CN110383854B - Detection circuit and method - Google Patents
Detection circuit and method Download PDFInfo
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- CN110383854B CN110383854B CN201880000300.6A CN201880000300A CN110383854B CN 110383854 B CN110383854 B CN 110383854B CN 201880000300 A CN201880000300 A CN 201880000300A CN 110383854 B CN110383854 B CN 110383854B
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Abstract
A detection circuit (104) and a detection method are provided. The detection circuit (104) comprises a transmission circuit (110) and a processing circuit (120). The transmission circuit (110) is used for receiving a first sound signal and is coupled to the audio playing driving unit (102). The transmission circuit (110) generates a second sound signal to the audio playback drive unit (102) according to the first sound signal, 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 whether the audio playback driving unit (102) is located in a predetermined resonance environment according to at least the first sound signal and the characteristic signal (CHS). The detection circuit (104) can detect the use situation of the audio playing driving unit (102) to adjust the operation state of the audio playing driving unit (102), so as to realize an intelligent audio playing system.
Description
Technical Field
The present invention relates to an audio playback driving unit, and more particularly, to a detection circuit for detecting whether the audio playback driving unit is located in a predetermined resonant environment and a method thereof.
Background
Existing audio playback systems use an audio playback driver/transducer (such as a speaker or headphone playback driver unit) to play back audio signals. For example, a user may wear a bluetooth headset to listen to music played by a mobile phone. However, when the user temporarily removes the bluetooth headset for some reason (e.g., talking with a person), the bluetooth headset may continue to play music, which not only increases unnecessary power consumption, but also shortens the life of the battery.
Therefore, an innovative audio playback detection mechanism is needed, which can detect the usage situation of the audio playback system/audio playback driving unit to adjust the operation state thereof (e.g., selectively enter the power saving mode) to realize an intelligent audio playback system.
Disclosure of Invention
An objective of the present invention is to provide a detection circuit for detecting whether an audio playback driving unit is located in a predetermined resonant environment and a related method thereof, so as to solve the above-mentioned problems.
Another objective of the present invention is to disclose a detection circuit and related method thereof, which can provide suitable audio playing quality according to the resonance environment of the audio playing driving unit, so as to meet the listening requirement of the user.
An embodiment of the invention discloses a detection circuit. The detection circuit comprises a transmission circuit and a processing circuit. The transmission circuit is used for receiving a first sound signal and is coupled to an audio playing driving unit, wherein the transmission circuit generates a second sound signal to the audio playing driving unit according to the first sound signal and generates a characteristic signal at least according to the first sound signal and the second sound 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 comprises the following steps: feeding a first sound signal into a first transmission path coupled with an audio playing driving unit to generate a second sound signal to the audio playing driving unit; generating a characteristic signal on a second transmission path coupled to the audio playback driving unit according to at least the first sound signal and the second sound signal, wherein the second transmission path is different from the first transmission path; and detecting whether the audio playing driving unit is positioned in a preset resonance environment or not according to at least the first sound signal and the characteristic signal.
Drawings
Fig. 1 is a functional block diagram of an audio playing system according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of an embodiment of the audio playback system shown in fig. 1.
Fig. 3 is a flowchart illustrating a method for detecting whether an audio playback driving unit is located in a predetermined resonance environment according to an embodiment of the present invention.
Wherein the reference numerals are as follows:
100. 200 audio playing system
102. 202 audio playing driving unit
104. 204 detection circuit
106. 206 signal generating 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
P1 IP input port
P2, P3, OP1 and OP2 output ports
Z _ I1, Z _ I2, Z _ R1, Z _ R2, Z _ X1, Z _ X2 impedance
Z _ Load predetermined input impedance
RS1 and RS2 resonant cavities
AS1, AS2, TD, TA, SL sound signals
SN noise signal
CHS, RD, RA signature
CS control signal
Detailed Description
The audio playback detection mechanism disclosed by the present invention can detect the resonant environment (or the geometric structure/shape of the resonant cavity) of the audio playback driving unit by detecting the signal response of the audio playback driving unit at the sound input side and using the audio playback driving unit as a sensing device of the surrounding environment. Further description is as follows.
Fig. 1 is a functional block diagram of an audio playing system according to an embodiment of the present invention. In this embodiment, the audio playback system 100 includes, but is not limited to, an audio playback driving unit (or audio playback transducer) 102, a detection circuit 104, and a signal generating circuit 106, wherein at least a portion of the audio playback system 100 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 portion of an electronic device (such as a mobile phone, a palm computer or a notebook computer), wherein the audio playback driving unit 102 is a playback driving unit (such as a speaker or an earphone) built in the electronic device; another example is: 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 palm computer, or a notebook computer), and the audio playback driving unit 102 may be a playback driving unit (such as a speaker or an earphone) externally connected to the electronic device; for another example, the signal generating circuit 106 may be at least a part of an electronic device (such as a mobile phone, a handheld computer, or a notebook computer), and the audio playback driving unit 102 and the detecting circuit 104 may be located in an audio playback device (such as a speaker or an earphone) externally connected to the electronic device.
The resonant environment of the audio playback driving unit 102 affects the signal response thereof, and the detection circuit 104 can detect the resonant environment (e.g., whether the resonant environment is a predetermined resonant environment) of the audio playback driving unit 102 according to the signal response of the audio playback driving unit 102. For example, in a case where the audio playback driver unit 102 is implemented by a playback driver unit of an earphone, when the audio playback driver unit 102 is in a first resonant environment (e.g., the earphone is worn by a user), the resonant cavity of the audio playback driver unit 102 has a first geometry/shape (e.g., the geometric resonance space inherent to the audio playback driver unit 102 is combined with the ear canal geometry space of the user), and the input impedance of the audio playback driver unit 102 may have a first frequency response characteristic; when the audio playback driver unit 102 is in the second resonant environment (e.g., the user removes the earphone), the resonant cavity of the audio playback driver unit 102 has a second geometry (e.g., a geometric resonant space inherent to the audio playback driver unit 102), and the input impedance of the audio playback driver unit 102 may have a second frequency response characteristic. Therefore, the detection circuit 104 can detect the resonant environment (or usage situation) of the audio playback driving unit 102 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 according to the sound signal AS1 provided by the signal generating circuit 106, so AS to detect 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 transmitting circuit 110 is coupled between the audio playback driving unit 102 and the signal generating circuit 106 for receiving the audio signal AS1 and transmitting the audio signal AS1 toward the audio playback driving unit 102 to generate the audio signal AS2 and obtain the feature signal CHS, wherein the transmitting circuit 110 can generate the feature signal CHS according to the audio signal AS1 and the audio signal AS 2. 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 used for receiving an audio signal AS1, the output port P2 is coupled to the audio playback driving unit 102, and the output port P3 is coupled to the processing circuit 120. The transmission circuit 110 can generate an audio signal AS2 according to the audio signal AS1, and output the audio signal AS2 to the audio playback driving unit 102 through the output port P2, and generate a feature signal CHS at least according to the audio signal AS1 and the audio signal AS2, and output the feature signal CHS 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, and is configured to receive the characteristic signal CHS, and detect whether the audio playback driving unit 102 is located in a predetermined resonant environment (e.g., detect whether a user wears an audio playback device including the audio playback driving unit 102) according to at least the sound signal AS1 and the characteristic signal CHS. For example, but not limited to, the processing circuit 120 may detect the input impedance or the frequency response of the audio playback driving unit 102 according to the signal strength information, the phase information and/or the gain information of the characteristic signal CHS and the sound signal AS1, so AS to detect whether the audio playback driving unit 102 is located in the predetermined resonance environment. In the embodiment, when the signal intensity of the feature signal CHS relative to the sound signal AS1 is within an intensity feature range and the phase variation of the feature signal CHS relative to the sound signal AS1 is within a phase feature range, the processing circuit 120 may determine that the audio playback driving unit 102 is located in the predetermined resonance environment; when the signal intensity of the feature signal CHS relative to the signal intensity of the sound signal AS1 is not within the intensity feature range, or the phase variation of the feature signal CHS relative to the sound signal AS1 is not within the phase feature range, the processing circuit 120 may determine that the audio playback driving 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 audio signal AS1 to directly detect the audio signal AS1 and the feature signal CHS, and can also receive the audio signal AS0 to indirectly detect the audio signal AS1 and the feature signal CHS, wherein the audio signal AS0 is a to-be-processed version of the audio signal AS1 before being output from the signal generating circuit 106. 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 AS 1. Similarly, the processing circuit 120 may directly detect the feature signal CHS, or may perform a pre-processing (such as an analog-to-digital conversion operation) on the feature signal CHS before detecting the processed feature signal CHS. In short, the design related changes follow the spirit of the present invention AS long AS the signal response of the audio playback driving unit 102 can be detected according to the acoustic signal AS1 and the characteristic signal CHS to detect the resonance environment of the audio playback driving unit 102.
Furthermore, in some embodiments, the transmission circuit 110 may be impedance matched for a predetermined input impedance, which may be the input impedance of the audio playback driving unit 102 in the predetermined resonance 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 the signal component from the sound signal AS1 in the characteristic signal CHS obtained by the transmission circuit 110 is detected to be smaller than a predetermined ratio, which means that the audio playback driving unit 102 currently has an input impedance equal to (or substantially equal to) the predetermined input impedance, the processing circuit 120 can determine that the audio playback driving unit 102 is located in the predetermined resonance environment.
To facilitate understanding of the technical features of the present invention, an exemplary circuit structure is used to describe the details of the audio playback detection mechanism disclosed in the present invention. However, this is for convenience of illustration only. Any implementation based on the circuit configuration shown in fig. 1 is possible. Please refer to fig. 2, which is a diagram illustrating an embodiment of the audio playing system 100 shown in fig. 1. The audio playback system 200 includes (but is not limited to) an audio playback driving unit 202, a detection circuit 204, and a signal generating circuit 206, wherein the audio playback driving unit 102, the detection circuit 104, and the signal generating circuit 106 shown in fig. 1 are respectively implemented by the audio playback driving unit 202, the detection circuit 204, and the signal generating circuit 206. In addition, the detection circuit 204 includes a transmission circuit 210 and a processing circuit 220, wherein 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, the signal generating circuit 206 includes, but is not limited to, a digital signal processing circuit 207, a digital-to-analog converter 208 (labeled "DAC"), and an output unit 209 (labeled "BF 1"), wherein the output unit 209 may be implemented by a power amplifier. The digital signal processing circuit 207 generates an acoustic signal TD (digital acoustic signal) to the digital-to-analog converter 208. The sound signal TD may be converted into a sound signal TA (analog sound signal) after being subjected to processing related to the output unit 209 by the digital-to-analog converter 208.
The sound signal TA passes through the transmission circuit 210 to form a sound signal SL to the audio playback driving unit 202, and the sound signal SL changes according to the change of the input impedance of the audio playback driving unit 202. The transmission circuit 210 further generates a characteristic signal RA to the processing circuit 220 according to the audio signal TA and the audio signal SL. In this embodiment, the transmission circuit 210 can detect the signal response (or input impedance change) of the audio playback driving unit 202 by circuit matching. For example, but not limited to, 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, an output port OP1, an output port OP2, and a plurality of transmission paths 212 and 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 is coupled between the input port IP and the output port OP 2.
The processing circuit 220 includes, but is not limited to, an input unit 222 (labeled "BF 2"), an analog-to-digital converter 224 (labeled "ADC"), and an impedance detector 226, wherein the input unit 222 may be implemented by a buffer. The analog-to-digital converter 224 may 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 may detect whether the audio playback driving unit 202 is located in the predetermined resonant environment according to the digital version (sound signal TD) corresponding to the sound signal TA and the digital version (characteristic signal RD) corresponding to the characteristic signal RA.
It is noted that in some embodiments, the output impedance of the output unit 209 (or the output impedance of the signal generating circuit 206) is small relative to the input impedance of the audio playback driving unit 202 (or the impedance of the electrical load of the signal generating circuit 206), so that different signal responses (such as the response characteristic of the characteristic signal RA) are generated according to the change of the resonant environment (the resonant cavity geometry/shape) of the audio playback driving unit 202, and the impedance detector 226 can detect the change of the input impedance of the audio playback driving unit 202, thereby determining the resonant environment of the audio playback driving unit 202.
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, where the predetermined input impedance Z _ Load is the input impedance of the audio playback driving unit 202 in the predetermined resonance environment (corresponding to the resonant cavity RS1) looking into the output port OP1, and the impedance Z _ I1 and the impedance Z _ I2 can be equal to (but not limited to) one-half of the predetermined input impedance Z _ Load. Furthermore, with proper design, when the audio playback driving unit 202 is located in the predetermined resonant environment, the transmission impedance between the output port OP1 and the output port OP2 (the transmission impedance of the transmission path 214) and the transmission impedance between the input port IP and the output port OP2 (the transmission impedance of the transmission path 216) can greatly reduce the signal component from the sound signal TA in the characteristic signal 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, so that the signal (corresponding to the sound signal SL) transferred to the output port OP2 through the transmission path 214 may cancel (or substantially cancel) the signal (corresponding to the sound signal TA) transferred to the output port OP2 through the transmission path 216, wherein the impedance Z _ R1 may be equal to the impedance Z _ R2, the impedance Z _ X1 may be equal to the impedance Z _ X2, and the impedance Z _ R1 and the impedance Z _ R2 may be equal to one-half of the impedance Z _ X1 (impedance Z _ X2). The characteristic signal RA is influenced little by the sound signal TA, and the signal strength of the sound signal TA is attenuated much (or to zero) relative to the signal strength of the sound signal TA itself. That is, in some circuit matching situations, the presence (or variation) of the acoustic signal TA has no (or little) effect on the signal generated by the output port OP 2.
In addition, since the presence (or variation) of the sound signal TA has no (or little) influence on the signal generated at the output port OP2 under some circuit matching conditions, on the other hand, the characteristic signal RA generated at the output port OP2 can have a high sensitivity to the variation of the circuit matching conditions. For example, the characteristic signal RA is sensitive to the input impedance variation of the audio playback driving unit 202 (the circuit matching condition changes).
Therefore, when the impedance detector 226 detects that the signal strength of the characteristic signal RD relative to the sound signal TD is within an intensity characteristic range (e.g., the signal strength of the characteristic signal RD is attenuated by more than 20 db or between 20 db and 40 db compared to the sound signal TD), which means that the signal component from the sound signal TA in the characteristic signal RA has been greatly reduced by the transmission circuit 210 through impedance matching, the impedance detector 226 (or the processing circuit 220) can detect that the audio playback driving unit 202 is located in the predetermined resonance environment. In addition, when the impedance detector 226 detects that the signal intensity of the characteristic signal RD relative to the sound signal TD is not within the intensity characteristic range, the impedance detector 226 (or the processing circuit 220) can detect that the audio playback driving unit 202 is not located in the predetermined resonance environment. For example, when the impedance detector 226 detects that the signal intensity of the characteristic signal RD relative to the sound signal TD is not within the intensity characteristic range but within another intensity characteristic range, the impedance detector 226 (or the processing circuit 220) can detect that the audio playback driving unit 202 is located in another predetermined resonant environment (corresponding to another resonant cavity RS2), wherein the predetermined resonant environment corresponding to the resonant cavity RS1 can be (but is not limited to) a user wearing a headphone containing the audio playback driving unit 202, and the predetermined resonant environment corresponding to the resonant cavity RS2 can be (but is not limited to) a user removing a headphone containing the audio playback driving unit 202.
In some embodiments, when the impedance detector 226 detects that the phase variation of the characteristic signal RD relative to the acoustic signal TD is within a phase characteristic range (e.g., the phase variation of the characteristic signal RD exceeds a predetermined angle or is within a predetermined variation range compared to the acoustic signal TD), which means that the transmission circuit 210 has greatly reduced the signal component from the acoustic signal TA in the characteristic signal RA through impedance matching, or means that the resonant cavity of the audio playback driving unit 202 is at a specific resonant frequency or at multiple resonant frequencies (overtones), the impedance detector 226 (or the processing circuit 220) can detect that the audio playback driving unit 202 is located in the predetermined resonant environment. When the impedance detector 226 detects that the phase change of the characteristic signal RD relative 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 in the predetermined resonance environment.
Furthermore, in some embodiments, when the impedance detector 226 detects that the signal intensity of the characteristic signal RD relative to the sound signal TD is within an intensity characteristic range and the phase variation of the characteristic signal RD relative to the sound signal TD is within a phase characteristic range (for example, the signal intensity of the characteristic signal RD is attenuated by more than 20 db compared to the sound signal TD and the phase variation of the characteristic signal RD is within a predetermined variation range), which means that the transmission circuit 210 has greatly reduced the signal component from the sound signal TA in the characteristic signal RA by impedance matching, or means that the resonant cavity of the audio playback driving unit 202 may be at a specific resonant frequency or at multiple resonant frequencies at the same time, the impedance detector 226 (or the processing circuit 220) can detect that the audio playback driving unit 202 is located in the predetermined resonant environment. When the impedance detector 226 detects that the signal intensity of the characteristic signal RD relative to the sound signal TD is not within the intensity characteristic range and the phase variation of the characteristic signal RD relative to the sound signal TD is not within the phase characteristic range, the impedance detector 226 (or the processing circuit 220) may detect that the audio playback driving unit 202 is not located in the predetermined resonance environment.
In short, when the resonant environment of the audio playback driving unit 202 changes, the characteristic signal RA generated by the transmission circuit 210 reflects the input impedance change of the audio playback driving unit 202, and the impedance detector 226 can detect the resonant environment of the audio playback driving unit 202 from the obtained signal characteristics (such as signal strength and/or phase change).
It is noted that in some embodiments, the transmission circuit 210 may perform impedance matching for the predetermined input impedance Z _ Load in a specific frequency range, wherein the specific frequency range may be within or outside the frequency range perceivable by human ears. For example, in the case that the audio playback driving unit 202 is used for playing back a sound signal (i.e., an audio signal perceivable by human ear, such as a symphony music audio signal generated by the signal generating circuit 206) with a frequency range within the frequency range of an audible sound wave (audible sound), the processing circuit 220 may detect the resonance environment of the audio playback driving unit 202 according to the frequency response of the sound signal (generated by the signal generating circuit 206) or detect the resonance environment of the audio playback driving unit 202 according to the frequency response of another sound signal (e.g., an ultrasonic signal) generated by the signal generating circuit 206. In other words, the specific frequency range may include at least one of a frequency range of the ultrasonic wave and a frequency range of the audible sound wave.
Furthermore, in some embodiments, the transmission circuit 210 may receive the noise signal SN from the audio playback driving unit 202 through the output port OP1, wherein the noise signal SN may be a sound signal of the surrounding environment (such as a heartbeat sound or a speaking sound of a human body). That is, the characteristic signal RA may include a signal component from the noise signal SN. Since the detection circuit 204 can sensitively detect the input impedance change (or frequency response) of 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 input impedance change of the audio playback driving unit 202 (for example, the signal strength of the characteristic signal RD is greatly attenuated relative to the signal strength of the sound signal TD), so that the impedance detector 226 can detect the resonance environment where the audio playback driving unit 202 is currently located according to the characteristic signal RA and the sound signal TA (or the characteristic signal RD and the characteristic signal TD), and is not easily interfered by the noise signal SN.
It should be noted that the above is for illustrative purposes only and is not meant to be a limitation of the present invention. In a design variation, it is also feasible to omit at least one of the transmission paths 212 and 216 as long as the processing circuit 220 can detect the impedance variation of the audio playback driving unit 202 caused by the change of the resonance environment. For example, in the case of omitting/removing the transmission path 216, the impedance detector 226 may directly perform a numerical calculation on the sound signal TA/TD and the characteristic signal RA/RD to determine the input impedance variation 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 may directly perform a numerical calculation on the sound signals TA/TD and the sound signal SL to determine the input impedance change of the audio playback driving unit 202.
In another design variation, the processing circuit 220 may further adjust a ratio between a transmission impedance of the transmission path 214 (such as the impedance Z _ R1 and/or the impedance Z _ R2) and a transmission impedance of the transmission path 216 (such as the impedance Z _ X1 and/or the impedance Z _ X2) to detect whether the audio playback driving unit 202 is located in the predetermined resonance environment according to 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. For example, but not limited to, the impedance Z _ X1 and the impedance Z _ X2 may 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 values of the impedance Z _ X1 and the impedance Z _ X2, so that the signal strength of the feature signal RA relative to the audio signal TA (or the signal strength of the feature signal RD relative to the audio signal TD) is within an intensity characteristic range, and/or the phase change of the feature signal RA relative to the audio signal TA (or the phase change of the feature signal RD relative to the audio signal TD) is within a phase characteristic range. When the signal intensity of the characteristic signal RA with respect to the sound signal TA is within the intensity characteristic range and/or the phase variation of the characteristic signal RA with respect to the sound signal TA (or the phase variation of the characteristic signal RD with respect to the sound signal TD) is within the phase characteristic range, the impedance detector 226 may detect whether the audio playback driving unit 202 is located in the predetermined resonance environment according to 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.
In yet another design variation, the transmission circuit 210 may also be implemented by other circuit configurations. For example, the transmission circuit 210 may use a transformer for circuit matching, and by means of current subtraction, the signal component from the sound signal TA in the characteristic signal RA is greatly reduced in the case that the audio playback driving unit 202 is located in the predetermined resonance environment.
The audio playback detection mechanism disclosed in the present invention can be summarized as the flow chart shown in fig. 3. Please refer to fig. 3, which is a flowchart illustrating a method for detecting whether an audio playback driving unit is located in a predetermined resonance environment according to the present invention. If the results obtained are substantially the same, the steps do not have to be performed in the order shown in fig. 3. For example, certain steps may be interposed therein. For convenience of explanation, the method shown in fig. 3 is described below in conjunction with the audio playback system 200 shown in fig. 2. However, it is also possible to apply the method shown in fig. 3 to the audio playback system 100 shown in fig. 1. The method can be briefly summarized as follows.
Step 310: and starting.
For example, the sound signal TD is generated by the digital signal processing circuit 207, and is converted into the sound signal TA by the digital-to-analog converter 208 and the output unit 209.
Step 320: the first sound signal is fed into a first transmission path coupled to the audio playing driving unit to generate a second sound signal to the audio playing driving unit.
For example, the audio signal TA is fed into the transmission path 212 coupled to the audio playback driving unit 202 to generate the audio signal SL to the audio playback driving unit 202.
Step 330: generating a characteristic signal on a second transmission path coupled to the audio playback driving unit according to at least the first sound signal and the second sound signal, wherein the second transmission path is different from the first transmission path.
For example, the transmission circuit 210 generates the characteristic signal RA according to at least the audio signal TA and the audio signal SL on a transmission path 214 coupled to the audio playback driving unit 202, wherein the transmission path 214 is different from the transmission path 212.
Step 340: and detecting whether the audio playing driving unit is positioned in the preset resonance environment at least according to the first sound signal and the characteristic signal.
For example, the processing circuit 220 detects whether the audio playback driving unit 202 is located in the predetermined resonance environment at least according to the sound signal TA and the characteristic signal RA.
In step 330, the transmission circuit 210 couples the audio 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 audio signal TA and the audio signal SL. The characteristic signal RA can reflect the circuit matching between the transmission circuit 210 and the audio playback driving unit 202. In addition, in some embodiments, the transmission paths 212, 214 and 216 are used to perform impedance matching on a predetermined input impedance (such as a predetermined input impedance Z _ Load) of the audio playback driving unit 202 under the predetermined resonance environment.
In step 340, when the signal intensity of the characteristic signal RA relative to the sound signal TA is within an intensity characteristic range (for example, the impedance detector 226 detects that the signal intensity of the characteristic signal RD relative to the sound signal TD has a large attenuation), and/or the phase variation of the characteristic signal RA relative to the sound signal TA is within a phase characteristic range, the impedance detector 226 can determine that the audio playback driving unit 202 is located in the predetermined resonance environment; when the signal intensity of the characteristic signal RA relative to the sound signal TA is not within the intensity characteristic range, and/or the phase variation of the characteristic signal RA relative to the sound signal TA is not within the phase characteristic range, the impedance detector 226 may determine that the audio playback driving unit 202 is not located in the predetermined resonance 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 paragraphs related to fig. 1 and fig. 2, further description is omitted here for brevity.
In summary, the detection circuit and the detection method thereof disclosed in the present invention can determine the resonant environment (or determine the resonant cavity geometry/shape) of the audio playback driving unit by detecting the signal response (such as the change of the input impedance) of the audio playback driving unit. The audio detection mechanism disclosed in the present invention can have a variety of applications. For example, the audio detection mechanism disclosed in the present invention can be used for wearing detection to detect whether a user wears an audio playing device having the audio playing driving unit, and adjust an operating state of the audio playing driving unit (e.g., enter a power saving mode) when the user does not wear the audio playing device, so as to implement an intelligent audio playing system. In another example, the audio detection mechanism disclosed herein can detect the wearing state of the user, such as tightly wearing or lightly wearing, to adjust the audio signal to be played (e.g., adjust the amplitude of the audio signal). The audio detection mechanism disclosed by the invention can adjust the sound signal to be played (for example, adjust the signal characteristics of high-frequency and/or low-frequency bands) so as to improve the audio playing quality. In another example, the audio detection mechanism disclosed in the present invention can be used to identify the structural features of the ear canal of the human ear by detecting the geometry/shape of the resonant cavity in which the audio playback driver is located.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (20)
1. A detection circuit, comprising:
a transmission circuit including an input port, a first output port and a second output port, a first transmission path is provided between the input port and the first output port, a second transmission path is provided between the first output port and the second output port, a third transmission path is provided between the input port and the second output port, the transmission circuit is configured to receive a first sound signal through the input port and is coupled to an audio playback driving unit through the first output port,
wherein the transmission circuit allows the first sound signal to be transmitted from the first transmission path to the audio playback driving unit and allows the first sound signal to be transmitted from the second transmission path and the third transmission path to the audio playback driving unit, so as to generate a second sound signal at the first output port according to the first sound signal and generate a characteristic signal at the second output port according to at least the first sound signal and the second sound signal; and
a processing circuit coupled to the transmission circuit to receive the characteristic signal through the second output port,
the processing circuit detects whether the audio playing driving unit is located in a preset resonance environment at least according to the first sound signal and the characteristic signal.
2. The detection circuit as claimed in claim 1, wherein the transmission circuit performs impedance matching with respect to a predetermined input impedance, and the predetermined input impedance is an input impedance of the audio playback driving unit in the predetermined resonance environment.
3. A detection circuit as claimed in claim 2 wherein said transmission circuit is a hybrid impedance matching circuit.
4. The detection circuit of claim 2, wherein the first transmission path has a first transmission impedance matched to the predetermined input impedance.
5. The detection circuit of claim 4, wherein the second transmission path has a second transmission impedance and the third transmission path has a third transmission impedance;
the processing circuit adjusts a ratio between the second transmission impedance and the third transmission impedance to detect whether the audio playback driving unit is located in the predetermined resonance environment according to the ratio between the second transmission impedance and the third transmission impedance, the first sound signal, and the characteristic signal.
6. A detection circuit as claimed in claim 5 wherein said second transmission impedance is one half of said third transmission impedance.
7. A detection circuit as claimed in claim 2 wherein said transmission circuit is impedance matched for said predetermined input impedance over a particular frequency range.
8. The detection circuit as claimed in claim 7, wherein the specific frequency range comprises at least one of a frequency range of ultrasonic waves and a frequency range of audible sound waves.
9. The detection circuit as claimed in any one of claims 1 to 8, wherein the processing circuit determines that the audio playback driving unit is located in the predetermined resonant environment when the signal intensity of the characteristic signal with respect to the first sound signal is within an intensity characteristic range and the phase variation of the characteristic signal with respect to the first sound signal is within a phase characteristic range; when the signal intensity 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 characteristic range, the processing circuit judges that the audio playing driving unit is not located in the predetermined resonance environment.
10. The detection 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 an intensity characteristic range, the processing circuit determines that the audio playback driving unit is located in the predetermined resonance environment; when the signal intensity of the characteristic signal relative to the first sound signal is not within the intensity characteristic range, the processing circuit judges that the audio playing driving unit is not located in the preset resonance environment.
11. The detection circuit according to any one of claims 1 to 8, wherein the processing circuit determines that the audio playback driving unit is located in the predetermined resonant environment when the phase variation of the characteristic signal with respect to the first sound signal is within a phase characteristic range; when the phase change of the characteristic signal relative to the first sound signal is not within the phase characteristic range, the processing circuit judges that the audio playing driving unit is not located in the preset resonance environment.
12. A detection method, comprising the steps of:
feeding a first sound signal from an input port to a first transmission path to which an audio playback drive unit is coupled to generate a second sound signal at a first output port coupled between the first transmission path and the audio playback drive unit, wherein the first transmission path is located between the input port and the first output port, the input port allowing the first sound signal to pass from the input port to the first output port through the first transmission path and allowing the first sound signal to pass from the input port to the first output port through a second transmission path and a third transmission path; the second transmission path is coupled between the input port and a second output port, and the third transmission path is coupled between the second output port and a first output port;
generating a characteristic signal at the second output port according to at least the first sound signal and the second sound signal; and
and detecting whether the audio playing driving unit is positioned in a preset resonance environment or not at least according to the first sound signal and the characteristic signal.
13. The method of claim 12, wherein generating a feature signal at the second output port based on at least the first audio signal and the second audio signal comprises:
the first sound signal is coupled to the second output port through the second transmission path to generate the characteristic signal at a second output port according to the first sound signal and the second sound signal.
14. The method of claim 13, wherein the first transmission path, the second transmission path, and the third transmission path are used to impedance match a predetermined input impedance, the predetermined input impedance being an input impedance of the audio playback driving unit in the predetermined resonance environment.
15. The method of claim 14, wherein the first transmission path has a first transmission impedance matched to the predetermined input impedance.
16. The method of claim 15, wherein the step of detecting whether the audio playback driving unit is located in a predetermined resonance environment at least according to 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; and
detecting whether the audio playing driving unit is located in the predetermined resonance environment according to the ratio between the second transmission impedance and the third transmission impedance, the first sound signal and the characteristic signal.
17. The method of claim 16, wherein the third transmission path has a third transmission impedance that is one-half of a second transmission impedance of the second transmission path.
18. The method of claim 14, wherein the first transmission path, the second transmission path, and the third transmission path are impedance matched to the predetermined input impedance over a particular frequency range.
19. The method of claim 18, wherein the specific frequency range belongs to a frequency range of an ultrasonic wave or an audible sound wave.
20. The method of claim 12, wherein the step of detecting whether the audio playback driving unit is located in a predetermined resonance environment at least according to the first sound signal and the characteristic signal comprises:
when the signal intensity of the characteristic signal relative to the first sound signal is within an intensity characteristic range and the phase change of the characteristic signal relative to the first sound signal is within a phase characteristic range, judging that the audio playing driving unit is positioned in the preset resonance environment; and
and when the signal intensity of the characteristic signal relative to the first sound signal is not in the intensity characteristic range or the phase change of the characteristic signal relative to the first sound signal is not in the phase characteristic range, judging that the audio playing driving unit is not positioned in the preset resonance environment.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| PCT/CN2018/076812 WO2019157698A1 (en) | 2018-02-14 | 2018-02-14 | Detection circuit and method |
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| CN110383854A CN110383854A (en) | 2019-10-25 |
| CN110383854B true CN110383854B (en) | 2021-06-18 |
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| CN102638744A (en) * | 2011-02-14 | 2012-08-15 | 索尼公司 | Sound signal output apparatus, speaker apparatus, and sound signal output method |
| CN102638742A (en) * | 2011-02-14 | 2012-08-15 | 索尼公司 | Sound signal output apparatus and sound signal output method |
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| JP2007281916A (en) * | 2006-04-07 | 2007-10-25 | Nittetsu Elex Co Ltd | Earphone microphone |
| JP4883103B2 (en) * | 2009-02-06 | 2012-02-22 | ソニー株式会社 | Signal processing apparatus, signal processing method, and program |
| CN105491483B (en) * | 2015-11-30 | 2018-11-02 | 歌尔股份有限公司 | Wearing state detection method, system and earphone for earphone |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102104388A (en) * | 2009-12-16 | 2011-06-22 | 鸿富锦精密工业（深圳）有限公司 | Audio play system and earphone used by same |
| CN102638744A (en) * | 2011-02-14 | 2012-08-15 | 索尼公司 | Sound signal output apparatus, speaker apparatus, and sound signal output method |
| CN102638742A (en) * | 2011-02-14 | 2012-08-15 | 索尼公司 | Sound signal output apparatus and sound signal output method |
| CN104244129A (en) * | 2014-09-03 | 2014-12-24 | 深圳奇沃智联科技有限公司 | Contact earphones capable of being automatically switched on or off |
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| WO2019157698A1 (en) | 2019-08-22 |
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