CN102665158B - Ground wire noise eliminating circuit - Google Patents
Ground wire noise eliminating circuit Download PDFInfo
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- CN102665158B CN102665158B CN201210149291.1A CN201210149291A CN102665158B CN 102665158 B CN102665158 B CN 102665158B CN 201210149291 A CN201210149291 A CN 201210149291A CN 102665158 B CN102665158 B CN 102665158B
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- ground wire
- power amplifier
- independent
- ground
- audiogenic device
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Abstract
The invention relates to a ground wire noise eliminating circuit, which is connected between a power amplifier (A) and independent sound source equipment (B), and is characterized by comprising a differential amplifier (U3-A) of which the output end is electrically connected with the audio signal input of the power amplifier and the input end is connected with the audio output of independent sound source equipment and independent sound source equipment ground (B-GND) respectively, wherein power amplifier ground (A-GND) is electrically connected with differential amplifier ground; and the power amplifier ground is electrically connected with the independent sound source equipment ground through common power supply (C) ground. The circuit has the advantages of good ground wire noise suppressing effect, high audio index, simple circuit, low cost, small size and contribution to production.
Description
Technical field
The present invention relates to electronic circuit, be specifically related to the ground wire noise isolation unit in a kind of ground wire noise canceller circuit, especially vehicle-mounted audio frequency circuit.
Background technology
As Fig. 1-3, vehicle-mounted audio frequency circuit comprises the DC power supply C that power amplifier A, independent audiogenic device B and power amplifier A and independent audiogenic device B are shared, three's ground wire shares, in actual applications, the electric current that flows through power amplifier A and independent audiogenic device B has certain Alternating Component, because the ground line resistance between power amplifier A, independent audiogenic device B, DC power supply C can not be 0, between three, will produce an alternating voltage, the alternating voltage between power amplifier A and independent audiogenic device B is exactly our usually said ground wire noise U for this reason
g, this noise can amplify through power amplifier A, and the sound that power amplifier A is given to loudspeaker obviously has noise.
This situation has two methods to solve at present:
(1) strengthen the power filter of power amplifier A and independent audiogenic device B, exchanging between power amplifier A and independent audiogenic device B diminished, thus minimizing ground wire noise; The overstriking of trying one's best of ground wire between power amplifier A, independent audiogenic device B, DC power supply C, U
gcan relatively reduce, but in practical application, on the power supply of power amplifier A and independent audiogenic device B, add filter and have certain limit, cost is also high, distance between power amplifier A, independent audiogenic device B, DC power supply C is longer sometimes, and ground wire overstriking is also the problem that very limited (as just far away in the distance between the GPS on automobile, CD player, storage battery) makes can not thoroughly solve in this way ground wire noise for this reason to the Resistance Influence between three;
(2) between power amplifier A and independent audiogenic device B, add voice frequency isolation transformer T1, specifically as shown in Figure 4.Due to ground wire noise U
gcannot be added to the input of power amplifier A, in this way of great use, but because the frequency response of audio frequency transformer is generally very poor, very serious on tonequality impact, audio frequency transformer volume is larger simultaneously in institute, and cost is also higher.
Summary of the invention
The technical issues that need to address of the present invention are, how a kind of ground wire noise canceller circuit is provided, and can eliminate that ground wire noise and cost are low, volume is little, are conducive to produce.
Above-mentioned technical problem of the present invention solves like this: build a kind of ground wire noise canceller circuit, be connected between power amplifier and independent audiogenic device, comprise that output is electrically connected to the differential amplifier that the input of described power amplifier audio signal, input connect respectively described independent audiogenic device audio frequency output and described independent audiogenic device ground, be electrically connected to described power amplifier ground and described differential amplifier; Described power amplifier ground and described independent audiogenic device ground by common source be electrically connected to, specifically type of attachment comprises three kinds of circuit shown in Fig. 1-3.
According to ground wire noise canceller circuit provided by the invention, described differential amplifier is positioned at described independent audiogenic device side, and described differential amplifier output and differential amplifier ground is electrically connected to respectively described power amplifier audio signal input and power amplifier by cable separately.
According to ground wire noise canceller circuit provided by the invention, described differential amplifier is positioned at described power amplifier side, and described differential amplifier two inputs are electrically connected to respectively described independent audiogenic device audio signal output and independent audiogenic device by cable separately.
According to ground wire noise canceller circuit provided by the invention, described differential amplifier is one or a plurality of, one by one the quantity of the quantity of corresponding described power amplifier audio signal input or described independent audiogenic device audio signal output.
According to ground wire noise canceller circuit provided by the invention, described differential amplifier is two, is built in binary channels amplifier integrated circuit.
According to ground wire noise canceller circuit provided by the invention, this ground wire noise canceller circuit also comprises the second electric capacity and first electric capacity of going here and there respectively between described differential amplifier input and described independent audiogenic device audio frequency output and described independent audiogenic device ground.
According to ground wire noise canceller circuit provided by the invention, this ground wire noise canceller circuit also comprises three electric capacity of string between described differential amplifier output and the input of described power amplifier audio signal.
According to ground wire noise canceller circuit provided by the invention, described independent audiogenic device is MP3, MP4, GPS or mobile TV, CD, DVD.
According to ground wire noise canceller circuit provided by the invention, described power amplifier is independent power amplifier, be built in power amplifier module or independent power amplifier in vehicle-mounted CD player.
According to ground wire noise canceller circuit provided by the invention, described common source is Vehicular accumulator cell or other DC equipment (comprise generator, transformer adds rectifying device etc.).
Ground wire noise canceller circuit provided by the invention, breaks through conventional thought, adopts differential amplifier to substitute isolating transformer or power filter, thereby to cancel out each other, replaces reducing or isolation U
g, compared with prior art, there is following advantage:
1, ground wire noise is had to good inhibition, can make the distance of power amplifier and audio frequency autonomous device draw far, and not have noise;
2, audio-frequency index is very high, can not exert an influence to signal;
3, circuit is simple, as long as a binary channels amplifier integrated circuit (IC) and a small amount of outside unit workpiece just can realize the audio frequency ground wire noise processed of two passages;
4, cost is low, and volume is little, is conducive to produce.
Accompanying drawing explanation
Below in conjunction with the drawings and specific embodiments, further the present invention is described in detail:
Fig. 1 is vehicle-mounted voicefrequency circuit syndeton one schematic diagram of tradition;
Fig. 2 is vehicle-mounted voicefrequency circuit syndeton two schematic diagrames of tradition;
Fig. 3 is vehicle-mounted voicefrequency circuit syndeton three schematic diagrames of tradition;
Fig. 4 is the traditional vehicle-mounted audio frequency circuit syndeton schematic diagram that adopts voice frequency isolation transformer mode;
Fig. 5 is the corresponding ground wire noise equivalent circuit of circuit shown in Fig. 1-3 schematic diagram;
Fig. 6 is vehicle-mounted audio frequency circuit principle schematic equivalent circuit provided by the invention;
Fig. 7 is vehicle-mounted audio frequency circuit embodiment mono-schematic equivalent circuit provided by the invention;
Fig. 8 is vehicle-mounted audio frequency circuit embodiment bis-schematic equivalent circuits provided by the invention;
Fig. 9 is vehicle-mounted audio frequency circuit specific embodiment circuit theory schematic diagram provided by the invention.
Embodiment
First, take the root of signal analysis as base description ground wire noise:
Physical circuit analysis as shown in Figure 5, ground wire noise U
gcan by output equivalent resistance R O and input equivalent resistance RI dividing potential drop, be given to the signal input part of power amplifier A, due to generally, RI is much larger than RO, for this reason, and ground wire noise U
gbe equivalent to be entirely added to the input of power amplifier A, that is to say the ground wire noise U that superposeed on signal
g', this ground wire noise U
galthough ' very little, by after power amplifier A, will become very large.
The second, according to the root of ground wire noise, core of the present invention is described:
As Fig. 6, ground wire noise canceller circuit of the present invention adds a differential amplifier U3-A between power amplifier A and independent audiogenic device B, the ground wire noise voltage U between power amplifier A and independent audiogenic device B
g, be added to positive and negative two inputs auspicious (output equivalent resistance R O stays seldom conventionally, can work as 0 Europe and see) of differential amplifier simultaneously, thereby cancel out each other at output.The present invention from ground wire noise occurring principle, breaks through conventional thought according to deep circuit analysis, need not reduce merely or isolate U like this
gbut make U
gbrought into play effect but cancelled out each other, the concrete device that circuit of the present invention is corresponding specifically comprises the implementation (wherein ground wire A refers to power amplifier ground, and ground wire B refers to independent audiogenic device) of two kinds:
(1) be positioned at power amplifier side
As Fig. 7, now the signal link between power amplifier A and independent audiogenic device B is exactly ground wire B and two lines of signal, and now, in power amplifier A, ground wire B is only as another input of differential amplifier U3-A, and ground wire A is as differential amplifier U3-A place of working.
(2) be positioned at independent audiogenic device side
As Fig. 8, now the signal link between power amplifier A and independent audiogenic device B is exactly signal and two lines of ground wire A, now at independent audiogenic device B, ground wire A is as differential amplifier U3-A place of working, and ground wire B is as the place of working except differential amplifier U3-A in another input of differential amplifier U3-A and independent audiogenic device B
The second, in conjunction with the specific embodiment of the invention, be elaborated:
As shown in Figure 9, corresponding diagram 8, differential amplifier U3-A in the specific embodiment of the invention is arranged on independent audiogenic device B side, the signal that independent audiogenic device ground B_GND exports with advance signal is respectively by the first capacitor C 1 two inputs of being connected differential amplifier U3-A corresponding to the second capacitor C 2, again by the 3rd capacitor C 3 and holding wire power amplifier A, in power amplifier A, power amplifier ground A_GND connects power amplifier ground A_GND in independent audiogenic device B by ground wire A, and for differential amplifier, U3-A provides place of working.This specific embodiment also may be used in Fig. 2 and 3 in power amplifier A and independent audiogenic device B circuit connecting form.
Certainly, the above is only preferred embodiment of the present invention, and the equivalence done according to structure, feature and flow process described in patent claim of the present invention therefore all changes or modifies, in being included in patent claim of the present invention and being.
Claims (10)
1. a ground wire noise canceller circuit, be connected between power amplifier (A) and independent audiogenic device (B), it is characterized in that, comprise that output is electrically connected to the input of described power amplifier audio signal, input connect respectively described independent audiogenic device audio frequency output and the described independent audiogenic device differential amplifier (U3-A) of (B_GND), be electrically connected to described power amplifier ground (A_GND) and described differential amplifier; Described power amplifier ground is electrically connected to by common source with described independent audiogenic device ground (C).
2. ground wire noise canceller circuit according to claim 1, it is characterized in that, described differential amplifier (U3-A) is positioned at described independent audiogenic device (B) side, and described differential amplifier output and differential amplifier ground is electrically connected to respectively described power amplifier audio signal input and power amplifier (A_GND) by cable separately.
3. ground wire noise canceller circuit according to claim 1, it is characterized in that, described differential amplifier (U3-A) is positioned at described power amplifier side (A), and described differential amplifier two inputs are electrically connected to respectively described independent audiogenic device audio signal output and independent audiogenic device (B_GND) by cable separately.
4. ground wire noise canceller circuit according to claim 1, it is characterized in that, described differential amplifier (U3-A) is one or a plurality of, one by one the quantity of the quantity of corresponding described power amplifier (A) audio signal input or the output of described independent audiogenic device (B) audio signal.
5. ground wire noise canceller circuit according to claim 4, is characterized in that, described differential amplifier (U3-A) is two, is built in binary channels amplifier integrated circuit.
6. according to ground wire noise canceller circuit described in claim 1-5 any one, it is characterized in that, this ground wire noise canceller circuit also comprises the second electric capacity (C2) and first electric capacity (C1) of going here and there respectively between described differential amplifier (U3-A) input and described independent audiogenic device audio frequency output and described independent audiogenic device ground (B_GND).
7. according to ground wire noise canceller circuit described in claim 1-5 any one, it is characterized in that, this ground wire noise canceller circuit also comprises three electric capacity (C3) of string between described differential amplifier (U3-A) output and the input of described power amplifier (A) audio signal.
8. according to ground wire noise canceller circuit described in claim 1-5 any one, it is characterized in that, independent audiogenic device (B) is MP3, MP4, GPS or mobile TV, CD, DVD.
9. according to ground wire noise canceller circuit described in claim 1-5 any one, it is characterized in that, power amplifier (A) is independent power amplifier, be built in power amplifier module or independent power amplifier in vehicle-mounted CD player.
10. according to ground wire noise canceller circuit described in claim 1-5 any one, it is characterized in that, common source (C) is Vehicular accumulator cell, generator or transformer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210149291.1A CN102665158B (en) | 2012-05-15 | 2012-05-15 | Ground wire noise eliminating circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210149291.1A CN102665158B (en) | 2012-05-15 | 2012-05-15 | Ground wire noise eliminating circuit |
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| Publication Number | Publication Date |
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| CN102665158A CN102665158A (en) | 2012-09-12 |
| CN102665158B true CN102665158B (en) | 2014-09-10 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210149291.1A Active CN102665158B (en) | 2012-05-15 | 2012-05-15 | Ground wire noise eliminating circuit |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105519132A (en) * | 2015-07-13 | 2016-04-20 | 深圳市柔宇科技有限公司 | Electronic system denoising device, wearable display device and electronic device |
| CN105047212B (en) * | 2015-07-27 | 2018-04-10 | Tcl通力电子（惠州）有限公司 | Audio playing circuit and player |
| CN113990252B (en) * | 2021-11-01 | 2023-03-10 | 厦门天马显示科技有限公司 | Drive circuit and display module |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2058795U (en) * | 1989-08-16 | 1990-06-27 | 王志华 | Antinoise micorphone |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7006643B2 (en) * | 2001-06-08 | 2006-02-28 | Logitech Europe S.A. | Differential audio amplification system |
| JP4482048B2 (en) * | 2008-05-30 | 2010-06-16 | 株式会社日本自動車部品総合研究所 | Receiver |
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2012
- 2012-05-15 CN CN201210149291.1A patent/CN102665158B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2058795U (en) * | 1989-08-16 | 1990-06-27 | 王志华 | Antinoise micorphone |
Non-Patent Citations (4)
| Title |
|---|
| "BA3121/D3121地隔离放大器电路IC性能特点及应用电路说明";和讯博客;《和讯博客》;20111209;应用图,内部框图与管脚排列图 * |
| "车载电脑共地干扰的几种解決办法";和训博客;《和讯博客》;20111213;全文 * |
| 和训博客."车载电脑共地干扰的几种解決办法".《和讯博客》.2011, |
| 和讯博客."BA3121/D3121地隔离放大器电路IC性能特点及应用电路说明".《和讯博客》.2011,应用图,内部框图与管脚排列图. |
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| CN102665158A (en) | 2012-09-12 |
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