TWI777729B - Adaptive active noise cancellation apparatus and audio playback system using the same - Google Patents

Abstract

The invention relates to an adaptive active noise cancellation apparatus and an audio playback system using the same. The adaptive active noise cancellation apparatus shapes an error signal and a noise signal according to a shape of an ideal noise. After that, the shaped noise signal and the shaped error signal are sent into a parameter adjusting unit to perform an adaptive parameter adjustment. Thus, the adaptive noise filter unit is not only can adaptively suppress noise and minimize the error signal, but also can suppress specific frequencies that are sensitive to the human ear.

Description

Adaptive active noise cancellation device and sound playback system using the same

The present invention relates to a noise cancellation technology, in particular to an adaptive active noise cancellation device and a sound playback system using the same.

Generally, the noise reduction technologies of earphones are divided into passive noise cancellation (passive noise cancellation, PNC) and active noise cancellation (active noise cancellation, ANC). Passive noise cancellation mainly isolates noise as much as possible through earphone insulation materials or special structures. Usually in-ear earplugs or full-circle earphones, if you wear them for a long time, your ears will swell and hurt, and excessive sound pressure will even affect your hearing. Active noise cancellation is to set up a special noise reduction circuit in the earphone, generally through an audio receiver (such as a micro microphone) and an anti-noise output chip, to receive and analyze the frequency of external noise and generate anti-phase sound waves, through the destructive interference of sound waves , to cancel out the noise.

In addition, the active noise cancellation technology includes a factory-preset active noise cancellation (ANC) filter and an adaptive ANC filter. The adaptive active noise cancellation filter basically generates different noise cancellation transfer functions according to the different environmental noises, and gradually compares the error between the noise and the generated anti-noise according to the number and time of the adaptive active noise cancellation filter operation. Convergence, thereby eliminating noise. The existing adaptive active noise cancellation filters provide different noise cancellation capabilities under different ambient noises, and are therefore relatively unreliable. How to reduce the influence of ambient noise on the noise cancellation ability has become an important work item in this field.

In view of this, how to reduce or eliminate the above-mentioned deficiencies in the related fields, and at the same time allow the adaptive active noise cancellation filtering technology to suppress the noise in a manner that conforms to the environmental noise, is a problem to be solved.

The invention provides a sound playing system, which outputs an anti-phase noise sound signal according to an anti-phase noise signal. The sound playing system includes an error microphone and an adaptive active noise cancellation device. The error microphone receives an ambient noise and an inverted noise sound signal to generate an error signal. The adaptive active noise cancellation device includes an automatic noise shaping circuit, an adaptive active noise filtering unit, a first transmission channel simulation unit and a parameter adjustment unit. The automatic noise shaping circuit receives the error signal, and according to a preset noise shape, shapes an interference signal into a shaped interference signal and the error signal into a shaped error signal, and outputs the shaped interference signal and the shaped error signal. The adaptive active noise filtering unit receives the interference signal, and outputs the anti-phase noise signal for generating the anti-phase noise sound signal. The first transmission channel simulation unit receives the shaped interference signal, and is used for generating an analog shaped interference signal according to a channel transfer function. The parameter adjustment unit receives the analog shaped interference signal and the shaped error signal, and uses an adaptive algorithm to adjust the filter coefficient of the adaptive active noise filter unit according to the simulated shaped interference signal and the shaped error signal.

In a preferred embodiment of the present invention, when the sound playback system is a feedback active noise reduction earphone, the interference signal is a restored ambient noise signal. In another preferred embodiment of the present invention, when the sound playback system is a feed-forward active noise reduction earphone, the sound playback system further includes an external noise receiving microphone for receiving an external sound noise, and converted into interference signals.

The spirit of the present invention is to first shape the received error signal and interference signal according to the shape of an ideal noise, and then send the shaped interference signal and the shaped error signal to the parameter adjustment unit for adaptation. Sex parameter adjustment. In this way, the adaptive active noise filtering unit can effectively suppress external noise and noise in the ear canal, In addition to minimizing the error signal, it can also suppress specific frequencies that the human ear is sensitive to.

Other advantages of the present invention will be explained in more detail in conjunction with the following description and drawings.

101: Ideal noise pattern

102: Noise suppression result of ideal noise type

103: General Environmental Noise

104: Noise suppression results for general environmental noise 103

301: Left wireless headset

302: Right wireless headset

303: Mobile Devices

40: Transmission channel

41: Adaptive Active Noise Cancellation Device

42: Sound channel response schematic block

411: External noise receiving microphone

412: Error Microphone

413: Automatic noise shaping circuit

414: Adaptive Active Noise Filtering Unit

415: The first transmission channel analog unit

416: Parameter adjustment unit

417: Second transmission channel analog unit

418: First Addition Circuit

419: Shaping filter parameter generation unit

420: first shaping filter

421: Second addition circuit

422: Second shaping filter

601, 901: Third shaping filter

1001, 1201: Feedforward active noise cancellation circuit

1002, 1102: Feedback active noise cancellation circuit

1004: Feedforward adaptive active noise filtering unit

1006: Third shaping filter

1010: The third transmission channel analog unit

1020: Second parameter adjustment unit

1005: Active Noise Filtering Unit

1101: Feedforward noise reduction circuit

1202: Feedback noise reduction circuit

1203: Feedback noise filtering unit

1301: Frequency Analysis Circuits

1302: Noise Shape Storage Circuit

1303: Parameter operation circuit

Figure 1 is a schematic diagram of the frequency response of the noise magnitude versus frequency for ideal noise and after the adaptive active noise cancellation function is turned on.

Fig. 2 is a schematic diagram showing the frequency response of the noise magnitude to the frequency after the general environmental noise and the adaptive active noise cancellation function are turned on.

FIG. 3 is a schematic diagram of an active noise-cancelling earphone according to a preferred embodiment of the present invention.

FIG. 4 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention.

FIG. 5 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention.

FIG. 6 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention.

FIG. 7 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention.

FIG. 8 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention.

FIG. 9 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention.

FIG. 10 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention.

FIG. 11 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention.

FIG. 12 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention.

FIG. 13 is a circuit block diagram of a shaping filter parameter generating unit of a sound playback system according to a preferred embodiment of the present invention.

The following description is a preferred implementation manner to complete the invention, and its purpose is to describe the basic spirit of the invention, but it is not intended to limit the invention. Reference must be made to the scope of the following claims for the actual inventive content.

It must be understood that the words "comprising" and "including" used in this specification are used to indicate the existence of specific technical features, values, method steps, operation processes, elements and/or components, but do not exclude the possibility of adding More technical features, values, method steps, job processes, elements, components, or any combination of the above.

The use of words such as "first", "second", "third", etc. in the claims is used to modify the elements in the claims, and is not used to indicate that there is a priority order, a prepositional relationship between them, or an element Prior to another element, or chronological order in which method steps are performed, is only used to distinguish elements with the same name.

It must be understood that when an element is described as being "connected" or "coupled" to another element, it can be directly connected, or coupled to the other element, and intervening elements may be present. In contrast, when an element is described as being "directly connected" or "directly coupled" to another element, there are no intervening elements present. Other words used to describe the relationship between elements can also be read in a similar fashion, such as "between" versus "directly interposed," or "adjacent" versus "directly adjoining," and the like.

Figure 1 is a schematic diagram of the frequency response of the noise magnitude versus frequency for ideal noise and after the adaptive active noise cancellation function is turned on. Referring to Figure 1, the horizontal axis is frequency and the vertical axis is amplitude. When the noise is the ideal noise type as shown in the reference numeral 101 in FIG. 1 , the noise suppression result will be similar to that shown in the reference numeral 102 . The suppression of noise is quite good. However, general ambient noise does not look like ideal noise so much.

Fig. 2 is a schematic diagram showing the frequency response of the noise magnitude to the frequency after the general environmental noise and the adaptive active noise cancellation function are turned on. Please refer to FIG. 2 , the reference numeral 103 is the general environmental noise; the reference numeral 104 is the noise suppression result for the general environmental noise 103 . Since the adaptive algorithm intends to partially suppress the larger amplitude noise when adapting, in this example, some of the higher frequency noise is suppressed. However, instead of being suppressed, eg low frequency noise is increased. Although from the frequency response diagram, the adaptive active noise cancellation filter technology does suppress noise, unfortunately, the general human ear is far more sensitive to low-frequency noise than high-frequency noise, although the noise suppression result 104 reflects The outgoing noise is indeed suppressed, but for the user, the noise becomes louder and uncomfortable.

FIG. 3 is a schematic diagram of an active noise-cancelling earphone according to a preferred embodiment of the present invention. Please refer to FIG. 3. In this embodiment, a wireless earbud is used as an example. The wireless earbud is a pair of devices with wireless communication capability, including a left wireless earbud 301 and a right wireless earbud ( right wireless earbud) 302, the left wireless earphone 301 and the right wireless earbud 302 are not connected to each other by a physical line.

Between the mobile device 303 and the left wireless earphone 301 and between the mobile device 303 and the right wireless earphone 302, a wireless communication protocol can be used to transmit packets carrying the user's voice signal or music, such as the Bluetooth Advanced Audio Distribution Specification ( advanced audio distribution profile (A2DP)) package.

In other embodiments, other peer-to-peer methods such as Wi-Fi Direct can also be used between the mobile device 303 and the left wireless headset 301 and between the mobile device 303 and the right wireless headset 302 -peer, P2P) wireless communication protocol, the present invention is not limited to this. In the above-mentioned embodiment, although the active noise canceling earphone is exemplified by a wireless earphone, those skilled in the art should know that the active noise canceling earphone can also be a wired earphone as an example, and the present invention is not limited to this. .

FIG. 4 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention. Please refer to FIG. 4 , the sound playback system includes an adaptive active noise cancellation device 41 , an external noise receiving microphone 411 and an error microphone 412 . The adaptive active noise cancellation device 41 includes an automatic noise shaping circuit 413 , an adaptive active noise filtering unit 414 , a first transmission channel simulation unit 415 and a parameter adjustment unit 416 . In this embodiment, a feed-forward active noise-cancelling earphone is used as an example.

It should be noted that the sound playback system relates to the acoustic domain as well as the electrical domain. For example, the symbols d(n) and y(n) indicated in the figure represent acoustic signals in the acoustic domain, and the remaining symbols represent electrical signals in the electrical domain. However, in order to simplify the analysis, in the following, if it is not necessary, it is not necessary to distinguish whether it is an electrical signal or an acoustic signal.

The sound channel response schematic block 42 can be called a primary path, which is used to represent the path between a reference microphone (in the embodiment of FIG. 4 , the reference microphone is the external noise receiving microphone 411 ) and the error microphone 412 . transmission, whereby the transformation of the acoustic signal after the transmission is analyzed, wherein the simulation result of the transmission is represented by the transfer function P ( z ). Ideally, the transfer function P ( z ) is estimated based on the acoustic signal received by the reference microphone and the acoustic signal received by the error microphone 412. However, in practice, it is impossible to obtain the acoustic signal, so the related electrical signal is used instead of the acoustic signal for analysis to obtain the transfer function P ( z ). In some possible implementations, the adaptive active noise cancellation device 41 is disabled and the transfer function is estimated based on the signal x (n) obtained through the reference microphone and based on the signal e (n) obtained through the error microphone 412 P ( z ), where no signal y (n) is generated because the adaptive active noise cancellation device 41 is disabled. Therefore, the signal e (n) is substantially the same as the signal d (n).

The transmission channel 40 may be referred to as a secondary path, which is used to represent the transmission of the adaptive active noise filtering unit 414 to the error microphone 412, thereby analyzing the electrical signal output by the adaptive active noise filtering unit 414 after passing through the The post-transmission transformation, where the channel transfer function S ( z ) is used to represent the simulated result of the transmission. In some possible implementations, external noise sources are removed and the transition is estimated based on the signal y' (n) output by the adaptive active noise filtering unit 414 and on the signal e (n) obtained via the error microphone 412 A function S ( z ) where there is no ambient noise d ( n ) due to no external noise sources. Therefore, the signal e (n) is substantially the same as the signal y (n).

The external noise receiving microphone 411 receives external sound noise (eg, ambient noise), and converts the external sound noise into a digital interference signal x ( n ). The adaptive active noise filtering unit 414 receives the interference signal x ( n ), and outputs an inverted noise signal y' ( n) based on the interference signal x(n ) .

The error microphone 412 receives the ambient noise d ( n ) in the ear canal and the anti-phase noise sound signal y ( n ), and converts a digital error signal e ( n ) accordingly, wherein the external sound noise responds to the indication area through the sound channel Block 42 translates to ambient noise d ( n ). Since the ambient noise d ( n ) and the anti-phase noise sound signal y ( n ) are, for example, analog sound signals, in the acoustic domain, the above-mentioned ambient noise d ( n ) and the anti-phase noise sound signal y ( n ) ) interfere with each other in the ear canal. For the convenience of description, an adder symbol 43 is additionally shown in the figure. Those skilled in the art should know that the adder symbol 43 is not a physical element, and is only used to represent the interference phenomenon of two analog sounds.

The adaptive active noise filtering unit 414 is used for generating an inverse noise signal y' ( n ) based on the interference signal x ( n ) and the error signal e ( n ), and the inverse noise signal y' ( n ) is converted through the transmission channel 40 into Invert the noise sound signal y ( n ). In some embodiments, the adaptive active noise filtering unit 414 includes a finite impulse response (FIR) filter. In detail, in the embodiment of the present invention, the adaptive active noise filtering unit 414 is, for example, an adaptive filter that adjusts coefficients in an iterative process through learning (adapt) and an algorithm. In an ideal situation, after the sound signals interfere with each other, the anti-phase noise sound signal y ( n ) can completely eliminate the environmental noise d ( n ), so that the error signal e ( n ) tends to zero. However, when actually eliminating noise, due to different filter designs and different filter coefficient algorithms, it is difficult to eliminate noise in a specific frequency band (especially the low-frequency noise to which the human ear is more sensitive). At the same time, in a real environment, due to the constant changes of external sound noise, the actual effect of noise cancellation will also change constantly, allowing users to hear loud and quiet noises.

According to this, ideally, a possible way is to shape the external sound noise to reduce the degree of environmental noise variation, so that the noise reduction filter can generate an effective anti-phase noise signal based on the low variation noise provided by the microphone. . However, in practice, it is difficult to shape the external sound noise propagating in the air. An alternative way is to shape the interference signal x ( n ) generated by the external noise receiving microphone 411 and the error signal e ( n ) generated by the error microphone 412 .

In addition, since the external sound noise changes at any time, it is necessary to dynamically adjust the shaping method. Since the ambient noise d ( n ) is derived from external sound noise, the degree of variation of the external sound noise can be identified by analyzing the ambient noise d ( n ).

The automatic noise shaping circuit 413 of the present disclosure is designed based on the above reasons, so that it can effectively suppress the environmental noise d ( n ), and can suppress the specific frequencies (generally low frequencies) that the human ear is more sensitive to. The detailed description is as follows.

In this embodiment, the automatic noise shaping circuit 413 includes a second transmission channel simulation unit 417, a first adding circuit 418, a shaping filter parameter generating unit 419, a first shaping filter 420, and a second adding circuit 421 and a second shaping filter 422. In some embodiments, the automatic noise shaping circuit 413 can be implemented with a digital signal processor (DSP).

As mentioned above, the automatic noise shaping circuit 413 is used for shaping the interference signal x ( n ) generated by the external noise receiving microphone 411 and the error signal e ( n ) generated by the error microphone 412, and providing the shaped signal To the parameter adjustment unit 416, the input signal received by the parameter adjustment unit 416 can retain the characteristics of the current environmental noise, and can adjust the frequency band distribution energy of the input signal. Therefore, the anti-phase noise signal y' ( n ) generated by the adaptive active noise filtering unit 414 can effectively suppress the environmental noise d ( n ), and can suppress the specific frequency (generally low frequency) to which the human ear is more sensitive.

進行整形並產生整形誤差訊號

。第一整形濾波器420以及第二整形濾波器422例如為數位濾波器(或等化器)，此兩整形濾波器420及422的整形濾波參數是由一整形濾波參數產生單元419所產生。其中，第一整形濾波器420接收第一整形濾波參數。第二整形濾波器422接收第二整形濾波參數。 Therefore, in this embodiment, the interference signal x ( n ) is shaped by the first shaping filter 420 to generate a shaped interference signal x' ( n ), and the second shaping filter 422 can be regarded as an error signal. The restored error signal of e ( n )

Shaping and generating shaped error signal

. The first shaping filter 420 and the second shaping filter 422 are, for example, digital filters (or equalizers), and the shaping filter parameters of the two shaping filters 420 and 422 are generated by a shaping filter parameter generating unit 419 . The first shaping filter 420 receives the first shaping filter parameter. The second shaping filter 422 receives the second shaping filter parameters.

In order to generate effective shaping filter parameters, the shaping filter parameter generating unit 419 is used to analyze the ambient noise d ( n ), thereby identifying the degree of variation of the external sound noise. It can be seen from the circuit block diagram in FIG. 4 that the output of the error microphone 412 is not the environmental noise d ( n ) but the above-mentioned error signal e ( n ). The error signal e ( n ) is a composite signal obtained by mutual interference between the ambient noise d ( n ) and the inverse noise signal y ( n ). Therefore, in this embodiment, in order to enable the shaping filter parameter generating unit 419 to obtain the environmental noise d ( n ) affected by the sound channel response indicating block 42, the error signal e ( n ) output by the error microphone 412 is deducted and inverted. The phase noise sound signal y ( n ) is used to restore the ambient noise d ( n ).

。誤差訊號e(n)扣除模擬反相噪音訊號

後，可還原出環境噪音d(n)。此模擬反相噪音訊號

類似於反相噪音聲音訊號y(n)所對應的電訊號。差別在於，反相噪音聲音訊號y(n)係屬於聲學領域，而模擬反相噪音訊號

則是屬於電領域。故在此第二傳輸通道模擬單元417之通道轉移函數標示為

，以區隔聲學通道轉移函數S(z)與電學之模擬通道轉移函數

。 To this end, the automatic noise shaping circuit 413 further includes a second transmission channel simulation unit 417 . The second transmission channel simulation unit 417 is used for simulating the channel transfer function S ( z ) of the transmission channel 40 in the electrical field, so as to convert the inverted noise signal y' ( n ) into a sound signal that is substantially the same as the inverted noise signal y ( n ) analog inverted noise signal

. The error signal e ( n ) is subtracted from the analog inverted noise signal

Then, the ambient noise d ( n ) can be restored. This analog inverted noise signal

Similar to the electrical signal corresponding to the inverse noise sound signal y ( n ). The difference is that the anti-phase noise sound signal y ( n ) belongs to the acoustic domain, while the analog anti-phase noise signal

It belongs to the field of electricity. Therefore, the channel transfer function of the second transmission channel simulation unit 417 is denoted as

, to separate the acoustic channel transfer function S ( z ) from the electrical analog channel transfer function

.

以及誤差訊號e(n)，以將誤差訊號e(n)扣除模擬反相噪音訊號

而產生一還原環境噪音訊號

。此還原環境噪音訊號

可以視為和環境噪音d(n)相同的訊號。同樣地，環境噪音d(n)係屬於聲音領域，而還原環境噪音訊號

則是屬於電領域。整形濾波參數產生單元419接收還原環境噪音訊號

，並且，根據內部儲存的預設雜訊形態以及還原環境噪音訊號

，產生第一整形濾波參數給上述第一整形濾波器420以及產生第二整形濾波參數給第二整形濾波器422。 Afterwards, the analog anti-phase noise signal is received by the first summing circuit 418

and the error signal e ( n ) to subtract the analog inversion noise signal from the error signal e ( n )

to generate a reduced ambient noise signal

. This restores the ambient noise signal

It can be regarded as the same signal as the ambient noise d ( n ). Likewise, the ambient noise d ( n ) belongs to the acoustic domain, and the ambient noise signal is restored

It belongs to the field of electricity. The shaping filter parameter generating unit 419 receives the restored ambient noise signal

, and restore the ambient noise signal according to the preset noise pattern stored in the internal

, generating a first shaping filter parameter for the first shaping filter 420 and generating a second shaping filter parameter for the second shaping filter 422 .

以及還原環境噪音訊號

，產生一還原誤差訊號

。同樣地，還原環境噪音 訊號

是由誤差訊號e(n)扣除模擬反相噪音訊號

以獲得，故，本實施例將還原環境噪音訊號

加上模擬反相噪音訊號

便可以還原並得到近似於原本的誤差訊號e(n)。在此為了做出區隔，還原誤差訊號例如以

作為表示。第二整形濾波器422則接收上述還原誤差訊號

，並將此還原誤差訊號

進行整形，以獲得整形誤差訊號

，並輸入給參數調整單元416。 In addition, the second summing circuit 421 receives the analog anti-phase noise signal

and restore the ambient noise signal

, generating a restoration error signal

. Similarly, restore the ambient noise signal

is the analog inversion noise signal subtracted from the error signal e ( n )

In order to obtain, therefore, this embodiment will restore the environmental noise signal

plus analog inverse noise signal

Then the error signal e ( n ) which is similar to the original can be recovered and obtained. In order to make a distinction here, the restored error signal is for example

as a representation. The second shaping filter 422 receives the restored error signal

, and restore this error signal

Shaping to obtain shaped error signal

, and input to the parameter adjustment unit 416 .

。需注意的是，根據線性統系統的數學原理，第一傳輸通道模擬單元415及第一整形濾波器420在電路架構的位置上是可互換的。 On the other hand, the interference signal x ( n ) output by the external noise receiving microphone 411 will also be filtered by the first shaping filter 420 . In this embodiment, the adaptive active noise cancellation device 41 adopts the filtered-X least mean square (filtered-X least mean square, FxLMS) algorithm. In other embodiments, the adaptive active noise cancellation device 41 may use other algorithms. According to the FxLMS algorithm, the shaped interference signal x' ( n ) output by the first shaping filter 420 also needs to pass through the first transmission channel simulation unit 415 . The first transmission channel simulation unit 415 is also used to simulate the channel transfer function S ( z ) of the transmission channel 40 in the electrical field, and convert the shaped interference signal x' ( n ) into an analog shaped interference signal

. It should be noted that, according to the mathematical principle of the linear system, the positions of the first transmission channel simulation unit 415 and the first shaping filter 420 are interchangeable in terms of circuit structure.

以及模擬整形干擾訊號

，利用例如最小均方法(least mean square，LSM)運算，獲得適應性主動雜訊濾波單元414的濾波參數W(z)，並持續地根據整形誤差訊號

以及模擬整形干擾訊號

，調整所輸出的參數W(z)，使上述誤差訊號e(n)達到最小化。 In this way, the parameter adjustment unit 416 can shape the error signal according to the

and analog shaped interference signal

, using, for example, the least mean square (LSM) operation to obtain the filtering parameter W ( z ) of the adaptive active noise filtering unit 414, and continuously shape the error signal according to the

and analog shaped interference signal

, and adjust the output parameter W ( z ) to minimize the above-mentioned error signal e ( n ).

，而在第5圖的實施例中，第二整形濾波器422則改為直接接收原始的誤差訊號e(n)。第二整形濾波器422基於誤差訊號e(n)輸出的整形誤差訊號其數學例如表示為 e'(n)。整形濾波參數產生單元419仍然接收還原環境噪音訊號

，所屬技術領域具有通常知識者可以藉由第4圖之實施例以及其對應的說明理解到，兩實施例無論是數學上或是電路作用上，皆為等效。故在此不予贅述。此實施例相對於第4圖的實施例，更可以節省了一個加法器421。故電路更加簡化，成本也相對較低。 FIG. 5 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention. Please refer to FIG. 4 and FIG. 5 at the same time. In the embodiment of FIG. 4, the second shaping filter 422 receives the restored error signal

, and in the embodiment of FIG. 5, the second shaping filter 422 directly receives the original error signal e ( n ). The shaped error signal output by the second shaping filter 422 based on the error signal e ( n ) is represented mathematically as e' ( n ), for example. The shaping filter parameter generating unit 419 still receives the restored ambient noise signal

, those with ordinary knowledge in the art can understand from the embodiment in FIG. 4 and its corresponding description that the two embodiments are equivalent in terms of mathematics and circuit functions. Therefore, it will not be repeated here. Compared with the embodiment in FIG. 4 , this embodiment can save one adder 421 . Therefore, the circuit is more simplified and the cost is relatively low.

，在第6圖的實施例中，第二整形濾波器422例如修改為直接接收還原環境噪音訊號

，並基於還原環境噪音訊號

產生一整形還原環境噪音訊號

。另外，模擬反相噪音訊號

也透過額外新增的第三整形濾波器601整形成一整形模擬反相噪音訊號

，其中，整形濾波參數產生單元419同樣地產生第三整形濾波參數給第三整形濾波器601。再者，加法器421則是將整形還原環境噪音訊號

以及整形模擬反相噪音訊號

相加，獲得整形誤差訊號

。所屬技術領域具有通常知識者可以藉由第4圖之實施例以及其對應的說明理解到，兩實施例無論是數學上或是電路作用上，皆為等效。故在此不予贅述。 FIG. 6 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention. Please refer to FIG. 4 and FIG. 6 at the same time. For the same reason, the second shaping filter 422 in FIG. 4 originally received the restored error signal.

, in the embodiment of FIG. 6, the second shaping filter 422 is modified to directly receive and restore the ambient noise signal, for example

, and based on the restoration of ambient noise signals

Generates a shaped and restored ambient noise signal

. In addition, the analog anti-phase noise signal

It is also shaped into a shaped analog anti-phase noise signal through the additionally added third shaping filter 601

, wherein the shaping filter parameter generating unit 419 similarly generates the third shaping filter parameter to the third shaping filter 601 . Furthermore, the adder 421 reshapes and restores the ambient noise signal

and shaping the analog inverse noise signal

Add to get the shaped error signal

. Those skilled in the art can understand from the embodiment in FIG. 4 and its corresponding description that the two embodiments are equivalent in terms of mathematics and circuit functions. Therefore, it will not be repeated here.

FIG. 7 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention. Please refer to FIG. 4 and FIG. 7 at the same time. The biggest difference between this embodiment and the embodiment of FIG. 4 is that the sound playback system of the embodiment of FIG. 7 is a feedback active noise reduction earphone. The characteristic of the feedback active noise reduction earphone is that there is no external noise receiving microphone 411 , only the error microphone 412 in the ear canal. Therefore, compared with the embodiment of FIG. 4 , the error signal e ( n ) generated by the error microphone 412 of this embodiment needs to be shaped by the automatic noise shaping circuit 413 . In the embodiment of FIG. 4 , both the interference signal x ( n ) generated by the external noise receiving microphone 411 and the error signal e ( n ) generated by the error microphone 412 need to be shaped by the automatic noise shaping circuit 413 .

作為外部雜訊。其中，由上述第4圖的說明可知，還原環境噪音訊號

為類似於環境噪音d(n)所對應的電訊號。換句話說，本實施例利用還原環境噪音訊號

來替代第4圖中的干擾訊號x(n)。 In the embodiment of the present invention, since the adaptive active noise cancellation device 41 uses, for example, the FxLMS algorithm, and according to the algorithm structure of the FxLMS, the adaptive active noise cancellation device 41 should take an external noise as an input. Therefore, in this embodiment, in the absence of the external noise receiving microphone 411 , the ambient noise signal output by the above-mentioned first summing circuit 418 is restored.

as external noise. Among them, it can be seen from the description of the above Figure 4 that the environmental noise signal is restored

is the electrical signal corresponding to the environmental noise d ( n ). In other words, the present embodiment utilizes the restoration of the ambient noise signal

to replace the interference signal x ( n ) in Figure 4.

為例。相同於第4圖的架構，第一整形濾波器420將還原環境噪音訊號

整形後，輸出一整形還原環境噪音訊號

至第一傳輸通道模擬單元415，再經由第一傳輸通道模擬單元415處理後輸出給參數調整單元416。由於數學運算和電路皆與第4圖的實施例類似。所屬技術領域具有通常知識者可以藉由第4圖之實施例以及其對應的說明推知本實施例的運作方法，故在此不予贅述。 Compared with the first shaping filter 420 in the embodiment of FIG. 4 , the input signal of the first shaping filter 420 in this embodiment is used to restore the ambient noise signal

For example. Same as the structure in FIG. 4, the first shaping filter 420 will restore the ambient noise signal

After shaping, output a shaping signal to restore environmental noise

to the first transmission channel simulation unit 415 , and then processed by the first transmission channel simulation unit 415 and then output to the parameter adjustment unit 416 . Since the mathematical operations and circuits are similar to the embodiment of FIG. 4 . Those with ordinary knowledge in the art can infer the operation method of this embodiment from the embodiment in FIG. 4 and the corresponding description thereof, so it is not repeated here.

，改為直接接收誤差訊號e(n)。由於數學運算和電路皆與第4圖、第5圖的實施例類似。所屬技術領域具有通常知識者可以藉由第4圖、第5圖之實施例以及其對應的說明推知本實施例的運作方法，故在此不予贅述。 FIG. 8 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention. Please refer to FIG. 4, FIG. 5 and FIG. 8 at the same time. In this embodiment, the sound playback system is also an example of a feedback active noise reduction earphone. However, similar to FIG. 5, the second shaping filter 422 originally receives restore error signal

, instead of directly receiving the error signal e ( n ). Since the mathematical operations and circuits are similar to the embodiments of Fig. 4 and Fig. 5 . Those with ordinary knowledge in the art can infer the operation method of the present embodiment from the embodiments in FIGS. 4 and 5 and their corresponding descriptions, and thus will not be repeated here.

，本實施例的 第二整形濾波器422改為直接接收還原環境噪音訊號

，並基於還原環境噪音訊號

產生整形還原環境噪音訊號

。另外，模擬反相噪音訊號

也透過額外新增的第三整形濾波器901整形成一整形模擬反相噪音訊號

。再者，加法器421則是將整形還原環境噪音訊號

以及整形模擬反相噪音訊號

相加，獲得整形誤差訊號

。由於數學運算和電路皆與第4圖、第7圖的實施例類似。所屬技術領域具有通常知識者可以藉由第4圖、第7圖之實施例以及其對應的說明推知本實施例的運作方法，故在此不予贅述。 FIG. 9 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention. Please refer to Fig. 4, Fig. 7 and Fig. 9 at the same time. This embodiment is also an example of the sound playback system as a feedback active noise reduction earphone. However, similar to Fig. 7, the second shaping filter of Fig. 7 is used as an example. The device 422 originally received the restoration error signal

, the second shaping filter 422 in this embodiment is changed to directly receive and restore the environmental noise signal

, and based on the restoration of ambient noise signals

Generates a shaped and restored ambient noise signal

. In addition, the analog anti-phase noise signal

It is also shaped into a shaped analog anti-phase noise signal through the additionally added third shaping filter 901

. Furthermore, the adder 421 reshapes and restores the ambient noise signal

and shaping the analog inverted noise signal

Add to get the shaped error signal

. Since the mathematical operations and circuits are similar to the embodiments shown in FIGS. 4 and 7 . Those with ordinary knowledge in the art can infer the operation method of the present embodiment from the embodiments in FIGS. 4 and 7 and their corresponding descriptions, so detailed descriptions are omitted here.

為例，用以將還原環境噪音訊號

整形為整形還原環境噪音訊號

。前饋式雜訊消除電路1001的操作部份類似於第4圖及其說明，反饋式雜訊消除電路1002的操作部份類似於第7圖及其說明。 FIG. 10 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention. Please refer to FIG. 4 , FIG. 7 and FIG. 10 at the same time. In this embodiment, the sound playback system is a hybrid active noise canceling headphone as an example, in other words, the adaptive active noise cancellation device It includes a feedforward noise cancellation circuit 1001 and a feedback noise cancellation circuit 1002 (separated by dotted lines in the figure). Compared with the first shaping filter 420 in the embodiment of FIG. 4 , the input signal of the first shaping filter 420 in this embodiment is used to restore the ambient noise signal

For example, to restore the ambient noise signal

Shaping is shaping and restoring environmental noise signals

. The operation part of the feedforward noise canceling circuit 1001 is similar to FIG. 4 and its description, and the operation part of the feedback noise canceling circuit 1002 is similar to that of FIG. 7 and its description.

，並提供 給參數調整單元1020。另一方面，參數調整單元1020所接收的整形誤差訊號

則例如是由反饋式雜訊消除電路1002中的第二整形濾波器422所提供，並且，在本實施例中，關於誤差訊號e(n)轉換為整形誤差訊號

的訊號處理原理相同第4圖，故在此不再詳加贅述。 The feedforward noise cancellation circuit 1001 at least includes a feedforward adaptive active noise filter unit 1004 (the filter coefficient in the figure is represented as WFF), a third shaping filter 1006, and a third transmission channel simulation unit 1010 , the second parameter adjustment unit 1020 . In the operation of the feedforward noise cancellation circuit 1001, the signal processing principle for the interference signal x ( n ) is the same as that shown in FIG. 4, and the third shaping filter 1006 is used to shape the interference signal x ( n ) into a shaped interference signal x' ( n ), and provided to the transmission channel simulation unit 1010. The transmission channel simulation unit 1010 then converts the shaped interference signal x' ( n ) into an analog shaped interference signal based on the channel transfer function S ( z ) of the analog transmission channel 40

, and provided to the parameter adjustment unit 1020 . On the other hand, the shaping error signal received by the parameter adjustment unit 1020

Then, for example, it is provided by the second shaping filter 422 in the feedback noise cancellation circuit 1002, and, in this embodiment, the error signal e ( n ) is converted into a shaping error signal

The signal processing principle is the same as that shown in Figure 4, so it will not be repeated here.

In addition, in FIG. 10, an adder 1003 is included for adding the inverse noise signal y ₁ ' ( n ) output by the feedforward adaptive active noise filtering unit 1004 and the feedback adaptive active noise filtering The inverted noise signal y ₂ ′ ( n ) output by the unit 1005 is superimposed and then output to the transmission channel 40 .

In this embodiment, since both the feedforward noise cancellation circuit 1001 and the feedback noise cancellation circuit 1002 are adaptive noise cancellation circuits, in this embodiment, the interference signal x ( n ) and The error signal e ( n ) is shaped and filtered through shaping filters (eg, shaping filters 420 , 422 and 1006 ), and the adaptive algorithm operation is performed respectively to obtain the filtering of the feed-forward active noise filter unit 1004 respectively. The coefficient W _FF ( z ) and the filter coefficient W _FB ( z ) of the feedback adaptive active noise filtering unit 1005 . In this embodiment of the present invention, the filter coefficients are obtained by, for example, an iterative operation using the least mean method (LMS), but the present invention is not limited thereto.

FIG. 11 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention. Please refer to FIG. 7, FIG. 10 and FIG. 11 at the same time. In this embodiment, the sound playback system also uses a hybrid ANC earphone as an example. However, the hybrid ANC Only the feedback noise cancellation circuit 1102 of the earphone adopts adaptive active noise cancellation, while the feedforward noise reduction circuit 1101 adopts static noise cancellation. Due to the use of static noise cancellation, compared with the feedforward active noise cancellation circuit 1001 in FIG. 10, the parameter adjustment unit 1020 and its related functional blocks, such as the third transmission channel simulation unit 1010, have been Removed, the feedforward noise reduction circuit 1101 includes an active noise filter unit 1105 that is static. The operation of the feedback noise cancellation circuit 1102 can be referred to FIG. 4 and FIG. 7 Examples of Figures. Therefore, it will not be repeated here.

。 FIG. 12 is a circuit block diagram of a sound playback system according to a preferred embodiment of the present invention. Please refer to FIG. 4, FIG. 10 and FIG. 12 at the same time. In this embodiment, the sound playback system also uses a hybrid active noise canceling earphone as an example. However, the hybrid active noise canceling In the earphone, only the feedforward noise cancellation circuit 1201 adopts adaptive noise cancellation, while the feedback noise reduction circuit 1202 adopts static active noise cancellation. The operation of the feed-forward noise cancellation circuit 1202 may refer to the embodiment in FIG. 4 . Therefore, it will not be repeated here. More particularly, the interference signal received by the feedback noise filtering unit 1203 of the feedback noise reduction circuit 1202 is the error signal e ( n ), rather than the restored environmental noise signal

.

進行時域轉頻域變換。參數運算電路1303再由雜訊形狀儲存電路1302取得內部儲存的理想雜訊的頻域參數，將還原環境噪音訊號

的頻域參數與理想雜訊的頻域參數兩者相除獲得整形濾波參數W(z)。 FIG. 13 is a circuit block diagram of the shaping filter parameter generating unit 419 of the sound playback system according to a preferred embodiment of the present invention. Referring to FIG. 13 , in this embodiment, the shaping filter parameter generating unit 419 includes a frequency analysis circuit 1301 , a noise shape storage circuit 1302 and a parameter operation circuit 1303 . The frequency analysis circuit 1301 in this embodiment is implemented by, for example, a fast Fourier transform (fast fourier transform, FFT) operation circuit, whereby the received environmental noise signal is restored

Perform time-domain to frequency-domain transformation. The parameter operation circuit 1303 obtains the frequency domain parameters of the ideal noise stored internally from the noise shape storage circuit 1302 to restore the ambient noise signal

The frequency domain parameters of , and the ideal noise frequency domain parameters are divided to obtain the shaping filter parameter W ( z ).

Although the above embodiment uses fast Fourier transform and division as examples, those with ordinary knowledge in the art should know that since the discrete Fourier transform of two signals is multiplied in the frequency domain (frequency domain), it is equivalent to the two discrete signals. The convolution operation is performed in the time domain, so the above-mentioned operations can be implemented in different mathematical ways, so the present invention is not limited thereto.

It is worth mentioning that, in the above-mentioned various embodiments, the number of shaping filters is at least two, and in order to have the same shaping and filtering effect on all noise or interference signals, Also, the filter parameters output by the shaping filter parameter generating unit to each shaping filter may be, for example, the same data. However, with common knowledge in the art, it should be inferred that in practical circuit design applications, in order to match the circuit design, the filtering parameters output by the shaping filter parameter generating unit to each shaping filter may also be different. In addition, in practical circuit design applications, the number of shaping filters of the adaptive active noise cancellation device may be only one, so the present invention does not limit the number of shaping filters and the design of filtering parameters of the shaping filters.

To sum up, the spirit of the present invention is to first shape the received error signal and the interference signal according to the shape of an ideal noise, and then send the shaped interference signal and the shaped error signal to the parameter adjustment unit for adaptive parameter adjustment. In this way, the adaptive active noise filtering unit can not only suppress the external noise and the noise of the ear canal effectively to minimize the error signal, but also suppress the specific frequency that the human ear is sensitive to.

Although FIGS. 4 to 13 include the above-described elements, it is not excluded that more other additional elements can be used to achieve better technical effects without departing from the spirit of the invention. Therefore, the present invention is not limited to using only the above-described sequence. In addition, those skilled in the art can also integrate several steps into one step, or in addition to these steps, perform more steps sequentially or in parallel, and the present invention is not limited thereby.

Although the present invention is described using the above embodiments, it should be noted that these descriptions are not intended to limit the present invention. On the contrary, this invention covers modifications and similar arrangements obvious to those skilled in the art. Therefore, the scope of the appended claims is to be construed in the broadest manner so as to encompass all obvious modifications and similar arrangements.

40: Transmission channel

41: Adaptive Active Noise Cancellation Device

411: External noise receiving microphone

412: Error Microphone

413: Automatic noise shaping circuit

414: Adaptive Active Noise Filtering Unit

415: The first transmission channel analog unit

416: Parameter adjustment unit

417: Second transmission channel analog unit

418: First Addition Circuit

419: Shaping filter parameter generation unit

420: first shaping filter

421: Second addition circuit

422: Second shaping filter

Claims (28)

An adaptive active noise cancellation device is suitable for a sound playing system, the sound playing system is used for outputting an anti-phase noise sound signal according to an anti-phase noise signal, wherein the sound playing system includes an error microphone for Receive an ambient noise and the anti-phase noise sound signal to generate an error signal, wherein the adaptive active noise cancellation device includes: an automatic noise shaping circuit, receiving the error signal, according to a preset noise shape, Shaping an interference signal into a shaping interference signal and shaping the error signal into a shaping error signal, and outputting the shaping interference signal and the shaping error signal; an adaptive active noise filtering unit, receiving the interference signal, and outputting the output for generating The inverse noise signal of the inverse noise sound signal; a first transmission channel simulation unit for receiving the shaping interference signal for generating an analog shaping interference signal according to a channel transfer function; and a parameter adjusting unit for receiving the shaping interference signal The analog shaped interference signal and the shaped error signal are adjusted according to the simulated shaped interference signal and the shaped error signal, and an adaptive algorithm is used to adjust the filter coefficient of the adaptive active noise filter unit. The adaptive active noise cancellation device as claimed in claim 1, wherein the automatic noise shaping circuit comprises: a second transmission channel simulation unit for receiving the inverted noise signal, and for generating a signal according to the channel transfer function analog anti-phase noise signal; a first summing circuit receives the analog anti-phase noise signal and the error signal to generate a restored environmental noise signal; a shaping filter parameter generating unit receives the restored environmental noise signal, and, according to The preset noise shape and the restored environmental noise signal generate first shaping filter parameters and second shaping filter parameters; a first shaping filter receives the first shaping filter parameters and the interference signal for generating the shaping filter interference signal; a second summing circuit for receiving the analog anti-phase noise signal and the restored environmental noise signal to generate a restored error signal; and a second shaping filter for receiving the second shaping filter parameter and the restored error signal , used to generate the shaped error signal. The adaptive active noise cancellation device as claimed in claim 2, wherein when the sound playback system is a feedback active noise cancellation earphone, the interference signal is the restored ambient noise signal. The adaptive active noise cancellation device according to claim 2, wherein, when the sound playback system is a feedforward active noise cancelling earphone, the sound playback system further comprises: an external noise receiving microphone for receiving An external sound noise is converted into the interference signal. The adaptive active noise cancellation device as claimed in claim 1, wherein the automatic noise shaping circuit comprises: a second transmission channel simulation unit for receiving the inverted noise signal, and for generating a signal according to the channel transfer function analog anti-phase noise signal; a first summing circuit receives the analog anti-phase noise signal and the error signal to generate a restored environmental noise signal; A shaping filter parameter generating unit receives the restored environmental noise signal, and generates a first shaping filter parameter and a second shaping filter parameter according to the preset noise shape and the restored environment noise signal; a first shaping filter, The first shaping filter parameter and the interference signal are received to generate the shaped interference signal; and a second shaping filter is received for the second shaping filter parameter and the error signal to generate the shaped error signal. The adaptive active noise cancellation device as claimed in claim 5, wherein when the sound playback system is a feedback active noise cancellation earphone, the interference signal is the restored ambient noise signal. The adaptive active noise cancellation device as claimed in claim 5, wherein, when the sound playback system is a feedforward active noise cancelling earphone, the sound playback system further comprises: an external noise receiving microphone for receiving An external sound noise is converted into the interference signal. The adaptive active noise cancellation device as claimed in claim 1, wherein the automatic noise shaping circuit comprises: a second transmission channel simulation unit for receiving the inverted noise signal, and for generating a signal according to the channel transfer function analog anti-phase noise signal; a first summing circuit receives the analog anti-phase noise signal and the error signal to generate a restored environmental noise signal; a shaping filter parameter generating unit receives the restored environmental noise signal, and, according to The preset noise shape and the restored environmental noise signal generate first shaping filter parameters, second shaping filter parameters and third shaping filter parameters; a first shaping filter receives the first shaping filter parameters and the interference signal , used to generate the shaping interference signal; a second shaping filter, receiving the second shaping filtering parameters and the restored environmental noise signal, to generate a shaping and restoring environmental noise signal; a third shaping filter, receiving the first Three shaping filter parameters and the analog anti-phase noise signal are used to generate a shaped analog anti-phase noise signal; and a second summing circuit receives the shaped analog anti-phase noise signal and the shaped and restored ambient noise signal to generate the shaping error signal. The adaptive active noise cancellation device as claimed in claim 8, wherein when the sound playback system is a feedback active noise cancellation earphone, the interference signal is the restored ambient noise signal. The adaptive active noise cancellation device as claimed in claim 8, wherein when the sound playback system is a feedforward active noise cancelling earphone, the sound playback system further comprises: an external noise receiving microphone for receiving An external sound noise is converted into the interference signal. The adaptive active noise cancellation device according to claim 1, wherein the sound playback system is a composite active noise cancelling earphone, wherein the interference signal is a restored ambient noise signal, and the sound playback system comprises: a The external noise receiving microphone is used to receive an external sound noise and convert it into a first Two interference signals; wherein, the adaptive active noise cancellation device further includes: an active noise filter unit, receiving a second interference signal, and outputting a second anti-phase noise signal for generating the anti-phase noise sound signal; a third summing circuit for receiving the inverse noise signal and the second inversion noise signal to superimpose the inversion noise signal and the second inversion noise signal, wherein the sound playback system according to the inversion The noise signal and the second anti-phase noise signal output an anti-phase noise sound signal. The adaptive active noise cancellation device of claim 11, wherein the active noise filtering unit is a feedforward adaptive active noise filtering unit, and the automatic noise shaping circuit is further configured to The second interference signal is shaped into a second shaped interference signal, wherein the adaptive active noise cancellation device further includes: a third transmission channel simulation unit, which receives the second shaped interference signal for according to the a channel transfer function to generate a second analog shaped interference signal; and a second parameter adjustment unit to receive the second analog shaped interference signal and the shaped error signal, and dynamically according to the second simulated shaped interference signal and the shaped error signal The filter coefficients of the feed-forward adaptive active noise filtering unit are adjusted to minimize the error signal. The adaptive active noise cancellation device of claim 1, wherein the sound playback system is a composite active noise reduction earphone, and the sound playback system further comprises: an external noise receiving microphone for receiving an external noise sound noise, which is converted into the interfering signal; Wherein, the adaptive active noise cancellation device further comprises: a feedback noise filter unit, which receives the error signal and outputs a second inversion noise signal for generating the inversion noise sound signal; and a third addition a circuit for receiving the anti-phase noise signal and the second anti-phase noise signal to superimpose the above-mentioned anti-phase noise signal and the second anti-phase noise signal, wherein the sound playing system is based on the anti-phase noise signal and the The second anti-phase noise signal outputs an anti-phase noise sound signal. The adaptive active noise cancellation device as claimed in claim 1, wherein the automatic noise shaping circuit at least includes a shaping filter parameter generating unit, and the shaping filter parameter generating unit includes: a frequency analysis circuit for receiving a restoration environment noise signal, and performing a frequency analysis algorithm on the restored environmental noise signal to obtain the frequency energy distribution corresponding to the restored environmental noise signal; a noise shape storage circuit for storing a frequency energy distribution corresponding to an ideal noise; and a The parameter operation circuit calculates the ratio of the frequency energy distribution corresponding to the restored environmental noise signal and the frequency energy distribution corresponding to the ideal noise according to the frequency energy distribution corresponding to the ideal noise, so as to obtain the shaping filtering parameters. A sound playback system, according to an inverted noise signal, outputs an inverted noise sound signal, the sound playback system comprises: an error microphone, receiving an environmental noise and the inverted noise sound signal to generate an error signal; and an error signal; Adaptive Active Noise Cancellation including: An automatic noise shaping circuit receives the error signal, and according to a preset noise shape, shapes an interference signal into a shaped interference signal, shapes the error signal into a shaped error signal, and outputs the shaped interference signal and the shaping error signal; an adaptive active noise filtering unit, receiving the interference signal, and outputting the inverse noise signal used to generate the inverse noise sound signal; a first transmission channel simulation unit, receiving the shaping interference signal, for according to A channel transfer function generates an analog shaped interference signal; and a parameter adjustment unit receives the analog shaped interference signal and the shaped error signal, and uses an adaptive algorithm according to the analog shaped interference signal and the shaped error signal, Adjust the filter coefficient of the adaptive active noise filtering unit. The sound playback system of claim 15, wherein the automatic noise shaping circuit comprises: a second transmission channel simulation unit for receiving the inversion noise signal, and for generating an analog inversion noise according to the channel transfer function signal; a first summing circuit for receiving the analog inversion noise signal and the error signal to generate a restored environmental noise signal; a shaping filter parameter generating unit for receiving the restored environmental noise signal, and according to the preset noise The shape and the restored environmental noise signal generate a first shaping filter parameter and a second shaping filter parameter; a first shaping filter receives the first shaping filter parameter and the interference signal for generating the shaping interference signal; a first shaping filter Two summing circuits for receiving the analog inversion noise signal and the restored ambient noise signal to generate a restored error signal; and a second shaping filter for receiving the second shaping filter parameter and the restored error signal signal to generate the shaped error signal. The sound playback system as claimed in claim 16, wherein when the sound playback system is a feedback active noise reduction earphone, the interference signal is the restored ambient noise signal. The sound playback system according to claim 16, wherein, when the sound playback system is a feedforward active noise reduction earphone, the sound playback system further comprises: an external noise receiving microphone for receiving an external noise noise signal and converted into the interference signal. The sound playback system of claim 15, wherein the automatic noise shaping circuit comprises: a second transmission channel simulation unit for receiving the inversion noise signal, and for generating an analog inversion noise according to the channel transfer function signal; a first summing circuit for receiving the analog inversion noise signal and the error signal to generate a restored environmental noise signal; a shaping filter parameter generating unit for receiving the restored environmental noise signal, and according to the preset noise The shape and the restored environmental noise signal generate a first shaping filter parameter and a second shaping filter parameter; a first shaping filter receives the first shaping filter parameter and the interference signal for generating the shaping interference signal; and a The second shaping filter receives the second shaping filter parameter and the error signal, and is used for generating the shaping error signal. The sound playback system as claimed in claim 19, wherein when the sound playback system is a feedback active noise reduction earphone, the interference signal is the restored ambient noise signal. The sound playback system according to claim 19, wherein, when the sound playback system is a feedforward active noise reduction earphone, the sound playback system further comprises: an external noise receiving microphone for receiving an external noise noise signal and converted into the interference signal. The sound playback system of claim 15, wherein the automatic noise shaping circuit comprises: a second transmission channel simulation unit for receiving the inversion noise signal, and for generating an analog inversion noise according to the channel transfer function signal; a first summing circuit for receiving the analog inversion noise signal and the error signal to generate a restored environmental noise signal; a shaping filter parameter generating unit for receiving the restored environmental noise signal, and according to the preset noise The shape and the restored environmental noise signal generate a first shaping filter parameter, a second shaping filter parameter and a third shaping filter parameter; a first shaping filter receives the first shaping filter parameter and the interference signal for generating the shaping the interference signal; a second shaping filter for receiving the second shaping filter parameter and the restored ambient noise signal for generating a shaped and restored ambient noise signal; a third shaping filter for receiving the third shaping filter parameter and The analog anti-phase noise signal is used to generate a shaped analog anti-phase noise signal; and a second summing circuit receives the shaped analog anti-phase noise signal and the shaping reduction loop ambient noise signal to generate the shaped error signal. The sound playback system of claim 22, wherein when the sound playback system is a feedback active noise cancelling earphone, the interference signal is the restored ambient noise signal. The sound playback system according to claim 22, wherein when the sound playback system is a feedforward active noise reduction earphone, the sound playback system further comprises: an external noise receiving microphone for receiving an external noise noise signal and converted into the interference signal. The sound playback system as claimed in claim 15, wherein the sound playback system is a composite active noise reduction earphone, wherein the interference signal is a restored ambient noise signal, and the sound playback system comprises: an external noise receiver The microphone is used to receive an external sound noise and convert it into a second interference signal; wherein, the adaptive active noise cancellation device further comprises: an active noise filter unit, which receives a second interference signal and outputs a signal for generating a second inversion noise signal of the inversion noise sound signal; a third summing circuit for receiving the inversion noise signal and the second inversion noise signal, so as to combine the inversion noise signal and the second inversion noise signal The anti-phase noise signal is superimposed, wherein the sound playing system outputs an anti-phase noise sound signal according to the anti-phase noise signal and the second anti-phase noise signal. The sound playback system of claim 25, wherein the active noise filtering unit is a feedforward adaptive active noise filtering unit, and the automatic noise shaping circuit is further configured to, according to the predetermined noise shape, The second interference signal is shaped to form a second shaped interference signal, wherein the adaptive active noise cancellation device further comprises: a third transmission channel simulation unit for receiving the second shaped interference signal, and used for, according to the channel transfer function, generating a second analog shaped interference signal; and a second parameter adjustment unit, receiving the second analog shaped interference signal and the shaped error signal, and dynamically adjusting the feedforward according to the second simulated shaped interference signal and the shaped error signal The filter coefficients of the adaptive active noise filtering unit are used to minimize the error signal. The sound playback system according to claim 15, wherein the sound playback system is a composite active noise reduction earphone, and the sound playback system further comprises: an external noise receiving microphone for receiving an external sound noise, and converted into the interference signal; wherein, the adaptive active noise cancellation device further comprises: a feedback noise filtering unit, receiving the error signal, and outputting a second inversion noise for generating the inversion noise sound signal signal; a third summing circuit for receiving the anti-phase noise signal and the second anti-phase noise signal to superimpose the above-mentioned anti-phase noise signal and the second anti-phase noise signal; and wherein the sound playback system is based on The anti-phase noise signal and the second anti-phase noise signal output an anti-phase noise sound signal. The sound playback system of claim 15, wherein the automatic noise shaping circuit is to At least one shaping filter parameter generation unit is included, and the shaping filter parameter generation unit includes: a frequency analysis circuit, which receives a restored environmental noise signal, and performs a frequency analysis algorithm on the restored environmental noise signal to obtain the restored environmental noise The frequency energy distribution corresponding to the signal; a noise shape storage circuit, which stores the frequency energy distribution corresponding to an ideal noise; and a parameter arithmetic circuit, which calculates the corresponding frequency energy distribution of the restored environmental noise signal according to the frequency energy distribution corresponding to the ideal noise. The ratio of the frequency energy distribution to the frequency energy distribution corresponding to the ideal noise to obtain the shaping filter parameters.

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