CN110133370A - A kind of measuring instrument and measurement method based on surface acoustic wave sensor - Google Patents
A kind of measuring instrument and measurement method based on surface acoustic wave sensor Download PDFInfo
- Publication number
- CN110133370A CN110133370A CN201910370387.2A CN201910370387A CN110133370A CN 110133370 A CN110133370 A CN 110133370A CN 201910370387 A CN201910370387 A CN 201910370387A CN 110133370 A CN110133370 A CN 110133370A
- Authority
- CN
- China
- Prior art keywords
- surface acoustic
- acoustic wave
- signal
- circuit
- resistance
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
- G01R23/02—Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage
- G01R23/10—Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage by converting frequency into a train of pulses, which are then counted, i.e. converting the signal into a square wave
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Control Of Amplification And Gain Control (AREA)
Abstract
The invention discloses a kind of measuring instrument and measurement method based on surface acoustic wave sensor, object under test physical quantity is converted to the variable quantity output surface acoustic wave signal of surface acoustic wave frequency by SAW sensor, surface acoustic wave signal obtains the controllable sinusoidal signal of amplitude by agc circuit fixed ampllitude, sinusoidal signal after fixed ampllitude passes through single order active band-pass filter filtering clutter, and then square-wave signal is shaped to by shaping circuit, square-wave signal after shaping passes through Order RC filter secondary filtering again, then, the frequency of surface acoustic wave signal is calculated by FPGA frequency measurement circuit for signal, surface acoustic wave signal frequency is input in single-chip microcontroller, measured physical quantity is obtained by calculation；The present invention uses agc circuit and shaping circuit, is able to carry out the frequency measurement of range electric signal by a relatively large margin；Using equal precision measuring frequency way, the accuracy and accuracy of measurement result are considerably increased.
Description
Technical field
The present invention relates to technology of instrument and meter fields, and in particular to a kind of measuring instrument and survey based on surface acoustic wave sensor
Amount method.
Background technique
Frequency is one of most important parameter in modem electronic circuitry, there is important meaning in various fields.Now,
Surface acoustic wave (Surface Acoustic Wave, SAW) sensor is a kind of using SAW device as sensing element,
Measured information is reflected by the variation of the speed or frequency of surface acoustic wave in SAW device, and is converted into electricity
The sensor of signal output.Surface acoustic wave sensor can the information such as precise measurement physics, chemistry, as temperature, stress, gas are close
Degree.It has formd and has been passed including surface acoustic wave pressure sensor, SAW Temperature Sensors, surface acoustic wave biological gene at present
The multiple types such as sensor, surface acoustic wave chemical vapor phase sensor and intelligence sensor.The use of surface acoustic wave sensor is also got over
Come more extensive, the measuring instrument based on surface acoustic wave sensor generally has the disadvantages that on the market at present
First: price is generally higher, the more difficult receiving of ordinary consumer；
Second: traditional measuring instrument lacks automatic growth control (Automatic Gain Control, AGC) shaping circuit
It is difficult to carry out shaping measurement to significantly signal；
Third: measurement accuracy is low, and stability is poor, and the reaction time is longer.
Summary of the invention
To solve deficiency in the prior art, the present invention provides a kind of measuring instrument based on surface acoustic wave sensor and measurement
Method solves traditional measuring instrument based on surface acoustic wave sensor and is difficult to measure that significantly signal, measurement accuracy be low, stability
Difference, the problem that the reaction time is longer, price is high.
In order to achieve the above objectives, the present invention adopts the following technical scheme: a kind of measurement based on surface acoustic wave sensor
Instrument, it is characterised in that: including surface acoustic wave sensor, agc circuit, single order active band-pass filter, shaping circuit, Order RC filter
Wave device, FPGA frequency measurement circuit, single-chip microcontroller, LCD display；Object under test physical quantity is converted to surface acoustic wave by SAW sensor
The variable quantity output surface acoustic wave signal of frequency, surface acoustic wave signal obtain the controllable sinusoidal letter of amplitude by agc circuit fixed ampllitude
Number, the sinusoidal signal after fixed ampllitude passes through the shaping circuit side of being shaped to by single order active band-pass filter filtering clutter
Wave signal, the square-wave signal after shaping pass through Order RC filter secondary filtering again, and then, signal passes through FPGA frequency measurement circuit meter
Calculation obtains the frequency of surface acoustic wave signal, and surface acoustic wave signal frequency is input in single-chip microcontroller, and physics to be measured is obtained by calculation
It measures and is stored in single-chip microcontroller, the measured physical quantity being calculated is shown by LCD display.
A kind of measuring instrument based on surface acoustic wave sensor above-mentioned, it is characterized in that: the agc circuit includes being sequentially connected
Two-stage amplifying circuit, detecting circuit, simple gate voltage limit comparison circuit, two-stage amplifying circuit input terminal connection surface acoustic wave pass
The output end of sensor, simple gate voltage limit comparison circuit output end are connected to the control of the programmable amplifier gain in two-stage amplifying circuit
Port forms closed-loop automatic gain circuit；The two-stage amplifying circuit includes sequentially connected programmable amplifying circuit with compared with
Example amplifying circuit；Two-stage amplifying circuit is used to amplify the surface acoustic wave signal exported from surface acoustic wave sensor；Detecting circuit is used
Low frequency signal is detected in the surface acoustic wave signal exported from two-stage amplifying circuit；Simple gate voltage limit comparison circuit is used to be two-stage
Programmable amplifying circuit in amplifying circuit, which provides, differentiates voltage.
A kind of measuring instrument based on surface acoustic wave sensor above-mentioned, it is characterized in that: the programmable amplifying circuit includes journey
Control amplifier chip, first resistor R1, second resistance R2,3rd resistor R3, the 5th resistance R5, the first DC power supply V1, second
DC power supply V2, positive stage gain control resistance terminal RG+, the negative stage gain control resistance terminal RG- of the programmable amplifier chip connect
Connect the both ends second resistance R2；The positive grade input terminal VIN+ connection surface acoustic wave sensor output port VG1 of signal, the negative grade input of signal
It is grounded after the VIN- connection resistance R3 of end；Supply port Vcc and Vee are separately connected the first DC power supply V1, the second DC power supply V2
After be grounded；It is used to receive simple gate voltage limit after the 5th resistance R5 of gain control end mouth Vg connection of programmable amplifier chip more electric
The output electric signal on road, the positive and negative signal input port of output port OUT connection in-phase proportion amplifier circuit.
A kind of measuring instrument based on surface acoustic wave sensor above-mentioned, it is characterized in that: the in-phase proportion amplifying circuit packet
Include in-phase proportion amplifier chip, the 7th resistance R7, the 8th resistance R8, the 9th resistance R9, the tenth resistance R10 and third direct current
Power supply V3, the 4th DC power supply V4, the 5th DC power supply V5；In-phase proportion amplifier chip negative input mouth connection the
It is grounded after nine resistance R9, positive grade input port connects the signal output port of connection programmable amplifier chip after the 7th resistance R7；
Positive and negative supply port is grounded after being separately connected third and fourth DC power supply V3, V4, and secondary supply port connects the 5th DC power supply
It is grounded after V5；Signal output port connects negative input mouth, the tenth electricity of signal output port connection after connecting the 8th resistance R8
Total output end VF1 after resistance R10 as entire agc circuit.
A kind of measuring instrument based on surface acoustic wave sensor above-mentioned, it is characterized in that: the detecting circuit includes the 11st
Resistance R11, twelfth resistor R12, first capacitor C1, diode D1, one end after eleventh resistor R11 is in parallel with first capacitor C1
Ground connection, another to be terminated at diode D1 cathode, diode D1 anode is connect with the signal output end of in-phase proportion amplifying circuit, the
12 resistance R12 are connect with simple gate voltage limit comparison circuit negative signal input terminal.
A kind of measuring instrument based on surface acoustic wave sensor above-mentioned, it is characterized in that: the simple gate voltage limit comparison circuit
Including simple gate voltage limit comparator chip, the 6th DC power supply V6, the 7th DC power supply V7, the 8th DC power supply V8, the 13rd
Resistance R13, the second capacitor C2, simple gate voltage limit comparator two supply ports of chip are separately connected the 7th DC power supply V7,
It is grounded after six DC power supply V6；Simple gate voltage limit comparator chip electrode input end mouth is grounded after connecting the 8th DC power supply V8,
Negative input mouth connects output port after being sequentially connected the second capacitor C2, thirteenth resistor R13, and output port connection is program-controlled to put
Big circuit is used to form automatic gain closed loop.
A kind of measuring instrument based on surface acoustic wave sensor above-mentioned, it is characterized in that: the shaping circuit is two-door rations the power supply
Press comparison circuit, including double threshold voltage comparator chip, the 9th DC power supply V9, the tenth DC power supply V10, the 14th resistance
R14, the 15th resistance R15；The positive and negative supply port of double threshold voltage comparator chip is separately connected the 9th DC power supply V9,
It is grounded after ten DC power supply V10, connects the 14th between double threshold voltage comparator chip output mouth and electrode input end mouth
Resistance R14, double threshold voltage comparator chip electrode input end mouth are grounded after connecting the 15th resistance R15, negative input mouth
Connect agc circuit output end.
A kind of measurement method of the measuring instrument based on surface acoustic wave sensor, it is characterized in that: comprising steps of
One, the defeated surface acoustic of the variable quantity for measured physical quantity being converted to by surface acoustic wave frequency by surface acoustic wave sensor
Wave signal；
Two, surface acoustic wave signal fixed ampllitude is obtained to the signal after fixed ampllitude；
Three, by the target signal filter clutter after steady spoke；
Four, by the signal shaping after fixed ampllitude at square-wave signal；
Five, square-wave signal is subjected to secondary filtering；
Six, the frequency of surface acoustic wave signal is measured according to filtered square-wave signal；
Seven, according to the signal frequency value that measures by the relational expression between measured physical quantity and surface acoustic wave frequency calculate to
Survey magnitude of physical quantity.
The measurement method of a kind of measuring instrument based on surface acoustic wave sensor above-mentioned, it is characterized in that: the step 6 has
Body is to utilize the frequency of equal precision measuring frequency way measurement surface acoustic wave signal according to square-wave signal.
Advantageous effects of the invention: being suitble to the instrument of various environment to make the present invention is based on surface acoustic wave sensor
With with the accuracy that ensure that measurement；Using agc circuit and shaping circuit, it is able to carry out the frequency of range electric signal by a relatively large margin
Rate measurement；Using equal precision measuring frequency way, the accuracy and accuracy of measurement result are considerably increased, measures to obtain measurement knot through experiment
Fruit accuracy can achieve 1.2%, using FPGA development board measuring signal frequency and the output of single-chip microcontroller LCD screen as a result, convenient
User directly can quickly read measurement result.
Detailed description of the invention
Fig. 1 is measuring instrument block diagram of the present invention；
Fig. 2 is program-controlled amplifier circuit figure in AGC module of the present invention；
Fig. 3 is in-phase proportion amplifier circuit figure in AGC module of the present invention；
Fig. 4 is detecting circuit figure in AGC module of the present invention；
Fig. 5 is simple gate voltage limit comparator circuit figure in AGC module of the present invention；
Fig. 6 is single order active band-pass filter circuit diagram of the present invention；
Fig. 7 is double threshold voltage comparator circuit figure of the present invention；
Fig. 8 is Order RC filter circuit figure of the present invention
Specific embodiment
The invention will be further described below in conjunction with the accompanying drawings.Following embodiment is only used for clearly illustrating the present invention
Technical solution, and not intended to limit the protection scope of the present invention.
As shown, a kind of measuring instrument based on surface acoustic wave sensor, including SAW sensor, agc circuit, single order have
Source bandpass filter, shaping circuit, Order RC filter, FPGA frequency measurement circuit, single-chip microcontroller and LCD display；Object under test object
Reason amount (such as pressure variety) is defeated by the variable quantity that SAW sensor (such as SAW pressure sensor) is converted to surface acoustic wave frequency
Surface acoustic wave signal, surface acoustic wave signal obtain the controllable sinusoidal signal of amplitude by agc circuit fixed ampllitude, the sine after fixed ampllitude
Signal is shaped to square-wave signal by shaping circuit by single order active band-pass filter filtering clutter, after shaping
Square-wave signal passes through Order RC filter secondary filtering again, and then, surface acoustic wave is calculated by FPGA frequency measurement circuit in signal
The frequency of signal, surface acoustic wave signal frequency are input in single-chip microcontroller, and measured physical quantity (such as pressure change is obtained by calculation
Amount) and be stored in single-chip microcontroller, the measured physical quantity being calculated is shown by LCD display；
FPGA frequency measurement circuit uses equal precision measuring frequency way, needs to input the letter of set frequency externally to FPGA frequency measurement circuit
Number (standard signal), single-chip microcontroller are also used to control the frequency of the standard signal of input FPGA frequency measurement circuit；
The agc circuit, single order active band-pass filter, shaping circuit, Order RC filter, FPGA frequency measurement circuit are not
The frequency of the multiple surface acoustic wave signals (SAW signal) exported from SAW sensor can be changed, FPGA frequency measurement circuit measurement obtains
Frequency is equal with the SAW signal frequency exported from SAW sensor；
Agc circuit includes two-stage amplifying circuit, detecting circuit, simple gate voltage limit comparison circuit, two-stage amplifying circuit it is defeated
Enter the output end of end connection SAW sensor, two-stage amplification circuit output end connects detecting circuit input terminal, detecting circuit output end
Simple gate voltage limit comparison circuit input terminal is connected, simple gate voltage limit comparison circuit output end is connected to the journey in two-stage amplifying circuit
Amplifier gain control port is controlled, closed-loop automatic gain circuit is formed.It is by the programmable amplifying circuit in two-stage amplifying circuit
Close loop negative feedback, to differentiation voltage provided by the output signal voltage of agc circuit and simple gate voltage limit comparison circuit compared with, use
In the gain size of adjustment programmable amplifying circuit, to realize the steady spoke to output signal.
For amplifying the SAW signal exported from SAW sensor, (such as pressure signal is SAW sine letter to two-stage amplifying circuit
Number), it is high-frequency signal；Detecting circuit is for detecting low frequency signal from the high frequency SAW signal that two-stage amplifying circuit exports；Simple gate
Voltage limit comparison circuit is used to provide differentiation voltage for the programmable amplifying circuit in two-stage amplifying circuit；
The two-stage amplifying circuit includes that the programmable amplifying circuit interconnected containing programmable amplifier is put with in-phase proportion
Big circuit, the input pin 3 of the output end OUT connection in-phase proportion amplifying circuit of programmable amplifying circuit.
As shown in Fig. 2, programmable amplifying circuit include programmable amplifier chip VCA820, first resistor R1, second resistance R2,
3rd resistor R3, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, the first DC power supply V1, the second DC power supply V2, institute
State positive stage gain control resistance terminal RG+, negative stage gain control the second electricity of resistance terminal RG- connection of programmable amplifier chip VCA820
The both ends R2 are hindered, for controlling the gain size of amplifier；The positive grade input terminal VIN+ connection SAW sensor output port VG1 of signal,
It is grounded after the negative grade input terminal VIN- connection resistance R3 of signal, for receiving signal.Supply port Vcc and Vee are separately connected first
It is grounded after DC power supply V1, the second DC power supply V2, for powering to chip.FB connection the 4th resistance R4 in resistance connecting pin is followed by
Output end OUT, is used for output signal, and port FB can also be directly grounded.Programmable amplifier gain control end mouth Vg connection the 5th
Be used to receive the output electric signal of simple gate voltage limit comparison circuit after resistance R5, for and above-mentioned gain control resistance end RG+ and
RG- controls gain size together.Grounding ports GND is grounded, and is grounded after pin Vref connection resistance R6, output port OUT connection
The positive and negative signal input port of in-phase proportion amplifier circuit.
As shown in figure 3, the in-phase proportion amplifying circuit in the two-stage amplifying circuit includes in-phase proportion amplifier chip
OPA695, the 7th resistance R7, the 8th resistance R8, the 9th resistance R9, the tenth resistance R10 and third DC power supply V3, the 4th are directly
Galvanic electricity source V4, the 5th DC power supply V5；The in-phase proportion amplifier chip OPA695 negative input mouth 2 connects the 9th resistance
It is grounded after R9, positive grade input port 3 connects the signal output port of connection programmable amplifier VCA820 chip after the 7th resistance R7
OUT, for receiving the signal exported from programmable amplifying circuit；Positive and negative supply port 4 and 7 is sequentially connected third and fourth respectively
It is grounded after DC power supply V3, V4, secondary supply port 6 is grounded after connecting the 5th DC power supply V5, for powering to chip.Signal is defeated
Exit port 9 connects negative input mouth 2 after connecting the 8th resistance R8, and the 8th resistance R8 serves as feedback resistance, can be anti-using bearing
The gain of signal is realized in feedback.Signal output port 9 also connects diode D1 in detecting circuit, for exporting amplified signal
To next stage detecting circuit.Total output end VF1 after the tenth resistance R10 of the connection of signal output port 9 as entire agc circuit.
As shown in figure 4, the detecting circuit includes eleventh resistor R11, twelfth resistor R12, capacitor C1 and one two
Pole pipe D1, eleventh resistor R11 latter end ground connection in parallel with first capacitor C1, it is another to be terminated at diode D1 cathode, it is used to structure
At a LC filter, that is, passive filter, institute can be very good to decay from the signal that in-phase proportion amplifier circuit exports not
The high-frequency signal needed.Diode D1 anode is connect with the signal output port 9 of in-phase proportion amplifier, and two poles are accessed in circuit
Pipe plays the role of pressure stabilizing rectification, twelfth resistor R12 and simple gate voltage limit comparator chip OPA820 negative signal input port 2
Connection.
As shown in figure 5, the simple gate voltage limit comparison circuit include simple gate voltage limit comparator chip OPA820, it is the 6th straight
Galvanic electricity source V6, the 7th DC power supply V7, the 8th DC power supply V8, thirteenth resistor R13, the second capacitor C2, simple gate voltage limit ratio
It is grounded after being separately connected the 7th DC power supply V7, the 6th DC power supply V6 compared with device chip supply port 4 and 7, DC power supply is used for
It powers to simple gate voltage limit comparator chip.Simple gate voltage limit comparator chip electrode input end mouth 3 connects the 8th DC power supply
It is grounded after V8, the 8th DC power supply V8, which is provided, differentiates voltage, for compared with the signal exported from detecting circuit.Negative input
Mouth 2 connects output port 6 after being sequentially connected the second capacitor C2, thirteenth resistor R13, and output port 6 connects programmable amplifying circuit
The 5th resistance R5 after connect programmable amplifier chip VCA820 gain control end mouth Vg, be used to form automatic gain closed loop return
Road.
Single order active band-pass filter circuit as shown in Figure 6 be used for by the signal of the total output port VF1 output of agc circuit into
Row filtering, filters off unwanted low-and high-frequency signal, retains useful intermediate frequency segment signal.First-order active filter circuit includes filtering
Device chip TL082, the 9th DC power supply V9, the tenth DC power supply V10, the 14th resistance R14, the 15th D.C. resistance R15,
Three capacitor C3, the 4th capacitor C4.Filter chip TL082 positive signal input port 3 is grounded, and negative signal input port 2 successively connects
It is used as the total input terminal VF2 of signal after meeting third capacitor C3, the 15th resistance R15, total input terminal VF2 is for connecting higher level's AGC electricity
The total output end VF1 in road.The positive and negative feeder ear 7,4 of filter chip is separately connected the tenth DC power supply V10 and the 9th DC power supply V9
After be grounded, the 14th resistance R14 and the 4th capacitor C4 it is in parallel after both ends connection negative signal input terminal 2 and filter chip signal it is defeated
Outlet 6, chip output 6 is as the negative letter of total output end VF3 connection junior shaping circuit double threshold voltage comparator chip TL084
Number input terminal 2.
As shown in fig. 7, shaping circuit, that is, double threshold voltage comparator circuit is used for single order active band-pass filter output end
The signal shaping of mouth VF3 output is at square-wave signal.Double threshold voltage comparator circuit includes double threshold voltage comparator chip
TL084, the 11st DC power supply V11, the 12nd DC power supply V12, the 16th resistance R16, the 17th resistance R17.Double threshold
The positive and negative supply port 4,11 of voltage comparator chip is separately connected the 12nd DC power supply V12, the 11st DC power supply V11 is followed by
Ground, for powering to double threshold voltage comparator chip, double threshold voltage comparator chip output mouth 1 and electrode input end mouth
Connect the 17th resistance R17 between 3, and the 17th resistance R17 is feedback resistance, achievees the purpose that shaping for forming negative-feedback,
Double threshold voltage comparator chip electrode input end mouth 3 is grounded after connecting the 16th resistance R16, the connection of negative input mouth 2 one
The output end VF3 of rank active band-pass filter circuit, for the signal after accepting filter, under the VF4 connection of reshaping signal output end
The signal input part of level-one Order RC filter circuit.
As shown in figure 8, Order RC filter circuit include input port VF5, output port VF6, the 18th resistance R18,
19th resistance R19, the 5th capacitor C5, the 6th capacitor C6.Resistance R18 and capacitor C5 connect and compose single order RC filter, resistance
R19 connect also composition single order RC filter with capacitor C6, and the two superposition constitutes an Order RC filter.Signal is from input terminal
After mouth VF5 input Order RC filter circuit, exported from output port VF6, which can effectively filter out in input signal and deposit
Clutter.The output end VF4 of circuit input end mouth VF5 connection shaping circuit, output port VF6 connection FPGA frequency measurement circuit
Input terminal.
FPGA frequency measurement circuit uses the FPGA development board of Xilinx Artix-7XC7A35T model, and FPGA development board passes through
The frequency for being input to FPGA exploitation partitioned signal is measured in verilog Programming with Pascal Language using equal precision measuring frequency way；FPGA development board
The output end VF6 of signal input part connection Order RC filter circuit.
The single-chip microcontroller uses the single-chip microcontroller of STM32F103ZET model, can be pre-filled with by the memory module built in it
The relational expression of physical quantity to be measured and surface acoustic wave frequency, built-in computation processor can be calculated and be inputted corresponding to frequency
Physical Quantity Calculation value shows the calculated value of physical quantity by LCD display.
A kind of measurement method of the measuring instrument based on surface acoustic wave sensor, comprising the following steps:
One, the defeated surface acoustic of the variable quantity for measured physical quantity being converted to by surface acoustic wave frequency by surface acoustic wave sensor
Wave signal；
Two, surface acoustic wave signal fixed ampllitude is obtained to the signal after fixed ampllitude；
Three, by the target signal filter clutter after steady spoke；
Four, by the signal shaping after fixed ampllitude at square-wave signal；
Five, square-wave signal is subjected to secondary filtering；
Six, filtered square-wave signal measures the frequency of surface acoustic wave signal using equal precision measuring frequency way；
Seven, according to the signal frequency value that measures by the relational expression between measured physical quantity and surface acoustic wave frequency calculate to
Survey magnitude of physical quantity.
Relationship of the present invention by taking surface acoustic wave pressure sensor as an example, between pressure value P and measurement frequency Δ f are as follows: Δ f
=mP,Wherein, f0The theory of frequency f when deformation occurs for piezoelectric material
Value, β are the direct proportion constant of < 1, and μ, a, c, E, h is parameter relevant to sensor internal structure.
The SAW signal amplitude exported from SAW sensor is different, and big small magnitude changes greatly, and the present invention can handle measurement
The sensor signal that amplitude changes greatly has the greater or lesser signal of measurement not available for other similar products on the market
Ability.
It should be understood by those skilled in the art that, embodiments herein can provide as method, system or computer program
Product.Therefore, complete hardware embodiment, complete software embodiment or reality combining software and hardware aspects can be used in the application
Apply the form of example.Moreover, it wherein includes the computer of computer usable program code that the application, which can be used in one or more,
The computer program implemented in usable storage medium (including but not limited to magnetic disk storage, CD-ROM, optical memory etc.) produces
The form of product.
The application is referring to method, the process of equipment (system) and computer program product according to the embodiment of the present application
Figure and/or block diagram describe.It should be understood that every one stream in flowchart and/or the block diagram can be realized by computer program instructions
The combination of process and/or box in journey and/or box and flowchart and/or the block diagram.It can provide these computer programs
Instruct the processor of general purpose computer, special purpose computer, Embedded Processor or other programmable data processing devices to produce
A raw machine, so that being generated by the instruction that computer or the processor of other programmable data processing devices execute for real
The device for the function of being specified in present one or more flows of the flowchart and/or one or more blocks of the block diagram.
These computer program instructions, which may also be stored in, is able to guide computer or other programmable data processing devices with spy
Determine in the computer-readable memory that mode works, so that it includes referring to that instruction stored in the computer readable memory, which generates,
Enable the manufacture of device, the command device realize in one box of one or more flows of the flowchart and/or block diagram or
The function of being specified in multiple boxes.
These computer program instructions also can be loaded onto a computer or other programmable data processing device, so that counting
Series of operation steps are executed on calculation machine or other programmable devices to generate computer implemented processing, thus in computer or
The instruction executed on other programmable devices is provided for realizing in one or more flows of the flowchart and/or block diagram one
The step of function of being specified in a box or multiple boxes.
The above is only a preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art
For member, without departing from the technical principles of the invention, several improvement and deformations can also be made, these improvement and deformations
Also it should be regarded as protection scope of the present invention.
Claims (9)
1. a kind of measuring instrument based on surface acoustic wave sensor, it is characterised in that: including surface acoustic wave sensor, agc circuit, one
Rank active band-pass filter, shaping circuit, Order RC filter, FPGA frequency measurement circuit, single-chip microcontroller, LCD display；Object under test
Physical quantity is converted to the variable quantity output surface acoustic wave signal of surface acoustic wave frequency by SAW sensor, and surface acoustic wave signal is logical
It crosses agc circuit fixed ampllitude and obtains the controllable sinusoidal signal of amplitude, the sinusoidal signal after fixed ampllitude is filtered by single order active band-pass filter
Noise wave removing, and then square-wave signal is shaped to by shaping circuit, the square-wave signal after shaping passes through Order RC filter two again
The frequency of surface acoustic wave signal is calculated by FPGA frequency measurement circuit for secondary filtering, then, signal, and surface acoustic wave signal frequency is defeated
Enter into single-chip microcontroller, measured physical quantity is obtained by calculation and is stored in single-chip microcontroller, the measured physical quantity being calculated passes through
LCD display is shown.
2. a kind of measuring instrument based on surface acoustic wave sensor according to claim 1, it is characterized in that: the agc circuit
Including sequentially connected two-stage amplifying circuit, detecting circuit, simple gate voltage limit comparison circuit, the input terminal of two-stage amplifying circuit connects
Connect the output end of surface acoustic wave sensor, what simple gate voltage limit comparison circuit output end was connected in two-stage amplifying circuit program-controlled puts
Big device gain control end mouth, forms closed-loop automatic gain circuit；The two-stage amplifying circuit includes sequentially connected programming amplifying
Circuit and in-phase proportion amplifying circuit；Two-stage amplifying circuit is used to amplify the surface acoustic wave letter exported from surface acoustic wave sensor
Number；Detecting circuit is for detecting low frequency signal from the surface acoustic wave signal that two-stage amplifying circuit exports；Simple gate voltage limit compares
Circuit is used to provide differentiation voltage for the programmable amplifying circuit in two-stage amplifying circuit.
3. a kind of measuring instrument based on surface acoustic wave sensor according to claim 2, it is characterized in that: the programming amplifying
Circuit includes programmable amplifier chip, first resistor R1, second resistance R2,3rd resistor R3, the 5th resistance R5, the first direct current
Source V1, the second DC power supply V2, positive stage gain control resistance terminal RG+, the negative stage gain control electricity of the programmable amplifier chip
Hinder the both ends end RG- connection second resistance R2；The positive grade input terminal VIN+ connection surface acoustic wave sensor output port VG1 of signal, letter
It is grounded after number negative grade input terminal VIN- connection resistance R3；Supply port Vcc and Vee are separately connected the first DC power supply V1, second
It is grounded after DC power supply V2；It is used to receive simple gate limit after the 5th resistance R5 of gain control end mouth Vg connection of programmable amplifier chip
The output electric signal of voltage comparator circuit, the positive and negative signal input port of output port OUT connection in-phase proportion amplifier circuit.
4. a kind of measuring instrument based on surface acoustic wave sensor according to claim 2, it is characterized in that: the in-phase proportion
Amplifying circuit include in-phase proportion amplifier chip, the 7th resistance R7, the 8th resistance R8, the 9th resistance R9, the tenth resistance R10 with
And third DC power supply V3, the 4th DC power supply V4, the 5th DC power supply V5；The in-phase proportion amplifier chip cathode input
Port is grounded after connecting the 9th resistance R9, and positive grade input port connects the signal of connection programmable amplifier chip after the 7th resistance R7
Output port；Positive and negative supply port is grounded after being separately connected third and fourth DC power supply V3, V4, secondary supply port connection the
It is grounded after five DC power supply V5；Signal output port connects negative input mouth, signal output port after connecting the 8th resistance R8
Connect total output end VF1 after the tenth resistance R10 as entire agc circuit.
5. a kind of measuring instrument based on surface acoustic wave sensor according to claim 2, it is characterized in that: the detecting circuit
Including eleventh resistor R11, twelfth resistor R12, first capacitor C1, diode D1, eleventh resistor R11 and first capacitor C1
Latter end ground connection in parallel, another to be terminated at diode D1 cathode, diode D1 anode and the signal of in-phase proportion amplifying circuit are defeated
Outlet connection, twelfth resistor R12 are connect with simple gate voltage limit comparison circuit negative signal input terminal.
6. a kind of measuring instrument based on surface acoustic wave sensor according to claim 2, it is characterized in that: the simple gate is rationed the power supply
Pressing comparison circuit includes simple gate voltage limit comparator chip, the 6th DC power supply V6, the 7th DC power supply V7, the 8th DC power supply
V8, thirteenth resistor R13, the second capacitor C2, simple gate voltage limit comparator two supply ports of chip are separately connected the 7th direct current
It is grounded after power supply V7, the 6th DC power supply V6；Simple gate voltage limit comparator chip electrode input end mouth connects the 8th DC power supply
It is grounded after V8, negative input mouth connects output port, output port after being sequentially connected the second capacitor C2, thirteenth resistor R13
Programmable amplifying circuit is connected, automatic gain closed loop is used to form.
7. a kind of measuring instrument based on surface acoustic wave sensor according to claim 1, it is characterized in that: the shaping circuit
For double threshold voltage comparator circuit, including double threshold voltage comparator chip, the 9th DC power supply V9, the tenth DC power supply V10,
14th resistance R14, the 15th resistance R15；The positive and negative supply port of double threshold voltage comparator chip is separately connected the 9th direct current
It is grounded after power supply V9, the tenth DC power supply V10, is gone here and there between double threshold voltage comparator chip output mouth and electrode input end mouth
Join the 14th resistance R14, double threshold voltage comparator chip electrode input end mouth is grounded after connecting the 15th resistance R15, cathode
Input port connects agc circuit output end.
8. a kind of measurement method of the measuring instrument based on surface acoustic wave sensor, it is characterized in that: comprising steps of
One, the variable quantity output surface acoustic wave that measured physical quantity is converted to surface acoustic wave frequency is believed by surface acoustic wave sensor
Number；
Two, surface acoustic wave signal fixed ampllitude is obtained to the signal after fixed ampllitude；
Three, by the target signal filter clutter after steady spoke；
Four, by the signal shaping after fixed ampllitude at square-wave signal；
Five, square-wave signal is subjected to secondary filtering；
Six, the frequency of surface acoustic wave signal is measured according to filtered square-wave signal；
Seven, determinand is calculated by the relational expression between measured physical quantity and surface acoustic wave frequency according to the signal frequency value measured
Manage magnitude.
9. the measurement method of a kind of measuring instrument based on surface acoustic wave sensor according to claim 8, it is characterized in that: institute
Step 6 is stated specifically, utilizing the frequency of equal precision measuring frequency way measurement surface acoustic wave signal according to square-wave signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910370387.2A CN110133370B (en) | 2019-05-06 | 2019-05-06 | Measuring instrument and measuring method based on surface acoustic wave sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910370387.2A CN110133370B (en) | 2019-05-06 | 2019-05-06 | Measuring instrument and measuring method based on surface acoustic wave sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110133370A true CN110133370A (en) | 2019-08-16 |
| CN110133370B CN110133370B (en) | 2021-03-16 |
Family
ID=67576271
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910370387.2A Active CN110133370B (en) | 2019-05-06 | 2019-05-06 | Measuring instrument and measuring method based on surface acoustic wave sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110133370B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110133370B (en) * | 2019-05-06 | 2021-03-16 | 南京邮电大学 | Measuring instrument and measuring method based on surface acoustic wave sensor |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1750413A (en) * | 2004-09-14 | 2006-03-22 | 三星电子株式会社 | The method of broadcast receiver and filtering noise signal |
| CN101865951A (en) * | 2009-12-23 | 2010-10-20 | 中国航空工业集团公司第六三一研究所 | Anti-interference frequency measuring method |
| CN204559529U (en) * | 2015-05-08 | 2015-08-12 | 长安大学 | A kind of signal conditioning circuit for SAW (Surface Acoustic Wave) oscillator output signal |
| CN108917863A (en) * | 2018-07-06 | 2018-11-30 | 绍兴文理学院 | The Constant charge soil intensity control system and method for electromagnetic flowmeter |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110133370B (en) * | 2019-05-06 | 2021-03-16 | 南京邮电大学 | Measuring instrument and measuring method based on surface acoustic wave sensor |
-
2019
- 2019-05-06 CN CN201910370387.2A patent/CN110133370B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1750413A (en) * | 2004-09-14 | 2006-03-22 | 三星电子株式会社 | The method of broadcast receiver and filtering noise signal |
| CN101865951A (en) * | 2009-12-23 | 2010-10-20 | 中国航空工业集团公司第六三一研究所 | Anti-interference frequency measuring method |
| CN204559529U (en) * | 2015-05-08 | 2015-08-12 | 长安大学 | A kind of signal conditioning circuit for SAW (Surface Acoustic Wave) oscillator output signal |
| CN108917863A (en) * | 2018-07-06 | 2018-11-30 | 绍兴文理学院 | The Constant charge soil intensity control system and method for electromagnetic flowmeter |
Non-Patent Citations (3)
| Title |
|---|
| 何鹏举 等: "声表面波(SAW)压力传感器输出频率的高精度测量方法研究", 《传感技术学报》 * |
| 李德明: "等精度多功能数字频率计", 《电子世界》 * |
| 李济同 等: "声表面波微力传感器信号处理电路的设计与仿真", 《传感技术学报》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110133370B (en) * | 2019-05-06 | 2021-03-16 | 南京邮电大学 | Measuring instrument and measuring method based on surface acoustic wave sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110133370B (en) | 2021-03-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN204556731U (en) | Internal resistance of cell measuring system | |
| CN101476903A (en) | General-purpose interface collection system of sensor | |
| CN205510002U (en) | Amplification and filtering circuit of special signal of telecommunication | |
| CN203785781U (en) | Handheld noise measuring device | |
| CN110133370A (en) | A kind of measuring instrument and measurement method based on surface acoustic wave sensor | |
| CN105807697A (en) | Programmable universal capacitance type liquid level sensing controller and control method thereof | |
| CN2919261Y (en) | AC current and voltage measuring circuit adopting AC sampling | |
| CN207007838U (en) | A kind of soil water potential digital sensor and soil water potential measurement system | |
| CN106767362A (en) | A kind of Transform Circuit for Displacement Capacitance Sensor | |
| CN206002207U (en) | A kind of infrared sensing signal processing circuit | |
| CN206460695U (en) | A kind of analog waveform generator experiment device for teaching | |
| CN204008003U (en) | A kind of pin-point accuracy pressure controller | |
| CN110007249A (en) | A kind of LED light driving power test method, apparatus and system | |
| CN208443925U (en) | A kind of multichannel small capacitance signal acquisition processing circuit | |
| CN115639408A (en) | High-precision soil conductivity self-adaptive monitoring system | |
| CN209247223U (en) | High-precision torque acquisition system based on ADS1255 | |
| CN108732407A (en) | A kind of alternating current voltage measuring circuit based on rectification and voltage division filtering | |
| CN107219392A (en) | A kind of real-time current signal-data processing system | |
| CN109945932A (en) | Low-power consumption quick response vortex-shedding meter | |
| CN113095017A (en) | General simulator for memory element | |
| CN103592342A (en) | Soil humidity detecting device | |
| CN204944606U (en) | Liquid level detection system | |
| CN205066813U (en) | Integrated form data acquisition system | |
| CN205015308U (en) | Soil -humidity sensor | |
| CN221238896U (en) | Circuit for measuring air negative oxygen ions based on capacitance principle |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |