CN102026063B - Pseudo differential audio input circuit and installation method thereof - Google Patents
Pseudo differential audio input circuit and installation method thereof Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R5/00—Stereophonic arrangements
- H04R5/04—Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments
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Abstract
The invention discloses a pseudo differential audio input circuit and an installation method thereof, wherein the circuit comprises a first passage, a second passage, a high frequency interference filtering component, a voltage regulation component and an audio output port, wherein the first passage and the second passage are connected with an audio input port; the high frequency interference filtering component is arranged on the first passage and the second passage and used for filtering high frequency differential mode interference and high frequency common mode interference; the voltage regulation component is connected to the first passage and the second passage and used for leading the bias voltage on the first passage to be equal to the bias voltage on the second passage; and the first passage is connected to the audio output port. By the invention, the problem of common mode interference in the prior art can be solved, thus achieving the aims of improving audio transmission and storage quality.
Description
Technical field
The present invention relates to the communications field, in particular to a kind of pseudo differential audio input circuit and method to set up thereof.
Background technology
Existing mobile communication terminal the inside, audio interface has two kinds, one is monomer microphone interface, and one is ear microphone interface, aspect processing of circuit, it can be single-ended audio signal input, wherein an end is received ground, and single-ended audio signal is difficult to avoid being interfered in signals transmission, sort circuit, cannot remove the common mode disturbances in analog channel, noise ratio is larger, another kind is pseudo-differential input, in existing design, as shown in Figure 1, circuit comprises earphone interface, two biasing resistor R1, R2, filter capacitor C3, C4, C5, capacitance C1, C2, and audio input port, wherein pass through R1, R2 will move bias voltage on audio frequency two paths, it is the basis of realizing pseudo-differential circuit, C3, C4 is connected respectively to ground, be used for filtering high frequency differential mode disturb, C3 cross-over connection two-way audio path filtering high frequency common mode is disturbed, 3 electric capacity are the filtering design to a certain characteristic frequency, C 1, C2 rises every constant current object at audio input port.Biasing resistor R1 as seen from the figure, R2 makes biasing on voice-frequency channel not on same level, be assumed to be respectively v1 and v2, when two-way audio input signal is subject to after common mode noise signal s interference, the signal of the interference on two-way audio signal path becomes v1*s and v2*s, when audio input port subtracts each other as difference, v1*s-v2*s=(v1-v2) s, because v1 is not equal to v2, so cannot reach the effect of difference channel elimination common mode disturbances, in audio signal, still there are a large amount of noises to exist, affect to a certain extent the transmission of audio frequency and store quality.
Summary of the invention
Main purpose of the present invention is to provide a kind of pseudo differential audio input circuit and method to set up thereof, at least to address the above problem.
According to an aspect of the present invention, provide a kind of pseudo differential audio input circuit, it comprises: the first path and the alternate path that are connected with audio input port; Be arranged on the High-frequency Interference filtering parts on described the first path and described alternate path, disturb and high frequency common mode interference for filtering high frequency differential mode; Be connected to the voltage regulator components of described the first path and described alternate path, for making the bias voltage on described the first path equal the bias voltage on described alternate path; The audio output port being connected with described the first path.
Further, described voltage regulator components comprises: the first biasing resistor R1, be connected between described the first path and bias voltage, and wherein, the tie point of described R1 and described the first path is the first connected node; The second biasing resistor R2, is connected between described alternate path and described bias voltage, and wherein, the tie point of described R2 and described alternate path is the second connected node; Adjusting resistance R3, is connected between described alternate path and ground, and wherein, the tie point of described R3 and described alternate path is described the second connected node; Wherein, the resistance between described R1, R2 and R3 is closed and is: make the voltage at described the first connected node place equate with the voltage at described the second connected node place by the resistance relation of described R1, R2 and R3.
Further, described R3 is adjustable resistance.
Further, above-mentioned pseudo differential audio input circuit also comprises: isolated part, be connected between described the first path and described audio output port, and disturb and noise for isolating extraneous direct current.
Further, described isolated part is inductance L 1, is connected between described the first connected node and described audio output port.
Further, described High-frequency Interference filtering parts comprise: the first capacitor C 1, is connected on described the first path, for isolated DC; The second capacitor C 2, is connected on described alternate path, for isolated DC; The 3rd capacitor C 3, one end is connected with described C1, and the other end is connected with described, disturbs for filtering high frequency differential mode; The 4th capacitor C 4, is connected across between described the first path and described alternate path, and one end is connected to described C1 and C3, and the other end is connected to described C2, disturbs for filtering high frequency common mode; The 5th capacitor C 5, one end is connected to described C2 and described C4, and the other end is connected to the ground, and disturbs for filtering high frequency differential mode.
According to a further aspect in the invention, provide a kind of method to set up of pseudo differential audio input circuit, wherein, described circuit comprises: the first path and the alternate path that are connected with audio input port; Be arranged on the High-frequency Interference filtering parts on described the first path and described alternate path, disturb and high frequency common mode interference for filtering high frequency differential mode; Be connected to the voltage regulator components of described the first path and described alternate path; The audio output port being connected with described the first path; Described method comprises: regulate described voltage regulator components so that the bias voltage on described the first path equals the bias voltage on described alternate path.
Further, described voltage regulator components comprises: the first biasing resistor R1, be connected between described the first path and bias voltage, and wherein, the tie point of described R1 and described the first path is the first connected node; The second biasing resistor R2, is connected between described alternate path and described bias voltage, and wherein, the tie point of described R2 and described alternate path is the second connected node; Adjusting resistance R3, is connected between described alternate path and ground; Wherein, regulate described voltage regulator components so that the bias voltage on described the first path equals the step of the bias voltage on described alternate path comprises: regulate described R3 value until the voltage at described the first connected node place equate with the voltage at described the second connected node place.
Further, said method also comprises: between described the first path and described audio output port, isolated part is set, disturbs and noise for isolating extraneous direct current.
Further, comprise in the step that isolated part is set between described the first path and described audio output port: between described the first connected node and described audio output port, inductance L 1 is set.
In the present invention, by the voltage regulator components arranging in difference channel, for two bias voltages on path are equated, solve and cannot eliminate the problem of common mode disturbances in prior art, and then reached the effect that improves audio transmission and store quality.
Brief description of the drawings
Accompanying drawing described herein is used to provide a further understanding of the present invention, forms the application's a part, and schematic description and description of the present invention is used for explaining the present invention, does not form inappropriate limitation of the present invention.In the accompanying drawings:
Fig. 1 is according to the connection diagram of the audio interface circuit of correlation technique;
Fig. 2 is according to the preferred connection diagram of the one of the pseudo differential audio input circuit of the embodiment of the present invention;
Fig. 3 is according to the preferred connection diagram of the another kind of the pseudo differential audio input circuit of the embodiment of the present invention.
Embodiment
Embodiment 1
Fig. 2 is taking ear microphone as having exemplified the pseudo differential audio input circuit according to the embodiment of the present invention.As shown in Figure 2, comprise according to the pseudo differential audio input circuit of the embodiment of the present invention:
1) the first path and the alternate path that are connected with audio input port;
2) be arranged on the High-frequency Interference filtering parts on described the first path and described alternate path, disturb and high frequency common mode interference for filtering high frequency differential mode; Preferably, High-frequency Interference filtering parts comprise: filter capacitor C3, C4, C5, capacitance C1, C2;
3) be connected to the voltage regulator components of described the first path and described alternate path, for making the bias voltage on described the first path equal the bias voltage on described alternate path; Preferably, voltage regulator components comprises: two pull-up resistor R1, R2, the resistance R 3 of simulation ear microphone negative terminal impedance;
4) audio output port being connected with described the first path, preferred, audio output port is earphone interface.
In this preferred embodiment, by the voltage regulator components arranging in difference channel, for two bias voltages on path are equated, solve and cannot eliminate the problem of common mode disturbances in prior art, and then reached the effect that improves audio transmission and store quality.
Preferably, can also comprise in the embodiment shown in Figure 2: the inductance L 1 of voice-frequency channel incoming end (ear microphone anode).Certainly, the present invention is not limited only to this, and inductance L 1 is optional.
The effect of the each parts in the circuit shown in Fig. 2 is below described:
1) inductance L 1, for isolating, extraneous direct current disturbs and the preliminary isolation of noise;
2) resistance R 1, R2 is respectively the biasing resistor of pseudo-differential two voice-frequency channels, two resistance are received same bias voltage, the internal resistance of ear microphone is generally 2.2k ohm, in order to make the audio signal of microphone generating obtain maximum distortionless effect, the clamping of audio frequency input channel, at 1/2nd bias voltages, is got to R1, and R2 is 2.2k ohm;
3) C4, C3, C5 filter capacitor, C3, C5, mainly plays the high frequency differential mode of a certain frequency range of filtering and disturbs, and the high frequency common mode of a certain frequency range of the main filtering of C4 is disturbed, and is mainly the common mode disturbances of 900MHz;
4) capacitor C 1, C2 is mainly used for isolating the DC level in audio signal path, and what the present invention mainly paid close attention to is the common mode disturbances of low frequency, is mainly low frequency signal because of what can hear for people's ear;
5) resistance R 3, regulates the bias voltage in audio signal path, and two path bias voltages are equated; Preferably, described R3 is adjustable resistance.
The implementation method of circuit: as shown in Figure 2,
Step S1, by two biasing resistor R1, R2, is connected respectively to same bias supply by audio signal two paths;
Step S2, in working order under, measure the level at test1 place, obtain voltage v1;
Step S3, in working order under, measure the level at test2 place, obtain voltage v2;
Step S4, the resistance of adjusting resistance R3, the partial pressure value at change v2 place, until the level at test2 place equals the level at test1 place;
Like this, when being subject on two-way audio path after common mode noise signal s interference, noise becomes v1*s and v2*s, v1*s-v2*s=when two paths of signals subtracts each other as difference (v1-v2) s, because v1 is identical with v2 level, so result is 0, has eliminated common mode disturbances, has improved the signal quality of audio frequency.
In this preferred embodiment, by two resistance R 1, R2 moves same bias voltage two-way audio signal on, 2, on the voice-frequency channel that there is no audio signal input (alternate path), an external resistance R 3, object is to make the test1 place level on the voice-frequency channel (the first path) of audio signal input to equate with the test2 place level on alternate path, utilizes differential principle elimination common mode disturbances.In addition, because the circuit in this preferred embodiment can be removed low frequency common mode disturbances at audio input end by differential signal, so can save the large electric capacity of common mode filtering.
Embodiment 2
The present invention can also be applicable to the situation of monomer microphone input, and as shown in Figure 3, pseudo differential audio input circuit comprises: the first path and the alternate path that are connected with audio input port; Be arranged on the High-frequency Interference filtering parts on described the first path and described alternate path, disturb and high frequency common mode interference for filtering high frequency differential mode; Be connected to the voltage regulator components of described the first path and described alternate path, for making the bias voltage on described the first path equal the bias voltage on described alternate path; The audio output port being connected with described the first path.
Preferably, described voltage regulator components comprises: the first biasing resistor R1, be connected between described the first path and bias voltage, and wherein, the tie point of described R1 and described the first path is the first connected node; The second biasing resistor R2, is connected between described alternate path and described bias voltage, and wherein, the tie point of described R2 and described alternate path is the second connected node; Adjusting resistance R3, is connected between described alternate path and ground, and wherein, the tie point of described R3 and described alternate path is described the second connected node; Wherein, the resistance between described R1, R2 and R3 is closed and is: make the voltage at described the first connected node place equate with the voltage at described the second connected node place by the resistance relation of described R1, R2 and R3.
Preferably, described R3 is adjustable resistance.
Preferably, pseudo differential audio input circuit also comprises: isolated part, be connected between described the first path and described audio output port, and disturb and noise for isolating extraneous direct current.
Preferably, described isolated part is inductance L 1, is connected between described the first connected node and described audio output port.
Preferably, described High-frequency Interference filtering parts comprise: the first capacitor C 1, is connected on described the first path, for isolated DC; The second capacitor C 2, is connected on described alternate path, for isolated DC; The 3rd capacitor C 3, one end is connected with described C1, and the other end is connected with described, disturbs for filtering high frequency differential mode; The 4th capacitor C 4, is connected across between described the first path and described alternate path, and one end is connected to described C1 and C3, and the other end is connected to described C2, disturbs for filtering high frequency common mode; The 5th capacitor C 5, one end is connected to described C2 and described C4, and the other end is connected to the ground, and disturbs for filtering high frequency differential mode.
It is basic identical that the described ear microphone of circuit structure shown in Fig. 3 and operation principle and embodiment 1 is inputted, and do not repeat them here.Because the present invention can apply in the circuit of mobile phone monomer microphone input, therefore, can on mobile phone terminal, play equally the effect of difference, can also reduce costs simultaneously.
Embodiment 3
The present invention also protects a kind of method to set up of pseudo differential audio input circuit, and wherein, described circuit comprises: the first path and the alternate path that are connected with audio input port; Be arranged on the High-frequency Interference filtering parts on described the first path and described alternate path, disturb and high frequency common mode interference for filtering high frequency differential mode; Be connected to the voltage regulator components of described the first path and described alternate path; The audio output port being connected with described the first path; Described method comprises: regulate described voltage regulator components so that the bias voltage on described the first path equals the bias voltage on described alternate path.
In this preferred embodiment, by the voltage regulator components arranging in difference channel, for two bias voltages on path are equated, solve and cannot eliminate the problem of common mode disturbances in prior art, and then reached the effect that improves audio transmission and store quality.
Preferably, described voltage regulator components comprises: the first biasing resistor R1, be connected between described the first path and bias voltage, and wherein, the tie point of described R1 and described the first path is the first connected node; The second biasing resistor R2, is connected between described alternate path and described bias voltage, and wherein, the tie point of described R2 and described alternate path is the second connected node; Adjusting resistance R3, is connected between described alternate path and ground; Wherein, regulate described voltage regulator components so that the bias voltage on described the first path equals the step of the bias voltage on described alternate path comprises: regulate described R3 value until the voltage at described the first connected node place equate with the voltage at described the second connected node place.
Preferably, said method also comprises: between described the first path and described audio output port, isolated part is set, disturbs and noise for isolating extraneous direct current.
Preferably, comprise in the step that isolated part is set between described the first path and described audio output port: between described the first connected node and described audio output port, inductance L 1 is set.
Obviously, those skilled in the art should be understood that, above-mentioned of the present invention each module or each step can realize with general calculation element, they can concentrate on single calculation element, or be distributed on the network that multiple calculation elements form, alternatively, they can be realized with the executable program code of calculation element, thereby, they can be stored in storage device and be carried out by calculation element, and in some cases, can carry out shown or described step with the order being different from herein, or they are made into respectively to each integrated circuit modules, or the multiple modules in them or step are made into single integrated circuit module to be realized.Like this, the present invention is not restricted to any specific hardware and software combination.
The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any amendment of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.
Claims (6)
1. a pseudo differential audio input circuit, is characterized in that, comprising:
The first path and the alternate path that are connected with audio input port;
Be arranged on the High-frequency Interference filtering parts on described the first path and described alternate path, disturb and high frequency common mode interference for filtering high frequency differential mode;
Be connected to the voltage regulator components of described the first path and described alternate path, for making the bias voltage on described the first path equal the bias voltage on described alternate path;
The audio output port being connected with described the first path;
Wherein, described pseudo differential audio input circuit also comprises: isolated part, be connected between described the first path and described audio output port, and disturb and noise for isolating extraneous direct current;
Wherein, described voltage regulator components comprises: the first biasing resistor R1, be connected between described the first path and bias voltage, and wherein, the tie point of described R1 and described the first path is the first connected node; The second biasing resistor R2, is connected between described alternate path and described bias voltage, and wherein, the tie point of described R2 and described alternate path is the second connected node; Adjusting resistance R3, is connected between described alternate path and ground, and wherein, the tie point of described R3 and described alternate path is described the second connected node; Wherein, the resistance between described R1, R2 and R3 is closed and is: make the voltage at described the first connected node place equate with the voltage at described the second connected node place by the resistance relation of described R1, R2 and R3.
2. pseudo differential audio input circuit according to claim 1, is characterized in that, described R3 is adjustable resistance.
3. pseudo differential audio input circuit according to claim 1, is characterized in that, described isolated part is inductance L 1, is connected between described the first connected node and described audio output port.
4. pseudo differential audio input circuit according to claim 1, is characterized in that, described High-frequency Interference filtering parts comprise:
The first capacitor C 1, is connected on described the first path, for isolated DC;
The second capacitor C 2, is connected on described alternate path, for isolated DC;
The 3rd capacitor C 3, one end is connected with described C1, and the other end is connected with described, disturbs for filtering high frequency differential mode;
The 4th capacitor C 4, is connected across between described the first path and described alternate path, and one end is connected to described C1 and C3, and the other end is connected to described C2, disturbs for filtering high frequency common mode;
The 5th capacitor C 5, one end is connected to described C2 and described C4, and the other end is connected to the ground, and disturbs for filtering high frequency differential mode.
5. a method to set up for pseudo differential audio input circuit, is characterized in that, described circuit comprises: the first path and the alternate path that are connected with audio input port; Be arranged on the High-frequency Interference filtering parts on described the first path and described alternate path, disturb and high frequency common mode interference for filtering high frequency differential mode; Be connected to the voltage regulator components of described the first path and described alternate path; The audio output port being connected with described the first path;
Described method comprises:
Regulate described voltage regulator components so that the bias voltage on described the first path equals the bias voltage on described alternate path;
Wherein, described method also comprises: between described the first path and described audio output port, isolated part is set, disturbs and noise for isolating extraneous direct current;
Wherein, described voltage regulator components comprises: the first biasing resistor R1, be connected between described the first path and bias voltage, and wherein, the tie point of described R1 and described the first path is the first connected node; The second biasing resistor R2, is connected between described alternate path and described bias voltage, and wherein, the tie point of described R2 and described alternate path is the second connected node; Adjusting resistance R3, is connected between described alternate path and ground; Wherein, regulate described voltage regulator components so that the bias voltage on described the first path equals the step of the bias voltage on described alternate path comprises: regulate described R3 value until the voltage at described the first connected node place equate with the voltage at described the second connected node place.
6. method according to claim 5, is characterized in that, the step that isolated part is set between described the first path and described audio output port comprises:
Between described the first connected node and described audio output port, inductance L 1 is set.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010561685.9A CN102026063B (en) | 2010-11-26 | 2010-11-26 | Pseudo differential audio input circuit and installation method thereof |
| PCT/CN2011/082624 WO2012068985A1 (en) | 2010-11-26 | 2011-11-22 | Pseudo-differential audio input circuit and arrangement method therefor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201010561685.9A CN102026063B (en) | 2010-11-26 | 2010-11-26 | Pseudo differential audio input circuit and installation method thereof |
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| CN102026063A CN102026063A (en) | 2011-04-20 |
| CN102026063B true CN102026063B (en) | 2014-12-10 |
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| CN201010561685.9A Active CN102026063B (en) | 2010-11-26 | 2010-11-26 | Pseudo differential audio input circuit and installation method thereof |
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| WO (1) | WO2012068985A1 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102026063B (en) * | 2010-11-26 | 2014-12-10 | 中兴通讯股份有限公司 | Pseudo differential audio input circuit and installation method thereof |
| CN103095240A (en) * | 2011-10-31 | 2013-05-08 | 成都高新区尼玛电子产品外观设计工作室 | Voice frequency PA output matching circuit |
| CN104703091A (en) * | 2013-12-06 | 2015-06-10 | 上海果壳电子有限公司 | Wearable equipment provided with noise elimination device |
| CN105992098B (en) * | 2015-01-30 | 2020-03-10 | 中兴通讯股份有限公司 | Audio input circuit and electronic terminal |
| CN105365600A (en) * | 2015-10-30 | 2016-03-02 | 北京理工大学 | Differential mode interference propagation path of electric vehicle motor driving system |
| CN107172540A (en) * | 2017-06-26 | 2017-09-15 | 上海与德科技有限公司 | A kind of Dolby circuit, filter circuit and the equipment of earphone Mike signal |
| CN107820160B (en) * | 2017-09-30 | 2020-11-06 | 深圳市艾特智能科技有限公司 | Signal input circuit |
| CN108563279A (en) * | 2018-07-11 | 2018-09-21 | 重庆线易电子科技有限责任公司 | Filter circuit of pressure-stabilizing and signal deteching circuit |
| CN109275071B (en) * | 2018-11-06 | 2022-03-04 | 珠海市杰理科技股份有限公司 | Audio processing device, chip, system and method |
| CN113473315B (en) * | 2021-07-31 | 2022-06-28 | 展讯通信（上海）有限公司 | Electronic device capable of improving output performance of earphone |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN200990687Y (en) * | 2006-12-21 | 2007-12-12 | 康佳集团股份有限公司 | Earphone interface circuit |
| CN201141908Y (en) * | 2008-01-25 | 2008-10-29 | 北京芯慧同用微电子技术有限责任公司 | Bias voltage generation device |
| CN201479352U (en) * | 2009-07-29 | 2010-05-19 | 比亚迪股份有限公司 | Audio adjusting circuit of earphone sender |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201307878Y (en) * | 2008-11-05 | 2009-09-09 | 宇龙计算机通信科技(深圳)有限公司 | Analog audio input circuit, mobile communication terminal and earphone |
| CN102026063B (en) * | 2010-11-26 | 2014-12-10 | 中兴通讯股份有限公司 | Pseudo differential audio input circuit and installation method thereof |
-
2010
- 2010-11-26 CN CN201010561685.9A patent/CN102026063B/en active Active
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- 2011-11-22 WO PCT/CN2011/082624 patent/WO2012068985A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN200990687Y (en) * | 2006-12-21 | 2007-12-12 | 康佳集团股份有限公司 | Earphone interface circuit |
| CN201141908Y (en) * | 2008-01-25 | 2008-10-29 | 北京芯慧同用微电子技术有限责任公司 | Bias voltage generation device |
| CN201479352U (en) * | 2009-07-29 | 2010-05-19 | 比亚迪股份有限公司 | Audio adjusting circuit of earphone sender |
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| WO2012068985A1 (en) | 2012-05-31 |
| CN102026063A (en) | 2011-04-20 |
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