CN206117607U - Active bandwidth -limited circuit of low frequency - Google Patents
Active bandwidth -limited circuit of low frequency Download PDFInfo
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- CN206117607U CN206117607U CN201621194464.1U CN201621194464U CN206117607U CN 206117607 U CN206117607 U CN 206117607U CN 201621194464 U CN201621194464 U CN 201621194464U CN 206117607 U CN206117607 U CN 206117607U
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- resistance
- electric capacity
- amplifier chip
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- resistor
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Abstract
The utility model discloses an active bandwidth -limited circuit of low frequency, including an operational amplifier chip U1, the 2nd operational amplifier chip U2, the 3rd operational amplifier chip U3, first resistance R1, second resistance R2, third resistance R3, fourth resistance R4, the 5th resistance R5, the 6th resistance R6, the 7th resistance R7, the 8th resistance R8, the 9th resistance R9, the tenth resistance R10, first electric capacity C1, second electric capacity C2, third electric capacity C3, fourth electric capacity C4, the 5th electric capacity C5 and the 6th electric capacity C6. Adopt the technical scheme of the utility model, adopt fertile this high pass filter of second order bart and fertile this low pass filter of quadravalence bart to constitute band pass filter group and carry out filtering amplification to the signal to can shorten the transition zone, filtering power frequency interference improves wave filter decay gain.
Description
Technical field
This utility model belongs to signal filtering field, more particularly to a kind of low-frequency active bandwidth-limited circuit.
Background technology
Signal also has substantial portion of noise signal after primary amplification, and these noises are made an uproar comprising power supply when starting
Sound, DC baseline drift noise and Hz noise noise.For passive filtering, active filter can not only be carried out
Power back-off, moreover it is possible to signal is amplified while filtering, while amplifier can also play buffering and the effect isolated.In order to
Overcome the shortcoming of passive filter circuit consumption signal energy, generally adopt Active Power Filter Technology, however, of the prior art active
Wave filter intermediate zone is longer and there is certain signal attenuation, and application effect is not good in narrow passband.
Therefore, for the defect of prior art, it is necessary to propose a kind of technical scheme in fact, with the skill for overcoming prior art to exist
Art problem.
Utility model content
In view of this, it is necessory to provide a kind of low-frequency active bandwidth-limited circuit such that it is able to shorten intermediate zone, filter
Hz noise, improves filter attenuation gain.
For the defect for overcoming prior art to exist, this utility model provides technical scheme below：
A kind of low-frequency active bandwidth-limited circuit, including the first amplifier chip U1, the second amplifier chip U2, the 3rd amplifier core
It is piece U3, first resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, the 7th electric
Resistance R7, the 8th resistance R8, the 9th resistance R9, the tenth resistance R10, the first electric capacity C1, the second electric capacity C2, the 3rd electric capacity C3, the 4th
Electric capacity C4, the 5th electric capacity C5 and the 6th electric capacity C6, wherein, one end of the first electric capacity C1 is connected with input signal, described
The other end of the first electric capacity C1 is connected with described one end of second electric capacity C2, one end of first resistor R1, second electric capacity
The other end of C2 is connected with the 3rd pin of first amplifier chip U1 and one end of second resistance R2, and described second
The other end ground connection of resistance R2, the 5th pin of the first amplifier chip U1, the 5th pin of the second amplifier chip U2 and the 3rd are transported
The 5th pin for putting chip U3 is connected with power supply+5V outfans, the second pin of the first amplifier chip U1, the second amplifier core
The second pin of the second pin of piece U2 and the 3rd amplifier chip U3 is connected with power supply -5V outfans, first resistor R1
One end phase of the other end and the first pin of the first amplifier chip U1, one end of the 5th resistance R5 and 3rd resistor R3
Connection, the other end of 3rd resistor R3 and the 4th pin of the first amplifier chip U1 and one end phase of the 4th resistance R4
Connection, the other end ground connection of the 4th resistance R4；The other end of the 5th resistance R5 and one end of the 7th resistance R7,
One end of the 6th resistance R6, one end of the 3rd electric capacity C3 are connected, the other end and second of the 3rd electric capacity C3
3rd pin common ground of amplifier chip U2, the other end of the 6th resistance R6 and the 4th of second amplifier chip U2
Pin is connected with one end of the 4th electric capacity C4, and the other end of the 4th electric capacity C4 is another with the 7th resistance R7
End, one end of the 8th resistance R8 are connected with the first pin of second amplifier chip U2, the 8th resistance R8's
One end of the other end and the 5th electric capacity C5, one end of the 9th resistance R9 and one end of the tenth resistance R10 are connected
Connect, the other end of the 5th electric capacity C5 and the 3rd pin common ground of the 3rd amplifier chip U3, the 9th resistance R9's
The other end is connected with described one end of 6th electric capacity C6 and the 4th pin of the 3rd amplifier chip U3, the 6th electric capacity C6's
The other end is connected with the other end of the tenth resistance R10 and the first pin of the 3rd amplifier chip U3, collectively as signal
Outfan.
Preferably, first amplifier chip U1, the second amplifier chip U2 and the 3rd amplifier chip U3 adopt amplifier core
Piece OPA188.
Compared with prior art, the technical solution of the utility model, using second order butterworth high pass filter and
Quadravalence Butterworth LPF constitutes band filter group and filtering is amplified to signal such that it is able to shorten intermediate zone,
Hz noise is filtered, filter attenuation gain is improved.
Description of the drawings
Fig. 1 is a kind of circuit theory diagrams of low-frequency active bandwidth-limited circuit of this utility model.
Specific examples below will further illustrate this utility model with reference to above-mentioned accompanying drawing.
Specific embodiment
Below with reference to accompanying drawing, the utility model is described in further detail.
To shorten intermediate zone, Hz noise is filtered, improve filter attenuation gain, this utility model is fertile using second order Bart
This high pass filter and quadravalence Butterworth LPF constitute band filter group and filtering are amplified to signal, referring to
Fig. 1, show the circuit theory diagrams of this utility model active bandpass filiter circuit, including the first amplifier chip U1, the second amplifier
Chip U2, the 3rd amplifier chip U3, first resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R4, the 5th resistance R5,
6th resistance R6, the 7th resistance R7, the 8th resistance R8, the 9th resistance R9, the tenth resistance R10, the first electric capacity C1, the second electric capacity
C2, the 3rd electric capacity C3, the 4th electric capacity C4, the 5th electric capacity C5 and the 6th electric capacity C6, wherein, one end of the first electric capacity C1 with it is defeated
Enter signal to be connected, the other end of the first electric capacity C1 and one end of the second electric capacity C2, one end phase of first resistor R1
Connection, the 3rd pin of the other end of the second electric capacity C2 and first amplifier chip U1 and the one of second resistance R2
End is connected, the other end of second resistance R2 ground connection, the 5th pin of the first amplifier chip U1, the second amplifier chip U2
5th pin of the 5th pin and the 3rd amplifier chip U3 is connected with power supply+5V outfans, and the of the first amplifier chip U1
The second pin of two pins, the second pin of the second amplifier chip U2 and the 3rd amplifier chip U3 with power supply -5V outfan phases
Connection, the other end of first resistor R1 and the first pin of the first amplifier chip U1, one end of the 5th resistance R5 and described
One end of 3rd resistor R3 is connected, the other end of 3rd resistor R3 and the 4th pin of the first amplifier chip U1 and described
One end of 4th resistance R4 is connected, the other end ground connection of the 4th resistance R4；The other end of the 5th resistance R5 and institute
State one end of the 7th resistance R7, one end of the 6th resistance R6, one end of the 3rd electric capacity C3 to be connected, the described 3rd is electric
Hold the other end of C3 and the 3rd pin common ground of the second amplifier chip U2, the other end of the 6th resistance R6 and described the
4th pin of two amplifier chips U2 is connected with one end of the 4th electric capacity C4, the other end of the 4th electric capacity C4 and institute
State the other end of the 7th resistance R7, one end of the 8th resistance R8 to be connected with the first pin of second amplifier chip U2
Connect, the other end of the 8th resistance R8 and one end of the 5th electric capacity C5, one end of the 9th resistance R9 and described
One end of ten resistance R10 is connected, and the other end of the 5th electric capacity C5 and the 3rd pin of the 3rd amplifier chip U3 connect jointly
Ground, the other end of the 9th resistance R9 is connected with described one end of 6th electric capacity C6 and the 4th pin of the 3rd amplifier chip U3
Connect, the other end and the other end of the tenth resistance R10 and first pin of the 3rd amplifier chip U3 of the 6th electric capacity C6
It is connected, collectively as signal output part.
In foregoing circuit, feed back the cascade of (MFB) low pass filter using two second order multiterminal and constitute fourth order low-pass wave filter,
Open-loop voltage gain and input impedance using integrated transporting discharging is all very high, output impedance than relatively low, after constituting active filter circuit
Also there is certain voltage amplification and cushioning effect.The unlimited gain multiple feedback low pass filters of ButterWorth are chosen, as
Second order filter structure, the feedback topology structure has high selectivity and precipitous excessive band, while can produce more
Rational device value, that is, resistance capacitance is in available scope, can select low-cost and high-precision device.Voltage controlled voltage source
High pass filter, using homophase connection, filter input impedance is high, and output impedance is low, equivalent to a voltage source, its circuit
Can be stable, gain is easily adjusted.
It is special according to Kirchhoff's theorem and negative feedback amplifier for single second order multiterminal feed back (MFB) low pass filter
Property can be obtained：
Wherein K be filter gain, ωcFor filter cutoff frequency, B and C is normalization coefficient.
Normalization coefficient B=1.414, C=1 can be obtained according to unlimited gain multiple feedback circuit topological structure, advised by experience
Then select C3It is similar to 10/fc, by design objective cut-off frequency fc=10Hz, can obtain C3=1uF, filter gain distinguishes 1 He
10, low-pass filter circuit device parameters are as shown in table 1.Simulation analysis can obtain the response of low pass filter amplitude-frequency characteristic, its 3dB cut-off frequency
For 8.237Hz, design requirement is met.Specifically related to parameter is as shown in the table.
The low-pass filter circuit component parameter type selecting of table 1
Voltage controlled voltage source circuit of high pass filter design principle is, using RC filter circuits and in-phase proportion amplifying circuit group
Into second order voltage controlled voltage source high pass filter, the wave filter has the characteristics of input impedance is high, and output impedance is low.Butterworth is high
The transmission function of bandpass filter is such as：
Wherein K be filter gain, ωcFor filter cutoff frequency.
According to design objective, cut-off frequency fc=0.1Hz, filter gain K=10, in f=0.1fcWhen, it is desirable to amplitude declines
Subtract more than 30dB, make R9=R20=R, C26=C27=C, fc=1/ (2 π RC).The high-pass filtering circuit component parameter such as institute of table 2
Show.Simulation result is the amplitude-frequency response of voltage controlled voltage source high pass filter, and its 3dB cut-off frequency is 0.099Hz, and pass-band performance satisfaction sets
Meter requires that physical circuit device parameters are as shown in table 2 below.
The high-pass filtering circuit component parameter type selecting of table 2
This utility model adopts active low-pass filter and high pass filter to constitute band logical of the frequency for 0.1Hz-10Hz
Wave filter.Wave filter amplitude frequency curve is very flat in passband, and with good intermediate zone characteristic, realizes preferably letter
Number filter effect and less signal attenuation, it is adaptable to the removal of noise in narrow bandwidth low frequency signal.
The explanation of above example is only intended to help and understands method of the present utility model and its core concept.Should refer to
Go out, for those skilled in the art, on the premise of without departing from this utility model principle, can also be to this
Utility model carries out some improvement and modification, and these are improved and modification also falls into this utility model scope of the claims
It is interior.
The foregoing description of the disclosed embodiments, enables professional and technical personnel in the field to realize or new using this practicality
Type.Various modifications to these embodiments will be apparent for those skilled in the art, determine herein
The General Principle of justice can in other embodiments be realized in the case of without departing from spirit or scope of the present utility model.Cause
This, this utility model is not intended to be limited to the embodiments shown herein, and is to fit to and principles disclosed herein
The most wide scope consistent with features of novelty.
Claims (2)
1. a kind of low-frequency active bandwidth-limited circuit, it is characterised in that including the first amplifier chip U1, the second amplifier chip U2,
It is 3rd amplifier chip U3, first resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R4, the 5th resistance R5, the 6th electric
Resistance R6, the 7th resistance R7, the 8th resistance R8, the 9th resistance R9, the tenth resistance R10, the first electric capacity C1, the second electric capacity C2, the 3rd
Electric capacity C3, the 4th electric capacity C4, the 5th electric capacity C5 and the 6th electric capacity C6, wherein, one end of the first electric capacity C1 and input signal
It is connected, the other end of the first electric capacity C1 is connected with described one end of second electric capacity C2, one end of first resistor R1, institute
The other end for stating the second electric capacity C2 is connected with the 3rd pin of first amplifier chip U1 and one end of second resistance R2
Connect, the other end ground connection of second resistance R2, the 5th pin of the first amplifier chip U1, the 5th of the second amplifier chip U2 the draw
5th pin of foot and the 3rd amplifier chip U3 is connected with power supply+5V outfans, the second pin of the first amplifier chip U1,
The second pin of the second pin of the second amplifier chip U2 and the 3rd amplifier chip U3 is connected with power supply -5V outfans, the
The other end of one resistance R1 and the first pin of the first amplifier chip U1, one end of the 5th resistance R5 and the 3rd resistor
One end of R3 is connected, the 4th pin and the 4th resistance of the other end of 3rd resistor R3 and the first amplifier chip U1
One end of R4 is connected, the other end ground connection of the 4th resistance R4；The other end of the 5th resistance R5 is electric with the described 7th
One end of resistance R7, one end of the 6th resistance R6, one end of the 3rd electric capacity C3 are connected, and the 3rd electric capacity C3's is another
One end and the 3rd pin common ground of the second amplifier chip U2, the other end and the second amplifier core of the 6th resistance R6
4th pin of piece U2 is connected with one end of the 4th electric capacity C4, and the other end of the 4th electric capacity C4 is electric with the described 7th
The resistance other end of R7, one end of the 8th resistance R8 are connected with the first pin of second amplifier chip U2, and described the
One end of the other end of eight resistance R8 and the 5th electric capacity C5, one end of the 9th resistance R9 and the tenth resistance R10
One end be connected, the other end of the 5th electric capacity C5 and the 3rd pin common ground of the 3rd amplifier chip U3, described
The other end of nine resistance R9 is connected with described one end of 6th electric capacity C6 and the 4th pin of the 3rd amplifier chip U3, and described
The other end of six electric capacity C6 is connected with the other end of the tenth resistance R10 and the first pin of the 3rd amplifier chip U3, altogether
With as signal output part.
2. low-frequency active bandwidth-limited circuit according to claim 1, it is characterised in that first amplifier chip U1,
Second amplifier chip U2 and the 3rd amplifier chip U3 adopt amplifier chip OPA188.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621194464.1U CN206117607U (en) | 2016-11-04 | 2016-11-04 | Active bandwidth -limited circuit of low frequency |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621194464.1U CN206117607U (en) | 2016-11-04 | 2016-11-04 | Active bandwidth -limited circuit of low frequency |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206117607U true CN206117607U (en) | 2017-04-19 |
Family
ID=58526083
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621194464.1U Expired - Fee Related CN206117607U (en) | 2016-11-04 | 2016-11-04 | Active bandwidth -limited circuit of low frequency |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN206117607U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107834996A (en) * | 2017-11-30 | 2018-03-23 | 贝兹维仪器(苏州)有限公司 | A kind of filter circuit |
-
2016
- 2016-11-04 CN CN201621194464.1U patent/CN206117607U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107834996A (en) * | 2017-11-30 | 2018-03-23 | 贝兹维仪器(苏州)有限公司 | A kind of filter circuit |
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|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20170419 Termination date: 20171104 |
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| CF01 | Termination of patent right due to non-payment of annual fee |