WO2019157698A1

WO2019157698A1 - Detection circuit and method

Info

Publication number: WO2019157698A1
Application number: PCT/CN2018/076812
Authority: WO
Inventors: 王欣民
Original assignee: 深圳市汇顶科技股份有限公司
Priority date: 2018-02-14
Filing date: 2018-02-14
Publication date: 2019-08-22
Also published as: CN110383854A; CN110383854B

Abstract

A detection circuit (104) and a detection method. The detection circuit (104) comprises a transmission circuit (110) and a processing circuit (120). The transmission circuit (110) is configured to receive a first sound signal and is coupled to an audio playback driver (102). The transmission circuit (110) generates, according to the first sound signal, a second sound signal and sends the signal to the audio playback driving unit (102), and generates a characteristic signal (CHS) according to at least the first sound signal and the second sound signal. The processing circuit (120) is coupled to the transmission circuit (110) to receive the characteristic signal (CHS), and the processing circuit (120) detects, according to at least the first sound signal and the characteristic signal (CHS), whether the audio playback driver (102) is located in a predetermined resonance environment. The detection circuit (104) can detect a usage context of the audio playback driver (102) to adjust the operating status of the audio playback driver (102), so as to implement an intelligent audio playback system.

Description

Detection circuit and method

Technical field

The present invention relates to an audio playback driving unit, and more particularly to a detection circuit for detecting whether an audio playback driving unit is located in a predetermined resonance environment and related methods.

Background technique

Existing audio playback systems use an audio playback driver/transducer (such as a playback drive unit of a speaker or earphone) to play a sound signal. For example, a user wears a Bluetooth headset to listen to music played on the phone. However, when the user temporarily removes the Bluetooth headset for some reason (for example, talking with a person), the Bluetooth headset continues to play music, which not only increases unnecessary power consumption, but also shortens the life of the battery.

Therefore, there is a need for an innovative audio playback detection mechanism that can detect the usage context of an audio playback system/audio playback driver unit to adjust its operational state (e.g., selectively enter a power save mode) to implement an intelligent audio playback system.

Summary of the invention

One of the objects of the present invention is to disclose a detection circuit for detecting whether an audio playback drive unit is located in a predetermined resonance environment and related methods to solve the above problems.

Another object of the present invention is to disclose a detection circuit and related method that can provide suitable audio playback quality according to the resonant environment in which the audio playback drive unit is located, to meet the listening needs of the user.

An embodiment of the invention discloses a detection circuit. The detection circuit includes a transmission circuit and a processing circuit. The transmission circuit is configured to receive a first sound signal and is coupled to the audio playback driving unit, wherein the transmission circuit generates a second sound signal according to the first sound signal to the audio playback driving unit, and at least according to the The first sound signal and the second sound signal generate a characteristic signal. The processing circuit is coupled to the transmission circuit to receive the characteristic signal, and the processing circuit detects whether the audio playback driving unit is located in a predetermined resonance environment according to at least the first sound signal and the characteristic signal.

An embodiment of the invention discloses a detection method. The method includes the steps of: feeding a first sound signal to a first transmission path coupled to an audio playback driving unit to generate a second sound signal to the audio playback driving unit; at least according to the first sound signal Generating, by the second sound signal, a feature signal on a second transmission path coupled to the audio playback driving unit, wherein the second transmission path is different from the first transmission path; and at least according to the first sound The signal and the characteristic signal detect whether the audio playback drive unit is in a predetermined resonance environment.

DRAWINGS

1 is a functional block diagram of an audio playback system in accordance with an embodiment of the present invention.

2 is a schematic diagram of an embodiment of the audio playback system shown in FIG. 1.

3 is a flow chart of a method for detecting whether an audio playback drive unit is located in a predetermined resonance environment according to an embodiment of the present invention.

Among them, the reference numerals are as follows:

100, 200 audio playback system

102, 202 audio playback drive unit

104, 204 detection circuit

106, 206 signal generation circuit

110, 210 transmission circuit

120, 220 processing circuit

207 digital signal processing circuit

208 digital to analog converter

209 output unit

212, 214, 216 transmission path

222 input unit

224 analog to digital converter

226 impedance detector

310, 320, 330, 340 steps

P1, IP input port

P2, P3, OP1, OP2 output ports

Z_I1, Z_I2, Z_R1, Z_R2, Z_X1, Z_X2 impedance

Z_Load predetermined input impedance

RS1, RS2 resonator

AS1, AS2, TD, TA, SL sound signals

SN noise signal

CHS, RD, RA characteristic signals

CS control signal

Detailed ways

The audio playback detection mechanism disclosed by the present invention can detect the signal response of the audio playback driving unit on the sound input side, and use the audio playback driving unit as a sensing device of the surrounding environment to detect the resonance of the audio playback driving unit. Environment (or geometry/shape of the cavity). Further explanation is as follows.

1 is a functional block diagram of an audio playback system in accordance with an embodiment of the present invention. In this embodiment, the audio playback system 100 includes, but is not limited to, an audio playback driver unit (or audio playback transducer) 102, a detection circuit 104, and a signal generation circuit 106, wherein at least a portion of the audio playback system 100 It can be implemented by an electronic device having an audio playback function. For example, the audio playback driving unit 102, the detecting circuit 104, and the signal generating circuit 106 may be at least a part of an electronic device (such as a mobile phone, a palmtop computer, or a notebook computer), wherein the audio playback driving unit 102 is built in the electronic device. Playing a driving unit (such as a playback drive unit of a speaker or a headphone); for example, the detecting circuit 104 and the signal generating circuit 106 may be at least a part of an electronic device such as a mobile phone, a palmtop computer or a notebook computer, and the audio playback driver The unit 102 may be a playback drive unit (such as a playback drive unit of a speaker or an earphone) externally connected to the electronic device; for example, the signal generation circuit 106 may be at least a part of an electronic device such as a mobile phone, a palmtop computer or a notebook computer. The audio playback driving unit 102 and the detecting circuit 104 can be located in an audio playing device (such as a speaker or an earphone) external to the electronic device.

The resonance environment in which the audio playback driving unit 102 is located may affect its signal response, and the detecting circuit 104 may detect the resonance environment in which the audio playback driving unit 102 is located according to the signal response of the audio playback driving unit 102 (for example, whether it is located or not) a predetermined resonance environment). For example, in the case where the audio playback driving unit 102 is implemented by the playback driving unit of the earphone, when the audio playback driving unit 102 is in the first resonance environment (for example, the user wears the earphone), the audio playback driver The resonant cavity of unit 102 has a first geometry/shape (eg, the geometric resonant space inherent to audio playback drive unit 102 in conjunction with the ear canal geometry of the user), and the input impedance of audio playback drive unit 102 can have a first frequency response characteristic When the audio playback drive unit 102 is in the second resonance environment (eg, the user removes the headphones), the resonant cavity of the audio playback drive unit 102 has a second geometry/shape (eg, inherent to the audio playback drive unit 102) The geometric resonance space), the input impedance of the audio playback drive unit 102 can have a second frequency response characteristic. Therefore, the detecting circuit 104 can detect the resonance environment (or use context) in which the audio playback driving unit 102 is located by detecting the input impedance or frequency response of the audio playback driving unit 102.

In this embodiment, the detecting circuit 104 outputs the sound signal AS2 to the audio playback driving unit 102 based on the sound signal AS1 supplied from the signal generating circuit 106, thereby detecting the input impedance/frequency response of the audio playback driving unit 102. The detection circuit 104 includes, but is not limited to, a transmission circuit 110 and a processing circuit 120. The transmission circuit 110 is coupled between the audio playback driving unit 102 and the signal generating circuit 106 for receiving the sound signal AS1, and transmits the sound signal AS1 to the audio playback driving unit 102, thereby generating the sound signal AS2 and obtaining the characteristic signal CHS. The transmission circuit 110 can generate the characteristic signal CHS according to the sound signal AS1 and the sound signal AS2. For example (but the invention is not limited thereto), the transmission circuit 110 includes an input port P1, an output port P2, and an output port P3. The input port P1 is configured to receive the sound signal AS1, the output port P2 is coupled to the audio playback drive unit 102, and the output port P3 is coupled to the processing circuit 120. The transmission circuit 110 can generate the sound signal AS2 according to the sound signal AS1, output to the audio playback driving unit 102 through the output port P2, and generate the characteristic signal CHS based on at least the sound signal AS1 and the sound signal AS2, and output to the processing circuit 120 through the output port P3.

The processing circuit 120 is coupled to the transmission circuit 110 and the signal generating circuit 106 for receiving the characteristic signal CHS, and detecting whether the audio playback driving unit 102 is located in a predetermined resonance environment according to at least the sound signal AS1 and the characteristic signal CHS (for example, detecting whether the user is The audio playback device including the audio playback drive unit 102 is worn. For example (but the invention is not limited thereto), the processing circuit 120 can detect the input impedance or frequency response of the audio playback driving unit 102 according to the signal strength information, phase information, and/or gain information of the characteristic signal CHS and the sound signal AS1. Thereby detecting whether the audio playback drive unit 102 is in a predetermined resonance environment. In a specific implementation, when the signal strength of the feature signal CHS relative to the sound signal AS1 is within a range of intensity characteristics, and the phase change of the feature signal CHS relative to the sound signal AS1 is within a phase feature range, the processing circuit 120 It can be determined that the audio playback driving unit 102 is located in the predetermined resonance environment; when the signal strength of the characteristic signal CHS is not within the intensity characteristic range with respect to the signal strength of the sound signal AS1, or the phase of the characteristic signal CHS relative to the sound signal AS1 When the change is not within the phase feature range, the processing circuit 120 can determine that the audio playback drive unit 102 is not located in the predetermined resonance environment. However, the invention is not limited thereto.

It should be noted that the processing circuit 120 can receive the sound signal AS1 to directly detect the sound signal AS1 and the characteristic signal CHS, and can also receive the sound signal AS0 to indirectly detect the sound signal AS1 and the characteristic signal CHS, wherein the sound signal AS0 is the sound signal AS1 The signal generation circuit 106 outputs the previous pending version. That is, the signal generating circuit 106 may perform preprocessing (such as a digital-to-analog conversion operation) on the sound signal AS0 to generate the sound signal AS1. Similarly, the processing circuit 120 may directly detect the feature signal CHS, or may perform pre-processing (such as analog-to-digital conversion operation) on the feature signal CHS, and then detect the processed feature signal CHS. In short, as long as the signal response of the audio playback driving unit 102 can be detected based on the sound signal AS1 and the characteristic signal CHS to detect the resonance environment in which the audio playback driving unit 102 is located, design-related changes are in accordance with the spirit of the present invention.

Moreover, in some embodiments, transmission circuit 110 can perform impedance matching for a predetermined input impedance, which can be an input impedance of audio playback drive unit 102 when in the predetermined resonant environment. The processing circuit 120 can detect a signal response with respect to the input impedance of the audio playback driving unit 102 based on the sound signal AS1 and the characteristic signal CHS. For example, when it is detected that the signal component from the sound signal AS1 among the characteristic signals CHS obtained by the transmission circuit 110 is less than a predetermined ratio, this means that the audio playback driving unit 102 currently has an input impedance equal to (or substantially equal to) the said The input impedance is predetermined, and the processing circuit 120 can determine that the audio playback drive unit 102 is in the predetermined resonant environment.

In order to facilitate the understanding of the technical features of the present invention, an exemplary circuit structure is used below to illustrate the details of the disclosed audio playback detection mechanism. However, this is only a convenient explanation. Any implementation employing a circuit structure based on Figure 1 is feasible. Please refer to FIG. 2, which is a schematic diagram of an embodiment of the audio playback system 100 shown in FIG. 1. The audio playback system 200 includes, but is not limited to, an audio playback driver unit 202, a detection circuit 204, and a signal generation circuit 206, wherein the audio playback driver unit 102, the detection circuit 104, and the signal generation circuit 106 shown in FIG. The playback drive unit 202, the detection circuit 204, and the signal generation circuit 206 are implemented. In addition, the detection circuit 204 includes a transmission circuit 210 and a processing circuit 220. The transmission circuit 110 and the processing circuit 120 shown in FIG. 1 can be implemented by the transmission circuit 210 and the processing circuit 220, respectively.

In this embodiment, signal generation circuit 206 includes, but is not limited to, digital signal processing circuit 207, digital to analog converter 208 (labeled "DAC"), and output unit 209 (labeled "BF1"), where output unit 209 It can be implemented by a power amplifier. The digital signal processing circuit 207 generates a sound signal TD (digital sound signal) to the digital to analog converter 208. After the processing by the digital-to-analog converter 208 and the output unit 209, the sound signal TD can be converted into a sound signal TA (analog sound signal).

The sound signal TA forms a sound signal SL to the audio playback driving unit 202 after passing through the transmission circuit 210, and the sound signal SL changes according to a change in the input impedance of the audio playback driving unit 202. The transmission circuit 210 also generates a characteristic signal RA to the processing circuit 220 based on the sound signal TA and the sound signal SL. In this embodiment, the transmission circuit 210 can detect the signal response (or input impedance variation) of the audio playback driving unit 202 by means of circuit matching. For example (but the invention is not limited thereto), the transmission circuit 210 may be implemented by a hybrid matching network (such as a hybrid impedance matching circuit), and may include an input port IP and an output port OP1. The output port OP2 and the plurality of transmission paths 212-216, wherein the transmission path 212 is coupled between the input port IP and the output port OP1, the transmission path 214 is coupled between the output port OP1 and the output port OP2, and the transmission path 216 It is coupled between the input port IP and the output port OP2.

Processing circuit 220 includes, but is not limited to, input unit 222 (labeled "BF2"), analog to digital converter 224 (labeled "ADC"), and impedance detector 226, where input unit 222 can be implemented by a buffer. The analog-to-digital converter 224 can convert the characteristic signal RA (analog signal) buffered by the input unit 222 to generate a characteristic signal RD (digital signal), and the impedance detector 226 can be based on the digital version corresponding to the sound signal TA (sound signal TD) The digital version (feature signal RD) corresponding to the feature signal RA detects whether the audio playback drive unit 202 is in a predetermined resonance environment.

It should be noted that in some embodiments, the output impedance of the output unit 209 (or the output impedance of the signal generating circuit 206) is relative to the input impedance of the audio playback driving unit 202 (the impedance of the electrical load of the signal generating circuit 206). It is said to be small, therefore, different signal responses (such as response characteristics of the characteristic signal RA) are generated according to changes in the resonant environment (resonator geometry/shape) of the audio playback drive unit 202, and the impedance detector 226 can detect The input impedance of the audio playback drive unit 202 changes, thereby determining the resonant environment in which the audio playback drive unit 202 is located.

For example, the transmission impedance between the input port IP and the output port OP1 (the transmission impedance of the transmission path 212) can be matched to a predetermined input impedance Z_Load, wherein the predetermined input impedance Z_Load is the audio playback driving unit 202 located at the The input impedance is seen from the output port OP1 in a predetermined resonance environment (corresponding to the resonant cavity RS1), and the impedance Z_I1 and the impedance Z_I2 may both be equal to, but not limited to, one-half of the predetermined input impedance Z_Load. Further, by appropriate design, when the audio playback driving unit 202 is located in the predetermined resonance environment, the transmission impedance between the output port OP1 and the output port OP2 (the transmission impedance of the transmission path 214) and the input port IP and The transmission impedance between the output ports OP2 (the transmission impedance of the transmission path 216) can greatly reduce the signal component from the sound signal TA among the characteristic signals RA. For example, the transmission impedance between the output port OP1 and the output port OP2 may be, but is not limited to, one-half of the transmission impedance between the input port IP and the output port OP2 to be passed through the transmission path 214 to the output port OP2. The signal (corresponding to the sound signal SL) can cancel (or substantially cancel) the signal (corresponding to the sound signal TA) transmitted to the output port OP2 through the transmission path 216, wherein the impedance Z_R1 can be equal to the impedance Z_R2, and the impedance Z_X1 can be equal to the impedance Z_X2 And the impedance Z_R1 and the impedance Z_R2 can both be equal to one-half of the impedance Z_X1 (impedance Z_X2). Relative to the signal strength of the sound signal TA itself, the characteristic signal RA is less affected by the sound signal TA, and the signal strength of the sound signal TA is attenuated a lot (or attenuated to zero). That is to say, in the case of some circuit matching, the presence (or variation) of the sound signal TA equivalently does not (or hardly affect) the signal generated by the output port OP2.

In addition, since the presence (or variation) of the sound signal TA does not (or hardly affect) the signal generated by the output port OP2 in the case of some circuit matching, on the other hand, on the output port The characteristic signal RA generated by OP2 can have a high sensitivity to changes in the circuit matching situation. For example, the characteristic signal RA can be very sensitive to changes in the input impedance of the audio playback drive unit 202 (the situation in which the circuit matching changes).

Therefore, when the impedance detector 226 detects that the signal strength of the characteristic signal RD with respect to the sound signal TD is within a range of intensity characteristics (eg, the signal strength of the characteristic signal RD is attenuated by more than 20 decibels compared to the sound signal TD, or The attenuation is between 20 decibels and 40 decibels, which means that the transmission circuit 210 has greatly reduced the signal component from the sound signal TA among the characteristic signals RA by impedance matching, and the impedance detector 226 (or the processing circuit 220) can detect The outgoing audio playback drive unit 202 is located in the predetermined resonant environment. In addition, when the impedance detector 226 detects that the signal strength of the feature signal RD with respect to the sound signal TD is not within the intensity characteristic range, the impedance detector 226 (or the processing circuit 220) can detect the audio playback driving unit 202. Not located in the predetermined resonant environment. For example, when the impedance detector 226 detects that the signal strength of the feature signal RD relative to the sound signal TD is not within the intensity feature range but is within another intensity feature range, the impedance detector 226 (or processing circuit) 220) It can be detected that the audio playback driving unit 202 is located in another predetermined resonance environment (corresponding to another resonant cavity RS2), wherein the predetermined resonance environment corresponding to the resonant cavity RS1 can be, but is not limited to, the user wears the audio playback driver. In the earphone of unit 202, the predetermined resonance environment corresponding to the resonant cavity RS2 may be, but is not limited to, the user removing the earphone including the audio playback driving unit 202.

In some embodiments, when the impedance detector 226 detects that the phase change of the feature signal RD relative to the sound signal TD is within a phase feature range (eg, the phase change of the feature signal RD exceeds the sound signal TD) a predetermined angle, or within a predetermined range of variation, which means that the transmission circuit 210 has substantially reduced the signal component from the sound signal TA among the characteristic signals RA by impedance matching, or means that the cavity of the audio playback driving unit 202 At a particular resonant frequency or at multiple resonant frequencies (overtones) at the same time, impedance detector 226 (or processing circuit 220) can detect that audio playback drive unit 202 is in the predetermined resonant environment. When the impedance detector 226 detects that the phase change of the characteristic signal RD with respect to the sound signal TD is not within the phase characteristic range, the impedance detector 226 (or the processing circuit 220) can detect that the audio playback driving unit 202 is not located. The predetermined resonance environment.

Moreover, in some embodiments, when the impedance detector 226 detects that the signal strength of the characteristic signal RD relative to the sound signal TD is within a range of intensity characteristics, and the phase change of the characteristic signal RD relative to the sound signal TD is between When the phase characteristic range is within (for example, the signal strength of the characteristic signal RD is attenuated by more than 20 decibels compared to the sound signal TD, and the phase change of the characteristic signal RD is within a predetermined variation range), which means that the transmission circuit 210 passes Impedance matching has substantially reduced the signal component from the sound signal TA among the characteristic signals RA, or means that the resonant cavity of the audio playback drive unit 202 may be at a particular resonant frequency or at multiple resonant frequencies simultaneously, the impedance detector 226 (or processing) The circuit 220) can detect that the audio playback drive unit 202 is in the predetermined resonant environment. When the impedance detector 226 detects that the signal strength of the characteristic signal RD with respect to the sound signal TD is not within the intensity characteristic range, and the phase change of the characteristic signal RD with respect to the sound signal TD is not within the phase characteristic range The impedance detector 226 (or processing circuit 220) can then detect that the audio playback drive unit 202 is not located in the predetermined resonant environment.

In short, when the resonance environment in which the audio playback driving unit 202 is located changes, the characteristic signal RA generated by the transmission circuit 210 can reflect the input impedance change of the audio playback driving unit 202, and the impedance detector 226 can obtain the obtained signal. Features such as signal strength and/or phase changes detect the resonant environment in which the audio playback drive unit 202 is currently located.

It should be noted that in some embodiments, the transmission circuit 210 may perform impedance matching for a predetermined frequency range Z_Load over a specific frequency range, wherein the specific frequency range may be within or outside the range of frequencies perceived by the human ear. . For example, the audio playback driving unit 202 is configured to play a sound signal whose frequency range is within an audible sound frequency range (ie, an ear-perceivable audio signal, such as a symphony generated by the signal generating circuit 206). In the case of an audio signal), the processing circuit 220 can simultaneously detect the resonance environment in which the audio playback driving unit 202 is located according to the frequency response of the sound signal (generated by the signal generation circuit 206), or according to the signal generation circuit 206. The frequency response of another generated sound signal (e.g., ultrasonic signal) is detected to detect the resonant environment in which the audio playback drive unit 202 is located. In other words, the specific frequency range may include at least one of a frequency range of the ultrasonic waves and a frequency range of the audible sound waves.

Moreover, in some embodiments, transmission circuit 210 may receive noise signal SN from audio playback drive unit 202 via output port OP1, which may be a sound signal of a surrounding environment (such as a heartbeat or speech sound of a human body). That is to say, the characteristic signal RA may contain a signal component from the noise signal SN. Since the detecting circuit 204 can sensitively detect the input impedance change (or frequency response) generated by the audio playback driving unit 202 in response to the change of the resonance environment, the characteristic signal RA generated by the transmission circuit 210 can still reflect the audio playback driving unit. The input impedance variation of 202 (eg, the signal strength of the characteristic signal RD is substantially attenuated relative to the signal strength of the sound signal TD) such that the impedance detector 226 can be based on the characteristic signal RA and the sound signal TA (or the characteristic signal RD and the characteristic signal TD) The resonance environment in which the audio playback drive unit 202 is currently located is detected, and is not susceptible to interference by the noise signal SN.

Please note that the above is for illustrative purposes only and is not intended to be a limitation of the invention. In a design variation, it is also possible to omit at least one of the plurality of transmission paths 212-216 as long as the processing circuit 220 can detect an impedance change caused by the change in the resonant environment of the audio playback drive unit 202. For example, in the case where the transmission path 216 is omitted/removed, the impedance detector 226 can directly perform a numerical calculation on the sound signal TA/TD and the characteristic signal RA/RD to determine the input impedance change of the audio playback driving unit 202. For another example, in the case of omitting/removing the transmission path 214 and the transmission path 216, the impedance detector 226 can directly perform a numerical calculation on the sound signal TA/TD and the sound signal SL to determine the input impedance of the audio playback driving unit 202. Variety.

In another design variation, processing circuit 220 may also adjust the transmission impedance of transmission path 214 (such as impedance Z_R1 and/or impedance Z_R2) to the transmission impedance of transmission path 216 (such as impedance Z_X1 and/or impedance Z_X2). The ratio between the two is based on the ratio between the transmission impedance of the transmission path 214 and the transmission impedance of the transmission path 216, the sound signal TA and the characteristic signal RA to detect whether the audio playback driving unit 202 is located in the predetermined resonance environment. For example (but the invention is not limited thereto), the impedance Z_X1 and the impedance Z_X2 may each be implemented by an impedance array, wherein the impedance detector 226 may generate a control signal CS to the impedance Z_X1 and the impedance Z_X2 to control the impedance Z_X1 and the impedance Z_X2. The impedance value is such that the signal strength of the characteristic signal RA relative to the sound signal TA (or the signal strength of the characteristic signal RD relative to the sound signal TD) is within a range of intensity characteristics and/or the phase of the characteristic signal RA relative to the sound signal TA The change (or the phase change of the characteristic signal RD with respect to the sound signal TD) is within a range of phase characteristics. When the signal strength of the characteristic signal RA relative to the sound signal TA is within the intensity characteristic range, and/or the phase change of the characteristic signal RA with respect to the sound signal TA (or the phase change of the characteristic signal RD with respect to the sound signal TD) When in the phase characteristic range, the impedance detector 226 may be based on a corresponding impedance ratio (such as a ratio between the impedance Z_X2 and the impedance Z_R1, and/or a ratio between the impedance Z_X1 and the impedance Z_R2), It is detected whether the audio playback drive unit 202 is located in the predetermined resonance environment.

In yet another design variant, the transmission circuit 210 can also be implemented by other circuit configurations. For example, the transmission circuit 210 may employ a transformer for circuit matching, and in a case of current subtraction, in a case where the audio playback driving unit 202 is located in the predetermined resonance environment, a signal from the sound signal TA among the characteristic signals RA is made. The composition has been greatly reduced.

The audio playback detection mechanism disclosed in the present invention can be simply summarized into the flowchart shown in FIG. Please refer to FIG. 3, which is a flowchart of a method for detecting whether an audio playback driving unit is located in a predetermined resonance environment. If the results obtained are substantially the same, the steps do not have to be performed in the order shown in FIG. For example, some steps can be placed in it. For convenience of explanation, the method shown in FIG. 3 will be described below in conjunction with the audio playback system 200 shown in FIG. 2. However, it is also feasible to apply the method shown in FIG. 3 to the audio playback system 100 shown in FIG. 1. The method can be summarized as follows.

Step 310: Start.

For example, the sound signal TD is generated by the digital signal processing circuit 207, and the sound signal TD is converted into the sound signal TA by the digital-to-analog converter 208 and the output unit 209.

Step 320: Feed the first sound signal to the first transmission path coupled to the audio playback driving unit to generate a second sound signal to the audio playback driving unit.

For example, the sound signal TA is fed to the transmission path 212 coupled to the audio playback driving unit 202 to generate the sound signal SL to the audio playback driving unit 202.

Step 330: Generate a feature signal according to the second transmission path coupled to the audio playback driving unit, according to the first sound signal and the second sound signal, where the second transmission path is different from the first A transmission path.

For example, the transmission circuit 210 generates a characteristic signal RA based at least on the transmission path 214 to which the audio signal SL is coupled to the audio playback drive unit 202, wherein the transmission path 214 is different from the transmission path 212.

Step 340: Detect whether the audio playback driving unit is located in the predetermined resonance environment according to at least the first sound signal and the characteristic signal.

For example, the processing circuit 220 detects whether the audio playback drive unit 202 is located in the predetermined resonance environment based at least on the sound signal TA and the feature signal RA.

In step 330, the transmission circuit 210 can couple the sound signal TA to the transmission path 214 through the transmission path 216 to generate the characteristic signal RA at the output port OP2 according to the sound signal TA and the sound signal SL. The feature signal RA can reflect the circuit matching situation between the transmission circuit 210 and the audio playback drive unit 202. Moreover, in some embodiments, transmission path 212, transmission path 214, and transmission path 216 are used to impedance match a predetermined input impedance, and the predetermined input impedance is when audio playback drive unit 202 is in the predetermined resonant environment. Input impedance (such as a predetermined input impedance Z_Load).

In step 340, when the signal strength of the feature signal RA relative to the sound signal TA is within a range of intensity characteristics (eg, the impedance detector 226 detects that the characteristic signal RD has a large amount of attenuation with respect to the signal strength of the sound signal TD), And/or when the phase change of the characteristic signal RA relative to the sound signal TA is within a phase characteristic range, the impedance detector 226 may determine that the audio playback driving unit 202 is located in the predetermined resonance environment; when the characteristic signal RA is relative to the sound signal TA When the signal strength is not within the range of the intensity characteristics, and/or the phase change of the characteristic signal RA relative to the sound signal TA is not within the phase feature range, the impedance detector 226 may determine that the audio playback driving unit 202 is not Located in the predetermined resonant environment.

Since the details of each step in the method shown in FIG. 3 should be understood by those skilled in the art after reading the relevant paragraphs of FIG. 1 and FIG. 2, further description will not be repeated here.

In summary, the detection circuit and related detection method disclosed by the present invention can detect the resonance environment of the audio playback driving unit by detecting the signal response of the audio playback driving unit (such as the change of the input impedance). Or determine the resonant cavity geometry/shape of the audio playback drive unit). The audio detection mechanism disclosed by the present invention can have a variety of applications. For example, the audio detection mechanism disclosed in the present invention can be used for wear detection to detect whether a user wears an audio playback device having the audio playback driving unit, and adjusts the user when the user does not wear the audio playback device. The operating state of the audio playback drive unit (for example, entering the power saving mode) implements an intelligent audio playback system. In another example, the disclosed audio detection mechanism can detect a user's wearing state, such as wearing it tightly or gently, to adjust the sound signal to be played (eg, adjusting the amplitude of the sound signal). The audio detection mechanism disclosed by the present invention can adjust the sound signal to be played (for example, adjusting the signal characteristics of the high frequency and/or low frequency bands) to improve the audio playback quality. In yet another example, the disclosed audio detection mechanism can be used to identify structural features of the human ear canal by detecting the resonant cavity geometry/shape in which the audio playback drive unit is located.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

A detection circuit, comprising:

a transmission circuit, configured to receive the first sound signal, and coupled to the audio playback driving unit,

Wherein the transmission circuit generates a second sound signal to the audio playback driving unit according to the first sound signal, and generates a feature signal based on at least the first sound signal and the second sound signal;

a processing circuit coupled to the transmission circuit to receive the characteristic signal,

The processing circuit detects whether the audio playback driving unit is located in a predetermined resonance environment based on at least the first sound signal and the characteristic signal.
The detection circuit of claim 1 wherein said transmission circuit performs impedance matching for a predetermined input impedance, said predetermined input impedance being an input impedance of said audio playback drive unit in said predetermined resonant environment.
The detection circuit of claim 2 wherein said transmission circuit is a hybrid impedance matching circuit.
The detecting circuit of claim 2, wherein the transmitting circuit comprises an input port, a first output port, and a second output port;

A first transmission impedance between the input port and the first output port is matched to the predetermined input impedance.
The detecting circuit of claim 4, wherein the input port and the second output port have a second transmission impedance, and the first output port and the second output port have Third transmission impedance;

The processing circuit adjusts a ratio between the second transmission impedance and the third transmission impedance to be based on a ratio between the second transmission impedance and the third transmission impedance, the first sound signal and The characteristic signal detects whether the audio playback drive unit is located in the predetermined resonance environment.
The detection circuit of claim 5 wherein said second transmission impedance is one-half of said third transmission impedance.
The detection circuit of claim 2 wherein said transmission circuit performs impedance matching for said predetermined input impedance over a particular frequency range.
The detecting circuit of claim 7, wherein said specific frequency range comprises at least one of a frequency range of the ultrasonic waves and a frequency range of the audible sound waves.
The detecting circuit according to any one of claims 1 to 8, wherein when the signal intensity of the characteristic signal relative to the first sound signal is within a range of intensity characteristics, and the characteristic signal is relative to When the phase change of the first sound signal is within the phase feature range, the processing circuit determines that the audio playback driving unit is located in the predetermined resonance environment; and when the characteristic signal is relative to the signal of the first sound signal When the intensity is not within the range of the intensity characteristic, or the phase change of the characteristic signal relative to the first sound signal is not within the phase feature range, the processing circuit determines that the audio playback driving unit does not Located in the predetermined resonant environment.
The detecting circuit according to any one of claims 1 to 8, wherein when the signal intensity of the characteristic signal relative to the first sound signal is within a range of intensity characteristics, the processing circuit determines The audio playback driving unit is located in the predetermined resonance environment; when the signal strength of the characteristic signal relative to the first sound signal is not within the intensity characteristic range, the processing circuit determines the audio playback driving unit Not located in the predetermined resonant environment.
The detecting circuit according to any one of claims 1 to 8, wherein when the phase change of the characteristic signal with respect to the first sound signal is within a phase characteristic range, the processing circuit determines The audio playback driving unit is located in the predetermined resonance environment; when the phase change of the characteristic signal relative to the first sound signal is not within the phase feature range, the processing circuit determines the audio playback driving unit Not located in the predetermined resonant environment.
A detection method is characterized in that it comprises the following steps:

Feeding the first sound signal to the first transmission path coupled to the audio playback driving unit to generate a second sound signal to the audio playback driving unit;

Generating a feature signal to the second transmission path coupled to the audio playback driving unit according to the first sound signal and the second sound signal, wherein the second transmission path is different from the first transmission path ;as well as

Detecting whether the audio playback driving unit is located in a predetermined resonance environment based on at least the first sound signal and the characteristic signal.
The method of claim 12, wherein the step of generating a feature signal based on at least the first sound signal and the second sound signal coupled to the second transmission path of the audio playback drive unit comprises:

Coupling the first sound signal to the second transmission path through a third transmission path to generate a characteristic signal according to the first sound signal and the second sound signal in a second transmission path, wherein the The three transmission paths are different from the first transmission path.
The method of claim 13 wherein said first transmission path, said second transmission path and said third transmission path are used for impedance matching of a predetermined input impedance, said predetermined input impedance being The input impedance of the audio playback drive unit in the predetermined resonant environment.
The method of claim 14 wherein said first transmission path has a first transmission impedance that matches said predetermined input impedance.
The method according to claim 15, wherein the step of detecting whether the audio playback driving unit is located in a predetermined resonance environment based on at least the first sound signal and the characteristic signal comprises:

Adjusting a ratio between a second transmission impedance of the second transmission path and a third transmission impedance of the third transmission path;

Detecting whether the audio playback driving unit is located in the predetermined resonance environment according to a ratio between the second transmission impedance and the third transmission impedance, the first sound signal and the characteristic signal.
The method of claim 16 wherein said second transmission path has a second transmission impedance that is one-half of a third transmission impedance of said third transmission path.
The method of claim 14 wherein said first transmission path, said second transmission path and said third transmission path are impedance matched to said predetermined input impedance over a particular frequency range
The method of claim 18 wherein said particular frequency range is in the frequency range of an ultrasonic or audible sound wave.
The method according to claim 12, wherein the step of detecting whether the audio playback driving unit is located in a predetermined resonance environment based on at least the first sound signal and the characteristic signal comprises:

Determining that the signal strength of the feature signal relative to the first sound signal is within a range of intensity characteristics, and a phase change of the feature signal relative to the first sound signal is within a phase feature range An audio playback drive unit is located in the predetermined resonant environment;

When the signal strength of the characteristic signal relative to the first sound signal is not within the intensity characteristic range, or the phase change of the characteristic signal relative to the first sound signal is not within the phase feature range When it is inside, it is judged that the audio playback drive unit is not located in the predetermined resonance environment.