CN106612479A - Loudspeaker based protective circuit - Google Patents
Loudspeaker based protective circuit Download PDFInfo
- Publication number
- CN106612479A CN106612479A CN201510698724.2A CN201510698724A CN106612479A CN 106612479 A CN106612479 A CN 106612479A CN 201510698724 A CN201510698724 A CN 201510698724A CN 106612479 A CN106612479 A CN 106612479A
- Authority
- CN
- China
- Prior art keywords
- signal
- speaker
- unit
- control
- 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
Abstract
The invention relates to a loudspeaker based protective circuit, and belongs to the technical field of sound signal processing. A microphone detects a sound signal of a resonant point of a loudspeaker, and forms and outputs a detection signal; and a determination unit forms a determination result according to the detection signal and a threshold signal, and shorts an input signal and an input end of the power amplification unit under the condition that the detection signal does not match the threshold signal. After that the input end of the power amplification unit is shorted, the power amplification unit does not output amplified signals to the loudspeaker, and signals of higher current and voltage cannot enter the loudspeaker; and when an input signal is in a normal state, the input end of the power amplification unit receives the input signal, an via ON/OFF control in the input end of the power amplification unit, it is effectively ensured that the current or voltage signals received by the loudspeaker in unit time are within a safe range, and a vibration system of the loudspeaker is protected effectively.
Description
Technical field
The present invention relates to a kind of sound signal processing technical field, more particularly to a kind of protection based on speaker
Circuit.
Background technology
Speaker is a kind of energy transducer for the signal of telecommunication being changed into acoustical signal, and ictus frequency electric energy is by electricity
Magnetic, piezoelectricity or electrostatic effect so as to which cone or diaphragm vibration simultaneously produce resonance (sympathetic response) with the air of surrounding
And send sound.Speaker is substantially by magnetic loop system (permanent magnet, stem stem, magnetic conductive board), vibration system
The three parts such as system (voice coil loudspeaker voice coil) and support auxiliary system (centring disk, frame, pad side) are constituted.Raise
Sound device is a most weak device in stereo set, and it is vibrational system (sound in speaker to trace it to its cause
Circle), magnetic loop system forms a magnetic field, and vibrational system does cutting magnetic line movement in the presence of electric current,
Vibrations are produced by cutting magnetic line movement and forms sound.But under low frequency signal state, vibroseis
The formation of cutting magnetic line is longer, easily so that vibrational system " jumps out " magnetic field range, works as vibrational system
Cutting zone relative with magnetic field becomes hour, and the inductance in vibrational system is made because of " chokes " that lack magnetic field
With and form short-circuit (burning out).
In order to avoid vibrational system burns out the generation of this phenomenon, in existing speaker circuit, it is provided with
One forward direction protection device, to the Oscillation Amplitude for limiting vibrational system, which adopts the work(for limiting vibrational system
Rate to realize the effect of amplitude limit, but under practical situation, speaker in the presence of different frequency, its institute
The resistance value of performance is different, only with simple Power Limitation, is not enough to be entirely limited its amplitude,
In addition, the electrical power (being formed by electric current and voltage) and acoustical power of speaker are also at unstable shape
State, with the change of temperature, its electrical power and acoustical power also change, in addition, speaker is located always
In open loop situations, the electric current and voltage of speaker are input to by detection, speaker can not be directly embodied
The electric current of itself, voltage, only with voltage method, protect also not comprehensive enough.
The content of the invention
For the deficiencies in the prior art, the present invention provides a kind of voice awakening method and movement based on mike
Terminal.
The technical purpose of the present invention is realized by following technological means：
A kind of protection circuit based on speaker, is applied to mobile terminal, wherein, including
The output signal to receive an output signal, and is converted into acoustical signal output by one speaker；
One mike, it is adjacent with the speaker and set, to detect the speaker in the sound of resonance point
Signal, and form detection signal output；
One judging unit, is preset with a threshold signal, to receive the detection signal, and according to the inspection
Survey signal and the threshold signal forms a judged result；
One control unit, in the presence of the judged result, control input signal and the output signal
It is turned on or off.
Preferably, the above-mentioned protection circuit based on speaker, wherein, also including a power amplification unit,
The speaker is arranged between described control unit.
Preferably, the above-mentioned protection circuit based on speaker, wherein, it is described in detection signal matching
In the state of threshold signal, the judging unit exports the first judged result；In first judged result
Control under, the power amplification unit receives the input signal, and amplifies the input signal and formed
Export to the output signal of the speaker；
In the state of the detection signal mismatches the threshold signal, the judging unit output second is sentenced
Disconnected result, under the control of second judged result, the power amplification unit receives the input letter
Number, and by the input signal between the input of the power amplification unit short circuit.
Preferably, the above-mentioned protection circuit based on speaker, wherein, described control unit is a switch,
The control end of the switch connects the judging unit.
A kind of protection circuit based on speaker, wherein, including
One output unit, to export one to drive the voltage signal of the speaker,
One detector unit, to detect the current signal being input into the speaker；
One computing unit, to form impedance letter to calculate according to the voltage signal and the current signal
Number；
One control unit, is connected between the output unit and the speaker, to according to the impedance
Signal to export a control signal, the control signal control the output unit and the speaker it
Between connection status.
Preferably, the above-mentioned protection circuit based on speaker, wherein, the computing unit is differentiation element,
To the amplitude of variation for calculating impedance signal described in adjacent moment.
Preferably, the above-mentioned protection circuit based on speaker, wherein, described control unit is provided with a width
Degree threshold value, in the state of the amplitude of variation exceedes the threshold range, described control unit output institute
Control signal is stated, the control signal is to make to disconnect between the output unit and the speaker.
Compared with prior art, it is an advantage of the invention that：
Mike is to detect the speaker in the acoustical signal of resonance point, and forms detection signal output；
Judging unit forms a judged result according to the detection signal and the threshold signal；In the detection letter
In the state of number mismatching the threshold signal, by the input signal in the defeated of the power amplification unit
Enter short circuit between end.After the input short circuit of power amplification unit, power amplification unit will not be exported
The signal of amplified process current signal to speaker and then larger, voltage signal cannot be introduced into raising one's voice
Device, when input signal is under normal condition, the input receives input signal of power amplification unit leads to
The on and off control of the input of overpower amplifying unit, was effectively ensured in the unit interval, and speaker is received
Current signal or voltage signal within the safety range, the vibrational system of effective protection speaker.
Description of the drawings
Fig. 1 is a kind of protection circuit structural representation based on speaker in the present invention；
Fig. 2 is a kind of connection diagram of embodiment in the present invention；
Fig. 3 is the circuit connection diagram of existing speaker；
Fig. 4 is a kind of protection circuit structural representation based on speaker in the present invention.
Specific embodiment
The invention will be further described with specific embodiment below in conjunction with the accompanying drawings, but not as the limit of the present invention
It is fixed.
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clearly
Chu, it is fully described by, it is clear that described embodiment is only a part of embodiment of the invention, and not
It is whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art are not making
The every other embodiment obtained on the premise of creative work, belongs to the scope of protection of the invention.
It should be noted that the embodiment and the feature in embodiment in the case where not conflicting, in the present invention
Can be mutually combined.
The invention will be further described with specific embodiment below in conjunction with the accompanying drawings, but not as the limit of the present invention
It is fixed.
As shown in figure 1, a kind of protection circuit based on speaker, is applied to mobile terminal, wherein, including
The output signal to receive an output signal, and is converted into acoustical signal output by one speaker；
Also include a power amplification unit, be arranged at the speaker between described control unit.
One mike, it is adjacent with the speaker and set, to detect the speaker in the sound of resonance point
Signal, and form detection signal output；In intelligent mobile terminal, usual mike and speaker two
Person is disposed adjacent, and need not change existing mobile terminal herein and arrange, make full use of mike, enter
One step improves the utilization rate of mike.Energy in addition generally acquired in the acoustical signal of resonance point is maximum,
Need only to detect the energy of resonance point, when the energy of resonance point is less than maximum, then other are frequently
The energy of domain signal is in a safe condition.
One judging unit, is preset with a threshold signal, to receive the detection signal, and according to described
Detection signal and the threshold signal form a judged result；
One control unit, in the presence of the judged result, control input signal and the output signal
It is turned on or off.In the state of the detection signal matches the threshold signal, the judging unit is defeated
Go out the first judged result；Under the control of first judged result, the power amplification unit receives institute
Input signal is stated, and amplifies the output signal that the input signal forms output to the speaker；
In the state of the detection signal mismatches the threshold signal, the judging unit output second judges
As a result, under the control of second judged result, the power amplification unit receives the input signal,
And by the input signal between the input of the power amplification unit short circuit.
A specific embodiment is enumerated, as shown in Fig. 2 the present invention adopts a closed-loop control system, Mike
Wind is to detect the speaker in the acoustical signal of resonance point, and forms detection signal output；Judge single
Unit forms a judged result according to the detection signal and the threshold signal；In the detection signal not
In the state of with the threshold signal, (usually the electric current of input signal exceedes the rated value or defeated of speaker
The voltage for entering signal exceedes the rated value of speaker), by the input signal in the power amplification unit
Short circuit between input.After the input short circuit of power amplification unit, power amplification unit will not be defeated
Go out the signal of amplified process current signal to speaker and then larger, voltage signal to cannot be introduced into raising
Sound device, when input signal is under normal condition, the input receives input signal of power amplification unit,
Controlled by the on and off of the input of power amplification unit, be effectively ensured in the unit interval, speaker connects
The current signal or voltage signal of receipts is within safety range, the vibrational system of effective protection speaker.
As further preferred embodiment, the above-mentioned protection circuit based on speaker, wherein, it is described
Control unit is a switch, and the control end of the switch connects the judging unit.Judge in described first
As a result the input connection of power amplification unit in the state of, is disconnected, in the shape of first judged result
Under state, the input connection of conducting power amplifying unit, so that input signal is grounded.
It is well known that speaker generally includes coil and magnetic cylinder, resistance, coil formed by inductance,
Under speaker operation state, a parasitic capacitance, the circuit knot of its speaker between coil and magnetic cylinder, are also formed
Composition is as shown in figure 3, its impedance is by capacitive reactance XC, induction reactance XLFormed with resistance R, wherein capacitive reactance XC
By electric capacity C-shaped into, when under speaker operation state, in the case where frequency determines, induction reactance XLAnd electricity
Resistance R is in known state, has capacitive reactance X onlyCIn unknown state, because of electric capacity C (wherein
This is prior art, is not repeated herein) capacitance be continually changing the (opposite face between coil and magnetic cylinder
Product is constantly converted), when the relative area between coil and magnetic cylinder reduces (coiler part jumps out magnetic cylinder),
The capacitance of electric capacity C diminishes, and when the relative quantity of the reduction of electric capacity C is larger, then shows that coil has and jumps completely
Go out the trend of magnetic cylinder.
Using above-mentioned discovery, present invention simultaneously provides a kind of protection circuit based on speaker, wherein, bag
Include
One output unit, to export one to drive the voltage signal of the speaker,
One detector unit, to detect the current signal being input into the speaker；
One computing unit, to form impedance letter to calculate according to the voltage signal and the current signal
Number；
One control unit, is connected between the output unit and the speaker, to according to the resistance
Antinoise signal controls the output unit and the speaker to export a control signal, the control signal
Between connection status.
The operation principle of the technical program is：Impedance can exactly be obtained by voltage signal and current signal
Signal, after impedance signal determines, and because induction reactance XLHold, it is known that can then calculate acquisition with resistance R
Anti- XCValue, and then may determine that between coil and magnetic cylinder relative distance whether beyond threshold range, in
Between coil and magnetic cylinder relative distance exceed threshold range when, then disconnect output unit and the speaker it
Between connection.
As further preferred embodiment, the above-mentioned protection circuit based on speaker, wherein, the meter
Calculation unit is differentiation element, to the amplitude of variation for calculating impedance signal described in adjacent moment.Using differential
Calculation, the amplitude of variation of adjacent moment impedance signal can be obtained, that is, go up a moment with lower a period of time
The variable quantity of relative distance between groove circle and magnetic cylinder.
As further preferred embodiment, the above-mentioned protection circuit based on speaker, wherein, the control
Unit processed is provided with an amplitude threshold, in the state of the amplitude of variation exceedes the threshold range, institute
State control unit and export the control signal, the control signal is raised with described to make the output unit
Disconnect between sound device.When between coil and magnetic cylinder, relative distance variable quantity in allowed band, is then permitted
Perhaps to the speaker output voltage signal, speaker is in normal operating conditions to output unit.It is anti-regular
Speaker cannot obtain the voltage signal of driving.
Preferred embodiments of the present invention are more than above are only, embodiments of the present invention and guarantor is not thereby limited
Shield scope, to those skilled in the art, should can appreciate that all utilization description of the invention and
The scheme obtained by equivalent and obvious change done by diagramatic content, should be included in
In protection scope of the present invention.
Claims (7)
1. a kind of protection circuit based on speaker, is applied to mobile terminal, it is characterised in that include
The input signal to receive an input signal, and is converted into acoustical signal output by one speaker；
One mike, it is adjacent with the speaker and set, to detect the speaker in the sound of resonance point
Signal, and form detection signal output；
One judging unit, is preset with a threshold signal, to receive the detection signal, and according to the inspection
Survey signal and the threshold signal forms a judged result；
One control unit, in the presence of the judged result, control input signal and the output signal
It is turned on or off.
2. the protection circuit based on speaker according to claim 1, it is characterised in that also including a work(
Rate amplifying unit, is arranged at the speaker between described control unit.
3. the protection circuit based on speaker according to claim 2, it is characterised in that
In the state of the detection signal matches the threshold signal, the judging unit output first judges
As a result；Under the control of first judged result, the power amplification unit receives the input signal,
And amplify the input signal output；
In the state of the detection signal mismatches the threshold signal, the judging unit output second is sentenced
Disconnected result, under the control of second judged result, the power amplification unit receives the input letter
Number, and by the input signal between the input of the power amplification unit short circuit.
4. the protection circuit based on speaker according to claim 1, it is characterised in that the control list
Unit is a switch, and the control end of the switch connects the judging unit.
5. a kind of protection circuit based on speaker, it is characterised in that include
One output unit, to export one to drive the voltage signal of the speaker,
One detector unit, to detect the current signal being input into the speaker；
One computing unit, to calculate to form an impedance signal according to the voltage signal and the current signal；
One control unit, is connected between the output unit and the speaker, to according to the impedance
Signal to export a control signal, the control signal control the output unit and the speaker it
Between connection status.
6. the protection circuit based on speaker according to claim 5, it is characterised in that the calculating list
Unit is differentiation element, to the amplitude of variation for calculating impedance signal described in adjacent moment.
7. the protection circuit based on speaker according to claim 6, it is characterised in that the control list
Unit is provided with an amplitude threshold, in the state of the amplitude of variation exceedes the threshold range, the control
Unit processed exports the control signal, and the control signal is to make the output unit with the speaker
Between disconnect.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510698724.2A CN106612479A (en) | 2015-10-23 | 2015-10-23 | Loudspeaker based protective circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510698724.2A CN106612479A (en) | 2015-10-23 | 2015-10-23 | Loudspeaker based protective circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN106612479A true CN106612479A (en) | 2017-05-03 |
Family
ID=58613317
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510698724.2A Pending CN106612479A (en) | 2015-10-23 | 2015-10-23 | Loudspeaker based protective circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106612479A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109275068A (en) * | 2018-08-27 | 2019-01-25 | 出门问问信息科技有限公司 | A kind of audio output circuit and equipment |
Citations (25)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4090032A (en) * | 1976-05-05 | 1978-05-16 | Wm. A. Holmin Corporation | Control system for audio amplifying system having multiple microphones |
| WO1994000089A1 (en) * | 1992-06-19 | 1994-01-06 | Joseph Sylvester Chang | Hearing protector |
| JP2002345091A (en) * | 2001-05-17 | 2002-11-29 | Toa Corp | Speaker fault detector and speaker fault detection method |
| JP2004304683A (en) * | 2003-04-01 | 2004-10-28 | Sharp Corp | Audio reproducing apparatus |
| JP2005354202A (en) * | 2004-06-08 | 2005-12-22 | Fuji Photo Film Co Ltd | Mobile reproducing apparatus |
| JP2006197407A (en) * | 2005-01-14 | 2006-07-27 | Yamaha Corp | Loudspeaker system |
| CN1960175A (en) * | 2005-11-03 | 2007-05-09 | 三星电子株式会社 | Method and apparatus to control output power of a power amplifier and audio player having the same |
| US20070147628A1 (en) * | 2004-04-01 | 2007-06-28 | Benway Randy E | Hearing protection device |
| JP2008085476A (en) * | 2006-09-26 | 2008-04-10 | Patoraito:Kk | Alarm tone generator |
| JP2008228157A (en) * | 2007-03-15 | 2008-09-25 | Toa Corp | Power amplifier |
| CN201374809Y (en) * | 2009-01-05 | 2009-12-30 | 深圳市同洲电子股份有限公司 | Loudspeaker protective device and mobile communication terminal |
| CN201557105U (en) * | 2009-11-02 | 2010-08-18 | 华格工业股份有限公司 | Waist hanging type wireless microphone emitter device |
| JP2011114933A (en) * | 2009-11-26 | 2011-06-09 | Kyocera Corp | Protective circuit |
| CN102118678A (en) * | 2011-04-02 | 2011-07-06 | 嘉兴中科声学科技有限公司 | Method and system for measuring speaker parameters by using current sensor |
| US20110182434A1 (en) * | 2010-01-28 | 2011-07-28 | Harris Corporation | Method to maximize loudspeaker sound pressure level with a high peak to average power ratio audio source |
| CN103327437A (en) * | 2012-03-20 | 2013-09-25 | Nxp股份有限公司 | A loudspeaker drive circuit for determining loudspeaker characteristics and/or diagnostics |
| CN103338419A (en) * | 2013-06-29 | 2013-10-02 | 青岛歌尔声学科技有限公司 | Method and device for removing headset scream |
| CN103369447A (en) * | 2012-03-27 | 2013-10-23 | 宏达国际电子股份有限公司 | Control method of sound producing, sound producing apparatus, and portable apparatus |
| CN103945306A (en) * | 2014-01-24 | 2014-07-23 | 立锜科技股份有限公司 | Detecting device and method for magnetic-force intensity parameter of loudspeaker |
| CN104113803A (en) * | 2014-07-17 | 2014-10-22 | 瑞声声学科技(深圳)有限公司 | Multi-voice-coil based loudspeaker system |
| US20150023507A1 (en) * | 2013-07-19 | 2015-01-22 | Nvidia Corporation | Speaker Protection in Small Form Factor Devices |
| CN204180020U (en) * | 2014-08-29 | 2015-02-25 | 意法半导体研发(深圳)有限公司 | For providing system and the circuit of overcurrent protection in D audio frequency amplifier circuit |
| CN104640054A (en) * | 2015-02-12 | 2015-05-20 | 广东欧珀移动通信有限公司 | Earphone/loudspeaker testing method and system for mobile terminal |
| CN204578757U (en) * | 2015-03-17 | 2015-08-19 | 钰太芯微电子科技（上海）有限公司 | Speaker compensation system and portable mobile termianl |
| CN205123979U (en) * | 2015-10-23 | 2016-03-30 | 钰太芯微电子科技（上海）有限公司 | Protection circuit based on speaker |
-
2015
- 2015-10-23 CN CN201510698724.2A patent/CN106612479A/en active Pending
Patent Citations (25)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4090032A (en) * | 1976-05-05 | 1978-05-16 | Wm. A. Holmin Corporation | Control system for audio amplifying system having multiple microphones |
| WO1994000089A1 (en) * | 1992-06-19 | 1994-01-06 | Joseph Sylvester Chang | Hearing protector |
| JP2002345091A (en) * | 2001-05-17 | 2002-11-29 | Toa Corp | Speaker fault detector and speaker fault detection method |
| JP2004304683A (en) * | 2003-04-01 | 2004-10-28 | Sharp Corp | Audio reproducing apparatus |
| US20070147628A1 (en) * | 2004-04-01 | 2007-06-28 | Benway Randy E | Hearing protection device |
| JP2005354202A (en) * | 2004-06-08 | 2005-12-22 | Fuji Photo Film Co Ltd | Mobile reproducing apparatus |
| JP2006197407A (en) * | 2005-01-14 | 2006-07-27 | Yamaha Corp | Loudspeaker system |
| CN1960175A (en) * | 2005-11-03 | 2007-05-09 | 三星电子株式会社 | Method and apparatus to control output power of a power amplifier and audio player having the same |
| JP2008085476A (en) * | 2006-09-26 | 2008-04-10 | Patoraito:Kk | Alarm tone generator |
| JP2008228157A (en) * | 2007-03-15 | 2008-09-25 | Toa Corp | Power amplifier |
| CN201374809Y (en) * | 2009-01-05 | 2009-12-30 | 深圳市同洲电子股份有限公司 | Loudspeaker protective device and mobile communication terminal |
| CN201557105U (en) * | 2009-11-02 | 2010-08-18 | 华格工业股份有限公司 | Waist hanging type wireless microphone emitter device |
| JP2011114933A (en) * | 2009-11-26 | 2011-06-09 | Kyocera Corp | Protective circuit |
| US20110182434A1 (en) * | 2010-01-28 | 2011-07-28 | Harris Corporation | Method to maximize loudspeaker sound pressure level with a high peak to average power ratio audio source |
| CN102118678A (en) * | 2011-04-02 | 2011-07-06 | 嘉兴中科声学科技有限公司 | Method and system for measuring speaker parameters by using current sensor |
| CN103327437A (en) * | 2012-03-20 | 2013-09-25 | Nxp股份有限公司 | A loudspeaker drive circuit for determining loudspeaker characteristics and/or diagnostics |
| CN103369447A (en) * | 2012-03-27 | 2013-10-23 | 宏达国际电子股份有限公司 | Control method of sound producing, sound producing apparatus, and portable apparatus |
| CN103338419A (en) * | 2013-06-29 | 2013-10-02 | 青岛歌尔声学科技有限公司 | Method and device for removing headset scream |
| US20150023507A1 (en) * | 2013-07-19 | 2015-01-22 | Nvidia Corporation | Speaker Protection in Small Form Factor Devices |
| CN103945306A (en) * | 2014-01-24 | 2014-07-23 | 立锜科技股份有限公司 | Detecting device and method for magnetic-force intensity parameter of loudspeaker |
| CN104113803A (en) * | 2014-07-17 | 2014-10-22 | 瑞声声学科技(深圳)有限公司 | Multi-voice-coil based loudspeaker system |
| CN204180020U (en) * | 2014-08-29 | 2015-02-25 | 意法半导体研发(深圳)有限公司 | For providing system and the circuit of overcurrent protection in D audio frequency amplifier circuit |
| CN104640054A (en) * | 2015-02-12 | 2015-05-20 | 广东欧珀移动通信有限公司 | Earphone/loudspeaker testing method and system for mobile terminal |
| CN204578757U (en) * | 2015-03-17 | 2015-08-19 | 钰太芯微电子科技（上海）有限公司 | Speaker compensation system and portable mobile termianl |
| CN205123979U (en) * | 2015-10-23 | 2016-03-30 | 钰太芯微电子科技（上海）有限公司 | Protection circuit based on speaker |
Non-Patent Citations (1)
| Title |
|---|
| 杨兴成: "基于DM368的列车数字功放设计及实现", 《中国优秀硕士学位论文全文数据库-信息科技辑》, pages 57 - 59 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109275068A (en) * | 2018-08-27 | 2019-01-25 | 出门问问信息科技有限公司 | A kind of audio output circuit and equipment |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2017161654A1 (en) | Single loudspeaker, loudspeaker system and method for adjusting vibration displacement of diaphragm | |
| CN102355214B (en) | Adjustable gain audio power amplification circuit | |
| CN205123979U (en) | Protection circuit based on speaker | |
| CN102438193B (en) | Safe earphone capable of automatically muting | |
| CN204929213U (en) | Audio signal detects control circuit | |
| CN204578757U (en) | Speaker compensation system and portable mobile termianl | |
| CN106612479A (en) | Loudspeaker based protective circuit | |
| CN205793346U (en) | A kind of towards earphone/headset loudspeaker broken string and short-circuit detecting circuit | |
| CN203785780U (en) | Audio signal detection circuit and audio signal processing circuit | |
| CN203261475U (en) | Super-high pitch loudspeaker with improved high-frequency bandwidth and sensitivity | |
| CN205793154U (en) | Earphone drive circuit and electronic equipment | |
| CN208924444U (en) | A kind of bluetooth headset | |
| CN105281190B (en) | A kind of radio-frequency power supply for laser | |
| CN203933932U (en) | A kind of uttering long and high-pitched sounds eliminated circuit and earphone | |
| CN206865728U (en) | A kind of noise canceller circuit and audio frequency apparatus | |
| CN106034272A (en) | Loudspeaker compensation system and portable mobile terminal | |
| CN205754753U (en) | A kind of double moving-coil monitoring headpone | |
| CN203912161U (en) | Noise eliminating circuit | |
| CN113346637A (en) | Method for eliminating foreign matter harm in wireless charging system | |
| CN205356659U (en) | Active speaker | |
| CN206084045U (en) | Numerical control pulse generator | |
| CN201589827U (en) | Detector for circuit breakpoint | |
| CN106160679A (en) | A kind of professional audio amplifier | |
| CN202558397U (en) | Build-in auxiliary engine circuit of intercom system of elevator | |
| CN106624218A (en) | Numerical control pulsed power supply |
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 |