CN113315480A - Audio processing chip and earphone - Google Patents
Audio processing chip and earphone Download PDFInfo
- Publication number
- CN113315480A CN113315480A CN202110599843.8A CN202110599843A CN113315480A CN 113315480 A CN113315480 A CN 113315480A CN 202110599843 A CN202110599843 A CN 202110599843A CN 113315480 A CN113315480 A CN 113315480A
- Authority
- CN
- China
- Prior art keywords
- audio
- signal
- analog
- processing chip
- input
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000012545 processing Methods 0.000 title claims abstract description 51
- 238000005070 sampling Methods 0.000 claims abstract description 32
- 230000005236 sound signal Effects 0.000 claims description 45
- 230000003044 adaptive effect Effects 0.000 claims description 22
- 238000006243 chemical reaction Methods 0.000 claims description 5
- 230000003321 amplification Effects 0.000 claims description 3
- 230000002238 attenuated effect Effects 0.000 claims description 3
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 210000005069 ears Anatomy 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
- H03G3/3005—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/10—Earpieces; Attachments therefor ; Earphones; Monophonic headphones
- H04R1/1041—Mechanical or electronic switches, or control elements
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2430/00—Signal processing covered by H04R, not provided for in its groups
- H04R2430/01—Aspects of volume control, not necessarily automatic, in sound systems
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Multimedia (AREA)
- Circuit For Audible Band Transducer (AREA)
Abstract
The invention provides an audio processing chip and an earphone.A sampling signal at a signal output end is obtained through a gain self-adaptive controller, the sampling signal is converted from analog quantity to digital quantity, a change-over switch is controlled by the sampling signal of the digital quantity to select a corresponding attenuation branch, and a signal input from an input end is transmitted to the signal output end by the change-over switch and the attenuation branch; compared with the prior art, the chip realizes automatic control of output volume, avoids overlarge volume of output sound, achieves the purpose of protecting hearing, uses less hardware, is convenient to implement and saves energy.
Description
Technical Field
The invention relates to the field of audio output equipment, in particular to an audio processing chip and an earphone.
Background
Recently, earphones are widely used, but users suffer from various degrees of damage to their ears while enjoying music and talking. Therefore, a gain adaptive control technique has been developed, which can control the volume of sound output from the earphone to protect the user's hearing. The existing gain adaptive controller comprises an evaluation unit for estimating the level of the input signal; a subtractor for calculating a difference between the level estimated by the evaluation unit and a predetermined reference value; and a gain controller outputting a control value by nonlinearly scaling the difference output by the subtractor. Although the technology achieves the purpose of automatically controlling the signal gain, the structure is complex. And the existing resistance attenuation also inevitably increases the energy consumption. In view of this, it is urgently needed to provide an audio processing chip carrying a novel gain adaptive controller to protect hearing, simplify the structure, and reduce energy consumption.
Disclosure of Invention
In view of the above-mentioned shortcomings in the prior art, the present invention provides an audio processing chip, comprising: an audio decoder for decoding the audio segments stored in the storage device; a digital-to-analog converter for converting the decoded digital audio signal into an analog audio signal; the audio amplifier is used for amplifying the analog audio signal converted by the digital-to-analog converter; the audio output port is used for outputting the amplified analog audio signal; and the gain self-adaptive controller is connected between the audio amplifier and the audio output port, amplified audio signals are input into the gain self-adaptive controller, the audio signals at the signal output end of the gain self-adaptive controller are sampled and subjected to integral processing, the audio signals are adjusted according to integral processing results, and the adjusted audio signals are output to the audio output port to realize automatic adjustment of the volume of output sound.
Preferably, the gain adaptive controller includes: the device comprises an input end, a signal output end, a change-over switch, an attenuation circuit, a signal sampling circuit and an analog-to-digital converter.
Preferably, the change-over switch is connected with an input end, the attenuation circuit is connected with the output end group of the change-over switch and the signal output end, the signal sampling circuit is connected with the signal output end, and the analog-to-digital converter is respectively connected with the sampling circuit and the control end group of the change-over switch.
Preferably, the attenuation circuit includes at least two attenuation branch groups, each attenuation branch group including a plurality of attenuation branches, each attenuation branch being used for attenuating a signal input from the input terminal to a different degree.
Preferably, each attenuation branch in each attenuation branch group of the attenuation circuit is not connected in series or is connected in series with resistors with different resistance values, so that signals input from the input end are attenuated to different degrees correspondingly.
Preferably, the signal sampling circuit is configured to obtain a sampled signal from the signal output terminal; the analog-to-digital converter is used for converting the sampling signal from an analog quantity to a digital quantity, and the digital quantity control conversion switch selects a corresponding attenuation branch in the attenuation circuit to transmit the signal input from the input end to the signal output end.
Preferably, the analog-to-digital converter divides the analog quantity of the sampling signal into N numerical value sections according to the size through presetting, wherein N is an integer greater than 1, and the numerical value sections are numbered 1, 2 and 3 … … N; corresponding to the N binary numbers, the N binary numbers are generated after analog-to-digital conversion; when a certain sampling signal falls into a certain numerical value section of the analog quantity, the analog-to-digital converter generates corresponding digital quantity according to the numerical value section; the digital quantity is input to the change-over switch through the control end group of the change-over switch.
Preferably, the change-over switch controls the off or on state of each output port in the output port group according to the digital quantity.
Preferably, the change-over switch controls the corresponding output port in the output port group to be switched on according to the digital quantity, and the other output ports are switched off.
Preferably, the audio processing chip further comprises a custom input interface for receiving a user setting for sampling signal analog quantity division, and then changing the preset setting in the analog-to-digital converter.
Preferably, the audio processing chip further comprises an ambient noise input interface for receiving ambient noise and changing the preset in the analog-to-digital converter based on the ambient noise adjustment.
Preferably, the audio processing chip further comprises a feedback controller, and the gain adaptive controller further comprises a feedback output end; the feedback controller is connected between the feedback output end of the gain self-adaptive controller and the audio amplifier and is used for gradually reducing the amplification amplitude of the audio amplifier to the audio signal when the change-over switch controls the audio signal to pass through the attenuation branch with the nonzero resistance value of the resistor in the attenuation circuit until the change-over switch controls the audio signal to pass through the attenuation branch with the zero resistance value of the resistor in the attenuation circuit.
The present invention also provides an earphone comprising: an input terminal for inputting an audio electrical signal; the loudspeaker is used for converting the audio signal into sound wave from the electric signal; the input end, the audio processing chip and the loudspeaker are connected in sequence; and audio signals are input to the audio processing chip through an input end for processing, the processed audio signals are output to the loudspeaker, and the audio signals are converted into sound waves.
Preferably, the earphone further comprises a wire controller, and a user can also manually control the volume output by the loudspeaker by adjusting the wire controller.
Preferably, the wire controller is connected between the speaker and the gain adaptive controller or between the input terminal and the gain adaptive controller.
The invention provides an audio processing chip and an earphone.A sampling signal at a signal output end is obtained through a gain self-adaptive controller, the sampling signal is converted from analog quantity to digital quantity, a change-over switch is controlled by the sampling signal of the digital quantity to select a corresponding attenuation branch, and the change-over switch and the attenuation branch are utilized to transmit a signal input from an input end to the signal output end; compared with the prior art, the chip realizes automatic control of output volume, avoids overlarge volume of output sound, achieves the purpose of protecting hearing, uses less hardware, is convenient to implement and saves energy.
Drawings
Fig. 1 is a block diagram of an audio processing chip according to an embodiment of the present invention.
Fig. 2 is a block diagram of a gain adaptive controller according to an embodiment of the present invention.
The audio processing chip-100, the audio decoder-110, the digital-to-analog converter-120, the audio amplifier-130, the gain adaptive controller-140, the audio output port-150, the feedback controller-160, the left input port-141, the right input port-142, the left output port-143, the right output port-144, the sampling circuit 145, the analog-to-digital converter-146, the change-over switch-147, the attenuation circuit-148, the feedback output port-149, the left control port group-A, the right control port group-B, the left output port group-C, the right output port group-D, the left attenuation branch group-E, the right attenuation branch group-F, the resistor-r 1, the r2, the r3 and the rn.
Detailed Description
In order to solve the problems of the existing earphone system, the audio processing chip and the earphone provided by the invention are realized by the following technical scheme:
example 1:
the present embodiment provides an audio processing chip 100, please refer to fig. 1, which includes: an audio decoder 110 for decoding the audio segments stored in the storage means; a digital-to-analog converter 120 for converting the decoded digital audio signal into an analog audio signal; an audio amplifier 130 for amplifying the analog audio signal converted by the digital-to-analog converter 120; an audio output port 150 for outputting the amplified analog audio signal; and the gain adaptive controller 140 is connected between the audio amplifier 130 and the audio output port 150, and the amplified audio signal is input to the gain adaptive controller 140, the audio signal at the signal output end of the gain adaptive controller 140 is sampled and subjected to integral processing, the audio signal is adjusted according to the integral processing result, and the adjusted audio signal is output to the audio output port 150, so that the volume of the output sound is automatically adjusted.
Specifically, the gain adaptive controller 140, please refer to fig. 2, which includes: left and right input terminals 141, 142, left and right signal output terminals 143, 144, a changeover switch 147, an attenuation circuit 148, a signal sampling circuit 145 and an analog-to-digital converter 146.
Specifically, the switch 147 is connected to the left and right input terminals 141 and 142, the attenuator circuit 148 is connected to the left and right output terminals C, D and the left and right signal output terminals 143 and 144 of the switch 147, the signal sampling circuit 145 is connected to the left and right signal output terminals 143 and 144, and the analog-to-digital converter 146 is connected to the sampling circuit 145 and the control terminal group A, B of the switch 17, respectively.
Specifically, the attenuation circuit 148 includes at least two attenuation branch groups, i.e., left and right attenuation branch groups E, F, each of which includes a plurality of attenuation branches, each of which is used for attenuating the signals inputted from the left and right input terminals 141, 142 to different degrees.
Specifically, each attenuation branch in each attenuation branch group of the attenuation circuit 148 is not connected in series or connected in series with resistors r1, r2, r3 and rn with different resistances, so that the signal input from the input end is attenuated to different degrees correspondingly.
Specifically, the signal sampling circuit 145 is configured to obtain sampling signals from the left and right signal output terminals 143, 144; the analog-to-digital converter 146 is configured to convert the sampled signal from an analog quantity to a digital quantity, and the digital quantity control switch 147 selects a corresponding attenuation branch in the attenuation circuit 148 to transmit the signal input from the left and right input terminals 141, 142 to the left and right signal output terminals 143, 144.
Specifically, the analog-to-digital converter 146 divides the analog quantity of the sampling signal into N number of value segments according to the preset size, where N is an integer greater than 1, and the number of the value segments is 1, 2, and 3 … … N; corresponding to the N binary numbers, the N binary numbers are generated after analog-to-digital conversion; when a sampling signal falls into a value section of the analog quantity, the analog-to-digital converter 146 generates a corresponding digital quantity according to the value section; the digital quantity is input to the changeover switch 147 via the left and right control terminal groups A, B of the changeover switch.
Specifically, the transfer switch 147 controls the off or on state of each output port in the left and right output terminal groups C, D according to the digital quantity.
Specifically, the switch 147 controls the corresponding output ports of the left and right output port groups C, D to be turned on and the other output ports to be turned off according to the digital quantity.
Specifically, the audio processing chip 100 further includes a custom input interface for receiving a user setting for the analog quantity division of the sampling signal and then changing the preset setting in the analog-to-digital converter 146.
Specifically, the audio processing chip 100 further comprises an ambient noise input interface for receiving ambient noise and changing the preset in the analog-to-digital converter 146 based on the ambient noise adjustment.
Specifically, the audio processing chip 100 further comprises a feedback controller 160, and the gain adaptive controller 140 further comprises a feedback output 149; the feedback controller 160 is connected between the feedback output end 149 of the gain adaptive controller 140 and the audio amplifier 130, and is configured to gradually reduce the amplification amplitude of the audio signal by the audio amplifier 130 when the change-over switch 147 controls the audio signal to pass through the attenuation branch with a nonzero resistance value in the attenuation circuit 148 until the change-over switch 147 controls the audio signal to pass through the attenuation branch with a zero resistance value in the attenuation circuit 148. Thereby reducing unnecessary power consumption.
The audio processing chip 100 provided by the invention obtains the sampling signal of the signal output end through the gain adaptive controller 140, converts the sampling signal from analog quantity to digital quantity, controls the change-over switch to select the corresponding attenuation branch by using the sampling signal of the digital quantity, and transmits the signal input from the input end to the signal output end by using the change-over switch and the attenuation branch; compared with the prior art, the chip realizes automatic control of output volume, avoids overlarge volume of output sound, achieves the purpose of protecting hearing, uses less hardware, is convenient to implement and saves energy.
Example 2:
the present embodiment provides a headset, including: an input terminal for inputting an audio electrical signal; the loudspeaker is used for converting the audio signal into sound wave from the electric signal; the input end of the audio processing chip 100, the audio processing chip 100 and the loudspeaker are connected in sequence; the audio signal is input to the audio processing chip processing 100 through the input end, and the processed audio signal is output to the speaker, so that the audio signal is converted into sound waves. The earphone provided by the invention has the same performance as the audio processing chip 100, and is not described again.
Specifically, the earphone further comprises a wire controller, and a user can manually control the volume output by the loudspeaker by adjusting the wire controller.
Specifically, the wire controller is connected between the speaker and the gain adaptive controller 140 or between the input terminal and the gain adaptive controller 140.
It should be noted that the above-mentioned embodiments are provided for further detailed description of the present invention, and the present invention is not limited to the above-mentioned embodiments, and those skilled in the art can make various modifications and variations on the above-mentioned embodiments without departing from the scope of the present invention.
Claims (15)
1. An audio processing chip, comprising: an audio decoder for decoding the audio segments stored in the storage device; a digital-to-analog converter for converting the decoded digital audio signal into an analog audio signal; the audio amplifier is used for amplifying the analog audio signal converted by the digital-to-analog converter; the audio output port is used for outputting the amplified analog audio signal; and the gain self-adaptive controller is connected between the audio amplifier and the audio output port, amplified audio signals are input into the gain self-adaptive controller, the audio signals at the signal output end of the gain self-adaptive controller are sampled and subjected to integral processing, the audio signals are adjusted according to integral processing results, and the adjusted audio signals are output to the audio output port to realize automatic adjustment of the volume of output sound.
2. The audio processing chip of claim 1, wherein the gain adaptive controller comprises: the device comprises an input end, a signal output end, a change-over switch, an attenuation circuit, a signal sampling circuit and an analog-to-digital converter.
3. The audio processing chip of claim 2, wherein the switch is connected to an input terminal, the attenuator circuit is connected to the set of output terminals of the switch and the signal output terminal, the signal sampling circuit is connected to the signal output terminal, and the analog-to-digital converter is connected to the sampling circuit and the set of control terminals of the switch, respectively.
4. The audio processing chip of claim 3, wherein the attenuation circuit comprises at least two attenuation branch groups, each attenuation branch group comprising a plurality of attenuation branches, each attenuation branch being configured to attenuate a signal input from the input terminal to a different degree.
5. The audio processing chip according to claim 4, wherein each attenuation branch in each attenuation branch group of the attenuation circuit is not connected in series or is connected in series with a resistor with a different resistance value, so that a signal input from the input terminal is attenuated to a corresponding different degree.
6. The audio processing chip of claim 5, wherein the signal sampling circuit is configured to obtain a sampled signal from the signal output; the analog-to-digital converter is used for converting the sampling signal from an analog quantity to a digital quantity, and the digital quantity control conversion switch selects a corresponding attenuation branch in the attenuation circuit to transmit the signal input from the input end to the signal output end.
7. The audio processing chip of claim 6, wherein the analog-to-digital converter divides the analog quantity of the sampled signal into N number of value segments by presetting, wherein N is an integer greater than 1, and the number of the value segments is 1, 2, 3 … … N; corresponding to the N binary numbers, the N binary numbers are generated after analog-to-digital conversion; when a certain sampling signal falls into a certain numerical value section of the analog quantity, the analog-to-digital converter generates corresponding digital quantity according to the numerical value section; the digital quantity is input to the change-over switch through the control end group of the change-over switch.
8. The audio processing chip of claim 7, wherein the switch controls an off state or an on state of each output port in the output port group according to the digital quantity.
9. The audio processing chip of claim 8, wherein the switch controls the corresponding output ports of the output port set to be turned on and the other output ports to be turned off according to the digital quantity.
10. The audio processing chip according to any one of claims 1 to 9, wherein the audio processing chip further comprises a custom input interface for receiving a user setting for analog quantity division of the sampled signal and then changing the preset setting in the analog-to-digital converter.
11. The audio processing chip of any of claims 1-9, wherein the audio processing chip further comprises an ambient noise input interface to receive ambient noise and to change the presettings in the analog-to-digital converter based on an ambient noise adjustment.
12. The audio processing chip of any of claims 1-9, wherein the audio processing chip further comprises a feedback controller, the gain adaptive controller further comprising a feedback output; the feedback controller is connected between the feedback output end of the gain self-adaptive controller and the audio amplifier and is used for gradually reducing the amplification amplitude of the audio amplifier to the audio signal when the change-over switch controls the audio signal to pass through the attenuation branch with the nonzero resistance value of the resistor in the attenuation circuit until the change-over switch controls the audio signal to pass through the attenuation branch with the zero resistance value of the resistor in the attenuation circuit.
13. An earphone, comprising: an input terminal for inputting an audio electrical signal; the loudspeaker is used for converting the audio signal into sound wave from the electric signal; the audio processing chip of any one of claims 1-12, wherein the input, the audio processing chip, and the speaker are connected in sequence; and audio signals are input to the audio processing chip through an input end for processing, the processed audio signals are output to the loudspeaker, and the audio signals are converted into sound waves.
14. The headset of claim 13, further comprising a cord control, wherein the user can manually control the volume of the speaker output by adjusting the cord control.
15. The headset of claim 13 or 14, wherein the wire controller is connected between the speaker and the gain adaptive controller or between the input and the gain adaptive controller.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110599843.8A CN113315480A (en) | 2021-05-31 | 2021-05-31 | Audio processing chip and earphone |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110599843.8A CN113315480A (en) | 2021-05-31 | 2021-05-31 | Audio processing chip and earphone |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113315480A true CN113315480A (en) | 2021-08-27 |
Family
ID=77376445
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110599843.8A Pending CN113315480A (en) | 2021-05-31 | 2021-05-31 | Audio processing chip and earphone |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113315480A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0220928A (en) * | 1988-07-08 | 1990-01-24 | Matsushita Electric Ind Co Ltd | Attenuation device |
| US6393079B1 (en) * | 1998-07-28 | 2002-05-21 | Motorola, Inc. | Transient-suppressing mode switch |
| KR20020059460A (en) * | 2001-01-06 | 2002-07-13 | 송재인 | Volume automatic control apparatus of portable digital audio appliance using earphone |
| US20060244549A1 (en) * | 2005-04-28 | 2006-11-02 | Rohm Company, Ltd. | Attenuator, variable gain amplifier using the same, and electronic equipment |
| CN101072016A (en) * | 2006-05-12 | 2007-11-14 | 鸿富锦精密工业（深圳）有限公司 | Gain automatic control device, method and audio processing device and earphone thereof |
| WO2016029461A1 (en) * | 2014-08-29 | 2016-03-03 | 安百特半导体有限公司 | Feedforward-and-feedback-combined noise cancellation earphone and drive circuit thereof |
| US20160071504A1 (en) * | 2014-09-05 | 2016-03-10 | Apple Inc. | Signal processing for eliminating speaker and enclosure buzz |
-
2021
- 2021-05-31 CN CN202110599843.8A patent/CN113315480A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0220928A (en) * | 1988-07-08 | 1990-01-24 | Matsushita Electric Ind Co Ltd | Attenuation device |
| US6393079B1 (en) * | 1998-07-28 | 2002-05-21 | Motorola, Inc. | Transient-suppressing mode switch |
| KR20020059460A (en) * | 2001-01-06 | 2002-07-13 | 송재인 | Volume automatic control apparatus of portable digital audio appliance using earphone |
| US20060244549A1 (en) * | 2005-04-28 | 2006-11-02 | Rohm Company, Ltd. | Attenuator, variable gain amplifier using the same, and electronic equipment |
| CN101072016A (en) * | 2006-05-12 | 2007-11-14 | 鸿富锦精密工业（深圳）有限公司 | Gain automatic control device, method and audio processing device and earphone thereof |
| WO2016029461A1 (en) * | 2014-08-29 | 2016-03-03 | 安百特半导体有限公司 | Feedforward-and-feedback-combined noise cancellation earphone and drive circuit thereof |
| US20160071504A1 (en) * | 2014-09-05 | 2016-03-10 | Apple Inc. | Signal processing for eliminating speaker and enclosure buzz |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| TWI469138B (en) | Method, apparatus and article of manufacture for modifying intelligibility of speech in a downlink voice signal during a call | |
| AU601861B2 (en) | Electronic telephone terminal having noise suppression function | |
| GB2137458A (en) | Digital handsfree telephone | |
| JP2009089397A (en) | Two-way communication device having single transducer, and method thereof | |
| KR102374789B1 (en) | Control of the noise transfer function in the signal path to reduce charge pump noise | |
| WO2018004569A1 (en) | Optimization of performance and power in audio system | |
| CN101072016B (en) | Gain automatic control device, method and audio processing device and earphone thereof | |
| US20200389731A1 (en) | Low-latency audio output with variable group delay | |
| CN109814833B (en) | Real-time control frequency response output device and application method thereof | |
| KR101623562B1 (en) | Portable sound amplifier having detachable mic module | |
| CN113315480A (en) | Audio processing chip and earphone | |
| US3395255A (en) | Loudspeaking telephone | |
| JP2009027412A (en) | Signal amplifying circuit, and audio system using the same | |
| CN201928424U (en) | Sound source frequency adjusting system and terminal | |
| WO1995006976A1 (en) | Variable gain amplifier | |
| JPS6199451A (en) | Telephone set | |
| EP1312168A1 (en) | Method and circuit for regulating the signal level fed to an analog-digital converter | |
| WO2017033260A1 (en) | Sound acquisition device, and sound acquisition method | |
| TWI641269B (en) | Audio playback device and audio control circuit of the same | |
| JP2586847B2 (en) | Electronic telephone | |
| CN109144457B (en) | Audio playing device and audio control circuit thereof | |
| US11894819B2 (en) | Audio monitoring system | |
| CA2374370A1 (en) | Universal tie line adapter | |
| KR910001082Y1 (en) | Circuit to suppress noise in the handset | |
| KR20100031278A (en) | Signla processing apparatus |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB02 | Change of applicant information | ||
| CB02 | Change of applicant information |
Address after: No. 2001, Yingbin West Road, Bacheng Town, Kunshan City, Suzhou City, Jiangsu Province, 215311 Applicant after: Kunshan Haifeiman Technology Group Co.,Ltd. Address before: 2 / F, North building, 1339 Shuixiu Road, Yushan Town, Kunshan City, Suzhou City, Jiangsu Province Applicant before: HEAD-DIRECT (KUNSHAN) Co.,Ltd. |
|
| CB02 | Change of applicant information | ||
| CB02 | Change of applicant information |
Address after: 215300 No. 2001 Yingbin West Road, Bacheng Town, Kunshan City, Suzhou City, Jiangsu Province Applicant after: Kunshan Haifeiman Technology Group Co.,Ltd. Address before: No. 2001, Yingbin West Road, Bacheng Town, Kunshan City, Suzhou City, Jiangsu Province, 215311 Applicant before: Kunshan Haifeiman Technology Group Co.,Ltd. |