CN111343539A - High signal-to-noise ratio vehicle-mounted audio-video system and implementation method thereof - Google Patents
High signal-to-noise ratio vehicle-mounted audio-video system and implementation method thereof Download PDFInfo
- Publication number
- CN111343539A CN111343539A CN202010117617.7A CN202010117617A CN111343539A CN 111343539 A CN111343539 A CN 111343539A CN 202010117617 A CN202010117617 A CN 202010117617A CN 111343539 A CN111343539 A CN 111343539A
- Authority
- CN
- China
- Prior art keywords
- power amplifier
- module
- attenuation
- audio
- signal
- 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
Classifications
-
- 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
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Amplifiers (AREA)
Abstract
The invention relates to the technical field of vehicle-mounted audio and video, in particular to a high signal-to-noise ratio vehicle-mounted audio and video system and an implementation method thereof. The invention adopts a built-in power amplifier IC with fixed gain, and the attenuation module is only built by a conventional triode and a resistor, so that the cost is well controlled; when the mode control module is adopted to identify the external power amplifier module through the CAN network or the external power amplifier mode is configured under the line, the attenuation amplitude of the attenuation module is controlled so as to control the input amplitude of the built-in power amplifier IC, thereby reducing the audio output amplitude and the bottom noise, realizing high signal-to-noise ratio and achieving the purpose of being compatible with high and low vehicle allocation models.
Description
Technical Field
The invention relates to the technical field of vehicle-mounted audio and video, in particular to a high signal-to-noise ratio vehicle-mounted audio and video system and an implementation method thereof.
Background
In order to save research and development cost and period, more and more vehicles and factories require platform development of vehicle navigation audio-visual systems, one host is required to be adapted to a plurality of vehicle types, and the purpose of being compatible with different functions is achieved through CAN information or offline configuration of vehicles. Some high joining in marriage type vehicles and join in marriage a more on-vehicle external power amplifier than low joining in marriage type, if direct with the loudspeaker output signal input of vehicle navigation audio-visual system to on-vehicle external power amplifier, then can appear the volume mismatch, the too big problem that damages external power amplifier or end noise is big of output amplitude, seriously influence experience and feel. Aiming at the defect, the prior art mainly overcomes the defect by two modes of software adjustment or selection of a built-in power amplifier IC with variable gain.
1. And (3) software implementation: the output amplitude of the audio processor is adjusted by software. The disadvantages are that: the signal-to-noise ratio is very low. The reason is that the audio processor belongs to the most noisy component in the audio path, and the amplitude of the bottom noise is a fixed value, independent of adjusting the amplitude of the output of the audio processor. The bottom noise is amplified and transmitted to the external power amplifier after passing through the power amplifier IC with fixed gain, so that the bottom noise is amplified again.
2. The method is realized by selecting a variable gain power amplifier IC: the output amplitude of the audio processor is improved, the gain of the power amplifier is reduced, and the amplification factor of the bottom noise of the audio processor is reduced due to the reduction of the amplification factor of the power amplifier while the output amplitude of the power amplifier is unchanged. The disadvantages are that: the price of the power amplifier IC with variable gain is much higher than that of the fixed gain; the workload of software is increased by bus control; the gain is only two grades of 26db/16db, and the applicable range is not wide enough.
Disclosure of Invention
The invention provides a high signal-to-noise ratio vehicle-mounted audio-video system and an implementation method thereof, and solves the technical problems that the output amplitude of the conventional fixed-gain built-in power amplifier IC is not matched with the vehicle-mounted external power amplifier and the signal-to-noise ratio of the system is very low, and the conventional variable-gain built-in power amplifier IC is high in price and has insufficient levels of control through a bus and gain adjustment.
In order to solve the technical problems, the invention provides a high signal-to-noise ratio vehicle-mounted audio and video system which is provided with an audio processing module, an internal power amplifier module, a mode control module, an attenuation module and a power amplifier detection module, wherein the attenuation module is connected between the audio processing module and the internal power amplifier module and is also connected with the mode control module;
the audio processing module is used for outputting a plurality of paths of initial audio signals;
the power amplifier detection module is used for generating an external power amplifier configuration signal and sending the external power amplifier configuration signal to the mode control module when detecting that the external power amplifier module or the off-line configuration external power amplifier mode is configured;
the mode control module is used for generating a corresponding attenuation control signal according to the external power amplifier configuration signal and sending the attenuation control signal to the attenuation module;
the attenuation module is used for attenuating the initial audio signal by a first attenuation amplitude under the action of the attenuation control signal, outputting a plurality of paths of externally-output audio signals to the internal power amplifier module, amplifying the signals and outputting the signals to the external power amplifier module.
Preferably, the attenuation module comprises an attenuation control circuit and a plurality of attenuation sub-circuits connected to the mode control module; each attenuation sub-circuit corresponds to one path of the initial audio signal;
the attenuation sub-circuit comprises first to third voltage division resistors and a first triode; the base electrode of the first triode is connected with the control output end of the attenuation control circuit, the emitter electrode of the first triode is connected with analog ground, the collector electrode of the first triode is connected with one end of the first divider resistor, the other end of the first divider resistor is connected with one end of the second divider resistor and one audio signal input end of the built-in power amplifier module, and the other end of the second divider resistor is connected with the corresponding audio signal output end of the audio processing module; the third voltage dividing resistor is connected between the other end of the first voltage dividing resistor and the analog ground.
Preferably, the attenuation control circuit comprises a second triode and a protection resistor; the base electrode of the second triode is connected with the control signal output end of the mode control module through the protective resistor, and the collector electrode of the second triode is connected with the base electrode of each first triode.
The first attenuation width a1 is 20log [ (R1 × R3+ R2 × R1+ R3))/(R1 × R2+ R3)) ], and R1, R2, and R3 respectively represent the resistance values of the first, second, and third voltage dividing resistors.
Specifically, the audio processing module outputs at least two of six initial audio signals, namely a front left channel, a front right channel, a rear left channel, a rear right channel, a center channel and a super bass channel.
In another case, the power amplifier detection module is further configured to not output any signal when the external power amplifier module is not detected or an off-line configuration external power amplifier mode is not detected;
the mode control module is also used for not outputting any signal when the power amplifier detection module does not output any signal;
the attenuation module is further configured to perform attenuation of a second attenuation amplitude on the initial audio signal when the mode control module does not output any signal, and then output the multi-path amplified audio signal to the built-in power amplifier module.
Preferably, the power amplifier detection module detects the external power amplifier module or the off-line configuration external power amplifier mode through a CAN network.
Specifically, the built-in power amplifier module adopts a gain-fixed power amplifier IC.
The invention also provides a method for realizing the high signal-to-noise ratio vehicle-mounted audio-video system, which comprises the following steps:
s1, a mode control module detects whether an external power amplifier module exists through a power amplifier detection module, if so, an external power amplifier configuration signal is generated and the next step is carried out, and if not, the step S5 is carried out;
s2, the mode control module generates a corresponding attenuation control signal according to the external power amplifier configuration signal;
s3, adjusting or manually adjusting a first attenuation amplitude of the built-in power amplifier module by the mode control module according to the attenuation control signal;
s4, the attenuation module attenuates the multi-channel initial audio signals output by the audio processing module according to the first attenuation amplitude, amplifies the signals by the built-in power amplifier module and outputs the signals to the external power amplifier module for playing;
and S5, the attenuation module attenuates the multi-channel initial audio signals output by the audio processing module according to a second attenuation amplitude, and the signals are amplified by the built-in power amplifier module and then played.
The invention provides a high signal-to-noise ratio vehicle-mounted audio-video system and a realization method thereof.A built-in power amplifier IC with fixed gain is adopted, and an arranged attenuation module is only built by a conventional triode and a resistor, so that the cost is well controlled; when the mode control Module (MCU) is adopted to identify the external power amplifier module through the CAN network or the external power amplifier mode is configured under the line, the attenuation amplitude of the attenuation module is controlled so as to control the input amplitude of the internal power amplifier IC, thereby reducing the audio output amplitude and the bottom noise, realizing high signal-to-noise ratio and achieving the purpose of being compatible with vehicles of high and low configuration.
Drawings
Fig. 1 is a block diagram of a high snr vehicle audio/video system according to an embodiment of the present invention;
fig. 2 is a structure refinement diagram of an attenuation module of an embodiment of the present invention.
And (3) graphic labeling: the audio processing module 1, the built-in power amplifier module 2, the mode control module 3, the attenuation module 4, the power amplifier detection module 5, the external power amplifier module 6, the attenuation control circuit 41 (the second triode Q2 and the protection resistor R4) and the attenuation sub-circuit 42 (the first to third voltage-dividing resistors R1 to R3 and the first triode Q1).
Detailed Description
The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, which are given solely for the purpose of illustration and are not to be construed as limitations of the invention, including the drawings which are incorporated herein by reference and for illustration only and are not to be construed as limitations of the invention, since many variations thereof are possible without departing from the spirit and scope of the invention.
As shown in fig. 1, an embodiment of the present invention provides a high snr vehicle audio/video system, which includes an audio processing module 1, an internal power amplifier module 2, a mode control module 3, an attenuation module 4, and a power amplifier detection module 5, where the attenuation module 4 is connected between the audio processing module 1 and the internal power amplifier module 2 and is also connected to the mode control module 3, the power amplifier detection module 5 is connected to the mode control module 3, and the internal power amplifier module 2 and the power amplifier detection module 5 are also connected to the external power amplifier module 6 when there is the external power amplifier module 6;
the audio processing module 1 is used for outputting a plurality of paths of initial audio signals;
the power amplifier detection module 5 is configured to generate an external power amplifier configuration signal and send the external power amplifier configuration signal to the mode control module 3 when detecting that the external power amplifier module 6 or an off-line external power amplifier mode is configured;
the mode control module 3 is configured to generate a corresponding attenuation control signal according to the external power amplifier configuration signal and send the attenuation control signal to the attenuation module 4;
the attenuation module 4 is configured to attenuate the initial audio signal by a first attenuation amplitude under the action of the attenuation control signal, and then output a plurality of paths of external audio signals to the internal power amplifier module 2 for signal amplification, and then output the signals to the external power amplifier module 6.
Specifically, the audio processing module 1 outputs at least two of six initial audio signals, i.e., a front left channel, a front right channel, a rear left channel, a rear right channel, a center channel, and a subwoofer channel.
As a preferred embodiment, as shown in fig. 2, the audio processing module 1 outputs four initial audio signals, i.e., a front left channel (audio FL), a front right channel (audio FR), a rear left channel (audio RL), and a rear right channel (audio RR), and correspondingly, the internal power amplifier module 2 and the external power amplifier module 6 correspond to the four initial audio signals.
In fig. 2, the attenuation module 4 comprises an attenuation control circuit 41 and four attenuation sub-circuits 42 connected to the mode control module 3; each attenuation sub-circuit 42 corresponds to one of the original audio signals.
The attenuator sub-circuit 42 comprises first to third voltage dividing resistors R1 to R3 and a first triode Q1; a base (B) of the first triode Q1 is connected to a control output terminal (a collector C of the second triode Q2) of the attenuation control circuit 41, an emitter (E) is connected to an Analog Ground (AGND), a collector (C) is connected to one end of the first voltage-dividing resistor R1, the other end of the first voltage-dividing resistor R1 is connected to one end of the second voltage-dividing resistor R2 and one audio signal input terminal of the internal power amplifier module 2, and the other end of the second voltage-dividing resistor R2 is connected to the corresponding audio signal output terminal of the audio processing module 1; the third voltage dividing resistor R3 is connected between the other end of the first voltage dividing resistor R1 and the Analog Ground (AGND).
Specifically, the attenuation control circuit 41 includes a second transistor Q2 and a protection resistor R4; the base (B) of the second transistor Q2 is connected with the control signal output end of the mode control module 3 through the protective resistor R4, and the collector (C) is connected with the base (B) of each first transistor Q1. In this embodiment, the first transistor Q1 is a transistor with a built-in current-limiting resistor, such as DTC343 TK.
When the mode control module 3 detects that the external power amplifier module 6 or the external power amplifier mode is configured offline through the CAN network, the external power amplifier module outputs an attenuation control signal, so that the second triode Q2 and the four first triodes Q1 are conducted, and an audio input signal of the (power amplifier IC of the) internal power amplifier module 2 is obtained by connecting the first divider resistor R1 and the third divider resistor R3 in parallel and then dividing the audio input signal by the second divider resistor R2. In this circuit connection state, the first attenuation amplitude a1 is 20log [ (R1 × R3+ R2 (R1+ R3))/(R1 (R2+ R3)) ] (a1 is an attenuation amount of the external amplification operation mode compared with the non-external amplification operation mode, that is, the signal amount of the non-external amplification operation is 1), R1, R2, and R3 respectively represent the resistance values of the first, second, and third voltage dividing resistors, and in a specific embodiment, the magnitude of the first attenuation amplitude a1 is determined according to the type of the external power amplifier module 6 (by adjusting the resistance values of R1, R2, and R3). In the embodiment, the resistances of the first, second, and third voltage dividing resistors R1-R3 are all selected, so that the first attenuation range is determined, and a higher attenuation range is set to be compatible with most external power amplifier modules 6, for example, R1 is 2K Ω, R2 is 8.2K Ω, R3 is 10K Ω, and a1 is 10 dB.
In another situation, the power amplifier detection module 5 is further configured to not output any signal when the external power amplifier module 6 is not detected or an off-line configuration external power amplifier mode is not detected;
the mode control module 3 is further configured to not output any signal when the power amplifier detection module 5 does not output any signal (Q1, Q2 are not conductive);
the attenuation module 4 is further configured to perform attenuation of a second attenuation amplitude on the initial audio signal when no signal is output by the mode control module 3, and output a multi-path amplified audio signal to the built-in power amplifier module 2.
Specifically, the audio input signal of (the power amplifier IC of) the built-in power amplifier module 2 is obtained by dividing the voltage of the second voltage dividing resistor R2 and the third voltage dividing resistor R3.
Preferably, the power amplifier detection module 5 detects the external power amplifier module 6 or the off-line configuration external power amplifier mode through a CAN network.
Preferably, in this embodiment, the built-in power amplifier module 2 employs a power amplifier IC with fixed gain.
The embodiment of the invention also provides a method for realizing the high signal-to-noise ratio vehicle-mounted audio and video system, which comprises the following steps:
s1, a mode control module 3 detects whether an external power amplifier module 6 exists through a power amplifier detection module 5, if so, an external power amplifier configuration signal is generated and the next step is carried out, and if not, the step S5 is carried out;
s2, the mode control module 3 generates a corresponding attenuation control signal according to the external power amplifier configuration signal;
s3, the mode control module 3 adjusts or manually adjusts the first attenuation amplitude of the built-in power amplifier module 2 according to the attenuation control signal;
s4, the attenuation module 4 attenuates the multi-path initial audio signals output by the audio processing module 1 according to the first attenuation amplitude A1, amplifies the signals by the built-in power amplifier module 2, and outputs the signals to the external power amplifier module 6 for playing;
and S5, the attenuation module 4 attenuates the multi-channel initial audio signals output by the audio processing module 1 according to a second attenuation amplitude (set as 1), and the signals are amplified by the built-in power amplification module 2 and then played.
According to the vehicle-mounted audio-video system with the high signal-to-noise ratio and the implementation method thereof, the built-in power amplifier IC with fixed gain is adopted, the arranged attenuation module 4 is only built by a conventional triode and a resistor, and the cost is well controlled; when the mode control module 3(MCU) is adopted to identify the external power amplifier module 6 or the off-line configuration external power amplifier mode through the CAN network, the attenuation amplitude of the attenuation module 4 is controlled to realize the control of the input amplitude of the internal power amplifier IC, so that the audio output amplitude and the bottom noise are reduced, the high signal-to-noise ratio is realized, and the purpose of being compatible with high-low vehicle allocation models is achieved.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.
Claims (9)
1. The utility model provides a high SNR vehicle audio-visual system, is equipped with audio processing module and built-in power amplifier module, its characterized in that: the audio processing module is connected with the built-in power amplifier module, the power amplifier detection module is connected with the mode control module, and the built-in power amplifier module and the power amplifier detection module are also connected with the external power amplifier module when the external power amplifier module exists;
the audio processing module is used for outputting a plurality of paths of initial audio signals;
the power amplifier detection module is used for generating an external power amplifier configuration signal and sending the external power amplifier configuration signal to the mode control module when detecting that the external power amplifier module or the off-line configuration external power amplifier mode is configured;
the mode control module is used for generating a corresponding attenuation control signal according to the external power amplifier configuration signal and sending the attenuation control signal to the attenuation module;
the attenuation module is used for attenuating the initial audio signal by a first attenuation amplitude under the action of the attenuation control signal, outputting a plurality of paths of externally-output audio signals to the internal power amplifier module, amplifying the signals and outputting the signals to the external power amplifier module.
2. The high snr vehicle audio/video system of claim 1, wherein:
the attenuation module comprises an attenuation control circuit and a plurality of attenuation sub-circuits which are connected with the mode control module; each attenuation sub-circuit corresponds to one path of the initial audio signal;
the attenuation sub-circuit comprises first to third voltage division resistors and a first triode; the base electrode of the first triode is connected with the control output end of the attenuation control circuit, the emitter electrode of the first triode is connected with analog ground, the collector electrode of the first triode is connected with one end of the first divider resistor, the other end of the first divider resistor is connected with one end of the second divider resistor and one audio signal input end of the built-in power amplifier module, and the other end of the second divider resistor is connected with the corresponding audio signal output end of the audio processing module; the third voltage dividing resistor is connected between the other end of the first voltage dividing resistor and the analog ground.
3. The high snr vehicle audio/video system of claim 2, wherein: the attenuation control circuit comprises a second triode and a protection resistor; the base electrode of the second triode is connected with the control signal output end of the mode control module through the protective resistor, and the collector electrode of the second triode is connected with the base electrode of each first triode.
4. The high snr vehicle audio/video system of claim 3, wherein: the first attenuation width a1 is 20log [ (R1 × R3+ R2 × R1+ R3))/(R1 × R2+ R3)) ], and R1, R2, and R3 respectively represent the resistance values of the first, second, and third voltage dividing resistors.
5. The high snr vehicle audio/video system of claim 2, wherein: the audio processing module at least outputs two of six initial audio signals of a front left channel, a front right channel, a rear left channel, a rear right channel, a middle channel and a super bass channel.
6. The high snr vehicle audio/video system of claim 4, wherein:
the power amplifier detection module is also used for not outputting any signal when the external power amplifier module is not detected or the off-line configuration external power amplifier mode is not detected;
the mode control module is also used for not outputting any signal when the power amplifier detection module does not output any signal;
the attenuation module is further configured to perform attenuation of a second attenuation amplitude on the initial audio signal when the mode control module does not output any signal, and then output the multi-path amplified audio signal to the built-in power amplifier module.
7. The high snr vehicle audio/video system of claim 1, wherein: the power amplifier detection module detects the external power amplifier module or the off-line configuration external power amplifier mode through the CAN network.
8. The high snr vehicle audio/video system according to any of the preceding claims, wherein: the built-in power amplifier module adopts a gain-fixed power amplifier IC.
9. A method for realizing a high signal-to-noise ratio vehicle-mounted audio-video system is characterized by comprising the following steps:
s1, a mode control module detects whether an external power amplifier module exists through a power amplifier detection module, if so, an external power amplifier configuration signal is generated and the next step is carried out, and if not, the step S5 is carried out;
s2, the mode control module generates a corresponding attenuation control signal according to the external power amplifier configuration signal;
s3, adjusting or manually adjusting a first attenuation amplitude of the built-in power amplifier module by the mode control module according to the attenuation control signal;
s4, the attenuation module attenuates the multi-channel initial audio signals output by the audio processing module according to the first attenuation amplitude, amplifies the signals by the built-in power amplifier module and outputs the signals to the external power amplifier module for playing;
and S5, the attenuation module attenuates the multi-channel initial audio signals output by the audio processing module according to a second attenuation amplitude, and the signals are amplified by the built-in power amplifier module and then played.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010117617.7A CN111343539A (en) | 2020-02-25 | 2020-02-25 | High signal-to-noise ratio vehicle-mounted audio-video system and implementation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010117617.7A CN111343539A (en) | 2020-02-25 | 2020-02-25 | High signal-to-noise ratio vehicle-mounted audio-video system and implementation method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111343539A true CN111343539A (en) | 2020-06-26 |
Family
ID=71187501
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010117617.7A Pending CN111343539A (en) | 2020-02-25 | 2020-02-25 | High signal-to-noise ratio vehicle-mounted audio-video system and implementation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111343539A (en) |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101051856A (en) * | 2007-01-30 | 2007-10-10 | 深圳国人通信有限公司 | Voltage control attenuator, method for realizing voltage control attenuator and application circuit |
| JP2010089617A (en) * | 2008-10-07 | 2010-04-22 | Panasonic Corp | Onboard audio device |
| CN101828333A (en) * | 2007-08-03 | 2010-09-08 | 沃福森微电子股份有限公司 | Amplifier circuit and method of amplifying a signal in an amplifier circuit |
| CN102404670A (en) * | 2011-11-16 | 2012-04-04 | 北京经纬恒润科技有限公司 | Vehicle-mounted audio frequency circuit |
| WO2012059782A1 (en) * | 2010-11-01 | 2012-05-10 | Continental Automotive Gmbh | Radio receiver with adaptive tuner |
| CN202907158U (en) * | 2012-11-30 | 2013-04-24 | 惠州市德赛西威汽车电子有限公司 | Vehicle-mounted digital-audio processing system for reducing background noise |
| CN203311848U (en) * | 2013-04-28 | 2013-11-27 | 惠州市德赛西威汽车电子有限公司 | Vehicle-borne multimedia system |
| CN103633950A (en) * | 2013-12-06 | 2014-03-12 | 广东好帮手电子科技股份有限公司 | Power amplifier control device and power amplifier control method of car-mounted multimedia device |
| CN104836535A (en) * | 2015-05-20 | 2015-08-12 | 西安电子科技大学 | Wide variable gain amplifier |
| CN106055303A (en) * | 2016-05-31 | 2016-10-26 | 惠州华阳通用电子有限公司 | Control method and device of power amplifier mode of car-mounted terminal |
| US20160360315A1 (en) * | 2015-06-02 | 2016-12-08 | Alpine Electronics, Inc. | Audio apparatus, and current control method |
| US20190132063A1 (en) * | 2017-11-02 | 2019-05-02 | Avago Technologies International Sales Pte. Limited | Low gain listen |
-
2020
- 2020-02-25 CN CN202010117617.7A patent/CN111343539A/en active Pending
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101051856A (en) * | 2007-01-30 | 2007-10-10 | 深圳国人通信有限公司 | Voltage control attenuator, method for realizing voltage control attenuator and application circuit |
| CN101828333A (en) * | 2007-08-03 | 2010-09-08 | 沃福森微电子股份有限公司 | Amplifier circuit and method of amplifying a signal in an amplifier circuit |
| JP2010089617A (en) * | 2008-10-07 | 2010-04-22 | Panasonic Corp | Onboard audio device |
| WO2012059782A1 (en) * | 2010-11-01 | 2012-05-10 | Continental Automotive Gmbh | Radio receiver with adaptive tuner |
| CN102404670A (en) * | 2011-11-16 | 2012-04-04 | 北京经纬恒润科技有限公司 | Vehicle-mounted audio frequency circuit |
| CN202907158U (en) * | 2012-11-30 | 2013-04-24 | 惠州市德赛西威汽车电子有限公司 | Vehicle-mounted digital-audio processing system for reducing background noise |
| CN203311848U (en) * | 2013-04-28 | 2013-11-27 | 惠州市德赛西威汽车电子有限公司 | Vehicle-borne multimedia system |
| CN103633950A (en) * | 2013-12-06 | 2014-03-12 | 广东好帮手电子科技股份有限公司 | Power amplifier control device and power amplifier control method of car-mounted multimedia device |
| CN104836535A (en) * | 2015-05-20 | 2015-08-12 | 西安电子科技大学 | Wide variable gain amplifier |
| US20160360315A1 (en) * | 2015-06-02 | 2016-12-08 | Alpine Electronics, Inc. | Audio apparatus, and current control method |
| CN106055303A (en) * | 2016-05-31 | 2016-10-26 | 惠州华阳通用电子有限公司 | Control method and device of power amplifier mode of car-mounted terminal |
| US20190132063A1 (en) * | 2017-11-02 | 2019-05-02 | Avago Technologies International Sales Pte. Limited | Low gain listen |
Non-Patent Citations (1)
| Title |
|---|
| 王昭: "适用于TD_SCDMA系统的极低功耗发射机", 《通信技术》 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7409067B2 (en) | Method and apparatus for adjusting frequency characteristic of signal | |
| EP2039221B1 (en) | Crosstalk cancellation using load impedence measurements | |
| CN104066036A (en) | Pick-up device and method | |
| US9967665B2 (en) | Adaptation of dynamic range enhancement based on noise floor of signal | |
| US8180072B2 (en) | Electronic volume device | |
| US5414386A (en) | Muting apparatus in car audio system | |
| CN1938957A (en) | Noise removing circuit | |
| US6760452B2 (en) | Multi-channel audio signal limiter with shared clip detection | |
| WO2020173227A1 (en) | Microphone preamplifier circuit having gain adjustment | |
| US20110150244A1 (en) | Audio Signal Amplifier for Karaoke Player | |
| US7200239B2 (en) | Acoustic apparatus having balance adjustment | |
| US20120039487A1 (en) | First stage amplifier circuit | |
| CN111343539A (en) | High signal-to-noise ratio vehicle-mounted audio-video system and implementation method thereof | |
| US8259962B2 (en) | Audio system configured to fade audio outputs and method thereof | |
| US10726873B2 (en) | Polymorphic playback system with signal detection filters of different latencies | |
| WO2024021651A1 (en) | Analog front-end chip and oscilloscope | |
| CN106060714A (en) | Control method and device for reducing sound source noises | |
| US20190131947A1 (en) | Audio circuit | |
| US20120328126A1 (en) | Audio signal processing circuit | |
| CN1114818A (en) | Car audio system with high signal output | |
| US6782107B1 (en) | Method and arrangement for automatically controlling the volume in an audio signal reproduction device | |
| CN102710913A (en) | Television and sound effect adjusting method and device of same | |
| JP6912967B2 (en) | Sound field correction data calculation device and sound field correction device | |
| JP3482123B2 (en) | Sound equipment | |
| CN202907158U (en) | Vehicle-mounted digital-audio processing system for reducing background noise |
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 | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20200626 |