Feed-forward active noise control electronics with heat dissipation and wind pressure compensation

Abstract

An electronic system with feedforward active noise control function with heat dissipation and wind pressure compensation includes a fan module, an embedded controller, a reference microphone, an error microphone, an active noise reduction controller, and a speaker module. The reference microphone captures the noise of the fan module during operation and provides a corresponding broadband noise signal, and the error microphone captures the overall noise of the electronic system during operation and outputs a corresponding error signal. The active noise reduction controller calculates the narrowband and broadband noise generated by the fan module during actual operation based on the broadband noise signal, the error signal, and the fan information provided by the embedded controller to provide a speaker control signal, and then drives the speaker module to provide an anti-phase noise signal, and adjusts the power of the speaker control signal based on the wind pressure caused by the current speed of the fan module.

Description

Technical Field

[0001] The invention provides an electronic system with heat dissipation and feedforward active noise control functions, in particular to an electronic system with heat dissipation and feedforward active broadband noise control functions with wind pressure compensation. Background Art

[0002] In the modern information society, computer systems have become an indispensable information tool for most people. In order to prevent components from overheating and causing power reduction or damage, computer systems generally use fans to provide heat dissipation to discharge the heat generated inside the device or to draw in cool air from outside the device.

[0003] The fan speed and static pressure determine the fan's air flow rate. The noise generated by the fan when it is running is approximately proportional to the fifth root of its speed. The faster the speed, the stronger the heat dissipation capacity, but the greater the noise. As the CPU becomes more powerful, the waste heat generated inside the device also increases. In addition, the trend of miniaturization will reduce the heat flow efficiency. How to balance heat dissipation and noise reduction is an important issue. Summary of the invention

[0004] The present invention provides an electronic system with a feedforward active noise control function with heat dissipation and wind pressure compensation, which comprises a fan module, an embedded controller, a reference microphone, an error microphone, an active noise reduction controller, and a speaker module. The fan module is used to operate according to a fan control signal to provide a heat dissipation function. The embedded controller is used to provide the fan control signal and a synchronization signal, wherein the synchronization signal includes information about the structure and operation settings of the fan module. The reference microphone is used to detect the broadband noise generated when the fan module is running to provide a corresponding broadband noise signal. The error microphone is used to detect the noise generated when the electronic system is running to provide a corresponding error signal. The active noise reduction controller is used to generate a speaker control signal according to the synchronization signal, the broadband noise signal and the error signal, and adjust the power of the speaker control signal according to the broadband noise signal, the error signal, a downwind transfer function and an upwind transfer function. The speaker module is used to provide an anti-phase noise signal according to the speaker control signal, wherein the anti-phase noise signal includes multiple noise elimination waveforms to offset the noise generated when the electronic system is running, the downwind transfer function is a transfer function between the speaker module and the error microphone when the fan module runs at a predetermined fan speed, and the upwind transfer function is a transfer function between the speaker module and the reference microphone when the fan module runs at the predetermined fan speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 14 is a functional block diagram of an electronic system with heat dissipation and wind pressure compensation feedforward active noise control functions according to an embodiment of the present invention.

[0006] Figure 2 FIG. 4 is a schematic diagram of an implementation of an ANC controller in an embodiment of the present invention.

[0007] Figure 3 A flowchart showing an electronic system in an offline mode according to an embodiment of the present invention

[0008] Figure 4 A transfer function diagram of a speaker module, a reference microphone, and an error microphone when transmitting signals in an electronic system according to an embodiment of the present invention is shown.

[0009] Figure 5 This is a flow chart of an electronic system in an embodiment of the present invention when operating in an online mode.

[0010] The reference numerals are described as follows:

[0011] 10: Processor

[0012] 20: Fan module

[0013] 30: Embedded Controller

[0014] 40: Speaker module

[0015] 50: Reference microphone

[0016] 55: Error microphone

[0017] 60: Active noise reduction controller

[0018] 62: Frequency Calculator

[0019] 64: Signal Generator

[0020] 66: Digital Filter

[0021] 68: Speaker module driving circuit

[0022] 71: First path compensation transfer function module

[0023] 72: Second path compensation transfer function module

[0024] 76: Adaptive filter

[0025] 100: Electronic Systems

[0026] 310-350, 510-550: Steps

[0027] S FG : Fan control signal

[0028] S MIC : Speaker control signal

[0029] S SYN : Synchronous signal

[0030] y(n): anti-phase noise signal

[0031] y'(n): processed inverted noise signal

[0032] y”(n): Inverted noise signal after transmission

[0033] e(n): error signal

[0034] f(n): broadband noise spectrum signal

[0035] d(n): noise signal

[0036] x(n): reference signal

[0037] x'(n): processed reference signal

[0038] C”(Z): Downwind transfer function

[0039] D”(Z): Upwind transfer function DETAILED DESCRIPTION

[0040] Figure 1 FIG. 1 is a functional block diagram of an electronic system 100 with heat dissipation and wind pressure compensation functions according to an embodiment of the present invention. The electronic system 100 includes a processor 10, a fan module 20, an embedded controller (EC) 30, a speaker module 40, a reference microphone 50, an error microphone 55, and an active noise cancellation (ANC) controller 60.

[0041] The processor 10 may be a central processing unit (CPU) or a graphics processing unit (GPU), which is a key computing engine in the electronic system 100 and is responsible for executing instructions and programs required by the operating system. It is also the main source of waste heat in the electronic system 100.

[0042] The fan module 20 may have different structures depending on its type, and mainly uses a motor to drive the fan blades to rotate to bring cooler air into the chassis and exhaust the hotter air inside, thereby achieving a heat dissipation effect. In the present invention, the fan module 20 will be based on a fan control signal S provided by the embedded controller 30 FG To run, the fan control signal SFG The larger the value of , the faster the motor speed in the fan module 20 is, the stronger the heat dissipation effect is, but it will also generate a lot of noise. During the operation of the electronic system 100, the fan module 20 is usually the main source of noise. In one embodiment, the fan control signal S FG It can be a square wave signal of pulse width modulation (PWM), and the motor speed in the fan module 20 is adjusted by changing its duty cycle. In one embodiment, the fan module 20 can include one or more axial fans or centrifugal fans. However, the number of fans, fan types and fan driving methods included in the fan module 20 do not limit the scope of the present invention.

[0043] The embedded controller 30 stores the EC codes of various operations of the related electronic system 100 and the timing of important signals when the system is turned on. In the off state, the embedded controller 30 will keep running to wait for the user's boot information; in the on state, the embedded controller 30 will control the standby / sleep state of the system, the keyboard controller, the charging indicator light, and the motor speed in the fan module 20. The embedded controller 30 usually includes a temperature sensor (not shown). Figure 1 ) to monitor the operating temperature of the processor 10 and output a fan control signal S accordingly FG When the operating temperature of the processor 10 is higher, the fan control signal S FG The larger the duty cycle, the faster the motor speed in the fan module 20; when the operating temperature of the processor 10 is lower, the fan control signal S FG The smaller the duty cycle, the slower the motor speed in the fan module 20.

[0044] The speaker module 40 is an electronic component that can convert electronic signals into sound signals, and generally includes a diaphragm and a driving circuit composed of an electromagnet and a voice coil. The speaker module 40 can generate a sound signal according to a speaker control signal S provided by the ANC controller 60. MIC To operate, when the speaker control signal S MIC When the 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 driving the surrounding air to vibrate and produce sound. In the embodiment of the present invention, the diaphragm of the speaker module 40 is arranged in the air outlet structure of the fan module 20, and can be adjusted according to the speaker control signal S MIC To generate an anti-phase noise signal y(n).

[0045] The reference microphone 50 is disposed near the fan blades in the fan module 20 to capture the noise generated when the fan module 20 is in operation, and transmits a measured broadband noise signal f(n) to the ANC controller 60, wherein the broadband noise signal f(n) includes a broadband noise spectrum of the airflow noise generated when the fan module 20 is in operation. In one embodiment, the reference microphone 50 may be a digital micro-electromechanical system (MEMS) microphone, which has high heat resistance, high vibration resistance, and high radio frequency interference resistance. However, the type of the reference microphone 50 does not limit the scope of the present invention.

[0046] The error microphone 55 is used to capture the overall noise of the electronic system 100 during operation, and output a corresponding error signal e(n) to the ANC controller 60, wherein d(n) represents the noise signal to be eliminated during the operation of the electronic system 100. Since the fan module 20 is the main noise source, the error microphone 55 can be set close to the air outlet of the fan module 20, wherein the distance between the reference microphone 50 and the ANC controller 60 is greater than the distance between the error microphone 55 and the ANC controller 60. In more detail, the error signal e(n) output by the error microphone 55 is the difference between the noise signal d(n) and the captured anti-phase noise signal y" (n), and the smaller the value of the error signal e(n), the better the noise reduction effect. In one embodiment, the error microphone 55 can be a digital MEMS microphone, which has the properties of high heat resistance, high vibration resistance and high resistance to radio frequency interference. However, the type of the error microphone 55 does not limit the scope of the present invention.

[0047] The ANC controller 60 may receive a synchronization signal S from the embedded controller 30. SYN , receiving a broadband noise signal f(n) from the reference microphone 50, and receiving an error signal e(n) from the error microphone 55, wherein the synchronization signal S SYN The information includes the structure of the fan module 20 (such as the number of fan blades) and the operation settings (such as the motor speed in different modes). SYN , broadband noise signal f(n), and a transfer function D”(Z) and a transfer function C”(Z) corresponding to a predetermined fan speed, the ANC controller 60 can calculate the broadband noise in the noise generated when the fan module 20 runs at the predetermined fan speed; according to the synchronization signal S SYN The ANC controller 60 can calculate the narrowband noise in the noise generated when the fan module 20 runs at a predetermined fan speed by using the error signal e(n). Based on the calculated wideband noise and narrowband noise, the ANC controller 60 can provide a speaker control signal S MICThe speaker module 40 is driven so that the anti-phase noise signal y(n) provided by the speaker module 40 can effectively offset the influence of the noise signal d(n), that is, the error signal e(n) is reduced to zero as much as possible.

[0048] Figure 2 FIG. 6 is a schematic diagram of an implementation of an ANC controller 60 according to an embodiment of the present invention. The ANC controller 60 includes a frequency calculator 62, a signal generator 64, a digital filter 66, a speaker module driving circuit 68, a first path compensation transfer function module 71, a second path compensation transfer function module 72, and an adaptive filter 76.

[0049] In the present invention, the electronic system 100 can operate in an offline mode and an online mode, wherein in the offline mode, 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 error microphone 55 at a specific fan speed can be calculated, and in the online mode, a feedforward active noise control with a wind pressure compensation mechanism can be provided.

[0050] Figure 3 A flow chart showing the operation of the electronic system 100 in the offline mode includes the following steps:

[0051] Step 310 : The fan module 20 operates at a specific fan speed.

[0052] Step 320: Measure the transfer function P′(Z) between the reference microphone 50 and the error microphone 55 at a specific fan speed.

[0053] Step 330 : measuring 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 error microphone 55 in a state without wind pressure.

[0054] Step 340: Calculate the transfer function K(Z) of the specific fan speed according to the transfer functions P'(Z), D'(Z), and C'(Z).

[0055] Step 350: Calculate the transfer function C" (Z) between the speaker module 40 and the reference microphone 50 and the transfer function D" (Z) between the speaker module 40 and the error microphone 55 at a specific fan speed based on the transfer functions K(Z), D' (Z) and C' (Z).

[0056] Figure 4 FIG. 1 shows a transfer function diagram of the signal transmission between the speaker module 40, the reference microphone 50, and the error microphone 55 in the electronic system 100. Figure 4In the figure, d(n) represents the noise signal to be eliminated during the 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 error microphone module 55, y(n) represents the anti-phase noise signal provided by the speaker module 40, and S MIC represents the speaker control signal output by the ANC controller 60, P(Z) represents the transfer function between the reference microphone 50 and the error microphone 55, D(Z) represents the transfer function between the speaker module 40 and the reference microphone 50, and C(Z) represents the transfer function between the speaker module 40 and the error microphone 55. When the fan module 20 operates at different fan speeds, the generated wind pressure will also be different, and the wind pressure caused by the rotation of the fan blades will affect the transfer function between the speaker module 40, the reference microphone 50 and the error microphone 55. Therefore, the present invention can obtain the transfer function corresponding to the wind pressure caused by each fan speed in the offline mode.

[0057] When the fan module 20 is running at a specific fan speed in step 310, the adaptive filter 76 then measures the transfer function P'(Z) between the reference microphone 50 and the error microphone 55 at the specific fan speed in step 320. More specifically, in step 320, the ANC controller 60 outputs the speaker control signal S MIC The speaker module 40 is turned off (the value of y(n) is 0), and the adaptive filter 76 adjusts the parameter W(Z) of the digital filter 66 according to the broadband noise signal f(n) measured by the reference microphone 50 and the error signal e(n) output by the error microphone module 55. After a predetermined period of adaptive signal processing, the parameter W(Z) of the digital filter 66 converges to a predetermined stable state, and 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 error microphone 55 at a specific fan speed.

[0058] In step 330, the present invention measures 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 error microphone 55 in a no-wind pressure state. More specifically, in step 330, the embedded controller 30 outputs the fan control signal S FG The fan module 20 is turned off, and the ANC controller 60 outputs a speaker control signal S MICTo control the speaker module 40 to provide an inverted noise signal y(n). In the offline mode, the inverted noise signal y(n) is a white noise as a test signal, and the adaptive filter 76 adjusts the parameter W(Z) of the digital filter 66 according to the inverted noise signal y(n) provided by the speaker module 40 and the error signal e(n) output by the error microphone module 55. 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 time the parameter W(Z) of the digital filter 66 can be used as the transfer function D'(Z) between the speaker module 40 and the reference microphone 50 in a state without wind pressure. Similarly, the adaptive filter 76 adjusts the parameter W(Z) of the digital filter 66 according to the inverted noise signal y(n) provided by the speaker module 40 and the error signal e(n) output by the error microphone module 55. After a predetermined period of adaptive signal processing, the parameter W(Z) of the digital filter 66 converges to a predetermined stable state. At this time, the parameter W(Z) of the digital filter 66 can be used as the transfer function C'(Z) between the speaker module 40 and the error microphone module 55 in the state without wind pressure.

[0059] In step 340, the present invention calculates the transfer function K(Z) of the specific fan speed based on the transfer functions P'(Z), D'(Z) and C'(Z). As mentioned above, the transfer function P'(Z) obtained in step 320 represents the transfer function between the reference microphone 50 and the error microphone 55 at the specific fan speed, and the product of the transfer functions C'(Z) and D'(Z) obtained in step 330 represents the transfer function between the reference microphone 50 and the error microphone 55 in the state of no wind pressure. Therefore, the value of the specific fan speed transfer function K(Z) calculated in step 340 is as follows:

[0060] K(Z)=P'(Z) / (C'(Z)*D'(Z))

[0061] In step 350, the present invention calculates the transfer function D"(Z) between the speaker module 40 and the reference microphone 50 at a specific fan speed, and calculates the transfer function C"(Z) between the speaker module 40 and the error microphone 55 based on the transfer functions K(Z), D'(Z) and C'(Z). C"(Z) represents the downwind transfer function between the speaker module 40 and the error microphone 55, and D"(Z) represents the upwind transfer function between the speaker module 40 and the reference microphone 50, and the values ​​are as follows:

[0062] C”(Z)=K(Z)*C'(Z)

[0063] D”(Z)=D'(Z) / K(Z)

[0064] In the offline mode, the present invention executes the above steps 310-350 for each fan speed, and then respectively calculates the downwind transfer function C" (Z) and the headwind transfer function D" (Z) corresponding to each fan speed. Then, when the electronic system 100 operates in the online mode, the ANC controller 60 can perform feedforward active noise control with a wind pressure compensation mechanism according to the downwind transfer function C" (Z) and the headwind transfer function D" (Z) corresponding to the actual fan speed.

[0065] Figure 5 This is a flow chart of the electronic system 100 in the online mode according to an embodiment of the present invention, which includes the following steps:

[0066] Step 510 : The reference microphone 50 captures the noise generated by the operation of the fan module 20 and provides a corresponding broadband noise signal f(n).

[0067] Step 520 : The error microphone 55 captures the overall noise of the electronic system 100 during operation, and provides a corresponding error signal e(n).

[0068] Step 530: The ANC controller 60 generates a signal based on the synchronization signal S provided by the embedded controller 30. SYN The number of fan blades in the fan module 20 and the motor speed in each mode are obtained, and the relevant speaker control signal S is calculated. MIC A reference signal x(n) with a reference power value.

[0069] Step 540: The ANC controller 60 obtains information such as the actual single-blade fundamental frequency, the actual single-blade frequency multiplication, the actual blade passing frequency (BPF), and the actual broadband noise spectrum when the fan module 20 is running according to the broadband noise signal f(n), the error signal e(n), and the reference signal x(n), and provides the speaker control signal S accordingly. MIC .

[0070] Step 550: The ANC controller 60 adjusts the loudspeaker control signal S according to the downwind transfer function C" (Z) and the upwind transfer function D" (Z). MIC characteristics.

[0071] Step 560: The speaker module 40 controls the speaker according to the speaker control signal S MIC Generate an anti-phase noise signal y(n); and execute step 510.

[0072] The noise source of the fan module 20 during operation comes from the air flow caused by the rotation of the motor, wherein the narrowband component may originate from the thickness noise of the volume displacement generated by the movement of the fan blades, or the BPF noise caused by the variable load force on the surface of the fan blades (including axial lift and fan surface tension). Since the BPF and related harmonics are related to the pressure disturbance generated when each fan blade passes through a fixed reference point, a specific narrowband noise will be generated when a periodic pressure wave is generated at the tip of the fan blade. On the other hand, when the air flow passes through the fan blades, it will peel off from the boundary layer (boundary layer) of the fan blades or both sides of the blade tip to form alternating vortices. This phenomenon is called vortex shedding. Vortex shedding will cause the instantaneous speed of the fluid on both sides of the fan blades to be different, and the instantaneous pressure on both sides of the fan blades at different fluid speeds will also be different, thus causing the fan blades to vibrate and generate specific broadband noise.

[0073] In step 510, the reference microphone 50 captures the noise caused by the blades of the fan module 20 when the electronic system 100 is running, and provides a corresponding broadband noise signal f(n). In step 520, the error microphone 55 captures the overall noise of the electronic system 100 when it is running and provides a corresponding error signal e(n). As mentioned above, the error signal e(n) provided by the error microphone 55 can reflect the noise reduction effect of the anti-phase noise signal y(n), and the noise signal d(n) mainly comes from the rotation of the fan blades when the fan module 20 is running.

[0074] In step 530 , the frequency calculator 62 of the ANC controller 60 may calculate the frequency of the ANC controller 60 according to the synchronization signal S provided by the embedded controller 30 . SYN The motor speed, single blade frequency point and number of blades of the fan module 20 are known, wherein the value of BPF is the product of the motor speed and the number of blades of the fan module 20. Assuming that the number of blades of the fan module 20 is 37, the following table 1 shows the data calculated by the frequency calculator 62, but does not limit the scope of the present invention. The unit of motor speed is rpm, and the unit of frequency is Hertz.

[0075] Motor speed Baseband Double frequency Triple frequency Four times the frequency Number of blades BPF BPFx2 BPFx3 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 33.4 200.1 266.8 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

[0076] Table 1

[0077] Next, the signal generator 64 of the ANC controller 60 generates a reference signal x(n) according to the data calculated by the frequency calculator 62, wherein the reference signal x(n) includes information such as the estimated frequency multiplication, estimated BPF, and sound pressure spectrum (dBSPL) at different motor speeds of the fan module 20, thereby determining the speaker control signal S MIC The reference power value of the digital filter 66 can be adjusted by adjusting the parameter W(Z) of the digital filter 66 to change the speaker control signal SMIC The power value.

[0078] In step 540, the ANC controller 60 calculates the actual single-blade fundamental frequency, actual single-blade frequency multiplication, actual BPF and actual broadband noise spectrum of the fan module 20 according to the broadband noise signal f(n), the error signal e(n) and the reference signal x(n), and provides the speaker control signal S accordingly. MIC To drive the speaker module driving circuit 68 to output the speaker control signal S MIC , and then drives the speaker module 40 to provide an inverted noise signal y(n), where W(Z) represents an adjustable operating parameter of the digital filter 66. In more detail, the inverted noise signal y(n) includes a plurality of noise cancellation waveforms, which are respectively inverse signals related to the actual single blade fundamental frequency, the actual single blade multiple frequency, the actual BPF fundamental frequency, the actual BPF multiple frequency and the broadband noise spectrum.

[0079] In step 550, the ANC controller 60 adjusts the characteristics of the speaker control signal SMIC according to the downwind transfer function C" (Z) and the headwind transfer function D" (Z). In more detail, the first path compensation transfer function module 71 performs signal processing on the anti-phase noise signal y(n) according to the headwind transfer function D" (Z) of the relevant current fan speed obtained in the offline mode, and outputs the corresponding processed anti-phase noise signal y' (n) to the signal generator 64. The signal generator 64 subtracts the processed anti-phase 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 performs signal processing on the reference signal x (n) according to the downwind transfer function C" (Z) of the relevant current fan speed obtained in the offline mode, and outputs the corresponding processed reference signal x' (n) to the adaptive filter 76.

[0080] The adaptive filter 76 is coupled to the second path compensation transfer function module 72 and the error microphone 55, and can perform signal processing on the processed reference signal x'(n) and the error signal e(n) according to a specific algorithm, thereby adjusting the parameter W(Z) of the digital filter 66. In more detail, the processed reference signal x'(n) includes information such as the motor speed, estimated single blade fundamental frequency, estimated frequency multiple, estimated BPF, and estimated wind pressure of the fan module 20. The adaptive filter 76 can then calculate the actual single blade fundamental frequency, actual frequency multiple, actual BPF and other related narrowband noise information when the fan module 20 is running according to the error signal e(n), and then adjust the parameter W(Z) of the digital filter 66 accordingly. In this way, when the digital filter 66 drives the speaker module driving circuit 68 to output the speaker control signal S MIC, the anti-phase noise signal y(n) generated by the speaker module 40 will reflect the actual operating status of the fan module 20, the wind pressure impact caused by the current fan speed and the current noise reduction level. More specifically, the anti-phase noise signal y(n) includes multiple noise elimination waveforms, which are respectively related to the actual single-blade fundamental frequency, the actual single-blade frequency multiplication, the actual BPF fundamental frequency, the actual BPF frequency multiplication, the broadband noise spectrum and the reverse signal of the actual wind pressure. After the signal transmission, the anti-phase noise signal y"(n) captured by the error microphone 55 can effectively offset the influence of the noise signal d(n), that is, try to reduce the error signal e(n) to 0.

[0081] In one embodiment, the adaptive filter 76 may perform signal processing on the processed reference signal x'(n) and the error signal e(n) according to a least mean square (LMS) algorithm. However, the algorithm used by the adaptive filter 76 does not limit the scope of the present invention.

[0082] In summary, in the electronic system 100 of the present invention, 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 error microphone 55 at each fan speed are first calculated in the offline mode. Then, in the online mode, the reference microphone 50 captures the noise caused by the blades of the fan module 20 when the electronic system 100 is running and provides a corresponding broadband noise signal f (n), while the error microphone 55 captures the overall noise of the electronic system 100 when it is running and provides a corresponding error signal e (n). Based on the broadband noise signal f(n), the error signal e(n), the transfer function D”(Z), the transfer function C”(Z) and the fan information provided by the embedded controller 30, the ANC controller 60 calculates the narrowband noise, broadband noise and the wind pressure compensation required when the fan module 20 is actually running, and then adjusts the microphone driving signal S according to the operating characteristics of the speaker module 40, the operating characteristics of the reference microphone 50, the operating characteristics of the error microphone 55, the environmental characteristics of the signal transmitted in the space from the speaker module 40 to the error microphone 55, and the environmental characteristics of the signal transmitted in the space from the speaker module 40 to the reference microphone 50. MIC The speaker module 40 is then driven accordingly to provide an inverted noise signal y(n), so that the inverted noise signal y(n) can offset the noise generated during the operation of the electronic system 100. By adaptively adjusting the reverse noise signal to adjust the value of the error signal to 0, the present invention can take into account the important issues of heat dissipation and noise reduction.

[0083] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the claims of the present invention should fall within the scope of the present invention.

Claims

1. An electronic system with heat dissipation and wind pressure compensation feedforward active noise control functions, comprising: A fan module, used to operate according to a fan control signal to provide a heat dissipation function; An embedded controller, used for providing the fan control signal and a synchronization signal, wherein the synchronization signal includes information on the structure and operation settings of the fan module; A reference microphone, used to detect the broadband noise generated by the fan module during operation to provide a corresponding broadband noise signal; An error microphone, used to detect the noise generated when the electronic system is running to provide a corresponding error signal; An active noise reduction controller, used to: generating a speaker control signal according to the synchronization signal, the broadband noise signal and the error signal; as well as adjusting the power of the speaker control signal according to the broadband noise signal, the error signal, a downwind transfer function and an upwind transfer function; as well as A speaker module is used to provide an anti-phase noise signal according to the speaker control signal, wherein: The anti-phase noise signal includes a plurality of noise elimination waveforms to offset the noise generated when the electronic system is running; The downwind transfer function is a transfer function between the speaker module and the error microphone when the fan module is running at a predetermined fan speed; and The upwind transfer function is a transfer function between the speaker module and the reference microphone when the fan module runs at the predetermined fan speed. The active noise reduction controller is also used to: measuring a first transfer function between the speaker module and the reference microphone and a second transfer function between the speaker module and the error microphone when the fan module is not running; measuring a third transfer function between the reference microphone and the error microphone when the fan module operates at the predetermined fan speed; Calculating a transfer function of the predetermined fan speed according to the first transfer function, the second transfer function and the third transfer function, wherein the transfer function of the predetermined fan speed is the third transfer function divided by the product of the first transfer function and the second transfer function; as well as The downwind transfer function and the headwind transfer function are calculated based on the transfer function of the predetermined fan speed, the first transfer function and the second transfer function, wherein the downwind transfer function is the product of the transfer function of the predetermined fan speed and the second transfer function, and the headwind transfer function is the first transfer function divided by the transfer function of the predetermined fan speed.

2. The electronic system as claimed in claim 1, wherein the active noise reduction controller is further used for: Calculate an actual single-blade base frequency, an actual single-blade multiple frequency, an actual blade pass frequency base frequency, an actual blade pass frequency multiple frequency and an actual broadband noise spectrum when the fan module is running at the predetermined fan speed according to the synchronization signal, the broadband noise signal and the error signal; The speaker control signal is generated according to the actual single blade fundamental frequency, the actual single blade multiple frequency, the actual blade pass frequency fundamental frequency, the actual blade pass frequency multiple frequency and the actual broadband noise spectrum.

3. The electronic system as claimed in claim 2, wherein the plurality of noise cancellation waveforms are respectively inverse signals related to the actual single blade fundamental frequency, the actual single blade frequency multiple, the actual blade pass frequency fundamental frequency, the actual blade pass frequency multiple and the broadband noise spectrum.

4. The electronic system as claimed in claim 1, wherein the active noise reduction controller comprises: a frequency calculator, used for obtaining an estimated single blade fundamental frequency, an estimated single blade multiple frequency and an estimated blade passing frequency fundamental frequency of the fan module according to the synchronization signal; a signal generator for generating a reference signal according to the estimated single blade fundamental frequency, the estimated single blade multiple frequency and the estimated blade pass frequency fundamental frequency; and A digital filter is used to perform operation on the reference signal to determine a reference power value of the speaker control signal.

5. The electronic system as claimed in claim 4, wherein the active noise reduction controller further comprises: An adaptive filter is used to adjust the parameters used by the digital filter when performing operations according to the downwind transfer function, the upwind transfer function, the broadband noise signal and the error signal, so as to adaptively adjust 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 perform signal processing on the reference signal, the broadband noise signal and the error signal.

7. The electronic system as claimed in claim 5, wherein the active noise reduction controller further comprises: a first path compensation transfer function module, coupled to the speaker module and the signal generator to receive the anti-phase noise signal, perform signal processing on the anti-phase noise signal according to the upwind transfer function, and output a corresponding processed anti-phase noise signal to the signal generator; and A second path compensation transfer function module is coupled to the adaptive filter and the signal generator to receive the reference signal, perform signal processing on the reference signal according to the downwind transfer function, and output a corresponding processed reference signal to the adaptive filter.

8. The electronic system as claimed in claim 7, wherein the signal generator is further used for: The processed anti-phase noise signal is subtracted from the broadband noise signal to provide the reference signal. 9 . The electronic system as claimed in claim 1 , wherein the error microphone is disposed at an air outlet of the fan module, and the reference microphone is disposed beside a blade of the fan module.

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