CN207266266U - Analog differential circuit and audio frequency apparatus - Google Patents
Analog differential circuit and audio frequency apparatus Download PDFInfo
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- CN207266266U CN207266266U CN201721263155.XU CN201721263155U CN207266266U CN 207266266 U CN207266266 U CN 207266266U CN 201721263155 U CN201721263155 U CN 201721263155U CN 207266266 U CN207266266 U CN 207266266U
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Abstract
The utility model discloses a kind of analog differential circuit and audio frequency apparatus, which includes：The Butterworth filter circuit that the audio signal of access is converted into exporting after negative differential signal, its input terminal are used for incoming audio signal, its output terminal is connected with the first input end of differential signal output circuit and the input terminal of low-pass filter circuit respectively；After the negative differential signal that Butterworth filter circuit is exported carries out anti-phase and filtering process, obtain principal-employment sub-signal and the low-pass filter circuit exported, its output terminal are connected with the second input terminal of differential signal output circuit；The differential signal output circuit for negative differential signal and principal-employment sub-signal export after divider filter processing, its decoding circuit of the first output terminal and the second output terminal respectively with the audio frequency apparatus are connected.The utility model significantly reduces the requirement to amplifier common-mode rejection ratio, so as to fulfill the requirement of the audio performances such as signal-to-noise ratio, distortion is improved.
Description
Technical field
Electronic circuit technology field is the utility model is related to, more particularly to a kind of analog differential circuit and audio frequency apparatus.
Background technology
In the audio frequency apparatuses such as television set, sound equipment, typically by the sound of the analog signal output received to audio frequency apparatus
In display system.In order to solve the problem of analog signal is easier to be interfered, is not suitable for Distance Transmission farther out, generally use is poor
Analog signal is switched to difference form transmission by parallel circuit, to improve antijamming capability.
At present, difference channel is formed using an in-phase proportion circuit and an anti-phase ratio circuit mostly.But this difference
In-phase proportion circuit in parallel circuit requires height to amplifier common-mode rejection ratio, can not realize that raising signal-to-noise ratio, distortion etc. are audio property
The requirement of energy.
Utility model content
The main purpose of the utility model is to propose one kind, it is intended to the requirement to amplifier common-mode rejection ratio is effectively reduced,
So as to fulfill the requirement for improving the audio performances such as signal-to-noise ratio, distortion.
To achieve the above object, the utility model proposes a kind of analog differential circuit, it is described applied in audio frequency apparatus
Analog differential circuit includes Butterworth filter circuit, low-pass filter circuit and differential signal output circuit, the Butterworth
The input terminal of filter circuit is used for incoming audio signal, and the output terminal of the Butterworth filter circuit is believed with the difference respectively
The input terminal connection of the first input end and the low-pass filter circuit of number output circuit；The output terminal of the low-pass filter circuit
It is connected with the second input terminal of the differential signal output circuit；The first output terminal and second of the differential signal output circuit
Decoding circuit of the output terminal respectively with the audio frequency apparatus is connected；Wherein,
The Butterworth filter circuit, for being exported after the audio signal of access is converted into negative differential signal；
The low-pass filter circuit, for the negative differential signal that exports the Butterworth filter circuit carry out it is anti-phase and
After filtering process, obtain principal-employment sub-signal and export；
The differential signal output circuit, for carrying out divider filter to the negative differential signal and the principal-employment sub-signal
Exported after processing to the decoding circuit of the audio frequency apparatus.
Preferably, the Butterworth filter circuit includes：
First Butterworth filter unit, left sound is converted into for accessing the left channel audio signal in the audio signal
Exported after road negative differential signal；
Second Butterworth filter unit, the right channel audio signal for accessing in the audio signal are converted into
Exported after R channel negative differential signal.
Preferably, the first Butterworth filter unit includes the first capacitance, the second capacitance, the 3rd capacitance, the first electricity
Resistance, second resistance, 3rd resistor and the first operational amplifier, the first end of first capacitance are filtered for first Butterworth
The input terminal of ripple unit, it is the first end of the second end of first capacitance through the first resistor and the second resistance, described
The first end of 3rd resistor and the interconnection of the first end of second capacitance, the second end of the second resistance and first computing
The first end of the inverting input of amplifier and the 3rd capacitance interconnects；The output terminal of first operational amplifier is described
The output terminal of first Butterworth filter unit, and it is mutual with the second end of the second end of the 3rd resistor and the 3rd capacitance
Even；The normal phase input end of first operational amplifier is connected with the first DC power supply；The second end ground connection of second capacitance.
Preferably, the second Butterworth filter unit includes the 4th capacitance, the 5th capacitance, the 6th capacitance, the 4th electricity
Resistance, the 5th resistance, the 6th resistance and the second operational amplifier, the first end of the 4th capacitance are filtered for second Butterworth
The input terminal of ripple unit, first end of the second end of the 4th capacitance through the 4th resistance and the 5th resistance, the 6th
The first end of resistance and the interconnection of the first end of the 5th capacitance, second end and second operation amplifier of the 5th resistance
The first end of the inverting input of device and the 6th capacitance interconnects；The output terminal of second operational amplifier is described second
The output terminal of Butterworth filter unit, and interconnected with the second end of the 6th resistance and the second end of the 6th capacitance；
The normal phase input end of second operational amplifier is connected with the second DC power supply；The second end ground connection of 5th capacitance.
Preferably, the low-pass filter circuit includes：
First low-pass filter unit, for the L channel negative differential signal for exporting the first Butterworth filter unit
Exported after being converted into L channel principal-employment sub-signal；
Second low-pass filter unit, for the R channel negative differential signal for exporting the second Butterworth filter unit
Exported after being converted into R channel principal-employment sub-signal.
Preferably, first low-pass filter unit is put including the 7th capacitance, the 7th resistance, the 8th resistance and the 3rd computing
Big device, the first end of the 7th resistance are the input terminal of first low-pass filter unit, the second end of the 7th resistance
The first end of inverting input, the 8th resistance with the 3rd operational amplifier and the first end interconnection of the 7th capacitance；
The output terminal of 3rd operational amplifier is the output terminal of first low-pass filter unit, and with the of the 8th resistance
The second end of two ends and the 7th capacitance interconnects；The normal phase input end of 3rd operational amplifier and the first DC power supply connect
Connect.
Preferably, second low-pass filter unit is put including the 8th capacitance, the 9th resistance, the tenth resistance and the 4th computing
Big device, the first end of the 9th resistance are the input terminal of second low-pass filter unit, the second end of the 9th resistance
The first end of inverting input, the tenth resistance with four-operational amplifier and the first end interconnection of the 8th capacitance；
The output terminal of the four-operational amplifier is the output terminal of first low-pass filter unit, and with the of the tenth resistance
The second end of two ends and the 8th capacitance interconnects；The normal phase input end of the four-operational amplifier and the second DC power supply connect
Connect.
Preferably, the differential signal output circuit includes multiple partial pressure units and corresponding with multiple partial pressure units sets
The capacitance put, the input terminal of multiple partial pressure units are a pair of with multiple output terminals one of the low-pass filter circuit respectively
It should connect, the first end of the output terminals of multiple partial pressure units respectively with multiple capacitances connects one to one, more
The second end of a capacitance connects one to one with the multiple input end of the decoding circuit respectively.
The utility model also proposes a kind of audio frequency apparatus, and the audio frequency apparatus includes decoding circuit and simulation as described above
Difference channel；The analog differential circuit includes Butterworth filter circuit, low-pass filter circuit and differential signal output circuit,
The input terminal of the Butterworth filter circuit is used for incoming audio signal, the output terminal difference of the Butterworth filter circuit
It is connected with the first input end of the differential signal output circuit and the input terminal of the low-pass filter circuit；The low-pass filtering
The output terminal of circuit is connected with the second input terminal of the differential signal output circuit；The first of the differential signal output circuit
The decoding circuit of output terminal and the second output terminal respectively with the audio frequency apparatus is connected；Wherein, the Butterworth filter circuit,
For being exported after the audio signal of access is converted into negative differential signal；The low-pass filter circuit, for by described bar
After the negative differential signal of special Butterworth filter circuit output carries out anti-phase and filtering process, obtain principal-employment sub-signal and export；It is described
Differential signal output circuit, for the negative differential signal and the principal-employment sub-signal are carried out export after divider filter processing to
The decoding circuit of the audio frequency apparatus.
Preferably, the decoding circuit includes decoding integrated chip.
In the present embodiment, when detecting left audio input interface and/or right audio channel input interface has simulation to believe
During number input, Butterworth filter circuit carries out the analog signal of single ended input anti-phase and amplifies and be converted into differential signal, and
High-frequency signal in differential signal is carried out to filter out processing, to obtain negative differential signal, and is exported to differential signal output circuit
With the input terminal of low-pass filter circuit.The negative differential signal of access is carried out 1 by low-pass filter circuit 20:1 anti-phase processing is converted into
Principal-employment sub-signal, and align the high-frequency signal in differential signal and carry out filtering out processing, to obtain after principal-employment sub-signal output to difference
Sub-signal output circuit.The negative differential signal and low-pass filter circuit that differential output circuit exports Butterworth filter circuit are defeated
The principal-employment sub-signal gone out carries out blocking filtering process, and is exported after carrying out voltage division processing to the decoding circuit of audio system, so that
Realize single-ended signal slip sub-signal and efficient, high-quality transmission.The Butterworth filter circuit and rank low pass of the utility model
Filter circuit is anti-phase ratio circuit, while is also negative-feedback circuit, can be effectively reduced to amplifier common-mode rejection ratio
It is required that the requirement so as to fulfill audio performances such as raising signal-to-noise ratio, distortions.The utility model also achieves the simulation of single ended input
Signal slip sub-signal exports, and then solves analog signal and is easier to be interfered, and is not suitable for asking for Distance Transmission farther out
Topic.
Brief description of the drawings
In order to illustrate the embodiment of the utility model or the technical proposal in the existing technology more clearly, below will be to embodiment
Or attached drawing needed to be used in the description of the prior art is briefly described, it should be apparent that, drawings in the following description are only
It is some embodiments of the utility model, for those of ordinary skill in the art, in the premise not made the creative labor
Under, other attached drawings can also be obtained according to the structure shown in these attached drawings.
Fig. 1 is the high-level schematic functional block diagram that the utility model analog differential circuit is applied to one embodiment of audio frequency apparatus；
Fig. 2 is the circuit of one embodiment of Butterworth filter circuit and low-pass filter circuit of analog differential circuit in Fig. 1
Structure diagram；
Fig. 3 is the electrical block diagram of one embodiment of differential signal output circuit of analog differential circuit in Fig. 1.
The embodiments will be further described with reference to the accompanying drawings for the realization, functional characteristics and advantage of the utility model aim.
Embodiment
The following is a combination of the drawings in the embodiments of the present utility model, and the technical scheme in the embodiment of the utility model is carried out
Clearly and completely describing, it is clear that described embodiment is only the part of the embodiment of the utility model, rather than all
Embodiment.Based on the embodiment in the utility model, those of ordinary skill in the art are not making creative work premise
Lower all other embodiments obtained, shall fall within the protection scope of the present invention.
If it is to be appreciated that related in the utility model embodiment directionality instruction (such as upper and lower, left and right, it is preceding,
Afterwards ...), then directionality instruction be only used for explain it is opposite between each component under a certain particular pose (as shown in drawings)
Position relationship, motion conditions etc., if the particular pose changes, directionality instruction also correspondingly changes correspondingly.
If, should " first ", " the in addition, relate to the description of " first ", " second " etc. in the utility model embodiment
Two " etc. description is only used for description purpose, and it is not intended that instruction or implying its relative importance or implicit indicating meaning
The quantity of the technical characteristic shown.Thus, " first " is defined, the feature of " second " can express or implicitly include at least one
A this feature.In addition, the technical solution between each embodiment can be combined with each other, but must be with ordinary skill
Personnel can be implemented as basis, and this technical side is will be understood that when the combination appearance of technical solution is conflicting or can not realize
The combination of case is not present, also not within the protection domain of the requires of the utility model.
The utility model proposes a kind of analog differential circuit, applied in audio frequency apparatus.
The audio frequency apparatus can be Android TV, portable computer, mobile phone, mini speaker, multi-path sound box sound bar
Deng the audio frequency apparatus with audio system.
In these audio frequency apparatuses, typically by the audio system of the analog signal output received to audio frequency apparatus.
In order to solve the problem of analog signal is easier to be interfered, is not suitable for Distance Transmission farther out, generally use difference channel handle
Analog signal switchs to difference form transmission, to improve antijamming capability.
Difference channel is formed using an in-phase proportion circuit and an anti-phase ratio circuit mostly.But this differential electrical
In-phase proportion circuit in road requires height to amplifier common-mode rejection ratio, can not realize and improve the audio performances such as signal-to-noise ratio, distortion
It is required that.
Reference Fig. 1 and Fig. 3, to solve the above-mentioned problems, in one embodiment of the utility model, the analog differential circuit bag
Include Butterworth filter circuit 10, low-pass filter circuit 20 and differential signal output circuit 30, the Butterworth filter circuit
10 input terminal is used for incoming audio signal, and the output terminal of the Butterworth filter circuit 10 is defeated with the differential signal respectively
Go out the input terminal connection of the first input end and the low-pass filter circuit 20 of circuit 30；The output of the low-pass filter circuit 20
End is connected with the second input terminal of the differential signal output circuit 30；First output terminal of the differential signal output circuit 30
It is connected with decoding circuit of second output terminal respectively with the audio frequency apparatus；Wherein,
The Butterworth filter circuit 10, it is defeated after negative differential signal for the audio signal of access to be converted into
Go out；
The low-pass filter circuit 20, the negative differential signal for the Butterworth filter circuit 10 to be exported carry out anti-
Mutually and after filtering process, obtain principal-employment sub-signal and export；
The differential signal output circuit 30, for carrying out partial pressure filter to the negative differential signal and the principal-employment sub-signal
Exported after ripple processing to the decoding circuit of the audio frequency apparatus.
It should be noted that the audio input interface J1 for inputting simulated audio signal is both provided with audio frequency apparatus,
And audio input interface J1 has left audio input interface AUX-L and right audio channel input interface AUX-R.The present embodiment
In, two input terminals of Butterworth filter circuit 10 are defeated with left audio input interface AUX-L and right audio channel respectively
Incoming interface AUX-R corresponds to connection, to access the simulated audio signal of single ended input, hereinafter referred to as analog signal.
Wherein, Butterworth filter circuit 10, i.e., unlimited gain multiple feedback circuit, Butterworth filter circuit 10 is to list
The analog signal of end input carries out anti-phase and amplification and is converted into differential signal, and the high-frequency signal in differential signal is filtered out
Processing, to obtain negative differential signal.
The input terminal of low-pass filter circuit 20 is connected with the output terminal of Butterworth filter circuit 10, by the minus tolerance of access
Sub-signal carries out 1:1 anti-phase processing is converted into principal-employment sub-signal, and aligns the high-frequency signal in differential signal and carry out filtering out processing,
To obtain principal-employment sub-signal.
The input terminal of differential signal output circuit 30 output terminal and low-pass filtering with Butterworth filter circuit 10 respectively
The output terminal connection of circuit 20, the negative differential signal and low-pass filter circuit 20 that Butterworth filter circuit 10 is exported export
Principal-employment sub-signal carry out blocking filtering process, and output after voltage division processing is carried out to the decoding circuit of audio system, so that real
Existing single-ended signal slip sub-signal and efficient, high-quality transmission.
In the present embodiment, when detecting that left audio input interface J1 and/or right audio channel input interface J1 have mould
When intending signal input, Butterworth filter circuit 10 carries out anti-phase and amplification to the analog signal of single ended input and is converted into difference letter
Number, and the high-frequency signal in differential signal is carried out to filter out processing, to obtain negative differential signal, and export to differential signal and export
The input terminal of circuit 30 and low-pass filter circuit 20.The negative differential signal of access is carried out 1 by low-pass filter circuit 20:1 anti-phase place
Reason is converted into principal-employment sub-signal, and aligns the high-frequency signal in differential signal and carry out filtering out processing, after obtaining principal-employment sub-signal
Export to differential signal output circuit 30.Negative differential signal that differential output circuit exports Butterworth filter circuit 10 and low
The principal-employment sub-signal that bandpass filter circuit 20 exports carries out blocking filtering process, and is exported after carrying out voltage division processing to audio system
Decoding circuit, so as to fulfill single-ended signal slip sub-signal and efficient, high-quality transmission.The Butterworth filtering of the utility model
Circuit 10 and rank low-pass filter circuit 20 are anti-phase ratio circuit, while are also negative-feedback circuit, can be effectively reduced pair
The requirement of amplifier common-mode rejection ratio, so as to fulfill the requirement of the audio performances such as signal-to-noise ratio, distortion is improved.The utility model is also realized
The analog signal slip sub-signal output of single ended input, and then solve analog signal and be easier to be interfered, it is not suitable for
Farther out the problem of Distance Transmission.
With reference to Fig. 1 and Fig. 3, in a preferred embodiment, the Butterworth filter circuit 10 includes：
First Butterworth filter unit 11, a left side is converted into for accessing the left channel audio signal in the audio signal
Exported after sound channel negative differential signal；
Second Butterworth filter unit 12, the right channel audio signal conversion being used to access in the audio signal
Exported after into R channel negative differential signal.
In the present embodiment, input terminal and the left audio input interface AUX-L of the first Butterworth filter unit 11 connect
Connecing, the left channel analog audio signal of access is carried out anti-phase and amplification is converted into differential signal, and in differential signal
High-frequency signal carries out filtering out processing, to obtain the negative differential signal of L channel.The input terminal of second Butterworth filter unit 12
It is connected with right audio channel input interface AUX-R, the right channel analog audio signal of access is carried out anti-phase and amplifies conversion
Into differential signal, and the high-frequency signal in differential signal is carried out to filter out processing, to obtain the negative differential signal of R channel.
With reference to Fig. 1 and Fig. 3, further, in above-described embodiment, the first Butterworth filter unit 11 includes first
Capacitance C1, the second capacitance C2, the 3rd capacitance C3, first resistor R1, second resistance R2,3rd resistor R3 and the first operational amplifier
The first end of U1, the first capacitance C1 be the first Butterworth filter unit 11 input terminal, the first capacitance C1
First end, the first end of 3rd resistor R3 and described second of the second end through the first resistor R1 Yu the second resistance R2
The first end interconnection of capacitance C2, the inverting input of the second end of the second resistance R2 and the first operational amplifier U1 and
The first end interconnection of the 3rd capacitance C3；The output terminal of the first operational amplifier U1 filters for first Butterworth
The output terminal of unit 11, and interconnected with the second end of the 3rd resistor R3 and the second end of the 3rd capacitance C3；Described
The normal phase input end of one operational amplifier U1 is connected with the first DC power supply VCC1；The second end ground connection of the second capacitance C2.
In the present embodiment, the first Butterworth filter unit 11 is profound and negative feedbck, so that circuit stability works.Wherein,
The gain of first Butterworth filter unit 11 can be adjusted according to the resistance value and 3rd resistor R3 ratios of first resistor R1.First electricity
R1 and the second capacitance C2 composition RC wave filters are hindered, to filter out the clutter in analog signal, second resistance R2 and the 3rd capacitance C3 groups
Into RC integrating circuit, RC wave filters and RC integrating circuit show as low-pass characteristic.First Butterworth filter unit 11 is cut
Only frequency f0, specifically can basis according to the parameter regulation of second resistance R2,3rd resistor R3, the second capacitance C2 and the 3rd capacitance C3
The following formula is calculated：
Wherein, C2, C3, R2, R3 distinguish the ginseng of the second capacitance C2, the 3rd capacitance C3, second resistance R2 and 3rd resistor R3
Numerical value, when (i.e. high frequency is made an uproar because various factors has interfering noise signal in the simulated audio signal of audio input interface J1 inputs
Sound) when, when noise frequency is more than cutoff frequency f0, second resistance R2,3rd resistor R3, the second capacitance C2 and the 3rd can be passed through
The filter circuit of capacitance C3 compositions filters, and cutoff frequency f0 is about 45KHZ in the present embodiment.It is understood that the present embodiment
The first Butterworth filter unit 11 be second order filter, more preferable compared with first-order filtering effect, cutoff frequency characteristic is more preferable.
With reference to Fig. 1 and Fig. 3, further, in above-described embodiment, the second Butterworth filter unit 12 includes the 4th
Capacitance C4, the 5th capacitance C5, the 6th capacitance C6, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6 and the second operational amplifier
The first end of U2, the 4th capacitance C4 be the first Butterworth filter unit 11 input terminal, the 4th capacitance C4
First end, the first end and described fiveth of sixth resistance R6 of the second end through the 4th resistance R4 Yu the 5th resistance R5
The first end interconnection of capacitance C5, the inverting input of the second end of the 5th resistance R5 and the second operational amplifier U2 and
The first end interconnection of the 6th capacitance C6；The output terminal of the second operational amplifier U2 filters for second Butterworth
The output terminal of unit 12, and interconnected with the second end of the 6th resistance R6 and the second end of the 6th capacitance C6；Described
The normal phase input end of two operational amplifier U2 is connected with the second DC power supply VCC2；The second end ground connection of the 5th capacitance C5.
In the present embodiment, the second Butterworth filter unit 12 is profound and negative feedbck, so that circuit stability works.Wherein,
The gain of second Butterworth filter unit 12 can be adjusted according to the resistance value of the 4th resistance R4 and the resistance value ratio of the 6th resistance R6.
First resistor R1 and the second capacitance C2 composition RC wave filters, to filter out the clutter in analog signal, the electricity of second resistance R2 and the 3rd
Hold C3 composition RC integrating circuit, RC wave filters and RC integrating circuit show as low-pass characteristic.First Butterworth filter unit
11 cutoff frequency f0 is according to the parameter regulation of second resistance R2,3rd resistor R3, the second capacitance C2 and the 3rd capacitance C3, specifically
It can be calculated according to the following formula：
Wherein, C5, C6, R5, R6 distinguish the ginseng of the 5th capacitance C5, the 6th capacitance C6, the 5th resistance R5 and the 6th resistance R6
Numerical value, when (i.e. high frequency is made an uproar because various factors has interfering noise signal in the simulated audio signal of audio input interface J1 inputs
Sound) when, when noise frequency is more than cutoff frequency f0, the 5th resistance R5, the 6th resistance R6, the 5th capacitance C5 and the 6th can be passed through
The filter circuit of capacitance C6 compositions filters, and cutoff frequency f0 is about 45KHZ in the present embodiment.It is understood that the present embodiment
The second Butterworth filter unit 12 be second order filter, more preferable compared with first-order filtering effect, cutoff frequency characteristic is more preferable.
With reference to Fig. 1 and Fig. 3, in a preferred embodiment, the low-pass filter circuit 20 includes：
First low-pass filter unit 21, for the L channel minus tolerance point for exporting the first Butterworth filter unit 11
Signal exports after being converted into L channel principal-employment sub-signal；
Second low-pass filter unit 22, for the R channel minus tolerance point for exporting the second Butterworth filter unit 12
Signal exports after being converted into R channel principal-employment sub-signal.
In the present embodiment, the first low-pass filter unit 21 is connected with the output terminal of the first Butterworth filter unit 11, and
The negative differential signal for the L channel that first Butterworth filter unit 11 is exported carries out 1:1 is anti-phase, and after filtering process
To the principal-employment sub-signal of L channel.Second low-pass filter unit 22 is connected with the output terminal of the second Butterworth filter unit 12,
And the negative differential signal for the R channel for exporting the second Butterworth filter unit 12 carries out 1:1 is anti-phase, and after filtering process
Obtain the principal-employment sub-signal of R channel.
With reference to Fig. 1 and Fig. 3, further, in above-described embodiment, first low-pass filter unit 21 includes the 7th capacitance
C7, the 7th resistance R7, the 8th resistance R8 and the 3rd operational amplifier U3, the first end of the 7th resistance R7 are low for described first
The input terminal of pass filtering unit 21, the second end of the 7th resistance R7 and the inverting input of the 3rd operational amplifier U3, institute
State the first end of the 8th resistance R8 and the first end interconnection of the 7th capacitance C7；The output terminal of the 3rd operational amplifier U3
For the output terminal of first low-pass filter unit 21, and with the second end of the 8th resistance R8 and the 7th capacitance C7
Second end interconnects；The normal phase input end of the 3rd operational amplifier U3 is connected with the first DC power supply VCC1.
In the present embodiment, the resistance value of the 7th resistance R7 and the 8th resistance R8 are identical, to realize the minus tolerance of L channel point letter
Number carry out 1:1 is anti-phase, therefore without zooming in or out contracting to negative differential signal, it is only necessary to it is anti-phase.7th capacitance C7 is used
The output terminal of the 3rd operational amplifier U3 can be transmitted in realizing high-frequency signal in not inverted processing, which adds
On principal-employment sub-signal, identical with the high-frequency signal phase on negative differential signal, amplitude is identical, can so cancel out each other, from
And improve the signal-to-noise ratio of difference, distortion.
With reference to Fig. 1 and Fig. 3, further, in above-described embodiment, second low-pass filter unit 22 includes the 8th capacitance
C8, the 9th resistance R9, the tenth resistance R10 and four-operational amplifier U4, the first end of the 9th resistance R9 is described second
The input terminal of low-pass filter unit 22, the second end of the 9th resistance R9 and the inverting input of four-operational amplifier U4,
The first end of the tenth resistance R10 and the first end interconnection of the 8th capacitance C8；The four-operational amplifier U4's is defeated
Outlet be first low-pass filter unit 21 output terminal, and with the second end of the tenth resistance R10 and it is described 8th electricity
Hold the second end interconnection of C8；The normal phase input end of the four-operational amplifier U4 is connected with the second DC power supply VCC2.
In the present embodiment, the resistance value of the 9th resistance R9 and the tenth resistance R10 are identical, to realize the minus tolerance of L channel point letter
Number carry out 1:1 is anti-phase, therefore without zooming in or out contracting to negative differential signal, it is only necessary to it is anti-phase.8th capacitance C8 is used
The output terminal of four-operational amplifier U4 can be transmitted in realizing high-frequency signal in not inverted processing, which adds
On principal-employment sub-signal, identical with the high-frequency signal phase on negative differential signal, amplitude is identical, can so cancel out each other, from
And improve the signal-to-noise ratio of difference, distortion.
With reference to Fig. 1 and Fig. 3, it is to be understood that in above-described embodiment, the first operational amplifier U1 and the 3rd operation amplifier
Device U3, the second operational amplifier U2 and four-operational amplifier U4 preferably realize that two-way IC is to be supplied with power supply using two-way IC
Electricity.Whole circuit uses four road operational amplifiers, and is parallel voltage negtive backword, so that amplifier small-signal operation and locating
In linear condition.The utility model makes full use of the common-mode rejection ratio of anti-phase input and homophase input to require the characteristics of relatively low, full
The higher signal-to-noise ratio of foot, distortion performance requirement.
The normal phase input end of the first operational amplifier U1 and the 3rd operational amplifier U3 and the first DC power supply VCC1 it
Between be additionally provided with the first power supply partial pressure unit 41, the first power supply partial pressure unit 41 includes the 11st resistance R11, the 12nd resistance
R12, the 9th capacitance C9 and the tenth capacitance C10, the first end of the 11st resistance R11 are connected with the first DC power supply VCC1, and the tenth
The second end of one resistance R11 and the 12nd resistance R12, the 9th capacitance C9, the first end of the tenth capacitance C10, and the first computing
The normal phase input end of amplifier U1 and the 3rd operational amplifier U3 interconnect；The second end of 11st resistance R11 and the 12nd resistance
R12, the 9th capacitance C9, the second end of the tenth capacitance C10 are grounded.11st resistance R11 and the 12nd resistance R12 series connection point
Pressure, has output to the first operational amplifier U1 and the 3rd operational amplifier by the source voltage of the first DC power supply VCC1
The normal phase input end of U3.9th capacitance C9 and the tenth capacitance C10 is used to filter out the clutter in the first DC power supply VCC1.According to point
Principle is pressed, as soon as the ratio of the tenth resistance R11 and the 12nd resistance R12 is bigger, the voltage got on the 11st resistance R11
It is bigger.In this way, just pass through the resistance value of the 11st resistance R11 and/or the 12nd resistance R12 of adjusting, you can the first computing of adjustment
The reference voltage of amplifier U1 and the 3rd operational amplifier U3, and then adjust operational precision.
Similarly, the second operational amplifier U2 and the 4th big device of computing normal phase input end and the second DC power supply VCC2 it
Between be additionally provided with second source partial pressure unit 42, second source partial pressure unit 42 includes the 13rd resistance R13, the 14th resistance
R14, the 11st capacitance C11 and the 12nd capacitance C12.The structure of 42 and first power supply partial pressure unit 41 of second source partial pressure unit
It is identical, therefore operation principle is identical and the technique effect that reaches is also identical, specifically can refer to the first power supply partial pressure unit 41, herein not
Repeat again.
With reference to Fig. 1 and Fig. 3, in a preferred embodiment, the differential signal output circuit 30 includes multiple partial pressure units
And the capacitance (figure does not indicate) being correspondingly arranged with multiple partial pressure units (figure does not indicate), multiple partial pressure units
Multiple output terminals of the input terminal respectively with the low-pass filter circuit 20 connect one to one, the output of multiple partial pressure units
Hold first end respectively with multiple capacitances to connect one to one, the second ends of multiple capacitances respectively with institute
The multiple input end for stating decoding circuit connects one to one.
In the present embodiment, in the first Butterworth filter unit 11, the second Butterworth filter unit 12, the first low pass filtered
On 21 and second low-pass filter unit of ripple unit, 22 output terminal, a partial pressure unit is respectively arranged with, and is denoted as the first partial pressure list
First 31, second partial pressure unit 32, the 3rd partial pressure unit 33 and the 4th partial pressure unit 34, wherein, the first partial pressure unit 31 includes dividing
Piezoresistance R31, R32, the second partial pressure unit 32 include divider resistance R33, R34, and the 3rd partial pressure unit 33 includes divider resistance
R35, R36, the 4th partial pressure unit include divider resistance R35, R36.First partial pressure list 31, the second partial pressure unit 32, the 3rd partial pressure
33 and the 4th partial pressure unit 34 of unit is used to the differential signal of access carrying out voltage division processing.It is understood that above-mentioned computing
Amplifier only difference mode signal is amplified processing, can also further suppression common mode signal by each partial pressure unit.Each partial pressure list
The divider resistance of member can be adjusted according to the requirement of rear end decoding circuit.Corresponding each partial pressure unit, the present embodiment are set respectively
A capacitance is equipped with, and is denoted as the first capacitance C31, the second capacitance C32, the 3rd capacitance C33, the 4th respectively
Capacitance C34.First capacitance C31, the second capacitance C32, the 3rd capacitance C33, C34 points of the 4th capacitance
The middle direct current signal of the differential signal of input is not isolated, suitable differential signal is obtained and is given to rear class processing.
The utility model also proposes a kind of audio frequency apparatus, and the audio frequency apparatus includes decoding circuit and simulation as described above
Difference channel.The detailed construction of the analog differential circuit can refer to above-described embodiment, and details are not described herein again；It is understood that
Due to having used above-mentioned analog differential circuit in the utility model audio frequency apparatus, the reality of the utility model audio frequency apparatus
Applying example includes whole technical solutions of above-mentioned analog differential circuit whole embodiments, and the technique effect reached also complete phase
Together, details are not described herein.
Wherein, the decoding circuit is preferably realized using decoding integrated chip, and decoding integrated chip is used for access
Differential signal carries out Decoding Analysis processing.
The above is only the preferred embodiment of the present invention, and it does not limit the scope of the patent of the present invention,
Under every utility model in the utility model is conceived, equivalent structure made based on the specification and figures of the utility model
Conversion, or directly/be used in other related technical areas indirectly and be included in the scope of patent protection of the utility model.
Claims (10)
1. a kind of analog differential circuit, applied in audio frequency apparatus, it is characterised in that the analog differential circuit is irrigated including Bart
This filter circuit, low-pass filter circuit and differential signal output circuit, the input terminal of the Butterworth filter circuit are used to connect
Enter audio signal, the output terminal of the Butterworth filter circuit first input end with the differential signal output circuit respectively
And the input terminal connection of the low-pass filter circuit；The output terminal of the low-pass filter circuit and the differential signal output circuit
The second input terminal connection；The first output terminal and the second output terminal of the differential signal output circuit are set with the audio respectively
Standby decoding circuit connection；Wherein,
The Butterworth filter circuit, for being exported after the audio signal of access is converted into negative differential signal；
The low-pass filter circuit, the negative differential signal for the Butterworth filter circuit to be exported carry out anti-phase and filtering
After processing, obtain principal-employment sub-signal and export；
The differential signal output circuit, for carrying out divider filter processing to the negative differential signal and the principal-employment sub-signal
Export afterwards to the decoding circuit of the audio frequency apparatus.
2. analog differential circuit as claimed in claim 1, it is characterised in that the Butterworth filter circuit includes：
First Butterworth filter unit, is converted into L channel for accessing the left channel audio signal in the audio signal and bears
Exported after differential signal；
Second Butterworth filter unit, the right channel audio signal for accessing in the audio signal are converted into right sound
Exported after road negative differential signal.
3. analog differential circuit as claimed in claim 2, it is characterised in that the first Butterworth filter unit includes the
One capacitance, the second capacitance, the 3rd capacitance, first resistor, second resistance, 3rd resistor and the first operational amplifier, described first
The first end of capacitance is the input terminal of the first Butterworth filter unit, and the second end of first capacitance is through described first
The first end of the first end of resistance and the second resistance, the first end of the 3rd resistor and second capacitance interconnects, institute
The second end of second resistance is stated to interconnect with the first end of the inverting input of first operational amplifier and the 3rd capacitance；
The output terminal of first operational amplifier be the first Butterworth filter unit output terminal, and with the described 3rd electricity
The second end of resistance and the interconnection of the second end of the 3rd capacitance；The normal phase input end and the first direct current of first operational amplifier
Power supply connects；The second end ground connection of second capacitance.
4. analog differential circuit as claimed in claim 2, it is characterised in that the second Butterworth filter unit includes the
Four capacitances, the 5th capacitance, the 6th capacitance, the 4th resistance, the 5th resistance, the 6th resistance and the second operational amplifier, the described 4th
The first end of capacitance is the input terminal of the second Butterworth filter unit, and the second end of the 4th capacitance is through the described 4th
The first end of the first end of resistance and the 5th resistance, the first end of the 6th resistance and the 5th capacitance interconnects, and described the
The second end of five resistance is interconnected with the inverting input of second operational amplifier and the first end of the 6th capacitance；It is described
The output terminal of second operational amplifier is the output terminal of the second Butterworth filter unit, and with the of the 6th resistance
The second end of two ends and the 6th capacitance interconnects；The normal phase input end of second operational amplifier and the second DC power supply connect
Connect；The second end ground connection of 5th capacitance.
5. analog differential circuit as claimed in claim 2, it is characterised in that the low-pass filter circuit includes：
First low-pass filter unit, for the L channel negative differential signal conversion for exporting the first Butterworth filter unit
Exported after into L channel principal-employment sub-signal；
Second low-pass filter unit, for the R channel negative differential signal conversion for exporting the second Butterworth filter unit
Exported after into R channel principal-employment sub-signal.
6. analog differential circuit as claimed in claim 5, it is characterised in that first low-pass filter unit includes the 7th electricity
Appearance, the 7th resistance, the 8th resistance and the 3rd operational amplifier, the first end of the 7th resistance is the first low-pass filtering list
The input terminal of member, the second end of the 7th resistance and the inverting input of the 3rd operational amplifier, the of the 8th resistance
The first end of one end and the 7th capacitance interconnects；The output terminal of 3rd operational amplifier is the first low-pass filtering list
The output terminal of member, and interconnected with the second end of the 8th resistance and the second end of the 7th capacitance；3rd computing is put
The normal phase input end of big device is connected with the first DC power supply.
7. analog differential circuit as claimed in claim 5, it is characterised in that second low-pass filter unit includes the 8th electricity
Appearance, the 9th resistance, the tenth resistance and four-operational amplifier, the first end of the 9th resistance is second low-pass filtering
The input terminal of unit, the second end of the 9th resistance and the inverting input of four-operational amplifier, the tenth resistance
First end and the interconnection of the first end of the 8th capacitance；The output terminal of the four-operational amplifier is second low-pass filtering
The output terminal of unit, and interconnected with the second end of the tenth resistance and the second end of the 8th capacitance；4th computing
The normal phase input end of amplifier is connected with the second DC power supply.
8. the analog differential circuit as described in claim 1 to 7 any one, it is characterised in that the differential signal output electricity
Road includes multiple partial pressure units and the capacitance that is correspondingly arranged with multiple partial pressure units, multiple partial pressure units it is defeated
Enter multiple output terminals of the end respectively with the low-pass filter circuit to connect one to one, the output terminal point of multiple partial pressure units
First end not with multiple capacitances connects one to one, the second ends of multiple capacitances respectively with the solution
The multiple input end of code circuit connects one to one.
9. a kind of audio frequency apparatus, it is characterised in that the audio frequency apparatus includes decoding circuit and as claim 1 to 8 is any one
Analog differential circuit described in.
10. audio frequency apparatus as claimed in claim 9, it is characterised in that the decoding circuit includes decoding integrated chip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721263155.XU CN207266266U (en) | 2017-09-27 | 2017-09-27 | Analog differential circuit and audio frequency apparatus |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721263155.XU CN207266266U (en) | 2017-09-27 | 2017-09-27 | Analog differential circuit and audio frequency apparatus |
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| CN207266266U true CN207266266U (en) | 2018-04-20 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110225425A (en) * | 2019-07-09 | 2019-09-10 | 深圳市中科蓝讯科技有限公司 | A kind of microphone input circuit |
| CN111200775A (en) * | 2018-11-19 | 2020-05-26 | 广州汽车集团股份有限公司 | Audio interface circuit, circuit group, automobile and audio access method |
-
2017
- 2017-09-27 CN CN201721263155.XU patent/CN207266266U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111200775A (en) * | 2018-11-19 | 2020-05-26 | 广州汽车集团股份有限公司 | Audio interface circuit, circuit group, automobile and audio access method |
| CN111200775B (en) * | 2018-11-19 | 2021-03-05 | 广州汽车集团股份有限公司 | Audio interface circuit, circuit group, automobile and audio access method |
| CN110225425A (en) * | 2019-07-09 | 2019-09-10 | 深圳市中科蓝讯科技有限公司 | A kind of microphone input circuit |
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