CN206640735U - A kind of filter circuit of noise cancelling headphone - Google Patents
A kind of filter circuit of noise cancelling headphone Download PDFInfo
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- CN206640735U CN206640735U CN201621148336.3U CN201621148336U CN206640735U CN 206640735 U CN206640735 U CN 206640735U CN 201621148336 U CN201621148336 U CN 201621148336U CN 206640735 U CN206640735 U CN 206640735U
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- noise reduction
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Abstract
A kind of filter circuit of noise cancelling headphone,It is characterized in that,Noise reduction microphone circuit is connected with filter circuit one end of the noise cancelling headphone,The circuit that the noise reduction microphone circuit on one side is connected with resistance R0 is provided with the first current node,The noise reduction microphone circuit other end ground connection,Another termination high level of resistance R0,The first current node lead line connects high pass circuit input,The high pass circuit output end connects gain amplifying circuit input,The gain amplifying circuit output end connects trap circuit input,The trap circuit output end passes through resistance R7 connection gain feedback input amplifiers,The gain feedback amplification circuit output end connects speaker circuit positive pole,The speaker circuit negative pole ground connection,So as on the basis of earphone noise reduction chip is combined,Reach wider noise reduction frequency range,Overall lifting earphone noise reduction,High-quality experience is brought to user.
Description
Technical field
The utility model belongs to ear speaker device technical field, more particularly to a kind of filter circuit of noise cancelling headphone.
Background technology
At present, in order to eliminate noise on one's own initiative, people's utility model " Active Noise Control " this technology.Its principle is：
All sound is all made up of certain frequency spectrum, if a kind of sound can be found, its frequency spectrum and the noise to be eliminated are complete
Equally, simply phase is just opposite (180 ° of difference), it is possible to is completely counterbalanced by this noise.Key is that how to obtain
That offsets the sound of noise.The method actually used is：Set about in itself from noise source, try former noise by electronic circuit
Phase is turned around.
Present earphone has more and more used active noise reduction techniques, and active noise reduction techniques are divided into digital noise reduction and simulation is dropped
Make an uproar two kinds.For simulating active noise reduction techniques, whether filter circuit frequency response can accurately be fitted headphone acoustic frequency response, be to influence
To the key factor of noise reduction quality.The Dolby circuit of active noise reduction earphone is using above-mentioned discrete component or uses special noise reduction
, the narrower situation of overall noise reduction frequency range scope be present, its noise reduction frequency range is big in the mode of the circuit realiration noise reduction outside chip cooperation
Generally in 100HZ to 500HZ, it can not realize the noise reduction of wider frequency segment limit, and noise reduction is not ideal, frequency response curve degree of fitting
It is not high.
Utility model content
The purpose of this utility model is to provide a kind of filter circuit of noise cancelling headphone, it is intended to before solving in the prior art
The Dolby circuit of noise cancelling headphone is presented using above-mentioned discrete component or using the circuit realiration noise reduction outside the cooperation of special noise reduction chip
Mode, the narrower situation of overall noise reduction frequency range scope be present, probably in 100HZ to 500HZ, it can not be realized its noise reduction frequency range
The problem of noise reduction of wider frequency segment limit, noise reduction is not ideal, and frequency response curve degree of fitting is not high.
The utility model is achieved in that a kind of filter circuit of noise cancelling headphone, the wave filter of the noise cancelling headphone
Noise reduction microphone circuit is connected with circuit on one side, the noise reduction microphone circuit on one side is provided with the resistance R0 circuits being connected
First current node, the noise reduction microphone circuit other end ground connection, another termination high level of resistance R0, first electricity
Node lead line connection high pass circuit input is flowed, the high pass circuit output end connects gain amplifying circuit input, institute
Gain amplifying circuit output end connection trap circuit input is stated, the trap circuit output end is anti-by resistance R7 connection gains
Input amplifier is presented, the gain feedback amplification circuit output end connects speaker circuit positive pole, the speaker circuit
Negative pole is grounded.
Further, the high pass circuit includes electric capacity C1 and resistance R1, and the electric capacity C1 concatenates with resistance R1, the electricity
Hold in C1 and gain amplifying circuit and be provided with the second current node, the electric capacity C1 between the first operational amplifier U1 electrode input ends
The other end connects the first current node, and the second current node lead line is provided with resistance R1, another terminations of resistance R1
Ground.
Further, the gain amplifying circuit includes the first operational amplifier U1, resistance R2 and resistance R3, and described first
The 3rd current node, the first operational amplifier U1 negative poles input are provided between operational amplifier U1 output ends and resistance R2
The 4th current node is provided between end and resistance R2, the circuit that the 4th current node is drawn is provided with resistance R3, the resistance
The R3 other ends are grounded；The positive source connection positive level of the first operational amplifier U1, the first operational amplifier U1 electricity
Source negative pole ground connection or negative level.
Further, the trap circuit includes resistance R4, resistance R5, electric capacity C3 and electric capacity C4, the resistance R4 and the
Be provided with the 5th current node between four current nodes, described electric capacity C3 one end is connected to the 5th current node, the resistance R4 and
Resistance R5 is sequentially connected in series, and the electric capacity C3 and electric capacity C4 are sequentially connected in series, and the resistance R5 other ends connect with the electric capacity C4 other ends
And the 6th current node is provided with connecting line, the 6th current node is connected with resistance R7, the resistance R4 and resistance R5
Between be provided with the 7th current node, the circuit that the 7th current node is drawn is provided with electric capacity C2, another terminations of electric capacity C2
Ground, is provided with the 8th current node between the electric capacity C3 and electric capacity C4, the circuit that the 8th current node is drawn is provided with resistance
R6, the resistance R6 other ends ground connection.
Further, the gain feedback amplifying circuit include electric capacity C5, resistance R9, electric capacity C6, electric capacity C7, electric capacity C8 and
Second operational amplifier U2, is provided with the 9th current node between the second operational amplifier U2 negative inputs and resistance R7,
The tenth current node, the 9th electric current are provided between the second operational amplifier U2 output ends and speaker circuit positive pole
The 11st current node is provided between node and the electric capacity C7, the 12nd is provided between the tenth current node and electric capacity C8
Current node, electric capacity C7 and electric capacity C8 is sequentially connected in series between the 11st current node and the 12nd current node, it is described
The 13rd current node is provided between electric capacity C7 and electric capacity C8, the circuit that the 13rd current node is drawn is provided with resistance R10,
The resistance R10 other ends ground connection；
Be provided with the 14th current node between 11st current node and resistance R9, the 12nd current node and
The 15th current node is provided between electric capacity C6, has been sequentially connected in series between the 14th current node and the 15th current node
Resistance R9 and electric capacity C6；
Be provided with the 16th current node between 14th current node and resistance R8, the 15th current node and
The 17th current node is provided between resistance R8, resistance is connected between the 16th current node and the 17th current node
Electric capacity C5 is parallel with R8, the resistance R8：
The second operational amplifier U2 electrode input ends ground connection, the second operational amplifier U2 positive sources connection is just
Level, the second operational amplifier U2 power cathodes ground connection or negative level.
Beneficial effect：Due to being connected with noise reduction microphone electricity on filter circuit one end of noise cancelling headphone of the present utility model
Road, the circuit that the noise reduction microphone circuit on one side is connected with resistance R0 are provided with the first current node, the noise reduction microphone
The circuit other end is grounded, another termination high level of resistance R0, and the first current node lead line connects high pass circuit
Input, the high pass circuit output end connect gain amplifying circuit input, and the gain amplifying circuit output end connection is fallen into
Wave circuit input, the trap circuit output end pass through resistance R7 connection gain feedback input amplifiers, the gain
Feedback amplifier output end connects speaker circuit positive pole, the speaker circuit negative pole ground connection, so as to combine earphone drop
Make an uproar on the basis of chip, reach wider noise reduction frequency range, it is overall to lift earphone noise reduction, high-quality body is brought to user
Test.
Brief description of the drawings
Fig. 1 is the circuit diagram of the filter circuit of noise cancelling headphone provided by the utility model.
Fig. 2 is that sound passage amplitude frequency curve provided by the utility model compares with wave filter actual measurement amplitude frequency curve fit solution
Figure.
Wherein, 1 is noise reduction microphone circuit, and 2 be the first current node, and 3 be the second current node, and 4 be the 3rd electric current section
Point, 5 be the 4th current node, and 6 be the 5th current node, and 7 be the 6th current node, and 8 be the 7th current node, and 9 be the 8th electricity
Node is flowed, 10 be the 9th current node, and 11 be the tenth current node, and 12 be the 11st current node, and 13 be the 12nd electric current section
Point, 14 be the 13rd current node, and 15 be the 14th current node, and 16 be the 15th current node, and 17 be the 16th electric current section
Point, 18 be the 17th current node, and 19 be speaker circuit, and 20 be that high pass circuit .21 is gain amplifying circuit, and 22 be trap
Circuit, 23 be gain feedback amplifying circuit.
Embodiment
In order that the purpose of this utility model, technical scheme and advantage are more clearly understood, below in conjunction with accompanying drawing and implementation
Example, the utility model is further elaborated.
Fig. 1 shows the circuit diagram of the filter circuit of the utility model noise cancelling headphone, a kind of filter of noise cancelling headphone
Ripple device circuit, noise reduction microphone circuit 1, the noise reduction microphone electricity are connected with filter circuit one end of the noise cancelling headphone
The circuit that the one end of road 1 is connected with resistance R0 is provided with the first current node 2, the other end of noise reduction microphone circuit 1 ground connection, institute
State another termination high level of resistance R0, described first electric current section, 2 lead line connection inputs of high pass circuit 20, the height
The output end of circuit passband 20 connects the input of gain amplifying circuit 21, and the output end of gain amplifying circuit 21 connects trap circuit 22
Input, the output end of trap circuit 22 are anti-by the input of resistance R7 connection gain feedbacks amplifying circuit 23, the gain
Present the output end of the amplifying circuit 23 connection positive pole of speaker circuit 19, the negative pole of speaker circuit 19 ground connection.
The high pass circuit 20 includes electric capacity C1 and resistance R1, and the electric capacity C1 concatenates with resistance R1, the electric capacity C1 and
The second current node 3 is provided with gain amplifying circuit 21 between first operational amplifier U1 electrode input ends, the electric capacity C1 is another
One end connects the first current node 2, and the lead line of the second current node 3 is provided with resistance R1, another terminations of resistance R1
Ground.
The gain amplifying circuit 21 includes the first operational amplifier U1, resistance R2 and resistance R3, first computing are put
It is big that the 3rd current node 4, the first operational amplifier U1 negative inputs and electricity are provided between device U1 output ends and resistance R2
The 4th current node 5 is provided between resistance R2, the circuit that the 4th current node 5 is drawn is provided with resistance R3, and the resistance R3 is another
One end is grounded；The positive source connection positive level of the first operational amplifier U1, the first operational amplifier U1 power supplys are born
Pole is grounded or negative level.
The trap circuit 22 includes resistance R4, resistance R5, electric capacity C3 and electric capacity C4, the resistance R4 and the 4th electric current section
The 5th current node 6 is provided between point 5, described electric capacity C3 one end is connected to the 5th current node 6, the resistance R4 and resistance R5
It is sequentially connected in series, the electric capacity C3 and electric capacity C4 are sequentially connected in series, and the resistance R5 other ends connect with the electric capacity C4 other ends and even
Wiring is provided with the 6th current node 7, and the 6th current node 7 is connected with resistance R7, between the resistance R4 and resistance R5
Provided with the 7th current node 8, the circuit that the 7th current node 8 is drawn is provided with electric capacity C2, and the electric capacity C2 other ends are grounded,
The 8th current node 9 is provided between the electric capacity C3 and electric capacity C4, the circuit that the 8th current node 9 is drawn is provided with resistance
R6, the resistance R6 other ends ground connection.
The gain feedback amplifying circuit 23 includes electric capacity C5, resistance R9, electric capacity C6, electric capacity C7, the fortune of electric capacity C8 and second
Amplifier U2 is calculated, the 9th current node 10 is provided between the second operational amplifier U2 negative inputs and resistance R7, it is described
The tenth current node 11, the 9th electric current section are provided between second operational amplifier U2 output ends and the positive pole of speaker circuit 19
Be provided with the 11st current node 12 between point 10 and the electric capacity C7, provided with the between the tenth current node 11 and electric capacity C8
12 current nodes 13, electric capacity C7 and electricity are sequentially connected in series between the 11st current node 12 and the 12nd current node 13
Hold C8, the 13rd current node 14, the line that the 13rd current node 14 is drawn are provided between the electric capacity C7 and electric capacity C8
Road is provided with resistance R10, the resistance R10 other ends ground connection；
The 14th current node 15, the 12nd electric current section are provided between 11st current node 12 and resistance R9
Be provided with the 15th current node 16 between point 13 and electric capacity C6, the 14th current node 15 and the 15th current node 16 it
Between be sequentially connected in series resistance R9 and electric capacity C6；
The 16th current node 17, the 15th electric current section are provided between 14th current node 15 and resistance R8
Be provided with the 17th current node 18 between point 16 and resistance R8, the 16th current node 17 and the 17th current node 18 it
Between be connected with resistance R8, the resistance R8 and be parallel with electric capacity C5；
The second operational amplifier U2 electrode input ends ground connection, the second operational amplifier U2 positive sources connection is just
Level, the second operational amplifier U2 power cathodes ground connection or negative level.
Fig. 2 shows sound passage amplitude frequency curve and wave filter actual measurement amplitude frequency curve fit solution compares figure, abscissa in Fig. 2
For frequency, unit hertz, ordinate is gain, unit decibel；The song representated by curve and GainL in figure representated by GainR
Line represents R channel amplitude frequency curve and L channel amplitude frequency curve respectively, and two curves are dotted line, wherein, the song representated by GainR
Line is the larger curve of density, and the curve representated by GainL is the less curve of density；Song representated by GainSimulated
Line is that wave filter surveys amplitude frequency curve, and curve is solid line；Therefore, can clearly find out at 100 hertz -2000 hertz from Fig. 2
In frequency range hereby, R channel amplitude frequency curve and L channel amplitude frequency curve are good with oscillograph actual measurement amplitude frequency curve fit solution
It is good.Draw a conclusion for：Noise reduction is notable in 100 hertz of -2000 frequency range, has widened the frequency range of noise reduction,
Overall lifting earphone noise reduction.
In the utility model, due to being connected with noise reduction wheat on filter circuit one end of noise cancelling headphone of the present utility model
Gram wind 1, the circuit that the noise reduction microphone 1 is connected with resistance R0 are provided with the first current node 2, and the noise reduction microphone 1 is another
One end is grounded, another termination high level of resistance R0, and the lead line of the first current node 2 connection high pass circuit 20 inputs
End, the output end of high pass circuit 20 connect the input of gain amplifying circuit 21, the output end of gain amplifying circuit 21 connection
The input of trap circuit 22, the output end of trap circuit 22 by the input of resistance R7 connection gain feedbacks amplifying circuit 23,
The output end of gain feedback amplifying circuit 23 connects the positive pole of loudspeaker 19, the negative pole of loudspeaker 19 ground connection, so as to combine
On the basis of earphone noise reduction chip, reach wider noise reduction frequency range, it is overall to lift earphone noise reduction, brought to user excellent
The experience of matter.
The advantages of general principle and principal character of the present utility model and the utility model has been shown and described above, one's own profession
The technical staff of industry is it should be appreciated that the utility model is not restricted to the described embodiments, described in above-described embodiment and specification
Simply illustrate principle of the present utility model, on the premise of the spirit and scope of the utility model is not departed from, the utility model is also
Various changes and modifications are had, these changes and improvements are both fallen within claimed the scope of the utility model, and utility model will
Protection domain is sought by appended claims and its equivalent thereof.
Claims (5)
1. a kind of filter circuit of noise cancelling headphone, it is characterised in that connected on filter circuit one end of the noise cancelling headphone
There is noise reduction microphone circuit, the circuit that the noise reduction microphone circuit on one side is connected with resistance R0 is provided with the first current node,
The noise reduction microphone circuit other end ground connection, another termination high level of resistance R0, the first current node lead-out wire
Road connects high pass circuit input, and the high pass circuit output end connects gain amplifying circuit input, the gain amplification electricity
Road output end connection trap circuit input, the trap circuit output end are defeated by resistance R7 connection gain feedback amplifying circuits
Enter end, the gain feedback amplification circuit output end connects speaker circuit positive pole, the speaker circuit negative pole ground connection.
2. the filter circuit of a kind of noise cancelling headphone according to claim 1, it is characterised in that the high pass circuit includes
Electric capacity C1 and resistance R1, the electric capacity C1 concatenate with resistance R1, the electric capacity C1 and the first operation amplifier in gain amplifying circuit
It is provided with the second current node between device U1 electrode input ends, the electric capacity C1 other ends connect the first current node, and described second
Current node lead line is provided with resistance R1, the resistance R1 other ends ground connection.
A kind of 3. filter circuit of noise cancelling headphone according to claim 1, it is characterised in that the gain amplifying circuit
Including the first operational amplifier U1, resistance R2 and resistance R3, set between the first operational amplifier U1 output ends and resistance R2
There is the 3rd current node, the 4th current node, institute are provided between the first operational amplifier U1 negative inputs and resistance R2
The circuit for stating the extraction of the 4th current node is provided with resistance R3, the resistance R3 other ends ground connection；The first operational amplifier U1
Positive source connection positive level, the first operational amplifier U1 power cathodes ground connection or negative level.
4. the filter circuit of a kind of noise cancelling headphone according to claim 1, it is characterised in that the trap circuit includes
Resistance R4, resistance R5, electric capacity C3 and electric capacity C4, are provided with the 5th current node, institute between the resistance R4 and the 4th current node
State electric capacity C3 one end and be connected to the 5th current node, the resistance R4 and resistance R5 are sequentially connected in series, the electric capacity C3 and electric capacity C4
It is sequentially connected in series, the resistance R5 other ends connect with the electric capacity C4 other ends and the 6th current node is provided with connecting line, described
6th current node is connected with resistance R7, and the 7th current node, the 7th electric current are provided between the resistance R4 and resistance R5
The circuit that node is drawn is provided with electric capacity C2, the electric capacity C2 other ends ground connection, the 8th is provided between the electric capacity C3 and electric capacity C4
Current node, the circuit that the 8th current node is drawn are provided with resistance R6, the resistance R6 other ends ground connection.
A kind of 5. filter circuit of noise cancelling headphone according to claim 1, it is characterised in that the gain feedback amplification
Circuit includes electric capacity C5, resistance R9, electric capacity C6, electric capacity C7, electric capacity C8 and the second operational amplifier U2, second operation amplifier
The 9th current node, the second operational amplifier U2 output ends and loudspeaker are provided between device U2 negative inputs and resistance R7
The tenth current node is provided between circuit anode, the 11st electric current section is provided between the 9th current node and the electric capacity C7
Point, the 12nd current node, the 11st current node and the 12nd are provided between the tenth current node and electric capacity C8
Electric capacity C7 and electric capacity C8 have been sequentially connected in series between current node, the 13rd electric current section is provided between the electric capacity C7 and electric capacity C8
Point, the circuit that the 13rd current node is drawn are provided with resistance R10, the resistance R10 other ends ground connection；
The 14th current node, the 12nd current node and electric capacity are provided between 11st current node and resistance R9
The 15th current node is provided between C6, resistance has been sequentially connected in series between the 14th current node and the 15th current node
R9 and electric capacity C6；
The 16th current node, the 15th current node and resistance are provided between 14th current node and resistance R8
The 17th current node is provided between R8, resistance R8 is connected between the 16th current node and the 17th current node,
Electric capacity C5 is parallel with the resistance R8；
The second operational amplifier U2 electrode input ends ground connection, the second operational amplifier U2 positive sources connect positive electricity
It is flat, the second operational amplifier U2 power cathodes ground connection or negative level.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621148336.3U CN206640735U (en) | 2016-10-21 | 2016-10-21 | A kind of filter circuit of noise cancelling headphone |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621148336.3U CN206640735U (en) | 2016-10-21 | 2016-10-21 | A kind of filter circuit of noise cancelling headphone |
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| Publication Number | Publication Date |
|---|---|
| CN206640735U true CN206640735U (en) | 2017-11-14 |
Family
ID=60261225
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621148336.3U Active CN206640735U (en) | 2016-10-21 | 2016-10-21 | A kind of filter circuit of noise cancelling headphone |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN206640735U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106658255A (en) * | 2016-10-21 | 2017-05-10 | 声源科技（深圳）有限公司 | Filter circuit for noise reduction headset |
-
2016
- 2016-10-21 CN CN201621148336.3U patent/CN206640735U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106658255A (en) * | 2016-10-21 | 2017-05-10 | 声源科技（深圳）有限公司 | Filter circuit for noise reduction headset |
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