CN202101788U - Ultrasonic thermometer based on FPGA - Google Patents
Ultrasonic thermometer based on FPGA Download PDFInfo
- Publication number
- CN202101788U CN202101788U CN2011201274975U CN201120127497U CN202101788U CN 202101788 U CN202101788 U CN 202101788U CN 2011201274975 U CN2011201274975 U CN 2011201274975U CN 201120127497 U CN201120127497 U CN 201120127497U CN 202101788 U CN202101788 U CN 202101788U
- Authority
- CN
- China
- Prior art keywords
- ultrasonic
- signal
- circuit
- fpga
- ultrasonic transducer
- 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.)
- Expired - Fee Related
Links
Images
Landscapes
- Measuring Temperature Or Quantity Of Heat (AREA)
Abstract
The utility model relates to an ultrasonic thermometer based on an FPGA, comprising an ultrasonic transducer drive circuit, an ultrasonic temperature sensor and an ultrasonic echo signal processing circuit, wherein the ultrasonic transducer drive circuit mainly comprises a digital analog converter D/A and a power amplification circuit, the ultrasonic temperature sensor comprises two ultrasonic transducers and an enclosed high heat conduction metal pipe bodies full of gas, the ultrasonic echo signal processing circuit mainly comprises a filter circuit, an amplification circuit, an analog digital converter A/D and an Field Programmable Gate Array (FPGA), wherein inside the FPGA, circuits, such as a signal generator, a random memory area and a processor, are constructed. The ultrasonic thermometer based on an FPGA enables the cost to be reduced by constructing circuits such as a processor in an FPGA; and simultaneously by using a high precision ultrasonic transmission time measure method, the precise temperature measure can be realized.
Description
Technical field
The utility model belongs to sophisticated sensor and detection technique field, is specifically related to a kind of thermometer with the ultrasonic technology precisely measuring temperature.
Background technology
Ultrasound wave has two important performances: the firstth, and directionality.Because frequency of ultrasonic is very high, wavelength is very short, so it can be along rectilinear propagation as light wave, and will advance around object unlike the lower sound wave of frequency.The secondth, ultrasonic wave energy is propagated in gas, liquid and solid, and velocity of propagation is identical in a kind of material, and velocity of propagation has nothing in common with each other in different materials, when running into the interface of different material, can reflect as light.Along with development of electronic technology, the increasing precision measurement that is applied to temperature etc. of ultrasonic technology.
When ultrasound wave was propagated in medium, velocity of propagation changed with the variation of state parameters such as temperature, pressure.The hundreds of approximately rice of velocity of propagation per second increased with the temperature rising when ultrasound wave was propagated in gas, and air middle pitch speed is 331.4 meter per seconds in the time of 0 ℃, is 340 meter per seconds in the time of 15 ℃, 1 ℃ of the every rising of temperature, and velocity of sound increases by 0.6 meter per second approximately.Record transmission range ultrasound wave travel-time under different temperatures when constant, just can record temperature.For example, hyperacoustic speed is 344 meter per seconds in the time of 20 ℃, and hyperacoustic speed is 344.6 meter per seconds in the time of 21 ℃, if hyperacoustic transmission range is 0.3 meter, then hyperacoustic transmission time is 8.7209 * 10 in the time of 20 ℃
-4Second, hyperacoustic transmission time is 8.7057 * 10 in the time of 21 ℃
-4Second, hyperacoustic transmission time difference is 1.52 * 10 in the time of 21 ℃ and 20 ℃ the time
-6Second.Guarantee to measure and reach 0.001 ℃ Measurement Resolution, require the resolution of ultrasonic transmission time measurement to reach and could realize 1 ~ 2 nanosecond.If with conventional hyperacoustic transmission time of timer counter circuit measuring, then the frequency of clock circuit will reach 1G at least, this obviously is difficult to realize for instrument development.
Summary of the invention
The utility model is to the problems referred to above; The ultrasonic thermometer that a kind of Measurement Resolution can reach 0.001 ℃ is disclosed; It adopts ultrasonic temperature sensor, FPGA circuit and software segmentation interpolation algorithm; Can under the prerequisite that guarantees the measurement real-time, realize the measurement of nanosecond ultrasonic transmission time, thereby realize the high-precision temperature measurement.
The technical scheme that the utility model adopts is:
A kind of high-sensitivity ultrasonic thermometer is used to realize that Measurement Resolution is superior to 0.001 ℃ precision temperature measurement.Thus, the high-precision ultrasonic thermometer of the utility model proposition comprises ultrasonic temperature sensor, on-site programmable gate array FPGA, signal amplification circuit, filtering circuit, A/D change-over circuit, D/A change-over circuit, power amplification circuit; Said ultrasonic temperature sensor is to be made up of ultrasonic transducer E1, ultrasonic transducer E2 and a body.
Said ultrasonic transducer E1 and ultrasonic transducer E2 are installed in the two ends in the body relatively, are full of the gas as the ultrasound wave medium in the body.
Include signal generator, circuit such as memory block, processor at random in the said on-site programmable gate array FPGA; Processor control-signals generator sine wave output drive signal; Be connected to the D/A change-over circuit, by the D/A change-over circuit said sine wave drive signal changed, the D/A change-over circuit connects power amplification circuit again; Signal is amplified; Power amplification circuit is connected with ultrasonic transducer E1, and signal is inputed to said ultrasonic transducer E1, and this ultrasonic transducer E1 converts said this input signal to mechanical vibration and produces ultrasonic signal.
Said ultrasonic transducer E2 receives the ultrasonic signal that said ultrasonic transducer E1 sends; Convert mechanical vibration into electric signal; The output ultrasonic wave echoed signal; And through with its amplifying circuit that is connected successively, filtering circuit and A/D change-over circuit, make said ultrasonic echo signal after amplification, filtering and A/D conversion, input to on-site programmable gate array FPGA successively; The digital sine conversion of signals that D/A converter is used for sending FPGA is an analog sinus signals, and power amplification circuit is used to amplify the power of this sinusoidal signal, makes it enough energy drives ultrasonic transducer E1.It is digital signal that said A/D converter is mainly used in a ultrasonic echo analog signal conversion, and input FPGA.
Said on-site programmable gate array FPGA sample simultaneously sine wave drive signal and the ultrasonic echo signal of input of output, and sampled data left in the internal memory; Said FPGA circuit major function has two: first function is that the processor control-signals generator of its built produces the digital sine signal, and this signal converts simulating signal to through D/A converter, and amplifies rear drive transducer E1 through power amplification circuit.Second function is to accomplish the ultrasonic echo signals sampling, and has data in the memory block at random that is configured in FPGA inside.
The said interior processor of on-site programmable gate array FPGA that is implemented in accurately calculates the pairing moment of ultrasonic propagation time terminal point from reading sampled data the memory block at random through the segmentation interpolation algorithm; Then, confirm the pairing moment of ultrasonic propagation time starting point according to the sine wave drive signal of output.Thereby accurately confirm the transmission time of ultrasound wave between two transducer E1, E2.Last processor is accurately confirmed the temperature of temperature sensor according to ultrasound wave different transmission times between two transducer E1, the E2 in the ultrasonic temperature sensor body.
Said transducer E1 is a piezoelectric transducer, can be the electrical signal conversion with certain energy mechanical vibration, and when the frequency of signal was in the frequency of ultrasonic scope, transducer E1 was electrical signal conversion a ultrasonic signal.Transducer E2 also is a piezoelectric transducer, converts mechanical vibration into electric signal, and when ultrasonic signal affacted on the ultrasonic transducer E2, it converted ultrasonic signal into electric signal, and this signal can be referred to as the ultrasonic echo signal.
The sinusoidal ultrasonic signal of periodicity of ultrasonic transducer E1 emission some; After this signal is propagated in gas and is arrived transducer E2; Excitation transducer E2 produces the ultrasonic echo signal, and the continuous pump of the ultrasonic signal that the amplitude of echoed signal receives along with transducer and increasing gradually is when pumping signal stops; The mechanical vibration of transducer still can continue under action of inertia and decay gradually; The amplitude of echoed signal also reduces gradually, so the ultrasonic echo signal is a luffing cyclical signal, and its cycle is corresponding to the cycle of ultrasonic signal.That cycle of echoed signal amplitude maximum is corresponding to the cycle of last sent that ultrasonic signal of transducer E1.
Hyperacoustic travel-time is exactly the corresponding time interval between that a bit and on the echoed signal that receives of transducer E2 arbitrarily on the ultrasonic signal that sends of transducer E1.The key of ultrasonic transmission time measurement is to confirm the starting point and the terminal point in travel-time.The starting point in travel-time can be the specific pairing moment on the ultrasonic signal that sends of transducer E1, the terminal point of time be on the echoed signal with corresponding that pairing moment of ultrasonic signal unique point.
Echoed signal is a Variable Amplitude cyclical signal, and the most characteristic ripple is that maximum ripple of amplitude in its waveform, can be referred to as characteristic wave, and characteristic wave is corresponding to last ripple of ultrasonic signal.In characteristic wave, the most characteristic point is zero crossing and peak point, can select the unique point of zero crossing as echoed signal.The unique point moment corresponding is exactly the terminal point in travel-time, and is corresponding with it, and the pairing moment of zero crossing of last that ripple can be confirmed as the starting point in travel-time in the ultrasonic signal waveform.
Because being the control of the processor in the FPGA, ultrasonic signal produces down, the starting point in travel-time, and just the zero crossing moment corresponding of last that ripple of ultrasonic signal is easy to confirm accurately that by processor its precision depends on the running frequency of FPGA.
The terminal point in travel-time, just the pairing moment of zero crossing is confirmed through the segmentation interpolation algorithm in the echoed signal characteristic wave.The segmentation interpolation algorithm is according to the waveform in that cycle of peak amplitude maximum in the at first definite echoed signal of the A/D sampled signal of the ultrasonic echo of storing among the FPGA; Confirm former and later two sampled points of zero crossing (ratio zero is big, and a ratio zero is little) pairing moment then; Be benchmark with former and later two sampled points of zero crossing at last; With fit method sampled point is segmented interpolation; Confirm the pairing moment of echoed signal zero crossing, i.e. in the pairing moment of ultrasonic propagation time terminal point, its precision depends primarily on the resolution of A/D sampling.
The ultrasonic thermometer principle of work based on FPGA that the utility model proposes is following: ultrasonic transducer E1 and ultrasonic transducer E2 are installed in the body two ends relatively; The processor that makes up in the programming gate array FPGA is controlled on-the-spot may command signal generator sine wave output drive signal; Let signal input to said ultrasonic transducer E1 through D/A change-over circuit and power amplification circuit successively, this ultrasonic transducer E1 converts said this input signal to mechanical vibration and produces ultrasonic signal.
Said ultrasonic transducer E2 receives the ultrasonic signal that said ultrasonic transducer E1 sends; And output ultrasonic wave echoed signal; By filtering circuit the ultrasonic echo signal that ultrasonic transducer E2 sends is carried out filtering; After being amplified by amplifying circuit, by the A/D change-over circuit echoed signal is sampled, sampled data is stored in earlier in the memory block that is configured in the FPGA again.
After sampling is accomplished; Processor is at first launched hyperacoustic data according to signal generator and is confirmed the pairing moment of ultrasonic propagation time starting point; Read the A/D sampled data of ultrasonic echo signal then in the FPGA; Employing accurately calculates the pairing moment of ultrasonic propagation time terminal point through the segmentation interpolation algorithm, and then accurately confirms the transmission time of ultrasound wave between two transducer E1, E2.Processor accurately calculates its corresponding temperature according to ultrasound wave different transmission times between two transducer E1, the E2 in the ultrasonic temperature sensor body then.
The utility model is owing to adopted hardware circuit and the software algorithm of subdivision based on FPGA; Can realize the measurement of the ultrasonic transmission time of nanosecond precision; Thereby realize that resolution is superior to 0.001 ℃ high-precision temperature measurement, and guarantee good real-time, reduced the cost of thermometer; Adopt high-precision ultrasonic transmission time measurement method simultaneously, can realize the precision temperature measurement.The utility model can be widely used in fields such as precision temperature measurement and control.
Description of drawings
Fig. 1 is a kind of ultrasonic thermometer structured flowchart based on FPGA;
Fig. 2 is the drive signal synoptic diagram that is added on the transducer E1;
Fig. 3 is the ultrasonic echo signal schematic representation that receives on the transducer E2;
Fig. 4 is a kind of ultrasonic thermometer working principle of hardware synoptic diagram based on FPGA;
Fig. 5 a-5b is a synoptic diagram of confirming the corresponding moment of ultrasonic propagation time terminal point institute.
Embodiment
Below in conjunction with Figure of description the technical scheme of the utility model is done further explain.
Referring to Fig. 1, this thermometer mainly comprises body 10, ultrasonic transducer E111, transducer E212, FPGA FPGE118, A/D change-over circuit 17, filtering circuit 16, amplifying circuit 15, power amplification circuit 14, D/A change-over circuit 13, display circuit 22 and keyboard circuit 23.Body 10, ultrasonic transducer E111, transducer E212 constitute temperature sensor, gassy in the body 10.Display circuit 22 is used for the temperature value that video-stream processor calculates, and keyboard circuit 23 is used for to the parameter of input temp meter and operating personnel's authority.
Referring to Fig. 2 is the drive signal on the ultrasonic transducer E1; It is that the digital sine signal that in FPGA, produces converts analog sinus signals to through the D/A change-over circuit; And then amplify through power amplification circuit and to form, the voltage of the V representation signal among the figure, t represents the time.The frequency of this signal is 1MHz, the about 10V of voltage, and the about 1.5A of electric current has about 15 watts electric energy, drives ultrasonic transducer E1 and converts electrical energy into mechanical energy, sends ultrasonic signal.
Referring to Fig. 3 is the ultrasonic echo signal of on transducer E2, exporting, the voltage of the V representation signal among the figure, and t represents the time.When the ultrasonic signal that transducer E1 sends was gone up through propagating into transducer E2 after certain travel-time, transducer E2 converted the mechanical energy of ultrasonic signal into electric energy, the output ultrasonic wave echoed signal.The electric signal of transducer E2 output is not before ultrasound wave propagates on the transducer E2; Amplitude is zero; After transducer E2 received ultrasonic signal, the electric signal amplitude of output increased gradually, reduced to decay to zero then gradually; Be a luffing periodic signal, that ripple of amplitude maximum is corresponding to last ripple of ultrasonic signal.The frequency of ultrasonic echo signal depends on the frequency of ultrasonic signal, also is 1MHz.
Referring to Fig. 4, after the synchronizing circuit 431 of processor 21 in FPGA18 sent the beginning sample command, FPGA18 started to the driving of ultrasonic transducer E111 with to ultrasonic transducer E212 output signals sampling simultaneously.
The signal generator 20 transmission frequencies that are implemented in the FPGA are the sinusoidal signal in 8 cycles of 1MHz, and this signal converts simulating signal into through D/A change-over circuit 13, after power amplification circuit 14 amplifies, is carried on the transducer E111 again, sends ultrasonic signal.After the electric signal of transducer E212 output amplifies through operational amplification circuit 15, through being connected to A/D change-over circuit 17 after filtering circuit 16 filtering.The inner controlling of sampling circuit 432 control A/D change-over circuits 17 of FPGA are digital signal with analog signal conversion, and deposit sampled value one by one in the memory block at random 19 that is implemented in the FPGA.After sampling was accomplished, the controlling of sampling circuit sent sampling done state information to processor 21, and processor 21 finishes once sampling after receiving sampling done state information.
After sampling finished, processor 21 was at first accurately confirmed the pairing moment T of starting point in the ultrasonic signal according to the data of the signal generator in the FPGA 431
QD
The pairing moment of ultrasonic transmission end time is through analyzing and calculate and realize with the segmentation interpolation algorithm all sampled datas of echoed signal.Referring to Fig. 5 a, analyze the ultrasonic echo signal of ultrasonic transducer E2 output and can know, be the repeatability that guarantees measurement, should in the waveform of peak amplitude maximum, extract the terminal point of ultrasonic transmission time.In the complete cycle of this waveform, the most tangible two unique points are peak point and zero crossing, and the time reference of confirming as zero crossing echoed signal obtains high precision more easily.
Referring to Fig. 5 a, the computing method in the pairing moment of ultrasonic transmission end time of the utility model are:
At first the A/D sampled point is compared in pointwise, finds out the maximal value of sampled point and just can confirm the waveform that amplitude is maximum easily, can be referred to as the eigenwert waveform to this waveform;
Secondly, referring to Fig. 5 b, confirm the pairing zero crossing P of ultrasonic transmission end time
0Sampled point P+1 of sampled point P in front and back, obviously the sampled value of sampled point P is greater than zero in characteristic wave, and the sampled value of sampled point P+1 is less than zero;
At last, as benchmark, can accurately calculate zero crossing P with sampled point P and 2 moment corresponding of P+1 with the segmentation interpolation algorithm
0In the pairing moment, concrete computing method are following:
If the SF of A/D is F
A/D, the time between adjacent two sampled points is to be T in the sampling period
A/DIs N from first sampled point to the hits the sampled point P, and the sampled value that sampled point P is corresponding is V1, and the pairing moment of sampled point P is T1; The sampled value that sampled point P+1 is corresponding is V2; The pairing moment of sampled point P is T1, sampled point P and zero crossing P
0Between time be T2, zero crossing P
0Moment corresponding is T
ZD, hyperacoustic transmission time is T, then:
In the less zone of near zero-crossing point, sinusoidal wave waveform approaches straight line, can confirm T2 according to the method for linear interpolation:
Then the pairing moment of zero crossing, promptly the pairing moment of ultrasonic transmission end time is:
Can know from following formula, the ultrasonic transmission end time corresponding resolution constantly be:
Referring to Fig. 5 b, the frequency of supposing the ultrasonic echo signal is 1M, and then the cycle is 1us; The resolution of A/D is 12; Can the amplitude of signal be divided into 4096 parts so; If the SF of A/D is 32 MHz, then arrive in the negative peaked half period in the positive maximal value of sine wave, can adopt 16 points at most; If regard sinusoidal wave positive maximal value as straight line to the waveform in the negative peaked half period, then obviously can know:
Observe sinusoidal wave positive maximal value and can find out that to the waveform in the negative peaked half period near zero-crossing point slope of a curve is much larger than near the slope of a curve peak value, then
Referring to Fig. 5, hyperacoustic transmission time is:
Because the pairing moment of ultrasonic transmission start time can accurately be confirmed; Then the resolution of ultrasonic transmission time measurement depend on the ultrasonic transmission end time corresponding resolution constantly, so the resolution of ultrasonic transmission time measurement is less than 0.122 nanosecond.Be installed in the transducer E1 at body two ends and the distance between the E2 and fix, record ultrasound wave travel-time between transducer E1 and E2 under different temperatures, just can record temperature.For example, the speed of ultrasound wave in gas is 344 meter per seconds in the time of 20 ℃, and the speed in the time of 21 ℃ is 344.6 meter per seconds, if the distance between transducer E1 and the E2 is 0.3 meter, then hyperacoustic transmission time is 8.7209 * 10 in the time of 20 ℃
-4Second, hyperacoustic transmission time is 8.7057 * 10 in the time of 21 ℃
-4Second, hyperacoustic transmission time difference is 1.52 * 10 in the time of 21 ℃ and 20 ℃ the time
-6Second.As stated, the resolution of ultrasonic transmission time measurement is superior to 1.0 * 10
-9Second, can realize that then resolution is superior to 0.001 ℃ temperature survey.
Claims (1)
1. ultrasonic thermometer based on FPGA, it is characterized in that: it comprises ultrasonic temperature sensor, on-site programmable gate array FPGA, signal amplification circuit, filtering circuit, A/D change-over circuit, D/A change-over circuit, power amplification circuit;
Said ultrasonic temperature sensor is to be made up of ultrasonic transducer E1, ultrasonic transducer E2 and a body, and said ultrasonic transducer E1 and ultrasonic transducer E2 are installed in the two ends in the body relatively, are full of the gas as the ultrasound wave medium in the body;
Include signal generator, memory block, processor at random in the said on-site programmable gate array FPGA; Processor control-signals generator sine wave output drive signal; Be connected to the D/A change-over circuit, by the D/A change-over circuit said sine wave drive signal changed, the D/A change-over circuit connects power amplification circuit again; Signal is amplified; Power amplification circuit is connected with ultrasonic transducer E1, and signal is inputed to said ultrasonic transducer E1, and this ultrasonic transducer E1 converts said this input signal to mechanical vibration and produces ultrasonic signal;
Said ultrasonic transducer E2 receives the ultrasonic signal that said ultrasonic transducer E1 sends; Convert mechanical vibration into electric signal; The output ultrasonic wave echoed signal; And through with its amplifying circuit that is connected successively, filtering circuit and A/D change-over circuit, make said ultrasonic echo signal after amplification, filtering and A/D conversion, input to on-site programmable gate array FPGA successively;
Said on-site programmable gate array FPGA sample simultaneously sine wave drive signal and the ultrasonic echo signal of input of output, and sampled data left at random in the memory block;
Said processor is from read sampled data the memory block at random.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN2011201274975U CN202101788U (en) | 2011-04-27 | 2011-04-27 | Ultrasonic thermometer based on FPGA |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN2011201274975U CN202101788U (en) | 2011-04-27 | 2011-04-27 | Ultrasonic thermometer based on FPGA |
Publications (1)
Publication Number | Publication Date |
---|---|
CN202101788U true CN202101788U (en) | 2012-01-04 |
Family
ID=45387794
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN2011201274975U Expired - Fee Related CN202101788U (en) | 2011-04-27 | 2011-04-27 | Ultrasonic thermometer based on FPGA |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN202101788U (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103575423A (en) * | 2013-11-18 | 2014-02-12 | 电子科技大学 | Local temperature detecting device and method based on ultrasonic detection |
CN104458054A (en) * | 2014-11-21 | 2015-03-25 | 广西智通节能环保科技有限公司 | Ultrasonic temperature measuring instrument |
KR20190009714A (en) * | 2017-07-19 | 2019-01-29 | 게오르그 피셔 시그닛 엘엘씨 | Combined ultrasonic temperature and conductivity sensor assembly |
-
2011
- 2011-04-27 CN CN2011201274975U patent/CN202101788U/en not_active Expired - Fee Related
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103575423A (en) * | 2013-11-18 | 2014-02-12 | 电子科技大学 | Local temperature detecting device and method based on ultrasonic detection |
CN103575423B (en) * | 2013-11-18 | 2015-12-09 | 电子科技大学 | Based on local temperature pick-up unit and the method for ultrasound examination |
CN104458054A (en) * | 2014-11-21 | 2015-03-25 | 广西智通节能环保科技有限公司 | Ultrasonic temperature measuring instrument |
KR20190009714A (en) * | 2017-07-19 | 2019-01-29 | 게오르그 피셔 시그닛 엘엘씨 | Combined ultrasonic temperature and conductivity sensor assembly |
CN109282846A (en) * | 2017-07-19 | 2019-01-29 | 乔治费希尔图章有限责任公司 | Combined type ultrasonic temperature and conductivity sensors device assembly |
CN109282846B (en) * | 2017-07-19 | 2022-03-18 | 乔治费希尔图章有限责任公司 | Combined ultrasonic temperature and conductivity sensor assembly |
KR102490359B1 (en) * | 2017-07-19 | 2023-01-18 | 게오르그 피셔 시그닛 엘엘씨 | Combined ultrasonic temperature and conductivity sensor assembly |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN101813528B (en) | Method for precisely measuring temperature by using ultrasonic technology and measuring instrument | |
CN201837420U (en) | Device for precisely measuring ultrasonic wave transmission time | |
CN201637503U (en) | Reflecting ultrasonic thermometer | |
CN100573191C (en) | Supersonic range finder | |
CN101813515B (en) | Method and device for precisely measuring ultrasonic wave transmission time | |
CN201637504U (en) | High-sensitivity ultrasonic thermometer | |
CN106771347B (en) | A kind of frequency sweep type ultrasonic wind measurement method | |
CN103995263B (en) | A kind of ultrasonic ranging method based on sequential | |
CN209745322U (en) | multi-parameter measuring instrument for fluid | |
CN202101788U (en) | Ultrasonic thermometer based on FPGA | |
CN102146791A (en) | Method and device for measuring working fluid level of oil well | |
JPWO2009125843A1 (en) | Ultrasonic propagation time measurement system | |
CN203758642U (en) | High precision and wide measuring range split type multiple sound track supersonic wave thermometer | |
CN107179676A (en) | Ultrasonic wave flight time measuring method based on digital demodulation | |
CN110987102A (en) | High-interference-resistance high-precision gas ultrasonic flowmeter and measuring method thereof | |
CN1167953C (en) | Ultrasonic liquid-flow measuring device | |
CN105180853A (en) | Electromagnetic ultrasonic metal material thickness measurement method | |
CN102203601A (en) | Method for determining the starting instant of a periodically oscillating signal response | |
CN103499386B (en) | A kind of method and apparatus of precision measurement frequency | |
CN101441200B (en) | Ultrasonic detection method and system | |
CN104535140A (en) | Resonant frequency testing method for energy converter of ultrasonic flowmeter | |
CN204495998U (en) | A kind of ultrasonic ranging system | |
CN201637502U (en) | High temperature and high pressure ultrasonic thermometer | |
CN203519458U (en) | Multichannel high-precision densimeter | |
CN115248250A (en) | Device and method for precisely measuring liquid concentration based on SOPC |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
C14 | Grant of patent or utility model | ||
GR01 | Patent grant | ||
C17 | Cessation of patent right | ||
CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120104 Termination date: 20130427 |