CN103648075A - Device and method for automatically detecting abnormality of power amplifier - Google Patents
Device and method for automatically detecting abnormality of power amplifier Download PDFInfo
- Publication number
- CN103648075A CN103648075A CN201310693584.0A CN201310693584A CN103648075A CN 103648075 A CN103648075 A CN 103648075A CN 201310693584 A CN201310693584 A CN 201310693584A CN 103648075 A CN103648075 A CN 103648075A
- Authority
- CN
- China
- Prior art keywords
- power amplifier
- abnormal
- voltage
- signal
- abnormality
- 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
Images
Landscapes
- Amplifiers (AREA)
Abstract
The invention provides a device and a method for automatically detecting abnormality of a power amplifier. The device comprises a power amplifier voltage detecting circuit used for detecting a voltage value output from the power amplifier to a loudspeaker, a power amplifier voltage abnormality judging circuit used for outputting a normal voltage level signal or an abnormal voltage level signal through an offset port, a microcontroller used for counting normal voltage electric pulses or abnormal voltage level pulses output by the offset port within a set period, determining the state of the power amplifier, and sending a power amplifier abnormality signal if the power amplifier is determined to be in an abnormal state, and a buzzer connected to the microcontroller and used for receiving the power amplifier abnormality signal and sending an abnormality prompt acoustical signal, wherein the abnormal prompt acoustical signal after being amplifier by the power amplifier is played through the loudspeaker. According to the invention, automatic detection of the voltage abnormality condition of the power amplifier is realized and manual detection is unnecessary; acoustical alarm or image display alarm is carried out if the power amplifier is abnormal, and the power amplifier is shut down after a set time period to protect the loudspeaker connected to the power amplifier.
Description
Technical field
The present invention relates to automobile audio technical field, be specifically related to the abnormal device and method of a kind of automatic detection power amplifier.
Background technology
Power amplifier is called for short power amplifier, be commonly called as " sound amplifier ", be equipment the most basic in sound system, its effect is amplifying to drive loud speaker to sound from sound signal source (being from sound console in professional sound system) or the ultra-weak electronic signal of pre-amplifier.Owing to considering power, impedance, distortion, the dynamic and different scope of application and regulating and controlling function, different power amplifiers is also different in inner signal processing, line design and production technology.
The most common failure that power amplifier occurs has that complete machine is not worked, voiceless sound output, sound is light, noise is large, distortion, utter long and high-pitched sounds etc.Prior art is as follows to the detection method of various faults:
After the idle fault of complete machine shows as energising, amplifier is without any demonstration, and each function key all lost efficacy, also without any sound, when not switching on.During maintenance, first should check power circuit.Available universal instrument is measured the DC resistance (mains switch should be connected) at attaching plug two ends, when normal, should have the resistance value of hundreds of ohm.If it is less than normal many to record resistance, and power transformer seriously generates heat, and illustrates that the primary return of power transformer has partial short-circuit place; If record resistance for infinitely great, should check whether fuse fuses, whether primary winding opens a way, have or not broken string between power line and plug.
So-called sound light fault, refers to that audio signal, in amplifying transmitting procedure, because certain amplifying stage amplification quantity changes or is attenuated in certain link, diminishes gain decline or the power output of amplifier.During maintenance, first should check that whether signal source and audio amplifier be normal, can check by the way of replacing.Then check all kinds of change over switches and control potentiometer, seeing that can volume become large.
The noise of amplifier has hum, cracker, induced noise and white noise etc.During maintenance, should first judge that noise comes from prime and still comes from late-class circuit.The signal attachment plug of forward and backward level can be taken off, if noise obviously diminishes, illustrate that fault is in front stage circuits; Otherwise fault is at late-class circuit.
Distortion fault be certain amplifying stage Point Drifting or the work of power amplifier push-pull output stage asymmetric due to.During maintenance, can, according to the situation of change of amplifier output power and distortion, judge concrete trouble location.
The fault of uttering long and high-pitched sounds is in circuit, to exist due to self-excitation, be divided into again low frequency utter long and high-pitched sounds and high frequency utter long and high-pitched sounds.Low frequency utter long and high-pitched sounds refer to " puff puff " that frequency is lower or " too " sound, normally due to power filter or decoupling bad due to, when uttering long and high-pitched sounds toward contact with hum.
In sum, existing power amplifier method for detecting abnormality very complicated, can not realize power amplifier and extremely automatically detect, wasting manpower and material resources; And in car entertainment terminal, also there is no power amplifier abnormal detection function, when power amplifier outputs to the electric voltage exception of loud speaker, loud speaker is easily burnt.
Summary of the invention
The invention provides abnormal device and the device of a kind of automatic detection power amplifier, can realize the electric voltage exception of automatic detection power amplifier, without manual detection; Detect power amplifier abnormal after, send and remind voice signal and display, and control shutdown, prevent that loud speaker from being destroyed.
In order to solve the problems of the technologies described above, the technical solution used in the present invention is:
One aspect of the present invention provides a kind of automatic detection power amplifier abnormal device, comprising:
Power amplifier voltage testing circuit, connects the voltage output end of power amplifier, outputs to the magnitude of voltage of loud speaker for detection of power amplifier;
The abnormal decision circuitry of power amplifier voltage, connects described power amplifier voltage testing circuit, when the power amplifier voltage value of inputting from described power amplifier voltage testing circuit is in default normal voltage threshold range, by offset port, exports normal voltage level signal; When the power amplifier voltage value of inputting from described power amplifier voltage testing circuit is default normal voltage threshold range, by offset port output abnormality voltage level signal;
Microcontroller, by its general input/output port, connect described offset port, for the normal voltage level pulse of described offset port output or abnormal voltage level pulse being counted in the cycle setting, and with the level pulse amount threshold of setting relatively after, determine the state of power amplifier, as be defined as abnormality, send power amplifier abnormal signal;
Buzzer, connects described microcontroller, and for receiving described power amplifier abnormal signal and sending abnormal prompting voice signal, described abnormal prompting voice signal, after power amplifier amplifies, is play by loud speaker.
Further, the abnormal device of described automatic detection power amplifier also comprises:
Image decoder, connects described microcontroller, for receiving described power amplifier abnormal signal output abnormality, reminds picture signal, and described abnormal prompting picture signal is showing screen display.
Further, the abnormal device of described automatic detection power amplifier also comprises:
Shutdown notification unit, connects described microcontroller, after receiving described power amplifier abnormal signal, sends shutdown notification message to each functional module, the preparation before shutting down after each functional module reception shutdown notification message.
Further, the abnormal device of described automatic detection power amplifier also comprises:
Shutdown unit, connects described microcontroller, for receiving described power amplifier abnormal signal and powered-down after the time period of setting.
The present invention provides a kind of automatic detection power amplifier abnormal method on the other hand, comprising:
Power amplifier voltage detecting step: detect the magnitude of voltage that power amplifier outputs to loud speaker;
The abnormal determining step of power amplifier voltage: when power amplifier voltage value is in default normal voltage threshold range, output normal voltage level signal; When power amplifier voltage value is outside default normal voltage threshold range, output abnormality voltage level signal;
The abnormal determining step of power amplifier: within the cycle of setting, the normal voltage level pulse of described offset port output or abnormal voltage level pulse are counted, and with the level pulse amount threshold of setting relatively after, determine the state of power amplifier, as be defined as abnormality, send power amplifier abnormal signal;
Buzzing alarming step: receive described power amplifier abnormal signal and send abnormal prompting voice signal, described abnormal prompting voice signal, after power amplifier amplifies, is play by loud speaker.
Further, the described abnormal method of automatic detection power amplifier also comprises:
Image shows alarm step: receive described power amplifier abnormal signal output abnormality and remind picture signal, described abnormal prompting picture signal is showing screen display.
Further, the described abnormal method of automatic detection power amplifier also comprises:
Shutdown notifying process: send shutdown notification message to each functional module after receiving described power amplifier abnormal signal, the preparation before shutting down after each functional module reception shutdown notification message.
Further, the described abnormal method of automatic detection power amplifier also comprises:
Shutdown procedures: receive described power amplifier abnormal signal and powered-down after the time period of setting.
The present invention, by detecting and judge the abnormal conditions of power amplifier voltage, determines that whether power amplifier is abnormal, thereby realizes the electric voltage exception situation of automatic detection power amplifier, without manual detection; As abnormal in power amplifier, carry out audible alarm or image display alarm, and shut down after the time period of setting, to protect the loud speaker being connected with power amplifier.
Accompanying drawing explanation
Fig. 1 is the structural representation of the abnormal device of automatic detection power amplifier of the present invention;
Fig. 2 is the circuit connection diagram of power amplifier in the present invention;
Fig. 3-1 shows the output voltage waveform of power amplifier;
Fig. 3-2 show the voltage oscillogram that the A in the power amplifier in Fig. 2 is ordered;
Fig. 3-3 show the voltage oscillogram that the B in the power amplifier in Fig. 2 is ordered;
Fig. 4 is the schematic flow sheet of the abnormal method of automatic detection power amplifier of the present invention.
Embodiment
Below in conjunction with accompanying drawing, specifically illustrate embodiments of the present invention, accompanying drawing is only for reference and use is described, does not form the restriction to scope of patent protection of the present invention.
As shown in Figure 1, embodiments of the invention relate in one aspect to the abnormal device of a kind of automatic detection power amplifier, comprising:
Power amplifier voltage testing circuit, connects the voltage output end of power amplifier, outputs to the magnitude of voltage of loud speaker for detection of power amplifier;
The abnormal decision circuitry of power amplifier voltage, connects described power amplifier voltage testing circuit, when the power amplifier voltage value of inputting from described power amplifier voltage testing circuit is in default normal voltage threshold range, by offset port, exports normal voltage level signal; When the power amplifier voltage value of inputting from described power amplifier voltage testing circuit is default normal voltage threshold range, by offset port output abnormality voltage level signal; In the present embodiment, described normal voltage level signal is high level, and described abnormal voltage level signal is low level.
Microcontroller, by its universal input/output (General Purpose Input Output, GPIO) port connects described skew (OFF SET) port, for the normal voltage level pulse of described offset port output or abnormal voltage level pulse being counted in the cycle setting, and with the level pulse amount threshold of setting relatively after, determine the state of power amplifier, as be defined as abnormality, send power amplifier abnormal signal; In the present embodiment, microcontroller detects once every 2ms, high level pulse counting to the output of described skew (OFF SET) port within the cycle of the 60S setting, setting high level pulse amount threshold is 10, if high level pulse quantity is lower than 10, be defined as abnormality, send power amplifier abnormal signal.
Buzzer, connects described microcontroller, and for receiving described power amplifier abnormal signal and sending abnormal prompting voice signal beep buzzer, beep buzzer, after power amplifier amplifies, is play by loud speaker.
Fig. 2 shows the circuit connection diagram of power amplifier, voltage source is connected with the voltage input end of power amplifier after connecting RC circuit, the output output voltage of power amplifier is to loud speaker, the offset port of power amplifier also connects universal input/output GPIO port of the controllers such as CPU or MCU by low pass filter (Low Pass Filter, L.P.F.).
Fig. 3-1 shows the output voltage waveform of power amplifier, wherein sets high voltage threshold Vs1 and low voltage threshold Vs2, and the offset voltage scope between high low voltage threshold Vs1 and Vs2 is normal voltage scope.
Fig. 3-2 show the voltage oscillogram that skew (OFF SET) the port A in the power amplifier in Fig. 2 is ordered, corresponding with the waveform of Fig. 3-1, and the power amplifier output voltage values in Fig. 3-1 is between high low voltage threshold Vs1 and Vs2 time, A point voltage output high level; Power amplifier output voltage values in Fig. 3-1 is during higher than high low voltage threshold Vs1 or lower than low voltage threshold Vs2, A point voltage output low level.
Fig. 3-3 show the voltage oscillogram that the B in the power amplifier in Fig. 2 is ordered, and B point is the voltage detecting point of A point after low pass filter L.P.F., and B point connects the controllers such as CPU or MCU.
In an embodiment of the present invention, the abnormal device of described automatic detection power amplifier also comprises:
Image decoder, connects described microcontroller, for receiving described power amplifier abnormal signal output abnormality, reminds picture signal, and described abnormal prompting picture signal is showing screen display, as shown " power amplifier fault (AMP ERROR) ".
In an embodiment of the present invention, the abnormal device of described automatic detection power amplifier also comprises:
Shutdown notification unit, connects described microcontroller, for receive send after described power amplifier abnormal signal shutdown notification message (as, after 5S by the notice of shutdown) preparation before receiving to each functional module, each functional module to shut down after shutdown notification message;
Shutdown unit, connects described microcontroller, for receive described power amplifier abnormal signal and the time period of setting (as, 5S) after powered-down.
As shown in Figure 4, embodiments of the invention relate to a kind of abnormal method of automatic detection power amplifier on the other hand, comprising:
Power amplifier voltage detecting step: detect the magnitude of voltage that power amplifier outputs to loud speaker;
The abnormal determining step of power amplifier voltage: when power amplifier voltage value is in default normal voltage threshold range, output normal voltage level signal; When power amplifier voltage value is outside default normal voltage threshold range, output abnormality voltage level signal; In the present embodiment, described normal voltage level signal is high level, and described abnormal voltage level signal is low level.
The abnormal determining step of power amplifier: within the cycle of setting, the normal voltage level pulse of described offset port output or abnormal voltage level pulse are counted, and with the level pulse amount threshold of setting relatively after, determine the state of power amplifier, as be defined as abnormality, send power amplifier abnormal signal; In the present embodiment, microcontroller detects once every 2ms, high level pulse counting to the output of described skew (OFF SET) port within the cycle of the 60S setting, setting high level pulse amount threshold is 10, if high level pulse quantity is lower than 10, be defined as abnormality, send power amplifier abnormal signal.
Buzzing alarming step: receive described power amplifier abnormal signal and send abnormal prompting voice signal beep buzzer, beep buzzer, after power amplifier amplifies, is play by loud speaker.
Image shows alarm step: receive described power amplifier abnormal signal output abnormality and remind picture signal, described abnormal prompting picture signal is showing screen display, as shown " power amplifier fault (AMP ERROR).
Shutdown notifying process: receive send after described power amplifier abnormal signal shutdown notification message (as, after 5S by the notice of shutdown) preparation before receiving to each functional module, each functional module to shut down after shutdown notification message.
Shutdown procedures: receive described power amplifier abnormal signal and the time period of setting (as, 5S) after powered-down.
Above disclosed is only preferred embodiment of the present invention, can not limit the scope of the present invention with this, and the equivalent variations of therefore doing according to the present patent application the scope of the claims, still belongs to the scope that the present invention is contained.
Claims (8)
1. automatically detect the abnormal device of power amplifier, it is characterized in that, comprising:
Power amplifier voltage testing circuit, connects the voltage output end of power amplifier, outputs to the magnitude of voltage of loud speaker for detection of power amplifier;
The abnormal decision circuitry of power amplifier voltage, connects described power amplifier voltage testing circuit, when the power amplifier voltage value of inputting from described power amplifier voltage testing circuit is in default normal voltage threshold range, by offset port, exports normal voltage level signal; When the power amplifier voltage value of inputting from described power amplifier voltage testing circuit is default normal voltage threshold range, by offset port output abnormality voltage level signal;
Microcontroller, by its general input/output port, connect described offset port, for the normal voltage level pulse of described offset port output or abnormal voltage level pulse being counted in the cycle setting, and with the level pulse amount threshold of setting relatively after, determine the state of power amplifier, as be defined as abnormality, send power amplifier abnormal signal;
Buzzer, connects described microcontroller, and for receiving described power amplifier abnormal signal and sending abnormal prompting voice signal, described abnormal prompting voice signal, after power amplifier amplifies, is play by loud speaker.
2. the abnormal device of automatic detection power amplifier according to claim 1, is characterized in that, also comprises:
Image decoder, connects described microcontroller, for receiving described power amplifier abnormal signal output abnormality, reminds picture signal, and described abnormal prompting picture signal is showing screen display.
3. the abnormal device of automatic detection power amplifier according to claim 1 and 2, is characterized in that, also comprises:
Shutdown notification unit, connects described microcontroller, after receiving described power amplifier abnormal signal, sends shutdown notification message to each functional module, the preparation before shutting down after each functional module reception shutdown notification message.
4. the abnormal device of automatic detection power amplifier according to claim 3, is characterized in that, also comprises:
Shutdown unit, connects described microcontroller, for receiving described power amplifier abnormal signal and powered-down after the time period of setting.
5. automatically detect the abnormal method of power amplifier, it is characterized in that, comprising:
Power amplifier voltage detecting step: detect the magnitude of voltage that power amplifier outputs to loud speaker;
The abnormal determining step of power amplifier voltage: when power amplifier voltage value is in default normal voltage threshold range, output normal voltage level signal; When power amplifier voltage value is outside default normal voltage threshold range, output abnormality voltage level signal;
The abnormal determining step of power amplifier: within the cycle of setting, the normal voltage level pulse of described offset port output or abnormal voltage level pulse are counted, and with the level pulse amount threshold of setting relatively after, determine the state of power amplifier, as be defined as abnormality, send power amplifier abnormal signal;
Buzzing alarming step: receive described power amplifier abnormal signal and send abnormal prompting voice signal, described abnormal prompting voice signal, after power amplifier amplifies, is play by loud speaker.
6. the abnormal method of automatic detection power amplifier according to claim 1, is characterized in that, also comprises:
Image shows alarm step: receive described power amplifier abnormal signal output abnormality and remind picture signal, described abnormal prompting picture signal is showing screen display.
7. the abnormal method of automatic detection power amplifier according to claim 1 and 2, is characterized in that, also comprises:
Shutdown notifying process: send shutdown notification message to each functional module after receiving described power amplifier abnormal signal, the preparation before shutting down after each functional module reception shutdown notification message.
8. the abnormal method of automatic detection power amplifier according to claim 3, is characterized in that, also comprises:
Shutdown procedures: receive described power amplifier abnormal signal and powered-down after the time period of setting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310693584.0A CN103648075A (en) | 2013-12-16 | 2013-12-16 | Device and method for automatically detecting abnormality of power amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310693584.0A CN103648075A (en) | 2013-12-16 | 2013-12-16 | Device and method for automatically detecting abnormality of power amplifier |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN103648075A true CN103648075A (en) | 2014-03-19 |
Family
ID=50253214
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310693584.0A Pending CN103648075A (en) | 2013-12-16 | 2013-12-16 | Device and method for automatically detecting abnormality of power amplifier |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103648075A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104469614A (en) * | 2014-12-12 | 2015-03-25 | 广州市迪士普音响科技有限公司 | Power amplifier fault self-recovery circuit and implementation method thereof |
| CN105407434A (en) * | 2015-12-28 | 2016-03-16 | 上海博泰悦臻网络技术服务有限公司 | Output control system for audio power amplifier and electronic apparatus with system |
| CN106453480A (en) * | 2016-08-01 | 2017-02-22 | 惠州华阳通用电子有限公司 | Module level function test and fault diagnosis method for vehicle information system |
| CN109963247A (en) * | 2017-12-25 | 2019-07-02 | 长城汽车股份有限公司 | Horn assembly detection circuit and horn assembly detection method |
| CN110223616A (en) * | 2019-04-26 | 2019-09-10 | 深圳康佳电子科技有限公司 | A kind of intelligent terminal display screen detection method, intelligent terminal and storage medium |
| CN110896516A (en) * | 2018-09-12 | 2020-03-20 | 拉碧斯半导体株式会社 | Semiconductor device and audio output device |
| CN110913323A (en) * | 2019-11-30 | 2020-03-24 | 航天科技控股集团股份有限公司 | Method for detecting heat dissipation performance of vehicle-mounted power amplifier |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5166854A (en) * | 1989-03-15 | 1992-11-24 | Kabushiki Kaisha Toshiba | Externally discernible power supply abnormality detection system |
| JP2003304123A (en) * | 2002-04-11 | 2003-10-24 | Kenwood Corp | Audio amplifier and its abnormality detecting method |
| CN1550949A (en) * | 2003-05-14 | 2004-12-01 | ��ķ�ɷ�����˾ | Regulator protection circuit and power supply device comprising same |
| CN102403961A (en) * | 2011-11-18 | 2012-04-04 | 沈奕 | Intelligent monitoring and protecting system of high-power audio amplifier |
| JP2012085040A (en) * | 2010-10-08 | 2012-04-26 | Mitsubishi Electric Corp | On-vehicle audio device |
| CN203151434U (en) * | 2013-04-22 | 2013-08-21 | 惠州三星电子有限公司 | Power amplifier protective circuit |
| CN103389665A (en) * | 2013-07-20 | 2013-11-13 | 西安电子科技大学 | Detection control device of high-power digital power amplifier |
-
2013
- 2013-12-16 CN CN201310693584.0A patent/CN103648075A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5166854A (en) * | 1989-03-15 | 1992-11-24 | Kabushiki Kaisha Toshiba | Externally discernible power supply abnormality detection system |
| JP2003304123A (en) * | 2002-04-11 | 2003-10-24 | Kenwood Corp | Audio amplifier and its abnormality detecting method |
| CN1550949A (en) * | 2003-05-14 | 2004-12-01 | ��ķ�ɷ�����˾ | Regulator protection circuit and power supply device comprising same |
| JP2012085040A (en) * | 2010-10-08 | 2012-04-26 | Mitsubishi Electric Corp | On-vehicle audio device |
| CN102403961A (en) * | 2011-11-18 | 2012-04-04 | 沈奕 | Intelligent monitoring and protecting system of high-power audio amplifier |
| CN203151434U (en) * | 2013-04-22 | 2013-08-21 | 惠州三星电子有限公司 | Power amplifier protective circuit |
| CN103389665A (en) * | 2013-07-20 | 2013-11-13 | 西安电子科技大学 | Detection control device of high-power digital power amplifier |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104469614A (en) * | 2014-12-12 | 2015-03-25 | 广州市迪士普音响科技有限公司 | Power amplifier fault self-recovery circuit and implementation method thereof |
| CN104469614B (en) * | 2014-12-12 | 2018-01-09 | 广州市迪士普音响科技有限公司 | A kind of power amplifier failure self-repairing circuit and its implementation |
| CN105407434A (en) * | 2015-12-28 | 2016-03-16 | 上海博泰悦臻网络技术服务有限公司 | Output control system for audio power amplifier and electronic apparatus with system |
| CN106453480A (en) * | 2016-08-01 | 2017-02-22 | 惠州华阳通用电子有限公司 | Module level function test and fault diagnosis method for vehicle information system |
| CN109963247A (en) * | 2017-12-25 | 2019-07-02 | 长城汽车股份有限公司 | Horn assembly detection circuit and horn assembly detection method |
| CN110896516A (en) * | 2018-09-12 | 2020-03-20 | 拉碧斯半导体株式会社 | Semiconductor device and audio output device |
| CN110896516B (en) * | 2018-09-12 | 2023-10-31 | 拉碧斯半导体株式会社 | Semiconductor device and sound output device |
| CN110223616A (en) * | 2019-04-26 | 2019-09-10 | 深圳康佳电子科技有限公司 | A kind of intelligent terminal display screen detection method, intelligent terminal and storage medium |
| CN110913323A (en) * | 2019-11-30 | 2020-03-24 | 航天科技控股集团股份有限公司 | Method for detecting heat dissipation performance of vehicle-mounted power amplifier |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103648075A (en) | Device and method for automatically detecting abnormality of power amplifier | |
| KR101972136B1 (en) | The safety emergency broadcasting apparatus using checking the speaker line | |
| KR101434302B1 (en) | Method for detecting badness speaker and the sound apparatus using the same | |
| JPH10153636A (en) | Automatic defection of short circuit of speaker for automobile audio device | |
| WO2018157688A1 (en) | Electronic device and loudness-based detection method | |
| TW200830926A (en) | Audio apparatus and mute circuit thereof | |
| US5319714A (en) | Audio phase polarity test system | |
| KR101081826B1 (en) | Self-diagnosis display device of digital amplification | |
| CN103379419A (en) | Audio frequency access test system | |
| JP6495515B1 (en) | Voice notification device | |
| CN107205204A (en) | Earphone fault detection method and examination earphone special | |
| CN103813257A (en) | Air-defense warning loudspeaker device capable of on-line monitoring and monitoring method | |
| JP6499525B2 (en) | Fire receiver | |
| CN108347288B (en) | Fault detection method and system for disaster early warning broadcast | |
| CN105142072A (en) | Audio apparatus with externally connected player and audio playing method thereof | |
| CN215679619U (en) | Medical equipment and alarm sound self-checking circuit thereof | |
| CN208765840U (en) | A kind of sensor for on-line testing buzzer | |
| JP2013012973A (en) | Digital amplifier, method of controlling digital amplifier, and program | |
| CN109658671A (en) | A kind of medical electrical equipment auditory alarm system and method | |
| US8520864B2 (en) | Projector and audio output method | |
| CN106211014A (en) | Loudspeaker detection method and device | |
| JPH04120427A (en) | Sound level measuring apparatus | |
| TWI559782B (en) | Sound output of the control circuit | |
| CN207677691U (en) | Audio amplifier circuit and signal amplify module | |
| CN208572267U (en) | A kind of television audio output control system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20140319 |
|
| RJ01 | Rejection of invention patent application after publication |