CN105353040B - A kind of wireless digital frequency type CMUT acoustic emission sensors system and its working method - Google Patents
A kind of wireless digital frequency type CMUT acoustic emission sensors system and its working method Download PDFInfo
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- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
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Abstract
A kind of wireless digital frequency type CMUT acoustic emission sensors system of present invention offer and its working method, the system comprises collection terminals and receiving terminal, CMUT and standard inductance are formed Resonance detector circuit by collection terminal, when CMUT carries out acoustic emission signal reception, signal, Resonance detector circuit output resonance signal are detected in the input terminal input wideband of Resonance detector circuit.The resonance signal is digitized, and receiving terminal is sent to by high speed, the low-consumption wireless communication technology, the frequency response of Resonance detector circuit is acquired in receiving terminal, and resonant frequency is extracted using the quick high accuracy frequency estimation algorithm for approaching CRB theoretical limits circle, sound pressure characteristic is characterized with this.System of the present invention has many advantages, such as good high sensitivity, precision height, noise robustness, using flexible and bandwidth, can be applied in the acoustic emission detection of industrial detection, building, traffic etc..
Description
Technical field
The present invention relates to acoustic emission detection fields, and in particular to a kind of wireless digital frequency type CMUT (Capacitive
Micromachined Ultrasonic Transducer, capacitance micro-machining ultrasonic sensor) acoustic emission sensor circuit and be
System.
Background technology
When material or inside configuration change or carry, most materials or structure can be with the shapes of stress wave (sound emission)
Formula releases energy, and this stress wave reflects the certain physical characteristics in rupture process of material, generation, plastic deformation with crackle
Etc. related.Therefore, material is under external force or endogenetic process, when inside generates flexible deformation, quick release of energy and generate transient state
The referred to as sound emission of the phenomenon that elastic wave.
Using the method for detection acoustic emission signal, it can be determined that certain of material or structure state.With instrument detection, note
Record, analysis acoustic emission signal and the technology using acoustic emission signal deduction acoustic emission source are known as acoustic emission testing technology.Sound emission
Detection technique has the characteristics such as globality, real-time, economy, can detect germinating, the expansion process of defect in real time, moreover it is possible to
Detect defect and its position in time, this is vital in non-destructive testing.Because of this, can not be produced in structure
Just it is placed under repair or is replaced before raw destruction.Therefore, the research and development of acoustic emission testing technology have important social effect and warp
Ji value, can be widely used in industry, traffic, the detection of building.
Acoustic emission sensor is located in the device on the surface of material or structure, the sound for receiving material or inside configuration
Emit signal, and be converted into electric signal, be then forwarded to signal processing analysis instrument and analyzed, is connection structure and analysis
Bridge between instrument.It selects suitable sensor to have great importance acoustic emission detection, directly influences accuracy of detection.
Selection sensor needs to consider the factors such as frequency bandwidth, sensitivity, the power consumption of sensor.
Acoustic emission sensor has piezoelectric transducer and capacitance sensor etc., capacitance sensor that can measure nm grades of displacement
Amount, and there is preferable frequency response bandwidth, but the circuit of current capacitance sensor detection capacitance and system design acquisition
Precision is relatively low, limits the popularization in its practical application.Existing acoustic emission sensor is mostly that the piezoelectricity based on piezoelectric effect passes
Sensor, there are following some problems:
First, existing acoustic emission sensor majority is made based on piezoelectric material, and sensitivity is low, size is big.Piezoelectric material
Itself it is mostly ceramic structure, mostly harder more crisp, sensitivity is low, while increasing size design and the difficulty of processing.Meanwhile such as
Fruit reduces size, then sensitivity further decreases, it is difficult to reach larger dynamic range.
Second, existing acoustic emission sensor is sent out with voltage amplitude information to characterize sound by circuit output voltage signal
It penetrates, accuracy of detection is low.From the point of view of Cramer-Rao Bound (CRB) parameter estimation theories, the frequency of signal can provide more smart
True information.The three elements of signal are disclosed in Cramer-Rao Bound parameter estimation theories：Frequency, amplitude, phase are estimated
In meter, the opposite estimated accuracy highest of frequency, cube directly proportional to number of samples (i.e. as shown in formula (1), evaluated error and sample
Points cube are inversely proportional), and the opposite estimated accuracy of amplitude and phase is directly proportional to number of samples, if sample rate is sufficiently high,
The precision of frequency parameter estimation is significantly larger than amplitude and phase.Specifically the evaluated error of real signal frequencies omega is
Wherein γ is signal-to-noise ratio, and M is sampling number.The evaluated error of amplitude A is
WhereinFor noise power.PhaseEvaluated error be
(formula 3)
According to above-mentioned theory, if sound pressure information can be carried by frequency parameter, the precision of detection can be improved.
Third, existing acoustic emission sensor output is analog signal, is susceptible to Environmental Noise Influence, noise immunity
It can be bad.
4th, existing acoustic emission sensor is connected by wired mode with the signal processing equipment of rear end, and shortage makes
Flexibility.At acoustic emission detection scene, need many cables by the processing of the collected data transmission of sensor to rear end
Device, connection are very complicated and inconvenient.In addition, staff need detection scene, with object to be detected be in it is closer away from
From.When if it is being detected to the extraordinary hazardous equipment such as oil-gas pipeline, pressure vessel, the operational hazards of testing staff are again numerous
It is trivial.If wirelessly acquisition and processing can be separated, as the operating side of wireless mouse is as receiving terminal, general
The data of front end are transferred to backstage by being wirelessly connected, it will offer convenience to user.
5th, existing acoustic emission sensor narrow bandwidth.Existing PZT (piezoelectric transducer) has two class of narrowband and broadband.Narrowband senses
Device obtains testing result by detecting the simulation output of resonance circuit, although precision is high, frequency band is extremely narrow.And broadband senses
Device band ratio narrow sensor is wide, such as the taper sound emission bandwidth that National Bureau of Standards makes is 50k-1000k, but its
Sensitivity is relatively low.The communication process of sound emission is the non-directional wave propagated by total since acoustic emission source.Allusion quotation
The frequency range of the acoustic emission wave of type is 1KHz-2MHz or higher.Therefore it in order to preferably detect acoustic emission signal, senses
Device needs to be operated on a wider frequency band.
In short, existing acoustic emission sensor has, sensitivity and accuracy of detection is not high, noise robustness is bad, using not
The problems such as enough flexible, bandwidth is not wide enough.
Invention content
To overcome, existing acoustic emission sensor sensitivity and accuracy of detection is not high, noise robustness is bad, using not clever enough
Living, the problems such as bandwidth is not wide enough, the present invention propose a kind of wireless digital frequency type CMUT acoustic emission sensors system and its work
Method.
(Capacitive Micromachined Ultrasonic Transducer, capacitance micro-machined ultrasonic pass CMUT
Sensor) it is the capacity plate antenna being miniaturized, bottom plate is fixed, and top plate is film, can be vibrated.When receiving acoustic pressure
When signal, vibration of thin membrane realizes energy conversion, and acoustic pressure is converted to the capacitance characteristic of CMUT.If it can detect capacitance characteristic
Counter it can release sound pressure characteristic.According to parameter estimation theories, if capacitance characteristic is carried in the frequency information of signal, pass through
The estimation of capacitance characteristic is realized in the estimation of frequency, can be substantially improved the precision of estimation.In addition, if can be by the sound of CMUT
The refutation process of the conversion of piezo-electric appearance-frequency and frequency-capacitance-acoustic pressure is divided into two parts circuit to realize, front end only needs to realize
The information collection and conversion of acoustic pressure-capacitance-frequency, the estimation of back-end realization frequency-capacitance-acoustic pressure are simultaneously exported to the rear end of user
The using flexible of system can be then substantially improved in processor.Therefore, it is an object of the present invention to be based on above-mentioned principle, proposes
A kind of wireless digital frequency type CMUT acoustic emission sensors circuit and system.
In a kind of wireless digital frequency type CMUT acoustic emission sensor systems of the present invention, CMUT is positioned over material or knot
Acoustic Emission Characteristic is converted to the capacitance characteristic of CMUT by the surface of structure for receiving acoustic emission signal.By CMUT and standard inductance
Resonance detector circuit is formed, signal is detected in the input terminal input wideband of Resonance detector circuit, passes through Resonance detector circuit output
The capacitance characteristic of resonance signal, CMUT is included in the frequency characteristic of resonance signal.The resonance signal is digitized, and passes through height
Speed, the low-consumption wireless communication technology are sent to receiving terminal, obtain the frequency response of Resonance detector circuit in receiving terminal, recycling is forced
The quick high accuracy frequency estimation algorithm of nearly CRB theoretical limits circle extracts resonant frequency, with the frequency response of Resonance detector circuit
Sound pressure characteristic is characterized with resonant frequency.
The wireless digital frequency type CMUT acoustic emission sensor systems, including collection terminal and receiving terminal.Collection terminal with
The transmission of data is carried out between receiving terminal with high speed, the wireless communication technique of low-power consumption.
Further implement ground, the collection terminal is directly positioned in sound emission structure, for acquiring acoustic emission signal
Device.Collection terminal includes data conditioning module, D/A converter, power amplifier, Resonance detector circuit, amplifier, A/D conversions
Device, wireless communication module and power supply.Data conditioning module and D/A converter, power amplifier, Resonance detector circuit successively phase
Even, Resonance detector circuit is sequentially connected with amplifier, A/D converter, and A/D converter is connected with data conditioning module again, data
Conditioning module is connected with wireless communication module again.
Further implement ground, the data conditioning module include control unit and storage unit, control unit for pair
The modules of collection terminal are controlled, and storage unit is then used to store digital wideband detection signal.The digital wideband
The frequency band of detection signal should cover the frequency band needed for acoustic emission detection, and linear frequency modulation or NLFM signal may be used.
D/A converter, which is used to digital wideband detection signal being converted to simulation wideband, detects signal.Power amplifier is used for wide to simulation
Frequency detection signal carries out power amplification.The Resonance detector circuit be it is in parallel with standard inductance obtaining by CMUT sensors and
Join Resonance detector circuit, wherein CMUT is used to receive the acoustic emission signal of sound emission structure generation, and wideband detection signal is input to
After Resonance detector circuit, output simulation resonance signal.Amplifier is used to be amplified simulation resonance signal, and A/D converter is used
Digital resonance signal is converted in resonance signal will be simulated.Wireless communication module is used to count into row data communication with receiving terminal
Word resonance signal is sent to receiving terminal, and existing high-speed low-power-consumption wireless communication technique, such as WIFI, 3G can be used to communicate skill
Art etc..The power supply of collection terminal is each module for power supply of collection terminal.
Further implement ground, the receiving terminal is connected with back-end processor, for receiving the digital resonance from collection terminal
Signal, and handled to obtain the frequency response characteristic and resonant frequency information of Resonance detector circuit, then above- mentioned information is exported
To back-end processor.The receiving terminal includes wireless communication module, signal processing module, usb interface module and power supply.Wirelessly
Communication module is connected with signal processing module, and signal processing module is connected with usb interface module.Wireless communication module is used for and adopts
Collect end into row data communication, using wireless communication technique corresponding with the wireless communication module of collection terminal.Signal processing module
Including signal processing unit and signal memory cell, signal processing unit is used to be acquired according to the digital resonance signal received humorous
The frequency response characteristic for detection circuit of shaking, and carry out quick high accuracy Frequency Estimation and find out resonant frequency.Storage unit is for depositing
It stores up the digital resonance signal received and needs the information stored in some other processing.The usb interface module uses existing
USB interface technology, the frequency response characteristic of Resonance detector circuit that signal processing module obtains and resonant frequency are sent to
Back-end processor carries out subsequent operation for user, and existing USB technologies can be used.The power supply of receiving terminal is each of receiving terminal
Module for power supply.
The course of work of above-mentioned wireless digital frequency type CMUT acoustic emission sensor systems comprises the steps of：
Step 1：The CMUT of collection terminal receives acoustic emission signal, and Resonance detector circuit inputs wideband and detects signal.CMUT connects
While receiving acoustic emission signal, the digital wideband stored in storage unit detection signal is input to D/ by the control unit of collection terminal
A converters are converted to analog signal by D/A converter, and Resonance detector circuit is input to after power amplifier amplifies.
Step 2：Resonance detector circuit output resonance signal is simultaneously sent to receiving terminal.Resonance detector circuit output simulates resonance
Signal, the simulation resonance signal are converted to digital resonance signal after amplifier amplifies using A/D converter.The number is humorous
After the signal that shakes enters data conditioning module, then sent by the wireless communication module of collection terminal.
Step 3：Receiving terminal receives digital resonance signal and handles.The wireless communication module of receiving terminal receives digital resonance letter
Number, and it is input to signal processing module, the frequency response curve of Resonance detector circuit is provided in signal processing module, and using soon
Fast high-precision frequency estimation algorithm carries out resonant frequency estimation.
Step 4：The frequency response curve and resonant frequency information of Resonance detector circuit are exported by USB interface to rear end
Device is managed, other operations are carried out for user.
Compared with prior art, the beneficial effects of the invention are as follows：
First, precision is higher than traditional acoustic emission sensor.Sound characteristics are converted to the frequency information of resonance signal, and
Receiving terminal calculated frequency response and the high-precision frequency estimation algorithm of use carry out resonant frequency estimation, with frequency response and resonance
Frequency characterizes sound pressure characteristic.In the case where sample of signal number is certain, the precision of frequency parameter estimation will be significantly larger than amplitude ginseng
Several estimated accuracies, estimation theory limit error and sample number cube are inversely proportional, and therefore, accuracy of detection can greatly improve.
Second, noise robustness is good.Designed system is that the inverting of sound pressure characteristic is carried out by digital signal, with tradition
Acoustic emission sensor output analog voltage compare, noise robustness is good, and signal-to-noise ratio is high.
Third, easy to use and flexible.Traditional acoustic emission sensor is connected by wired mode with back-end processor, is made
With dumb.Collected information is sent to receiving terminal by the present invention by high speed, the low-consumption wireless communication technology, receiving terminal
Testing result is directly supplied to backend user with USB interface, therefore, using flexible, application is more extensive.
4th, size is small, high sensitivity.The acoustic emission sensor of the present invention replaces piezoelectric material using CMUT, has ruler
It the characteristics of very little small, high sensitivity, is detected conducive to small sound emission.
5th, detect bandwidth.The sensor frequency band of the band ratio piezoelectric material of CMUT sensors is wider and designed
It is wideband continuous frequency modulation signal that the signal of Resonance detector circuit is inputted in circuit system, therefore, acoustic emission sensor frequency
Band is more wider than traditional acoustic emission sensor frequency band.
Description of the drawings
Fig. 1 is the system block diagram of the embodiment of the present invention；
Fig. 2 is the receiving terminal block diagram of the embodiment of the present invention；
Fig. 3 is the response of Resonance detector channel frequency and the resonant frequency method of estimation flow chart of the embodiment of the present invention；
Fig. 4 is the wireless digital frequency type CMUT acoustic emission sensors circuit and working-flow of the embodiment of the present invention
Figure；
Specific implementation mode
The specific implementation mode of the present invention is described further below in conjunction with the accompanying drawings, but the implementation of the present invention is not limited to
This.
As shown in Figure 1, being the wireless digital frequency type CMUT acoustic emission sensor system block diagrams of the embodiment of the present invention.Wirelessly
Numerical frequency formula CMUT acoustic emission sensor systems include collection terminal and receiving terminal, collection terminal and receiving terminal skill by radio communication
Art carries out data transmission.Wireless digital frequency type CMUT acoustic emission sensors circuit and the collection terminal of system are to be directly positioned on sound
On emitting structural, the device for acquiring acoustic emission signal.The collection terminal includes data conditioning module, D/A converter, work(
Rate amplifier, Resonance detector circuit, amplifier, A/D converter, wireless communication module and power supply.
The data conditioning module includes control unit and storage unit, and control unit is used for each mould to collection terminal
Block is controlled, and memory module is then used to store digital wideband detection signal.The frequency band of the digital wideband detection signal
The frequency band needed for acoustic emission detection should be covered, the chirps such as linear frequency modulation or NLFM signal may be used.
Assume to use analog frequency from f in the present embodiment0=100 × 103Hz to f1=2 × 106Hz, duration T=20ms
Linear FM signal.Its expression formula is：
Wherein, ω0It is the starting angular frequency of linear FM signal, ω0=2 π f0/fs, fsFor sample rate, k is frequency modulation rate, k
=(f1-f0)/(fs 2T), N is the sample number of digital signal, N=fsT。For phase, random initial phase can be taken.A is width
Degree, can select according to actual conditions, A=1 is selected in the present embodiment.
D/A converter, which is used to digital wideband detection signal being converted to simulation wideband, detects signal.Power amplifier is used for
Power amplification is carried out to simulation wideband detection signal.The Resonance detector circuit is in parallel with standard inductance by CMUT sensors
Obtained parallel resonance detection circuit, wherein CMUT are used to receive the acoustic emission signal of sound emission structure, and it is defeated that wideband detects signal
Enter to Resonance detector circuit, output simulation resonance signal.Amplifier is used to be amplified simulation resonance signal, A/D conversions
Device is converted to digital resonance signal for that will simulate resonance signal.Wireless communication module is used for receiving terminal into row data communication,
Existing wireless communication technique can be used, for example is carried out data transmission with WIFI or 3G network.Power supply is each of collection terminal
Module for power supply.
As shown in Fig. 2, being the receiving terminal of the wireless digital frequency type CMUT acoustic emission sensor systems of the embodiment of the present invention
Block diagram.Receiving terminal includes wireless communication module, signal processing module, usb interface module and power supply.Wireless communication module be used for
Collection terminal is into row data communication, using wireless communication technique corresponding with the wireless communication module of collection terminal.Signal processing mould
Block includes signal processing unit and signal memory cell, and signal processing unit is used to be acquired according to the digital resonance signal received
The frequency response characteristic of Resonance detector circuit, and carry out quick high accuracy Frequency Estimation and find out resonant frequency.Storage unit is used for
It stores the digital resonance signal received and needs the information stored in some other processing.The usb interface module uses existing
Some USB interface technologies, the frequency response characteristic and resonant frequency of the Resonance detector circuit that signal processing module is obtained are sent
To back-end processor subsequent operation is carried out for user.The power supply of receiving terminal is each module for power supply of receiving terminal.
With reference to Fig. 3, explains the frequency response characteristic for solving Resonance detector circuit in the present embodiment and carry out resonance frequency
The method of rate estimation.Assuming that the digital resonance signal received is y (n), n=0,1 ... .N-1 carries out the fast of 2N points to y (n)
Fast Fourier transformation obtains Fourier transform spectrum Y (the j ω for receiving signalk), k=0,1 ... .2N-1.Emit signal x (n), n
=0,1 ... .N-1 carries out the Fast Fourier Transform (FFT) of 2N points, obtains Fourier transform spectrum X (the j ω for sending signalk), k=0,
1,....2N-1.It is intercepted on the Fourier transform spectrum for sending signal and reception signal where emitting the bandwidth that wideband detects signal
One section, i.e., the starting point of frequency spectrum be k0=int (f0N/fs), cut off k1=int (f1N/fs), wherein int (x) function tables
Show the integer part for returning to x.Then, can find out Resonance detector circuit amplitude-frequency response spectrum H (l) be：
Wherein ωk=2 π k/2N.The maximum value on amplitude-frequency response H (l), i.e. spectral peak are searched for, if spectrum peak position is lm, right
It is k to answer the position in P (k)m=lm+k0.Next, being calculated with the Frequency Estimation for approaching CRB theoretical limits circle in document
Method --- the reasonable combined method of spectral line composes enterprising line frequency estimation in amplitude-frequency response, and can obtain Resonance detector frequency is：
Wherein u and v is weighting coefficient, respectively,
With reference to Fig. 4, illustrate the work of the wireless digital frequency type CMUT acoustic emission sensors circuit and system
Process：
Step 1：The CMUT of collection terminal acquires acoustic emission signal, and Resonance detector circuit inputs wideband and detects signal.CMUT connects
Quiet down transmitting while, the digital wideband detectable signal stored in storage unit is input to D/A and turned by the control unit of collection terminal
Parallel operation is converted to analog signal by D/A converter, and Resonance detector circuit is input to after power amplifier amplifies.
Step 2：Resonance detector circuit output resonance signal is simultaneously sent to receiving terminal.Resonance detector circuit output simulates resonance
Signal, the simulation resonance signal are converted to digital resonance signal after amplifier amplifies using A/D converter.The number is humorous
After the signal that shakes enters data conditioning module, sent by the wireless communication module of collection terminal.
Step 3：Receiving terminal receives digital resonance signal and handles.The wireless communication module of receiving terminal receives digital resonance letter
Number, and it is input to signal processing module, the frequency of Resonance detector circuit is found out according to (formula 4)-(formula 6) in signal processing module
Rate response curve, and carry out resonant frequency estimation.
Step 4：The frequency response curve and resonant frequency information of Resonance detector circuit are exported by USB interface to rear end
Device is managed, other operations are carried out for user.
Claims (3)
1. a kind of wireless digital frequency type CMUT acoustic emission sensor systems, it is characterised in that include collection terminal and receiving terminal, institute
It states in collection terminal, the surface that CMUT is placed on to material or structure receives acoustic emission signal, and acoustic emission information is converted to
CMUT and standard inductance are formed Resonance detector circuit by the capacitance characteristic of CMUT, are inputted in the input terminal of Resonance detector circuit wide
Frequency detection signal, by Resonance detector circuit output resonance signal, the capacitance characteristic of CMUT is included in the frequency spy of resonance signal
In property, which is digitized, and technology is sent to receiving terminal by radio communication；Resonance detector electricity is obtained in receiving terminal
The frequency response on road is recycled the high-precision frequency estimation algorithm extraction resonant frequency for approaching CRB theoretical limits circle, is examined with resonance
The frequency response of slowdown monitoring circuit and resonant frequency characterize sound pressure characteristic；With wireless communication technique into line number between collection terminal and receiving terminal
According to transmission；Collection terminal is directly positioned in sound emission structure, the device for acquiring acoustic emission signal；Collection terminal includes number
According to conditioning module, D/A converter, power amplifier, Resonance detector circuit, amplifier, A/D converter, wireless communication module and
Power supply；Data conditioning module is sequentially connected with D/A converter, power amplifier, Resonance detector circuit, Resonance detector circuit with put
Big device, A/D converter are sequentially connected, and A/D converter is connected with data conditioning module again, data conditioning module and with wireless communication
Module is connected；
The data conditioning module includes control unit and storage unit, and control unit is used to carry out the modules of collection terminal
Control, and storage unit is then used to store digital wideband detection signal；The frequency band of the digital wideband detection signal should cover
Frequency band needed for acoustic emission detection, using linear frequency modulation or NLFM signal；D/A converter is for examining digital wideband
It surveys signal and is converted to simulation wideband detection signal；Power amplifier is used to carry out power amplification to simulation wideband detection signal；Institute
The Resonance detector circuit stated is by CMUT sensors obtained parallel resonance detection circuit in parallel with standard inductance, and wherein CMUT is used
In the acoustic emission signal for receiving the generation of sound emission structure, after wideband detection signal is input to Resonance detector circuit, output simulation is humorous
Shake signal；Amplifier is used to be amplified simulation resonance signal, and A/D converter is converted to number for that will simulate resonance signal
Resonance signal；Wireless communication module is used to that digital resonance signal to be sent to receiving terminal into row data communication with receiving terminal；Acquisition
The power supply at end is the composition module for power supply in collection terminal.
2. wireless digital frequency type CMUT acoustic emission sensor systems according to claim 1, it is characterised in that receiving terminal
It is connected with back-end processor, for receiving the digital resonance signal from collection terminal, and is handled to obtain Resonance detector circuit
Frequency response characteristic and resonant frequency information, then above- mentioned information is exported to back-end processor；The receiving terminal includes nothing
Line communication module, signal processing module, usb interface module and power supply；Wireless communication module is connected with signal processing module, signal
Processing module is connected with usb interface module；Wireless communication module is used to use into row data communication with collection terminal and collection terminal
The corresponding wireless communication technique of wireless communication module；Signal processing module includes that signal processing unit and signal storage are single
Member, signal processing unit are used to acquire the frequency response characteristic of Resonance detector circuit according to the digital resonance signal received, and
It carries out quick high accuracy Frequency Estimation and finds out resonant frequency；Storage unit is used to store the digital resonance signal received and processes
The information stored is needed in journey；The usb interface module uses USB interface technology, the resonance that signal processing module is obtained
The frequency response characteristic and resonant frequency of detection circuit are sent to back-end processor and carry out subsequent operation for user, receiving terminal
Power supply is the composition module for power supply of receiving terminal.
3. the working method of wireless digital frequency type CMUT acoustic emission sensor systems described in claim 1, it is characterised in that
It comprises the steps of：
Step 1：The CMUT of collection terminal receives acoustic emission signal, and Resonance detector circuit inputs wideband and detects signal；CMUT reception sound
While emitting signal, the digital wideband stored in storage unit detection signal is input to D/A and turned by the control unit of collection terminal
Parallel operation is converted to analog signal by D/A converter, and Resonance detector circuit is input to after power amplifier amplifies；
Step 2：Resonance detector circuit output resonance signal is simultaneously sent to receiving terminal；Resonance detector circuit output simulates resonance letter
Number, which is converted to digital resonance signal after amplifier amplifies using A/D converter, the number resonance
After signal enters data conditioning module, then sent by the wireless communication module of collection terminal；
Step 3：Receiving terminal receives digital resonance signal and handles, and the wireless communication module of receiving terminal receives digital resonance signal,
And it is input to signal processing module, the frequency response curve of Resonance detector circuit is provided in signal processing module, and using quickly
High-precision frequency estimation algorithm carries out resonant frequency estimation；
Step 4：The frequency response curve and resonant frequency information of Resonance detector circuit are exported by USB interface to back-end processing
Device is handled for user.
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| US20060004289A1 (en) * | 2004-06-30 | 2006-01-05 | Wei-Cheng Tian | High sensitivity capacitive micromachined ultrasound transducer |
| RU2502470C2 (en) * | 2007-06-01 | 2013-12-27 | Конинклейке Филипс Электроникс, Н.В. | Light-weight wireless ultrasonic sensor |
| CN101750609A (en) * | 2008-12-02 | 2010-06-23 | 黄勇力 | Capacitance type micromachined ultrasonic transducer capable of performing wireless telemetric sensing operation |
| JP5552062B2 (en) * | 2009-02-06 | 2014-07-16 | 株式会社日立メディコ | Ultrasonic diagnostic equipment |
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