CN103472012B - Signal conditioning circuit used for monitoring crop growth information - Google Patents
Signal conditioning circuit used for monitoring crop growth information Download PDFInfo
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- CN103472012B CN103472012B CN201310423209.4A CN201310423209A CN103472012B CN 103472012 B CN103472012 B CN 103472012B CN 201310423209 A CN201310423209 A CN 201310423209A CN 103472012 B CN103472012 B CN 103472012B
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Abstract
The invention discloses a signal conditioning circuit used for monitoring crop growth information. The signal conditioning circuit is characterized by comprising a primary amplifier circuit, an instrument amplifier circuit and a peak signal detecting circuit, wherein a current signal input end of the primary amplifier circuit is connected with the output end of a photoelectric detector, a voltage output end of the primary amplifier circuit is connected with a voltage input end of the instrument amplifier circuit, and a conditioning signal output end of the instrument amplifier circuit is connected with a conditioning signal input end of the peak signal detecting circuit. The signal conditioning circuit used for monitoring crop growth information adopts a photodiode for receiving sensitive spectral information reflected by crop canopy and converts the sensitive spectral information into an electrical signal, wherein the electrical signal mainly comprises a fixed-frequency signal (an effective signal), a low-frequency sunlight interference signal and a high-frequency electromagnetic wave interference signal.
Description
Technical field
The present invention relates to a kind of signal conditioning circuit for plant growth information monitoring, particularly relate to based on actively
The signal conditioning circuit of the plant growth information lossless monitoring of light source, belongs to plant growth information intelligent detection neck
Territory.It is exclusively used in the acquisition real-time, easy, lossless of farmland crop growth information.
Background technology
Plant growth information lossless monitor is to refer to for acquisition plant growth quick, lossless in information agriculture application
Mark, instructs the accurate management regulation of field-crop.According to different monitoring principle, plant growth information lossless
Monitor can be to be divided into based on passive light source mode with based on active light source mode two class.With based on passive light source
Plant growth information lossless monitor is compared, and plant growth information lossless monitor based on active light source has
Do not limited by weather, the advantage of round-the-clock monitoring.Two kinds of concrete implementation moulds are contained based on active light source mode
Formula is respectively non-spectral modulating mode and spectral modulation pattern, compared with non-spectral modulating mode, spectral modulation
Pattern has the features such as high, strong, the good stability of capacity of resisting disturbance of certainty of measurement.Patent 201210554515.7
Disclose the device of a kind of portable crop growth information monitor based on active light source, it is proposed that use light
The method that plant growth information is monitored by spectrum modulation technique in real time, but have no that it is about spectroscopic acquisition
The relevant report of signal conditioning circuit design in device.
The design of signal conditioning circuit is the key of plant growth information lossless monitoring device based on modulated light source
Technology.In the design of plant growth information lossless monitoring device based on modulated light source, photodetector is defeated
Go out signal the faintest, and containing interference information such as daylight, electromagnetic wave and noises, it is impossible to amplified by simple
Use after process.Need by signal conditioning circuit, photodetector output signal is suitably buffered,
Amplification, filtering, shaping etc. operate so that it is output signal is easy to late-class circuit and is processed and analyze.
Summary of the invention
It is an object of the invention to overcome above-mentioned the deficiencies in the prior art, it is provided that a kind of real-time is good, workability
The one that energy is stable, antisum interference performance is strong, measurement result accurately, is not restricted by weather is raw for crop
The signal conditioning circuit of long message monitoring, for the reality of plant growth information lossless monitor based on active light source
Now providing technical support, the realization for the precise management of Digital Agriculture provides data support, it is achieved farmland ring
Low cost under border, in high precision, the growth information of portable type measuring crop.
Technical scheme is as follows:
A kind of signal conditioning circuit for plant growth information monitoring, puts including previous amplifier circuit, instrument
Big device circuit and peak signal detecting circuit；The current signal input of previous amplifier circuit connects light electrical resistivity survey
Surveying device outfan, the voltage output end of previous amplifier circuit connects the voltage input end of instrument amplifier circuit,
The modulated signal input of the modulated signal outfan connecting peak value signal detecting circuit of instrument amplifier circuit.
Previous amplifier circuit reception photodetector output low current signal, and low current signal is amplified,
Be converted to voltage signal；Instrument amplifier circuit receives the voltage signal of photoelectric switching circuit output, enters it
The amplification of row signal, filtering, shaping etc. operate；It is defeated that peak signal detecting circuit receives instrument amplifier circuit
The modulated signal gone out, carries out peak extraction to it.
Described previous amplifier circuit includes the first operational amplifier U1, the first resistance R1, the second resistance R2
With the 3rd resistance R3；The reverse input end of the first operational amplifier U1 connects photodetector input and with
One end of one resistance R1 connects；The input end grounding in the same direction of the first operational amplifier U1；First resistance R1
The other end be connected with second resistance R2 one end and the 3rd resistance R3 one end respectively, the second resistance R2 another
End is connected to ground, and the outfan of the 3rd resistance R3 other end and the first operational amplifier U1 connects.
Described instrument amplifier circuit includes the second operational amplifier U2, the 3rd operational amplifier U3, the 4th fortune
Calculate amplifier U4, the first electric capacity C1, the second electric capacity C2, the 3rd electric capacity C3, the 4th electric capacity C4, the 4th
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 and the 11st resistance R11；One end of first electric capacity C1 connects the first operational amplifier
The outfan of U1, the other end connects the input in the same direction of the second operational amplifier U2；Second operational amplifier
U2 reverse input end is connected with the 4th resistance R4 one end and the 6th resistance R6 one end respectively；Second operation amplifier
U2 outfan is respectively with the 6th resistance R6 other end, second electric capacity C2 one end and the 8th resistance R8 one end even
Connect；3rd operational amplifier U3 input in the same direction and the 5th resistance R5 one end connect；3rd operational amplifier
U3 reverse input end is connected with the 4th resistance R4 other end and the 7th resistance R7 one end respectively；3rd computing is put
Big device U3 outfan respectively with the 7th resistance R7 other end, the 3rd electric capacity C3 one end and the 9th resistance R9 mono-
End connects；Four-operational amplifier U4 input in the same direction is respectively at the 9th resistance R9 other end and the tenth resistance
R10 one end connects；Four-operational amplifier U4 reverse input end is respectively at the 8th resistance R8 other end and
11 resistance R11 one end connect；Four-operational amplifier U4 outfan is another respectively at the 11st resistance R11
One end and the 12nd resistance R12 one end connect；The 5th resistance R5 other end, the tenth resistance R10 other end,
The second electric capacity C2 other end, the 3rd electric capacity C3 other end are connected to ground；12nd resistance R12 and the 4th electricity
Hold C4 and form low pass filter.
Described peak signal detecting circuit include the 5th operational amplifier U5, the first conducting diode D1, the tenth
Three resistance R13, the 5th electric capacity C5；The input in the same direction of the 5th operational amplifier U5 is electric with the 12nd respectively
The resistance R12 other end and the 4th electric capacity C4 one end connect, the 4th electric capacity C4 other end ground connection；5th computing is put
Big device U5 outfan and first conducting diode D1 one end connect；5th operational amplifier U5 reversely inputs
End is respectively at the first conducting diode D1 other end, the 13rd resistance R13 one end and the 5th electric capacity C5 one end
Connect；The 13rd resistance R13 other end and the 5th electric capacity R5 other end are connected to ground, the 13rd resistance R13
Low pass filter is formed with the 5th electric capacity R5.
The relational expression that resistance in described instrument amplifier circuit should meet is: R6=R7, R8=R9.The
The resistance of six resistance R6 and the 7th resistance R7 is identical, and the resistance of the 8th resistance R8 and the 9th resistance R9 is identical.
Beneficial effects of the present invention:
The signal conditioning circuit for plant growth information monitoring of the present invention uses photodiode to receive crop
The sensitivity spectrum information of canopy reflection, is translated into the signal of telecommunication, mainly contains fixed frequency letter in the signal of telecommunication
Number (useful signal), low frequency daylight interference signal and high-frequency electromagnetic wave interference signal.
The signal conditioning circuit for plant growth information monitoring of the present invention uses capacity coupled mode by light
Power conversion circuit couples together with instrument amplifier circuit, can effectively remove the low frequency daylight interference in signal.
Instrument amplifier circuit can effectively suppress high-frequency electromagnetic wave interference with low pass filter in peak signal detecting circuit
Signal.
The instrument amplifier circuit of the signal conditioning circuit for plant growth information monitoring of the present invention uses three
Operational amplifier configuration increases common mode rejection ratio and the differential mode amplification of circuit, improves signal condition electricity
The stability on road and reliability.
The photodiode of the signal conditioning circuit for plant growth information monitoring of the present invention uses without biasing
Connect, capacity of resisting disturbance and the job stability of circuit can be effectively ensured.
The peak-detector circuit of the signal conditioning circuit for plant growth information monitoring of the present invention is for A/D
Modulated signal peak value can not be directly measured in conversion, and exports stable crest voltage, processes for late-class circuit and divides
Analysis.
Accompanying drawing explanation
Fig. 1 is the connection diagram of the signal conditioning circuit for plant growth information monitoring of the present invention；
Fig. 2 is the former of the photoelectric switching circuit of the signal conditioning circuit for plant growth information monitoring of the present invention
Reason figure；
Fig. 3 is the instrument amplifier circuit of the signal conditioning circuit for plant growth information monitoring of the present invention
Schematic diagram；
Fig. 4 is the peak signal detecting circuit of the signal conditioning circuit for plant growth information monitoring of the present invention
Schematic diagram.
Detailed description of the invention
Below in conjunction with specific embodiments, the present invention is described in detail.
As it is shown in figure 1, the signal conditioning circuit of the present invention include previous amplifier circuit, magnifier and
Peak signal detecting circuit forms；Wherein previous amplifier circuit receives photodetector output weak current letter
Number, and low current signal is amplified, is converted to voltage signal, instrument amplifier circuit input connects prime and puts
Big device circuit output, the input of peak signal detecting circuit connects magnifier output, previous amplifier circuit
It is connected with using capacitive coupling between instrument amplifier circuit.
As in figure 2 it is shown, described previous amplifier circuit include the first operational amplifier U1, the first resistance R1,
Second resistance R2 and the 3rd resistance R3；It is defeated that the reverse input end of the first operational amplifier U1 connects photodetector
Enter to hold IN the one end with the first resistance R1 to be connected；The input end grounding in the same direction of the first operational amplifier U1；
The other end of the first resistance R1 is connected with second resistance R2 one end and the 3rd resistance R3 one end respectively, and second
The resistance R2 other end is connected to ground, the 3rd resistance R3 other end and the outfan of the first operational amplifier U1
Connect.First operational amplifier U1 selects low noise, zero shift track to track operational amplifier A D8551；The
One resistance R1 and the 3rd resistance R3 is 1K Ω, and the second resistance R2 is 100 Ω.
As it is shown on figure 3, described instrument amplifier circuit includes the second operational amplifier U2, the 3rd operation amplifier
Device U3, four-operational amplifier U4, the first electric capacity C1, the second electric capacity C2, the 3rd electric capacity C3, the 4th
Electric capacity C4, the 4th 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 and the 11st resistance R11；One end of first electric capacity C1 connects
The outfan of the first operational amplifier U1, the other end connects the input in the same direction of the second operational amplifier U2；
Second operational amplifier U2 reverse input end connects with the 4th resistance R4 one end and the 6th resistance R6 one end respectively
Connect；Second operation amplifier U2 outfan respectively with the 6th resistance R6 other end, second electric capacity C2 one end and
8th resistance R8 one end connects；3rd operational amplifier U3 input in the same direction and the 5th resistance R5 one end are even
Connect；3rd operational amplifier U3 reverse input end respectively with the 4th resistance R4 other end and the 7th resistance R7
One end connects；3rd operational amplifier U3 outfan respectively with the 7th resistance R7 other end, the 3rd electric capacity C3
One end and the 9th resistance R9 one end connect；Four-operational amplifier U4 input in the same direction is respectively at the 9th resistance
The R9 other end and the tenth resistance R10 one end connect；Four-operational amplifier U4 reverse input end is respectively at
The eight resistance R8 other ends and the 11st resistance R11 one end connect；Four-operational amplifier U4 outfan is respectively
Connect in the 11st resistance R11 other end and the 12nd resistance R12 one end；The 5th resistance R5 other end,
The tenth resistance R10 other end, the second electric capacity C2 other end, the 3rd electric capacity C3 other end are connected to ground；The
12 resistance R12 and the 4th electric capacity C4 form low pass filter.Second operational amplifier U2 and the 3rd computing
Amplifier U3 all selects high accuracy chopping zero-stabilizing operational amplifier TLC2652；Four-operational amplifier U4 selects
By low noise, zero shift track to track operational amplifier A D8551；First electric capacity C1, the second electric capacity C2,
Three electric capacity C3 and the 4th electric capacity C4 are the ceramic condenser of 0.1uF；4th resistance R4 is 10K Ω, the 5th
Resistance R5 is 5K Ω, and the 6th resistance R6, the 7th resistance R7, the 8th resistance R8 and the 9th resistance R9 are equal
Being 500K Ω for 10K Ω, the tenth resistance R10 and the 11st resistance R11, the 12nd resistance R12 is 1K Ω.
As shown in Figure 4, shown peak signal detecting circuit includes the 5th operational amplifier U5, the first conducting two
Pole pipe D1, the 13rd resistance R13, the 5th electric capacity C5；The input in the same direction of the 5th operational amplifier U5 divides
It is not connected with the 12nd resistance R12 other end and the 4th electric capacity C4 one end, the 4th electric capacity C4 other end ground connection；
5th operational amplifier U5 outfan and first conducting diode D1 one end connect；5th operational amplifier U5
Reverse input end is respectively at the first conducting diode D1 other end, the 13rd resistance R13 one end and the 5th electric capacity
C5 one end connects；The 13rd resistance R13 other end and the 5th electric capacity R5 other end be connected to ground, the 13rd
Resistance R13 and the 5th electric capacity R5 forms low pass filter.5th operational amplifier U5 selects low noise, low
The operational amplifier OPA335 of drift；First conducting diode D1 selects IN4148；5th electric capacity C5 choosing
With the electrochemical capacitor of 22uF；13rd resistance R13 is 10K Ω.
The operation principle of circuit of the present invention is as follows:
The current signal I1 of photodiode output is input to preamplifying circuit one end, defeated as whole circuit
Enter signal.First operational amplifier U1, the first resistance R1, the second resistance R2 and the 3rd resistance R3 composition
T-shaped resistor network preamplifying circuit, by photodiode export current signal I1 amplify and be converted to
Voltage signal, if the first amplifier output end voltage is VO1, according to " empty short " and " empty disconnected " of operation amplifier,
Can obtain the relational expression of VO1 Yu I1:
Second operational amplifier U2, the 3rd operational amplifier U3, four-operational amplifier U4, the 4th resistance
R4, the 5th resistance R5, the 6th resistance R6, the 7th resistance R7, the 8th resistance R8, the 9th resistance R9,
Tenth resistance R10 and the 11st resistance R11 forms three amplifier differential amplifier circuits, if whole instrument is put
Big circuit output signal is VO2, according to " empty short " and " empty disconnected " of operational amplifier, can obtain VO2 and
The relational expression of VO1:
First electric capacity C1 coupling preamplifying circuit and magnifier, can effectively remove preamplifying circuit
Daylight interference in output voltage signal, it is achieved the anti-sunlight interference of signal conditioning circuit；Second electric capacity C2
The height in signal is filtered with the low pass filter of the 8th resistance R8, the 3rd electric capacity C3 and the 9th resistance R9 composition
Frequency interference, it is ensured that signal reliability and stability.
5th operational amplifier U5, the first conducting diode D1, the 13rd resistance R13 and the 5th electric capacity C5
Composition modulated signal peak-detector circuit, it is achieved the collection of modulated signal peak value and holding, it is simple to rear class simulation/
Numeral conversion, microsystem process etc.；When modulated signal is positive half cycle, the first conducting diode D1 conducting,
5th electric capacity C5 charging is until modulated signal peak value, and when signal peak reduces, the 5th electric capacity C5 passes through the
13 resistance R13 discharge, it is ensured that the output of modulated signal peak value and holding.
Embodiment described above is only to be described the preferred embodiment of the present invention, not to this
Bright spirit and scope are defined, without departing under design concept premise of the present invention, and unskilled labor in this area
Various modification that technical scheme is made by journey technical staff and improvement, all should fall into the guarantor of the present invention
Protecting scope, the technology contents that the present invention is claimed the most all is recorded in detail in the claims.
Claims (1)
1., for a signal conditioning circuit for plant growth information monitoring, it is characterized in that including previous amplifier circuit, instrument amplifier circuit and peak signal detecting circuit；The current signal input of previous amplifier circuit connects photodetector outfan, the voltage output end of previous amplifier circuit connects the voltage input end of instrument amplifier circuit, the modulated signal input of the modulated signal outfan connecting peak value signal detecting circuit of instrument amplifier circuit；Described previous amplifier circuit includes the first operational amplifier U1, the first resistance R1, the second resistance R2 and the 3rd resistance R3；The reverse input end of the first operational amplifier U1 connects photodetector input and the one end with the first resistance R1 is connected；The input end grounding in the same direction of the first operational amplifier U1；The other end of the first resistance R1 is connected with second resistance R2 one end and the 3rd resistance R3 one end respectively, and the second resistance R2 other end is connected to ground, and the outfan of the 3rd resistance R3 other end and the first operational amplifier U1 connects；Described instrument amplifier circuit includes the second operational amplifier U2, the 3rd operational amplifier U3, four-operational amplifier U4, the first electric capacity C1, the second electric capacity C2, the 3rd electric capacity C3, the 4th electric capacity C4, the 4th 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 and the 11st resistance R11；One end of first electric capacity C1 connects the outfan of the first operational amplifier U1, and the other end connects the input in the same direction of the second operational amplifier U2；Second operational amplifier U2 reverse input end is connected with the 4th resistance R4 one end and the 6th resistance R6 one end respectively；Second operation amplifier U2 outfan is connected with the 6th resistance R6 other end, second electric capacity C2 one end and the 8th resistance R8 one end respectively；3rd operational amplifier U3 input in the same direction and the 5th resistance R5 one end connect；3rd operational amplifier U3 reverse input end is connected with the 4th resistance R4 other end and the 7th resistance R7 one end respectively；3rd operational amplifier U3 outfan is connected with the 7th resistance R7 other end, the 3rd electric capacity C3 one end and the 9th resistance R9 one end respectively；Four-operational amplifier U4 input in the same direction connects respectively at the 9th resistance R9 other end and the tenth resistance R10 one end；Four-operational amplifier U4 reverse input end connects respectively at the 8th resistance R8 other end and the 11st resistance R11 one end；Four-operational amplifier U4 outfan connects respectively at the 11st resistance R11 other end and the 12nd resistance R12 one end；The 5th resistance R5 other end, the tenth resistance R10 other end, the second electric capacity C2 other end, the 3rd electric capacity C3 other end are connected to ground；12nd resistance R12 and the 4th electric capacity C4 forms low pass filter；Described peak signal detecting circuit includes the 5th operational amplifier U5, the first conducting diode D1, the 13rd resistance R13, the 5th electric capacity C5；The input in the same direction of the 5th operational amplifier U5 is connected with the 12nd resistance R12 other end and the 4th electric capacity C4 one end respectively, the 4th electric capacity C4 other end ground connection；5th operational amplifier U5 outfan and first conducting diode D1 one end connect；5th operational amplifier U5 reverse input end connects respectively at the first conducting diode D1 other end, the 13rd resistance R13 one end and the 5th electric capacity C5 one end；The 13rd resistance R13 other end and the 5th electric capacity R5 other end are connected to ground, the 13rd resistance R13 and the 5th electric capacity R5 and form low pass filter；The relational expression that resistance in described instrument amplifier circuit should meet is: R6=R7, R8=R9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310423209.4A CN103472012B (en) | 2013-09-16 | 2013-09-16 | Signal conditioning circuit used for monitoring crop growth information |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310423209.4A CN103472012B (en) | 2013-09-16 | 2013-09-16 | Signal conditioning circuit used for monitoring crop growth information |
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| CN103472012A CN103472012A (en) | 2013-12-25 |
| CN103472012B true CN103472012B (en) | 2017-01-11 |
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| CN112540050B (en) * | 2020-11-24 | 2022-12-27 | 威海精讯畅通电子科技有限公司 | Water quality detector and detection method thereof |
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| US8482742B2 (en) * | 2009-02-06 | 2013-07-09 | Seiko Epson Corporation | Measuring apparatus and measuring method |
| CN102768186B (en) * | 2012-06-27 | 2014-12-03 | 南京农业大学 | Nondestructive rapid detection device and detection method for field crop growth information |
| CN102759366B (en) * | 2012-07-11 | 2014-11-26 | 北京理工大学 | Detection device of optical fiber gyroscope optical module |
| CN103149162B (en) * | 2012-12-19 | 2015-04-29 | 南京农业大学 | Portable crop growth information monitor based on active light source |
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