cancellation waveforms, which are the inverse signals related to the actual single-blade fundamental frequency, the actual single-blade octave, the actual BPF fundamental frequency, the actual BPF octave, the broadband noise spectrum, and the actual wind pressure, respectively. After signal transmission, the inverted noise signal y(n) generated by the speaker module 40 can effectively cancel the influence of the noise signal d(n), that is, reduce the virtual error signal e'(n) to 0 as much as possible.

[0090] In one embodiment, the adaptive filter 76 may perform signal processing on the processed reference signal x'(n) and the virtual error signal e'(n) according to the Least mean square (LMS) algorithm. However, the algorithm used by the adaptive filter 76 does not limit the scope of the present invention.

[0091] In summary, in the electronic system 100 of the present invention with heat dissipation and feedforward active noise control functions, the beamforming control module 70 first controls the orientation of the multi-channel speaker module 40 in offline mode so that the sound output direction of each speaker can be aligned with a specific position (e.g., the expected position when the user operates the electronic system 100). Then, the transfer function P(Z) between the reference microphone 50 and the physical error microphone 80, the transfer function D(Z) between the speaker module 40 and the reference microphone 50, and the transfer function C(Z) between the speaker module 40 and the physical error microphone 80 are calculated at each fan speed. In online mode, the beamforming control module 70 controls the orientation of the multi-channel speaker module 40, ensuring that the sound output direction of each speaker is aligned with a specific location (e.g., the user's expected or actual location when operating the electronic system 100). The reference microphone 50 captures the noise caused by the fan module 20 blades during operation and provides a corresponding broadband noise signal f(n). The virtual microphone module 70 provides a virtual error signal e'(n) based on the transfer function P'(Z) between the reference microphone 50 and the physical microphone 80 at a specific fan speed, the transfer function C'(Z) between the speaker module 40 and the physical microphone 70 under no-wind-pressure conditions, the broadband noise signal f(n), and the anti-phase noise signal y(n). This is based on the synchronization signal S. SYN The active noise cancellation controller 60 can calculate the broadband noise generated by the fan module 20 when it runs at a predetermined fan speed, based on the broadband noise signal f(n), the virtual error signal e'(n), and the transfer functions C'(Z) and D'(Z) obtained in offline mode, and then provide the speaker control signal S accordingly. MIC The multi-channel speaker module 40 is driven so that the anti-phase noise signal y(n) provided by the speaker module 40 can effectively cancel the influence of the noise signal d(n). Since the virtual microphone module 70, which operates according to the transfer functions P'(Z) and C'(Z), can simulate the operation of the physical error microphone 80, the electronic system 100 of the present invention can provide feedforward active noise control without the need for an additional physical error microphone. Since the beamforming control module 70 can adjust the orientation of the multi-channel speaker module 40 in real time so that it can send the anti-phase noise signal y(n) to the position of the user when operating the electronic system 100, the feedforward active noise control function can be effectively provided without the need for an additional speaker on the fan path at the rear of the electronic system 100.

[0092] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made in accordance with the claims of the present invention should be included within the scope of the present invention.

Claims

1. An electronic system with heat dissipation and feedforward active noise control functions, comprising: A fan module is used to operate according to a fan control signal to provide heat dissipation. An embedded controller is used to provide control signals for the fan; A reference microphone is used to detect the broadband noise generated by the fan module during operation and to provide a corresponding broadband noise signal; A multi-channel loudspeaker module, comprising at least a first loudspeaker and a second loudspeaker, for providing an anti-phase noise signal according to a loudspeaker control signal; A beamforming control module is used to provide a beamforming control signal to control the orientation of the multi-channel speaker module, so as to align the sound output directions of the first speaker and the second speaker to a specific position; and An active noise cancellation controller is used to: A virtual error signal is provided based on a first transfer function, a second transfer function, the broadband noise signal, and the inverted noise signal; and The speaker control signal is generated based on a synchronization signal, the wideband noise signal, and the virtual error signal; in: The synchronization signal contains information about the structure and operating settings of the fan module; The first transfer function is the transfer function between the reference microphone and a physical error microphone when the multi-channel speaker module is not running; The second transfer function is the transfer function between the multi-channel speaker module and the physical error microphone when the fan module is not running; The inverted noise signal contains multiple noise cancellation waveforms to cancel out the noise generated during the operation of the electronic system; and The physical error microphone is positioned at this specific location; and This specific location is a desired position for a user when operating the electronic system.

2. The electronic system of claim 1, further comprising: An image recognition unit is used to detect the actual position of a user when operating the electronic system, wherein the beamforming control module is further used to provide the beamforming control signal based on the actual position.

3. The electronic system as claimed in claim 1, wherein: This active noise cancellation controller is also used for: The first transfer function between the reference microphone and the physical error microphone is measured when the multi-channel speaker module is not running. The second transfer function between the multi-channel speaker module and the physical error microphone is measured when the fan module is not running. A third transfer function is measured between the multi-channel speaker module and the reference microphone when the fan module is not running. The virtual error signal is calculated based on the first transfer function and the second transfer function, wherein the value of the virtual error signal is the product of the first transfer function and the broadband noise signal plus the product of the second transfer function and the inverted noise signal; and During the measurement of the first transfer function, the second transfer function, and the third transfer function, the specific position is the expected position of the user when operating the electronic system.

4. The electronic system of claim 3, wherein the active noise cancellation controller comprises: A virtual microphone module is used to provide the virtual error signal based on the first transfer function and the second transfer function; A frequency calculator is used to determine, based on the synchronization signal, an estimated single-blade fundamental frequency, an estimated single-blade harmonic frequency, and an estimated blade passage frequency fundamental frequency of the fan module; A signal generator is used to generate a reference signal based on the estimated single-blade fundamental frequency, the estimated single-blade harmonic frequency, and the estimated blade transmission frequency fundamental frequency; and A digital filter is used to perform calculations on the reference signal to determine a reference power value for the loudspeaker control signal.

5. The electronic system of claim 4, wherein the active noise cancellation controller further comprises: An adaptive filter is used to adjust the parameters used by the digital filter when performing operations based on the second transfer function, the third transfer function and the virtual error signal, thereby adaptively adjusting the power value of the speaker control signal.

6. The electronic system of claim 5, wherein: The adaptive filter uses a least mean square algorithm to process the reference signal, the broadband noise signal, and the virtual error signal.

7. The electronic system of claim 5, wherein the active noise cancellation controller further comprises: A first path compensation transfer function module, coupled to the multi-channel speaker module, receives the anti-phase noise signal, then processes the anti-phase noise signal according to the third transfer function, and outputs the corresponding processed anti-phase noise signal to the signal generator; and A second path compensation transfer function module is coupled to the signal generator to receive the reference signal, then performs signal processing on the reference signal according to the second transfer function, and outputs the corresponding processed reference signal to the adaptive filter.

8. The electronic system of claim 7, wherein the signal generator is further configured to: The wideband noise signal is subtracted from the processed inverted noise signal to provide the reference signal.

9. The electronic system of claim 1, wherein the active noise cancellation controller is further configured to: Based on the synchronization signal, the broadband noise signal, and the virtual error signal, the following parameters are calculated for the fan module operating at a predetermined fan speed: a fundamental frequency of an actual single blade, an overtone of an actual single blade, a fundamental frequency of an actual blade passage frequency, an overtone of an actual blade passage frequency, and an actual broadband noise spectrum; and The loudspeaker control signal is generated based on the actual single blade fundamental frequency, the actual single blade harmonic frequency, the actual blade passing frequency fundamental frequency, the actual blade passing frequency harmonic frequency, and the actual broadband noise spectrum.

10. The electronic system of claim 9, wherein the plurality of noise cancellation waveforms are inverse signals relating to the actual single blade fundamental frequency, the actual single blade harmonic frequency, the actual blade passage frequency fundamental frequency, the actual blade passage frequency harmonic frequency, and the broadband noise spectrum.

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