CN206459717U - A kind of Modulation Continuous Wave Radar water level telemetering device - Google Patents
A kind of Modulation Continuous Wave Radar water level telemetering device Download PDFInfo
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Abstract
The utility model discloses a kind of Modulation Continuous Wave Radar water level telemetering device, the device includes radar transmit-receive, radar signal screening amplifying circuit and microcontroller；Radar transceiver includes phaselocked loop, transmitting antenna, the first frequency mixer and reception antenna；Phaselocked loop output end connects transmitting antenna, and the linear FM signal that phaselocked loop output end is exported is launched by transmitting antenna；Two inputs of first frequency mixer connect phaselocked loop output end and reception antenna respectively, and echo-signal is received by reception antenna；The output end connection radar signal of first frequency mixer screens the input of amplifying circuit, the output end of radar signal screening amplifying circuit connects the ADC sampling ends of microcontroller, and the signal that the output end for screening amplifying circuit for radar signal by microcontroller is exported carries out sampling processing.The utility model can effectively overcome the influence of temperature drift, it is ensured that the linearity of radar transceiver tranmitting frequency, effectively improve the measurement accuracy of indicator water gage.
Description
Technical field
The utility model is related to a kind of radar type level measurement device, more particularly to a kind of Modulation Continuous Wave Radar water
Position telemetering equipment.
Background technology
With the development and progress of hydrologic monitoring technology, contactless level measuring mode is with its quick, safety, precision
High, applied widely the advantages of, gets the attention.Indicator water measuring apparatus uses contactless level measuring mode,
Without separately founding stilling well, do not influenceed by debris in water, measurement accuracy is high, can be applied to that floating object is more, silt content greatly, water quality bar
The not good par test of part, freshwater monitoring, high flood rob the particular job such as survey, dangerous regimen measurement, and it is using flood control as main syllabus
Measurement in played great effect, and ensure that the safety of survey crew, therefore, the newly-built hydrologic monitoring website of China
Level measuring is carried out using radar type water-level measuring equipment mostly.
What application was more at present is the radar based on linear frequency modulation continuous wave (LFMCW) mode, and modulation system requirement exists
The linear increasing or decreasing of radar transmitter frequency in time domain, as shown in figure 1, wherein solid line is the transmission signal of radar transceiver,
Dotted line is the echo-signal that radar transceiver is received.However, the core component voltage controlled oscillator (VCO) itself in radar transceiver
In the presence of certain non-linear, and it can be influenceed by temperature change, the two factors are to cause the nonlinear pass of radar transceiver
Key, is directly affected to indicator water measurement result precision.Conventional mode is by surveying radar transceiver not at present
VCO curves under synthermal are simultaneously stored in table, then according to the current temperature value of temperature sensor measurement, are adjusted using look-up table
The VCO curves of radar are saved, are allowed to keep linear.But this method has two, one to be that temperature survey is often present stagnant
Property, especially in the larger occasion of temperature change, causes VCO curves to mismatch, so as to produce measurement error afterwards.Two be each thunder
Intrinsic VCO characteristics up to transceiver have more or less difference, like this, to carry out VCO to each radar transceiver bent
Line is measured, it is necessary to expend substantial amounts of workload.
Indicator water gage generally is exported using RS232 or 485 interfaces on the market, is not possessed data and is wirelessly transferred and distant
Brake, wants to realize the long-range real-time monitoring to waterlevel data, it is necessary to external special telemetering terminal.The master so existed
Problem is wanted there are three：One is the Data Transport Protocol and acquisition mode matching problem between telemetry terminal system and water-level measuring equipment,
Which increase technological development difficulty and equipment debugging time, two be that this method is unfavorable for flood season and high flood and robs survey etc. needing frequently to change
Become the application scenario of metering system.Three be that can not carry out long-range update to indicator water gage software to upgrade, and wants to complete radar water
The function upgrading of position meter, it is necessary to operated to website scene.
Utility model content
The purpose of this utility model is to overcome the shortcoming and deficiency of prior art, and there is provided a kind of linear frequency modulation continuous wave thunder
Up to water level telemetering device, the device can overcome the influence of temperature drift, it is ensured that the linearity of radar transceiver tranmitting frequency, have
Effect improves the measurement accuracy of indicator water gage.
The purpose of this utility model is achieved through the following technical solutions：A kind of Modulation Continuous Wave Radar water level telemetering dress
Put, including radar transceiver, radar signal screening amplifying circuit and microcontroller；The radar transceiver includes phaselocked loop, hair
Penetrate antenna, the first frequency mixer and reception antenna；The phaselocked loop output end connects transmitting antenna, passes through transmitting antenna transmitting lock phase
The linear FM signal of ring output end output；Two inputs of first frequency mixer connect phaselocked loop output end and connect respectively
Antenna is received, echo-signal is received by reception antenna；The output end connection radar signal screening amplification electricity of first frequency mixer
The input on road, the output end of radar signal screening amplifying circuit connects the ADC sampling ends of microcontroller, passes through microcontroller pin
The signal that the output end output of amplifying circuit is screened to radar signal carries out sampling processing.
It is preferred that, in addition to data transmission unit and host computer, the microcontroller connection data transmission unit, pass through number
The communication with host computer is realized according to transmission unit；The microcontroller uploads water level information to upper by data transmission unit
Machine, host computer sends a control signal to microcontroller by data transmission unit.
Further, the data transmission unit is communicated by GPRS wireless transmission methods with host computer.
Further, the power supply of the radar transceiver enables leads ends connection microcontroller, and host computer passes through micro-control
The break-make of device control radar transceiver power supply processed.
It is preferred that, the phaselocked loop includes reference frequency source, input frequency divider, phase discriminator, loop filter, voltage-controlled shaken
Swing device, the second frequency mixer, low pass filter, program divider and fixed-frequency source；Reference frequency source is connected by inputting frequency divider
The normal phase input end of phase discriminator is connect, the output end of program divider connects the inverting input of phase discriminator, the output end of phase discriminator
Voltage controlled oscillator is connected by loop filter, the output end and fixed-frequency source of voltage controlled oscillator connect the second frequency mixer respectively
Two inputs, the input that the output end of the second frequency mixer passes through low pass filter linker frequency divider；Described program
The frequency dividing ratio control end connection microcontroller of frequency divider, passes through the frequency dividing ratio of microcontroller timing adjustment program divider.
Further, reference frequency source is 30MHz active crystal oscillator, and it is 24GHZ signals that fixed-frequency source, which provides frequency,.
Further, the input frequency divider, phase discriminator and program divider are integrated in a chip, the chip
For ADF4110 or ADF4002.
Further, radar signal screening amplifying circuit includes being sequentially connected first order amplifying circuit, second
Level amplifying circuit and third level amplifying circuit, wherein first order amplifying circuit, second level amplifying circuit and third level amplifying circuit
Output end be connected respectively the ADC inputs of microcontroller；Sampled respectively by microcontroller first order amplifying circuit,
Second amplifying circuit and the signal of third level amplifying circuit output；The first order amplifying circuit and second level amplifying circuit are to put
The changeless amplifying circuit of big multiple, the third level amplifying circuit is to include the amplification of PGA (programmable gain amplifier)
Circuit, microcontroller connects PGA by SPI interface, and the gain for adjusting PGA is programmed by SPI interface.
Further, the first order amplifying circuit includes the first operational amplifier and the second operational amplifier, first
The inverting input of operational amplifier connects one end of the 3rd electric capacity by first resistor；After first electric capacity and the second electric capacity are in parallel
Wherein one end connects the output end of the first frequency mixer, and the other end connects the other end of the 3rd electric capacity；After 3rd capacitance connection is in parallel
The first electric capacity and the second electric capacity one end by the first diode connect dc source, pass through the second diode be grounded；First
The inverting input of operational amplifier connects the output of the first operational amplifier by the 4th electric capacity after parallel connection and second resistance
End, the normal phase input end of the first operational amplifier, which is sequentially connected after 3rd resistor and the 5th electric capacity, to be grounded, 3rd resistor and second
One termination dc source of capacitance connection；The output end of first operational amplifier connects after being sequentially connected the 6th electric capacity and the 4th resistance
Connect the inverting input of the second operational amplifier, the inverting input of the second operational amplifier by the 7th electric capacity after parallel connection and
5th resistance connects the output end of the second operational amplifier, and the normal phase input end of the second operational amplifier is sequentially connected the 6th resistance
It is grounded with after the 8th electric capacity, a termination dc source of the 6th resistance and the 8th capacitance connection；The output of second operational amplifier
The output end as first order amplifying circuit is held, the first ADC inputs of microcontroller are connected；
The second level amplifying circuit includes the 3rd operational amplifier and four-operational amplifier, first order amplifying circuit
Output end is sequentially connected the inverting input that the 3rd operational amplifier is connected after the 9th electric capacity and the tenth electric capacity, the 9th electric capacity and the
One end of ten capacitance connections is by the output end of the operational amplifier of the 11st capacitance connection the 3rd, and the 9th electric capacity and the tenth electric capacity connect
The one end connect also passes through the 7th resistance eutral grounding；The inverting input of 3rd operational amplifier passes through the 12nd electric capacity in parallel and the
Eight resistance connect the output end of the 3rd operational amplifier, the normal phase input end of the 3rd operational amplifier be sequentially connected the 9th resistance and
It is grounded after 13rd electric capacity, a termination dc source of the 9th resistance and the 13rd capacitance connection；Third operational amplifier it is defeated
Go out end and be sequentially connected the inverting input that four-operational amplifier is connected after the 14th electric capacity and the tenth resistance, the 4th operation amplifier
The inverting input of device connects the output end of four-operational amplifier by the 15th electric capacity and the 11st resistance in parallel；4th
The normal phase input end of operational amplifier is sequentially connected after the 12nd resistance and the 16th electric capacity and is grounded, the 12nd resistance and the 16th
One termination dc source of capacitance connection；The output end of four-operational amplifier connects as the output end of second level amplifying circuit
Connect the 2nd ADC inputs of microcontroller；
PGA CH ports pass through the output end of capacitance connection second level amplifying circuit, PGA in the third level amplifying circuit
CH ports connect PGA VREF ends by resistance, PGA VREF ends connection dc source, microcontroller connected by SPI interface
PGA is met, PGA multiplication factor is adjusted by microcontroller；PGA output end connects as the output end of third level amplifying circuit
Connect the 3rd ADC inputs of microcontroller.
Further, the multiplication factor of the first order amplifying circuit is 1000, the times magnification of second level amplifying circuit
Number is 100.
The utility model has the following advantages and effect relative to prior art：
(1) the utility model device includes radar transceiver, radar signal screening amplifying circuit and microcontroller, wherein thunder
Include phaselocked loop, transmitting antenna, the first frequency mixer and reception antenna up to transceiver；Phaselocked loop output end connects transmitting antenna, leads to
Cross the linear FM signal of transmitting antenna transmitting phaselocked loop output end output；The echo letter that first frequency mixer is received to reception antenna
Number and the linear FM signal of phaselocked loop output end output carry out Frequency mixing processing, obtained difference frequency signal sieved by radar signal
Select after amplifying circuit enhanced processing and to be inputted by the ADC sampling ends of microcontroller into microcontroller, is directed to by microcontroller
The difference frequency signal of the output end output of radar signal screening amplifying circuit carries out sampling processing, and for the difference after sampling processing
Frequency signal obtains water level information after being analyzed and processed.The utility model radar transceiver is exported by phaselocked loop needs what is launched
Signal, can effectively overcome the influence of temperature drift, it is ensured that the linearity of radar transceiver tranmitting frequency.Lead in the utility model
This mode of hardware phase-locked-loop frequency locking is crossed, has the advantages that frequency locking speed is fast, frequency locking precision is high and real-time is high.
(2) microcontroller passes through data transmission unit realization and the communication of host computer, wherein microcontroller in the utility model
The water level information that device is got is uploaded to host computer by data transmission unit, therefore, it is possible to realize that remote water-level is monitored；It is upper
The microcontroller software that machine is sent, which updates upgrading control signal and sample frequency regulation control signal, can pass through data transfer
Unit is sent to microcontroller, therefore microcontroller can realize the response of remote control signal, nothing by data transmission unit
Need staff to reach the spot and software upgrading upgrading in microcontroller can be achieved, greatly facilitate the fortune of the utility model device
Row and maintenance.The power supply of other radar transceiver of the present utility model enables leads ends connection microcontroller, when need not detect
During water level, host computer can send the control instruction of radar transceiver closing to microcontroller, and radar is cut off by microcontroller
The power supply of transceiver.Host computer can send dormancy control instruction to microcontroller simultaneously, microcontroller is entered park mode,
Greatly save power consumption.Wherein data transmission unit can with GPRS (General Packet Radio Service, it is general
Grouping service wireless) wireless transmission method communicated with host computer so that and the utility model device can be realized and is wirelessly transferred
And telemetry function, and it is high with efficiency of transmission, reliable communications, effectively anti-rain declines, and transmission speed is very fast, low in energy consumption and special
Suitable for the advantage of field remote measuring application scenario.
(3) voltage controlled oscillator output signal of phaselocked loop and fixed-frequency source output signal difference in the utility model device
Input obtains both difference frequency signals and frequency signal and higher order term into the second frequency mixer after being mixed by the second frequency mixer
Frequency component；Difference frequency signal and frequency signal and higher order term frequency component are filtered out and frequency signal and height after low pass filter
Rank frequency component, the difference frequency signal of output is inputted to program divider as the signal for treating frequency locking, and reference frequency source is by defeated
Enter the signal of frequency divider output and the signal of program divider output is separately input into phase discriminator, the output end of phase discriminator passes through ring
Path filter is inputted to voltage controlled oscillator, the signal of control voltage controlled oscillator output.Reference frequency source is one wherein in phaselocked loop
Fixed frequency source, the frequency dividing ratio of input frequency divider can independently be set according to the frequency interval of desired frequency locking, and be passed through
Frequency dividing ratio in microcontroller timing reprogramming frequency divider can adjust frequency locking band limits, realize the line of default modulation frequency range
The autonomous setting and modification of property and frequency locking frequency range.
(4) radar signal screening amplifying circuit includes three-stage amplifier, the wherein first order and second in the utility model
Level operational amplification circuit is the amplifying circuit of fixed multiplication factor, and the third level is the amplifying circuit of adjustable gain section.This practicality is new
In type can according to the appropriate multiplication factor for choosing first order amplifying circuit and second level amplifying circuit of water level height, with suitable for
The radar transceiver measurement demand different from target water surface distance.For the amplifying circuit of third level adjustable gain, pass through micro-control
The sampled value that device sampling processed is obtained carrys out the gain of feedback regulation amplifier, to adapt to farther target water surface distance.
(5) signal of the three-stage amplifier output of radar signal screening amplifying circuit is separately input into the utility model
The multichannel ADC inputs of microcontroller are sampled, and microcontroller can be directed to from the first order according to sampling threshold amplifies electricity
Obtained signal of being sampled in road, second level amplifying circuit and third level amplifying circuit judged, with from first order amplifying circuit,
The output end of second level amplifying circuit and third level amplifying circuit selects the signal all the way as useful signal；Pass through this side
Formula realizes automatic range switching function so that the utility model device meets long range and short-range measurement demand simultaneously, changes
The quality of kind radar difference frequency signal, reduces measurement error.
Brief description of the drawings
Fig. 1 is LFMCW radar modulation principle figures.
Fig. 2 is the utility model apparatus structure block diagram.
Fig. 3 is phase-locked loop structures schematic diagram in the utility model device.
Fig. 4 is the circuit theory diagrams of the loop filter of phaselocked loop in the utility model device.
Fig. 5 is the schematic diagram of radar signal screening amplifying circuit in the utility model device.
Fig. 6 is the circuit theory diagrams of radar signal screening amplifying circuit first order amplifying circuit in the utility model device.
Fig. 7 is the circuit theory diagrams of radar signal screening amplifying circuit second level amplifying circuit in the utility model device.
Fig. 8 is the circuit theory diagrams of radar signal screening amplifying circuit third level amplifying circuit in the utility model device.
Fig. 9 is that radar signal screening amplifying circuit third level amplifying circuit is connected with microcontroller in the utility model device
Circuit theory diagrams.
Embodiment
The utility model is described in further detail with reference to embodiment and accompanying drawing, but implementation of the present utility model
Mode not limited to this.
Embodiment
Present embodiment discloses a kind of Modulation Continuous Wave Radar water level telemetering device, as shown in Fig. 2 being received including radar
Send out device, radar signal screening amplifying circuit, microcontroller, data transmission unit and host computer；Radar transceiver include phaselocked loop,
Transmitting antenna, the first frequency mixer and reception antenna；Phaselocked loop output end connects transmitting antenna, and phaselocked loop is launched by transmitting antenna
The linear FM signal of output end output；Two inputs of the first frequency mixer connect phaselocked loop output end and receive day respectively
Line, echo-signal is received by reception antenna；The output end connection radar signal of first frequency mixer screens the input of amplifying circuit
End, the output end of radar signal screening amplifying circuit connects the ADC sampling ends of microcontroller, is believed by microcontroller for radar
The signal of the output end output of number screening amplifying circuit carries out sampling processing.
The present embodiment said apparatus realizes that the principle of water level telemetering is as follows：Phaselocked loop output end is defeated in radar transceiver first
The linear FM signal gone out is inputted into the first frequency mixer, while being launched by transmitting antenna；Received in radar transceiver
Antenna receives echo-signal, and is sent in the first frequency mixer；The output end output of phaselocked loop is linear in radar transceiver
Reception antenna receives echo-signal and is mixed in the first frequency mixer in FM signal and radar transceiver, output difference frequency letter
Number；The difference frequency signal of first frequency mixer output is inputted to radar signal and screens amplifying circuit, and microcontroller is sieved for radar signal
The signal for selecting amplifying circuit to export carries out sampling processing, and the signal obtained to sampling is analyzed and processed, at analysis
Reason result obtains water level information.
It can be seen that, the present embodiment launches the linear FM signal that phaselocked loop output end is exported by transmitting antenna；First mixing
The linear FM signal for echo-signal and phaselocked loop the output end output that device is received to reception antenna carries out Frequency mixing processing, obtains
Difference frequency signal by radar signal screen amplifying circuit enhanced processing after inputted by the ADC sampling ends of microcontroller to micro-control
In device processed, the difference frequency signal that the output end for screening amplifying circuit for radar signal by microcontroller is exported is carried out at sampling
Reason, and water level information is obtained after being analyzed and processed for the difference frequency signal after sampling processing.The present embodiment radar transceiver
The signal for needing to launch is exported by phaselocked loop, the influence of temperature drift can be effectively overcome, it is ensured that radar transceiver transmitting frequency
The linearity of rate.By this mode of hardware phase-locked-loop frequency locking in the utility model, with frequency locking speed is fast, frequency locking precision is high
And the high advantage of real-time.
In the present embodiment, microcontroller connection data transmission unit is realized logical with host computer by data transmission unit
Letter；Microcontroller uploads water level information to host computer by data transmission unit, and host computer is sent by data transmission unit and controlled
Signal processed to microcontroller, the power supply of radar transceiver enables leads ends connection microcontroller；Data transfer list in the present embodiment
Member is communicated by GPRS wireless transmission methods with host computer.The water level information that microcontroller is got in the present embodiment passes through
SPI interface is sent to data transfer unit, and data transmission unit receives the water level of the serial data form of microcontroller transmission
During information, the water level information of IP data is converted into, and host computer is sent to by GPRS wireless transmission methods, while host computer
The control signal of transmission sends data transmission unit to by GPRS wireless transmission methods, and data transmission unit receives control letter
After number, by the IP Data Format Transforms of control signal into serial ports data format, microcontroller is then sent to by serial ports；Wherein
The control signal that host computer is sent includes software upgrading upgrading control signal, level measuring time interval controls signal, dormancy control
Signal processed and radar transceiver break-make control signal.For example run into the situation that high flood robs survey that to carry out, microcontroller will be conventional
It is an every 1 minute water level information of measurement or uninterrupted formula measurement in real time that a water level information time update is measured per 15min
Water level information, to obtain even closer water level information, above-mentioned situation, host computer is by sending level measuring time interval control
Signal processed can be completed remotely.When not needing sensed water level, host computer can send the control instruction of radar transceiver closing
To microcontroller, the power supply of radar transceiver is cut off by microcontroller.Host computer can send dormancy control instruction extremely simultaneously
Microcontroller, makes microcontroller enter park mode, greatlys save power consumption.Therefore microcontroller can pass through data transfer
Unit realizes the response of remote control signal, is reached the spot without staff and software upgrading liter in microcontroller can be achieved
Level, greatly facilitates the operation and maintenance of the utility model device.
In the present embodiment, as shown in figure 3, phaselocked loop includes reference frequency source, input frequency divider, phase discriminator, loop
Wave filter, voltage controlled oscillator, the second frequency mixer, low pass filter, program divider and fixed-frequency source；Reference frequency source passes through
The normal phase input end that frequency divider connects phase discriminator is inputted, the output end of program divider connects the inverting input of phase discriminator, mirror
The output end of phase device connects voltage controlled oscillator by loop filter, and the output end and fixed-frequency source of voltage controlled oscillator connect respectively
Connect two inputs of the second frequency mixer, the input that the output end of the second frequency mixer passes through low pass filter linker frequency divider
End；The frequency dividing ratio control end connection microcontroller of described program frequency divider, passes through microcontroller timing adjustment program divider
Frequency dividing ratio N；
When the present embodiment radar transceiver use K-band (24GHz) when, then preset modulation frequency range be 24.005GHz~
24.255GHz, reference frequency source is fixed frequency source, and from 30MHz active crystal oscillator, the frequency of fixed-frequency source is
24GHz, as shown in figure 4, loop filter uses three rank passive filters.Frequency divider, phase discriminator and journey are inputted in the present embodiment
Sequence frequency divider is integrated in a chip, and the function of three parts is realized by the chip, as shown in figure 3, integrated in the present embodiment
The chip of input frequency divider, phase discriminator and program divider selects ADF4110, naturally it is also possible to use ADF4002.
The operation principle of phaselocked loop is as follows in the present embodiment：The voltage controlled oscillator output signal and fixed-frequency source of phaselocked loop
Output signal is separately input into the second frequency mixer, and the difference frequency signal and frequency that both are obtained after being mixed by the second frequency mixer are believed
Number and higher order term frequency component；Difference frequency signal and frequency signal and higher order term frequency component are filtered out after low pass filter
With frequency signal and higher order term frequency component, the difference frequency signal of output is inputted to program divider, reference as the signal for treating frequency locking
The signal of signal and program divider output of the frequency source by input frequency divider output is separately input into phase discriminator, phase discriminator
Output end is inputted to voltage controlled oscillator, the signal of control voltage controlled oscillator output by loop filter.
The frequency f of pll output signal in the present embodimentOUTFor：
fOUT=△ fN+f24G；
Wherein f24G=24GHz is the frequency of reference frequency source output signal, fREFINFor the frequency of reference frequency source output signal
Rate；R is the frequency dividing ratio of input frequency divider, and △ f are phase demodulation frequency；Wherein the frequency dividing ratio R of input frequency divider is according to phaselocked loop frequency locking
Frequency interval set, wherein when R be 30 when, then phase demodulation frequency △ f select 1MHz in the present embodiment.
Wherein N is the frequency dividing ratio of program divider, and the frequency dividing ratio N of program divider can be adjusted by microcontroller
It is whole, it is specially that Interruption can be set in the microcontroller, and the renewal program divider N in interruption.Radar emission is believed
Number modulating bandwidth △ F be △ f (Nmax-Nmin), when default transmitting band bandwidth is 250MHz, then Nmax-Nmin=
250；Wherein take Nmax=255 be the maximum that frequency dividing ratio N takes, and takes Nmin=5 be the minimum value that frequency dividing ratio N takes.By phaselocked loop,
The linear transmitting frequency range f of radar transceiverOUTFor 24.005GHz~24.255GHz.
As shown in figure 5, the present embodiment radar signal screening amplifying circuit include being sequentially connected first order amplifying circuit, the
Second amplifying circuit and third level amplifying circuit, wherein first order amplifying circuit, second level amplifying circuit and third level amplification electricity
The output end on road is connected respectively the ADC inputs of microcontroller；Sampled respectively by microcontroller first order amplifying circuit,
Second level amplifying circuit and the signal of third level amplifying circuit output；The first order amplifying circuit and second level amplifying circuit are
The changeless amplifying circuit of multiplication factor, the third level amplifying circuit is to include putting for PGA (programmable gain amplifier)
Big circuit, microcontroller connects PGA by SPI interface, is programmed by SPI interface first in the gain for adjusting PGA, the present embodiment
The multiplication factor A1 of level amplifying circuit is 1000；The multiplication factor A2 of second level amplifying circuit is 100 in the present embodiment.
As shown in fig. 6, first order amplifying circuit includes the first operational amplifier and the second operational amplifier in the present embodiment,
One end that the inverting input of first operational amplifier passes through the electric capacity C3 of first resistor R1 connections the 3rd；First electric capacity C1 and second
Wherein one end connects the output end of the first frequency mixer after electric capacity C2 is in parallel, and the other end connects the 3rd electric capacity C3 other end；3rd
One end of the first electric capacity C1 and the second electric capacity C2 after electric capacity C3 connections are in parallel are led to by the first diode D1 connection dc sources
Cross the second diode D2 ground connection；The inverting input of first operational amplifier passes through the 4th electric capacity C4 and second resistance after parallel connection
The output end of R2 the first operational amplifiers of connection, the normal phase input end of the first operational amplifier is sequentially connected 3rd resistor R3 and
It is grounded after five electric capacity C5, a termination dc source of 3rd resistor R3 and the second electric capacity C2 connections；First operational amplifier it is defeated
Go out end and be sequentially connected the inverting input that the second operational amplifier is connected after the 6th electric capacity C6 and the 4th resistance R4, the second computing is put
The inverting input of big device by the 7th electric capacity C7 after parallel connection and the 5th resistance R5 the second operational amplifiers of connection output end,
The normal phase input end of second operational amplifier is sequentially connected after the 6th resistance R6 and the 8th electric capacity C8 and is grounded, the 6th resistance R6 and the
One termination dc source of eight electric capacity C8 connections；The output end of second operational amplifier as first order amplifying circuit output
End, connects the first ADC inputs of microcontroller；The signal SignIn that the first mixer output is exported in the present embodiment passes through
First electric capacity C1 and the second electric capacity C2 blockings, and inputted after the first diode D1 and the second diode D2 amplitude limits to first
In level amplifying circuit；The signal SignOut1 of the output end output of first order amplifying circuit is inputted to the first ADC of microcontroller
Input.
As shown in fig. 7, second level amplifying circuit includes the 3rd operational amplifier and four-operational amplifier in the present embodiment,
The output end of first order amplifying circuit, which is sequentially connected after the 9th electric capacity C9 and the tenth electric capacity C10, connects the anti-of the 3rd operational amplifier
One end of phase input, the 9th electric capacity C9 and the tenth electric capacity C10 connections passes through the operational amplifier of the 11st electric capacity C11 connections the 3rd
Output end, one end of the 9th electric capacity C9 and the tenth electric capacity C10 connections also passes through the 7th resistance eutral grounding；3rd operational amplifier
Inverting input passes through the 12nd electric capacity C12 of parallel connection and the output end of the operational amplifier of the 8th resistance R8 connections the 3rd, the 3rd
The normal phase input end of operational amplifier is sequentially connected after the 9th resistance R9 and the 13rd electric capacity C13 and is grounded, the 9th resistance R9 and the
One termination dc source of 13 electric capacity C13 connections；The output end of 3rd operational amplifier be sequentially connected the 14th electric capacity C14 and
The inverting input of four-operational amplifier is connected after tenth resistance R9, the inverting input of four-operational amplifier passes through parallel connection
The 15th electric capacity C15 and the 11st resistance R11 connection four-operational amplifiers output end；The positive of four-operational amplifier
Input is sequentially connected after the 12nd resistance R12 and the 16th electric capacity C16 and is grounded, the 12nd resistance R12 and the 16th electric capacity C16
One termination dc source of connection；The output end of four-operational amplifier is connected micro- as the output end of second level amplifying circuit
2nd ADC inputs of controller；The signal SignOut2 that the output end of second level amplifying circuit is exported is inputted to micro-control
2nd ADC inputs of device processed.
As shown in figure 8, PGA CH ports are amplified by the capacitance connection second level in third level amplifying circuit in the present embodiment
The output end of circuit, PGA CH ports connect PGA VREF ends, PGA VREF ends connection dc source, micro-control by resistance
Device processed connects PGA by SPI interface so that microcontroller adjusts PGA multiplication factor by SPI interface programming；PGA's is defeated
Go out end as the output end of third level amplifying circuit, connect the 3rd ADC inputs of microcontroller, i.e., by third level amplifying circuit
Output end output signal SignOut3 input to the 3rd ADC inputs of microcontroller.It is illustrated in figure 9 in the present embodiment
PGA and microcontroller connection figure.
Can putting according to water level height suitably selection first order amplifying circuit and second level amplifying circuit in the present embodiment
Big multiple, with suitable for the radar transceiver measurement demand different from target water surface distance.Wherein radar transceiver is from target water
Face is more remote, and echo-signal is weaker so that the amplitude of difference frequency signal is also smaller, and this is unfavorable for the processing of difference frequency signal.When difference frequency letter
During number amplitude very little, the precision of identification will be reduced, and in order to keep the precision of identification, the present embodiment can be according to radar transceiver
The amplifying circuit of different amplification is selected with the different distance of the target water surface, when radar transceiver and the distance of the target water surface compared with
It is when big, then more appropriate to increase the multiplication factor of first order amplifying circuit and second level amplifying circuit.Radar is believed in the present embodiment
The multiplication factor A1 of number screening amplifying circuit first order amplifying circuit is 1000, and the multiplication factor A2 of second level amplifying circuit is
100。
The signal of the three-stage amplifier output of radar signal screening amplifying circuit is separately input into micro-control in the present embodiment
The multichannel ADC inputs of device processed are sampled, and microcontroller can be directed to according to sampling threshold from first order amplifying circuit, the
Obtained signal of being sampled in second amplifying circuit and third level amplifying circuit judged as follows, with from first order amplifying circuit,
The output end of second level amplifying circuit and third level amplifying circuit selects the signal all the way as useful signal：
(1) sampling threshold of first order amplifying circuit output signal is set as ADLimit1, sets second level amplifying circuit
The sampling threshold of output signal is ADLimit2, sets the sampling threshold of third level amplifying circuit output signal as ADLimit3；
ADLimit1, ADLimit2 and ADLimit3 are the 75% of sampling full scale value wherein in the present embodiment.(2) first by micro-control
The first order amplifying circuit output signal SignOut1 and sampling threshold ADLimit1 that device sampling processed is obtained is compared, and works as micro-control
When the maximum for the first order amplifying circuit output signal SignOut1 that device sampling processed is obtained is more than sampling threshold ADLimit1, then
Obtained first order amplifying circuit output signal SignOut1 is sampled as useful signal from microcontroller；Otherwise carry out following
Operation；(3) sample microcontroller obtained second level amplifying circuit output signal SignOut2 and sampling threshold ADLimit2
It is compared, when the maximum for the second level amplifying circuit output signal SignOut2 that microcontroller sampling is obtained is more than sampling threshold
During value ADLimit2, then the obtained second level amplifying circuit output signal SignOut2 that sampled from microcontroller is as effective letter
Number；Otherwise obtained third level amplifying circuit output signal SignOut3 is sampled as useful signal from microcontroller, then
Into following operation；(4) when microcontroller samples obtained third level amplifying circuit output signal less than sampling threshold
ADLimit3, increases the gain of PGA in third level amplifying circuit by microprocessor control；Otherwise subtracted by microprocessor control
PGA gain in small third level amplifying circuit.
The present embodiment can realize automatic range switching function through the above way.For example when radar transceiver and target water
The distance in face is less than 5 meters, then the useful signal chosen is first order amplifying circuit output signal, when radar transceiver and target water
The distance in face is 5~10 meters, then the useful signal chosen is second level amplifying circuit output signal；When radar transceiver and target
When the distance of the water surface is more than 15 meters, then the signal that the useful signal chosen exports for third level amplifying circuit, therefore the present embodiment
Middle radar signal screening amplifying circuit can meet long range and short-range measurement demand, improve the matter of radar difference frequency signal
Amount, reduces measurement error.
Other microcontroller can carry out FIR filtering, FFT, frequency spectrum refinement for the useful signal and slide flat
Water level information is obtained after equal filtering process, measurement result saltus step and error as caused by water wave etc. can be effectively overcome, with survey
Accuracy of measurement and the high advantage of measurement stability.
Above-described embodiment is the utility model preferably embodiment, but embodiment of the present utility model is not by above-mentioned
The limitation of embodiment, it is other it is any without departing from Spirit Essence of the present utility model with made under principle change, modify, replace
Generation, combination, simplification, should be equivalent substitute mode, are included within protection domain of the present utility model.
Claims (10)
1. a kind of Modulation Continuous Wave Radar water level telemetering device, including radar transceiver, it is characterised in that also including radar
Signal screening amplifying circuit and microcontroller；The radar transceiver includes phaselocked loop, transmitting antenna, the first frequency mixer and reception
Antenna；The phaselocked loop output end connects transmitting antenna, and the linear frequency modulation that phaselocked loop output end is exported is launched by transmitting antenna
Signal；Two inputs of first frequency mixer connect phaselocked loop output end and reception antenna respectively, are connect by reception antenna
Receive echo-signal；The output end connection radar signal of first frequency mixer screens the input of amplifying circuit, radar signal sieve
The output end of amplifying circuit is selected to connect the ADC sampling ends of microcontroller, by microcontroller for radar signal screening amplification electricity
The signal of the output end output on road carries out sampling processing.
2. Modulation Continuous Wave Radar water level telemetering device according to claim 1, it is characterised in that also including data
Transmission unit and host computer, the microcontroller connect data transmission unit, are realized and host computer by data transmission unit
Communication；The microcontroller uploads water level information to host computer by data transmission unit, and host computer passes through data transmission unit
Send a control signal to microcontroller.
3. Modulation Continuous Wave Radar water level telemetering device according to claim 2, it is characterised in that the data are passed
Defeated unit is communicated by GPRS wireless transmission methods with host computer.
4. Modulation Continuous Wave Radar water level telemetering device according to claim 2, it is characterised in that the radar is received
The power supply for sending out device enables leads ends connection microcontroller, the break-make that host computer passes through microprocessor control radar transceiver power supply.
5. Modulation Continuous Wave Radar water level telemetering device according to claim 1, it is characterised in that the phaselocked loop
Include reference frequency source, input frequency divider, phase discriminator, loop filter, voltage controlled oscillator, the second frequency mixer, LPF
Device, program divider and fixed-frequency source；Reference frequency source connects the normal phase input end of phase discriminator, program by inputting frequency divider
The output end of frequency divider connects the inverting input of phase discriminator, and the output end of phase discriminator connects VCO by loop filter
Device, the output end and fixed-frequency source of voltage controlled oscillator connect two inputs of the second frequency mixer respectively, the second frequency mixer
The input that output end passes through low pass filter linker frequency divider；The frequency dividing ratio control end connection of described program frequency divider is micro-
Controller, passes through the frequency dividing ratio of microcontroller timing adjustment program divider.
6. Modulation Continuous Wave Radar water level telemetering device according to claim 5, it is characterised in that reference frequency source
For 30MHz active crystal oscillator, it is 24GHZ signals that fixed-frequency source, which provides frequency,.
7. Modulation Continuous Wave Radar water level telemetering device according to claim 5, it is characterised in that the input point
Frequency device, phase discriminator and program divider are integrated in a chip, and the chip is ADF4110 or ADF4002.
8. Modulation Continuous Wave Radar water level telemetering device according to claim 1, it is characterised in that the radar letter
Number screening amplifying circuit includes first order amplifying circuit, second level amplifying circuit and the third level amplifying circuit being sequentially connected, its
The output end of middle first order amplifying circuit, second level amplifying circuit and third level amplifying circuit is connected respectively microcontroller
ADC inputs；Sampled respectively by microcontroller first order amplifying circuit, second level amplifying circuit and third level amplifying circuit is defeated
The signal gone out；The first order amplifying circuit and second level amplifying circuit are the changeless amplifying circuit of multiplication factor, described
Third level amplifying circuit is to include the amplifying circuit of PGA (programmable gain amplifier), and microcontroller is connected by SPI interface
PGA, the gain for adjusting PGA is programmed by SPI interface.
9. Modulation Continuous Wave Radar water level telemetering device according to claim 8, it is characterised in that the first order
Amplifying circuit includes the first operational amplifier and the second operational amplifier, and the inverting input of the first operational amplifier passes through first
Resistance connects one end of the 3rd electric capacity；Wherein one end connects the output of the first frequency mixer after first electric capacity and the second electric capacity are in parallel
End, the other end connects the other end of the 3rd electric capacity；One end of the first electric capacity and the second electric capacity after 3rd capacitance connection is in parallel leads to
The first diode connection dc source is crossed, is grounded by the second diode；The inverting input of first operational amplifier passes through simultaneously
The 4th electric capacity and second resistance after connection connect the output end of the first operational amplifier, the normal phase input end of the first operational amplifier
It is sequentially connected after 3rd resistor and the 5th electric capacity and is grounded, a termination dc source of 3rd resistor and the second capacitance connection；First
The output end of operational amplifier is sequentially connected the inverting input that the second operational amplifier is connected after the 6th electric capacity and the 4th resistance,
The inverting input of second operational amplifier connects the second operational amplifier by the 7th electric capacity after parallel connection and the 5th resistance
Output end, the normal phase input end of the second operational amplifier is sequentially connected after the 6th resistance and the 8th electric capacity and is grounded, the 6th resistance and
One termination dc source of the 8th capacitance connection；The output end of second operational amplifier as first order amplifying circuit output
End, connects the first ADC inputs of microcontroller；
The second level amplifying circuit includes the 3rd operational amplifier and four-operational amplifier, the output of first order amplifying circuit
End is sequentially connected the inverting input that the 3rd operational amplifier is connected after the 9th electric capacity and the tenth electric capacity, the 9th electric capacity and the tenth electricity
Hold one end of connection by the output end of the operational amplifier of the 11st capacitance connection the 3rd, the 9th electric capacity and the tenth capacitance connection
One end also passes through the 7th resistance eutral grounding；The inverting input of 3rd operational amplifier passes through the 12nd electric capacity in parallel and the 8th electricity
The output end of resistance the 3rd operational amplifier of connection, the normal phase input end of the 3rd operational amplifier is sequentially connected the 9th resistance and the tenth
It is grounded after three electric capacity, a termination dc source of the 9th resistance and the 13rd capacitance connection；The output end of third operational amplifier
The inverting input that four-operational amplifier is connected after the 14th electric capacity and the tenth resistance is sequentially connected, four-operational amplifier
Inverting input connects the output end of four-operational amplifier by the 15th electric capacity and the 11st resistance in parallel；4th computing
The normal phase input end of amplifier is sequentially connected after the 12nd resistance and the 16th electric capacity and is grounded, the 12nd resistance and the 16th electric capacity
One termination dc source of connection；The output end of four-operational amplifier is connected micro- as the output end of second level amplifying circuit
2nd ADC inputs of controller；
PGA CH ports pass through the output end of capacitance connection second level amplifying circuit, PGA CH in the third level amplifying circuit
Port connects PGA VREF ends by resistance, and PGA VREF ends connection dc source, microcontroller is connected by SPI interface
PGA, PGA multiplication factor is adjusted by microcontroller；PGA output end is used as the output end of third level amplifying circuit, connection
3rd ADC inputs of microcontroller.
10. Modulation Continuous Wave Radar water level telemetering device according to claim 8, it is characterised in that described first
The multiplication factor of level amplifying circuit is 1000, and the multiplication factor of second level amplifying circuit is 100.
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| CN201621215124.2U CN206459717U (en) | 2016-11-09 | 2016-11-09 | A kind of Modulation Continuous Wave Radar water level telemetering device |
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| CN201621215124.2U CN206459717U (en) | 2016-11-09 | 2016-11-09 | A kind of Modulation Continuous Wave Radar water level telemetering device |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106441504A (en) * | 2016-11-09 | 2017-02-22 | 珠江水利委员会珠江水利科学研究院 | Linear frequency modulation continuous wave radar water level telemeasuring device and method |
| CN108801866A (en) * | 2018-08-03 | 2018-11-13 | 常州海马科技有限公司 | Circuit, method for amplifying signal and the particulate matter sensors of particulate matter sensors |
| CN110987121A (en) * | 2019-08-30 | 2020-04-10 | 厦门四信通信科技有限公司 | Radar-based level measurement method, device, equipment and storage medium |
-
2016
- 2016-11-09 CN CN201621215124.2U patent/CN206459717U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106441504A (en) * | 2016-11-09 | 2017-02-22 | 珠江水利委员会珠江水利科学研究院 | Linear frequency modulation continuous wave radar water level telemeasuring device and method |
| CN108801866A (en) * | 2018-08-03 | 2018-11-13 | 常州海马科技有限公司 | Circuit, method for amplifying signal and the particulate matter sensors of particulate matter sensors |
| CN110987121A (en) * | 2019-08-30 | 2020-04-10 | 厦门四信通信科技有限公司 | Radar-based level measurement method, device, equipment and storage medium |
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