CN209707695U - Waveform detection circuit - Google Patents
Waveform detection circuit Download PDFInfo
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- CN209707695U CN209707695U CN201820231060.8U CN201820231060U CN209707695U CN 209707695 U CN209707695 U CN 209707695U CN 201820231060 U CN201820231060 U CN 201820231060U CN 209707695 U CN209707695 U CN 209707695U
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Abstract
The utility model embodiment is related to a kind of waveform detection circuit, comprising: central processing unit, signal generator, magnet exciting coil, induction coil group, first filter, the first amplifying circuit and analog-digital converter；Central processing unit is connected with signal generator；Central processing unit sends enabling signal to signal generator according to the enabled instruction that user inputs；Signal generator generates alternating current according to enabling signal；Induction coil group is placed in magnet exciting coil, and is electrically connected with first filter；Induction coil group generates the first detection data according to the detection magnetic field after variation；First filter is filtered the first detection data, obtains the second detection data；First amplifying circuit carries out signal enhanced processing to the second detection data, obtains third detection data；Analog-digital converter carries out analog-to-digital conversion process to third detection data, obtains the 4th detection data；Central processing unit parses the 4th detection data, generates prompt information according to parsing result, and show.
Description
Technical field
The utility model relates to metal detection technical field more particularly to a kind of waveform detection circuits.
Background technique
With the development of society, safety problem has been to be concerned by more and more people.Whether airport, station, subway, discrepancy
Border, law court, prison, narcotic house, detention house, hospital, school, large-scale deduction venue, important international conference, international exhibitions etc., it is right
The safety check of visitor is all essential.So-called safety check exactly checks passenger or spectators by certain technological means and facility
Whether gun, cutter, ammunition and inflammable and explosive dangerous goods etc. are carried, so that possible security risk is intercepted, pre- anti-violence
Crime or the generation of accident.
Existing safety check circuit is checked one by one generally by hand-held detector, to visitor, safety check low efficiency.Separately
A kind of mode is by gate or detector gate, and the metal carried to people carries out detection alarm.But existing gate
Or the circuit in detector gate, sensitivity is not high, and performance is also not sufficiently stable.
Utility model content
The purpose of the utility model is to provide a kind of waveform detection circuits, detect metal object according to electromagnetic induction principle,
And the collected analog signal of institute is filtered by way of setting filter and amplifying circuit, is amplified, shaping and modulus
Conversion, obtains digital signal, and digital signal is further screened, judges and analyzed, and final accurate judgement is detected
Whether object is metal object and which kind of metal object detected object is, and waveform provided by the embodiment of the utility model detection is electric
The sensitivity on road is high, and performance is stablized.
To achieve the above object, the utility model provides a kind of waveform detection circuit, comprising: the waveform detection circuit
It include: central processing unit, signal generator, magnet exciting coil, induction coil group, first filter and analog-digital converter；
The central processing unit is connected with the signal generator；The central processing unit refers to according to the starting that user inputs
It enables to the signal generator and sends enabling signal；
The signal generator is electrically connected with the induction coil group；The signal generator is raw according to the enabling signal
The magnet exciting coil is sent at alternating current, and by the alternating current；The magnet exciting coil is produced according to the alternating current
Raw detection magnetic field；
The induction coil group is placed in the magnet exciting coil, and is electrically connected with the first filter；
When metal object passes through the detection magnetic field, the detection magnetic field changes；The induction coil group according to
Detection magnetic field after variation generates the first detection data, and first detection data is sent to first filter；
The first filter is connected with the analog-digital converter；The first filter to first detection data into
Row filtering processing, obtains the second detection data, and second detection data is sent to the analog-digital converter；
The analog-digital converter is connected with the central processing unit；The analog-digital converter carries out mould to third detection data
Number conversion process, obtains the 4th detection data, and the 4th detection data is sent to central processing unit；
The central processing unit parses the 4th detection data, generates prompt information according to parsing result, and show.
Preferably, the circuit further includes the first amplifying circuit；
First amplifying circuit is connected with the first filter and the analog-digital converter respectively；First amplification
Circuit carries out signal enhanced processing to second detection data, obtains third detection data, and by the third detection data
It is sent to analog-digital converter.
Preferably, the circuit further includes the second amplifying circuit；Second amplifying circuit occurs with the signal respectively
Device is connected with the magnet exciting coil；
Second amplifying circuit receives the alternating current that the signal generator is sent, to most alternating currents into
Row amplification, and amplified alternating current is sent to the magnet exciting coil；The magnet exciting coil is according to the amplified friendship
Time-dependent current generates detection magnetic field.
Preferably, the circuit further includes second filter；The second filter respectively with the analog-digital converter and
The central processing unit is connected；
4th detection data is sent to second filter by the analog-digital converter；
The second filter samples the 4th detection data in statistical time, obtains multiple 4th detection numbers
According to；
Mean value calculation is carried out to the multiple 4th detection data group, obtains the average wave number of the 4th detection data, and will
The average wave number of 4th detection data is sent to the central processing unit.
It is further preferred that the average wave number of the 4th detection data includes waveform phase angular data and wave-shape amplitude number
According to.
It is further preferred that the circuit further includes the first infrared sensor and the second infrared sensor；
The second filter passes sequentially through first infrared sensor and described second red according to the metal object
The time of outer sensor obtains the statistical time.
It is further preferred that first amplifying circuit and second amplifying circuit are multi-level differential amplifying circuit.
A kind of waveform detection circuit provided by the utility model detects metal object according to electromagnetic induction principle, and passes through
The mode for being arranged filter and amplifying circuit is filtered the collected analog signal of institute, amplifies, shaping and analog-to-digital conversion, obtains
Further screened, judged and analyzed to digital signal, and to digital signal, it is final accurate determine detected object whether be
Which kind of metal object metal object and detected object are, and the sensitivity of waveform detection circuit provided by the embodiment of the utility model
Height, performance are stablized.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of waveform detection circuit provided by the embodiment of the utility model；
Fig. 2 is signal amplification circuit figure in waveform detection circuit provided by the embodiment of the utility model.
Specific embodiment
Below by drawings and examples, the technical solution of the utility model is described in further detail.
Fig. 1 is the structural schematic diagram of waveform detection circuit provided by the embodiment of the utility model, as shown in Figure 1, this is practical
The waveform detection circuit that new embodiment provides includes: central processing unit 1, signal generator 2, the second amplifying circuit 3, excitation wire
Circle 4, induction coil group 5, first filter 6, the first amplifying circuit 7, second filter 9 and analog-digital converter 8.
Wherein, central processing unit 1 can be understood as the control unit and processing unit of waveform detection circuit, be responsible for entire electricity
The execution on road, such as single-chip microcontroller.Central processing unit 1 is connected with signal generator 2.Central processing unit 1 is opened according to what user inputted
Dynamic instruction sends enabling signal to signal generator 2, so that signal generator 2 generates alternating current according to enabling signal.
The alternating current of the generation of signal generator 2 needs to amplify current strength by the second amplifying circuit 3.Second amplification
The premiere feature of circuit 3 is to improve signal-to-noise ratio as far as possible, so that amplified alternating current can produce stable detection magnetic field.
In a specific example, the second amplifying circuit 3 uses AD620 instrument amplifier.The letter being made of AD620
Number amplifying circuit is as shown in Fig. 2, signal amplification circuit includes signal input part 1, electric wire ground terminal 2, resistance branch end 3 and signal
Output end 4, alternating current are inputted by signal input part 1, amplified to be exported again by signal output end 4.The three of signal input part 1
Pole pipe provides simple differential bipolar input, by the feedback of amplifier inside input stage, keeps the collector electricity of input triode
It flows constant, and is added to input voltage on external gain control resistance R.Because AD620 design volume is small, power consumption is very low, thus
Suitable for low-voltage, the application of low-power consumption.
Second amplifying circuit 3 is connected with magnet exciting coil 4, and the second amplifying circuit 3 exports amplified alternation to magnet exciting coil 4
Electric current, according to electromagnetic induction principle, so that magnet exciting coil generates detection magnetic field according to amplified alternating current.This process can
To be interpreted as the process of electric magnetisation.
Induction coil group 5 is set to the inside of magnet exciting coil 4, when metal object is by detection magnetic field, detection magnetic field hair
Changing, induction coil group 5 experience the variation of sine wave in detection magnetic field by magnetic-coupled mode, and according to the spy after variation
It surveys magnetic field and generates the first detection data.First detection data can be understood as voltage and or current analog signal.This process can
To be interpreted as the process of the raw electricity of magnetic.
Specifically, induction coil group 5 includes the first induction coil and the second induction coil.First induction coil and the second sense
Coil differential concatenation is answered, so that the second electricity caused by the first electromotive force and the second induction coil caused by the first induction coil
Kinetic potential is equal in magnitude and contrary.
Ideally, since the first induction coil is identical as the electromotive force size of the second induction coil, but opposite in phase,
So the voltage that induction coil group 5 exports, which can be regarded as, levels off to zero.When there is electronic product by magnet exciting coil 4, magnetic field is detected
It changes, leads to the electromotive force of the first induction coil and the second induction coil not rebalancing, to there is voltage output, generate the
One detection data.
Since waveform detection circuit is worked using electromagnetic field, and the distracter of electromagnetic field is extremely complex, and interference may
From circuit surrounding enviroment, it is also possible to from circuit itself, so it is inevitable for being filtered.Therefore, induction coil
Group 5 needs for the first detection data to be sent to first filter 6, and first filter 6 is filtered the first detection data
Afterwards, the second detection data is obtained.
Since after being once filtered, entrained signal message opposite can reduce in the second detection data, so
It after being once filtered, is needing to carry out a signal enhanced processing again.Therefore, first filter 6 is needed second
Detection data is sent to the first amplifying circuit 7, and the first amplifying circuit 7 carries out multi-level differential enhanced processing to the second detection data,
While amplified signal, signal noise is further decreased.First amplifying circuit 7 is filtered the second detection data
Afterwards, it obtains third detection data and obtains third detection data.At this point, third detection data is still voltage and or current simulation letter
Number.
Since voltage and or current signal data cannot be directly subsequently can by computer, to third detection data into
Before row processing, need to convert digital signal for third detection data.Therefore, the first amplifying circuit 7 needs third detecting number
According to being sent to analog-digital converter 8.Analog-digital converter 8 carries out analog-to-digital conversion process to third detection data, obtains the 4th detection number
According to.4th detection data can be understood as the digital signal that can be readable by a computer, handle.
The conversion accuracy and conversion speed of analog-digital converter 8 determine the attainable accuracy and speed of circuit institute, although alternation
Current signal is direct current tempolabile signal, but analog-digital converter 8 needs enough conversion accuracies.Therefore, analog-digital converter 8 is selected
Conversion chip need to be multrirange, two channels, 12 high-precision conversion chips.Wherein, two channels are for collecting induction coil
First induction coil of same level position and the signal of the second induction coil in group 5.
Third detection data is after analog-to-digital conversion, into Digital Signal Processing link, still carries out primary filtering here
Processing.It should be noted that the filtering processing that first filter 6 is carried out is the filtering processing of analog signal, and the second filtering
The filtering processing that device 9 is carried out is the filtering processing of digital signal.
Specifically, the 4th detection data is sent to second filter 9 by analog-digital converter 8, second filter 9 is first to system
The 4th detection data in timing is sampled, and multiple 4th detection datas are obtained.Then, second filter 9 is to multiple
Four detection data groups carry out mean value calculation, obtain the average wave number of the 4th detection data.The average wave number packet of 4th detection data
Include waveform phase angular data and wave-shape amplitude data.This process can be understood as second filter 9 and carry out multiple repairing weld and count
Average filter is calculated, then according to just profound wave processing, extracts the process at its range value and phase angle.
Wherein, waveform phase angular data can be understood as a certain alternating voltage at any time (or spatial position) make it is sinusoidal or
When varies with cosine, a numerical value of alternating voltage amount (or position) state at any one time is determined, it can be according to formula U=
Umsin (ω t+ Φ u) is obtained.U indicates that the virtual value of alternating voltage, Um indicate the maximum value of the alternating voltage, and ω is alternating current
Angular frequency, t is the time, and Φ u is the initial phase of the alternating voltage, and (ω t+ Φ u) is then phase angle.
Preferably, waveform detection circuit provided by the embodiment of the utility model further includes the first infrared sensor 11 and
Two infrared sensors 12.First infrared sensor 11 and the second infrared sensor 12 are for determining that metal object passes through induction coil
The time of group, that is, the sampling statistics time that second filter 9 samples the 4th detection data.When metal object passes through
When the first infrared sensor 11, start timing, when metal object passes through the second infrared sensor 12, timing terminates.Timing institute
The obtained time is statistical time.
It is further preferred that second filter 9 selects FIR filter (Finite Impulse Response).
After obtaining waveform phase angular data and wave-shape amplitude data, second filter 9 is by waveform phase angular data and wave
Shape amplitude data is sent to central processing unit 1,1 Comprehensive Correlation waveform phase angular data of central processing unit and wave-shape amplitude data with
Preset threshold range determines through the object of induction coil group whether be metal object and metal object according to comparing result
For which kind of metal object.
Specifically, preset threshold range includes preset phase angular dimensions and preset wave-shape amplitude threshold value.Central processing
Whether device 1 determines whether wave-shape amplitude data exceed preset wave-shape amplitude threshold value, and determine waveform phase angular data default
Phase angle parameter area in.Preset phase angular dimensions includes 0 °, 45 °, 90 °, 120 ° and 180 °.
If wave-shape amplitude data exceed preset wave-shape amplitude threshold value, and waveform phase angle less than 0 °, then explanation is current
Object by induction coil group is mobile phone；
If wave-shape amplitude data exceed preset wave-shape amplitude threshold value, and waveform phase angle is more than or equal to 0 ° and is less than
45 °, then illustrate to be currently the metal object similar to tinplate can-like by the object of induction coil group；
If wave-shape amplitude data exceed preset wave-shape amplitude threshold value, and waveform phase angle is more than or equal to 45 ° and is less than
90 °, then illustrate to be currently the metal object similar to aluminum tank body shape by the object of induction coil group；
If wave-shape amplitude data exceed preset wave-shape amplitude threshold value, and waveform phase angle is more than or equal to 90 ° and is less than
120 °, then illustrate to be currently the metal object similar to copper tank body shape by the object of induction coil group；
If wave-shape amplitude data exceed preset wave-shape amplitude threshold value, and waveform phase angle is more than or equal to 120 ° and small
In 180 °, then illustrate to be currently the metal object similar to weapons shape by the object of induction coil group.
In one example, prompt information can be the acoustic information of sound amplifying circuit output, when central processing unit is examined
When measuring metal, Xiang Shengyin amplifying circuit sends alarm signal, and sound amplifying circuit exports alarm sound.
In another example, prompt information can be the optical information of light emitting diode output, when central processing unit detects
When to metal, alarm signal is sent to light emitting diode, light emitting diode is flashed to alarm.
In another example, prompt information can be the display image information of display screen output, when central processing unit is examined
When measuring metal, alarm signal is sent to display screen, display screen shows the article of alarm, such as knife, mobile phone etc..
The display screen can be liquid crystal display (Liquid Crystal Display, LCD).
In another example, prompt information can be any combination of above-mentioned three kinds of situations, to realize type of alarm
Diversification.
Preferably, preset phase angular dimensions and preset wave-shape amplitude threshold value can be control unit and inputted according to user
Enabled instruction parse.For example, being inputted when whether it is cutter that user only need to detect object to be detected to central processing unit
The enabled instruction of " detection cutter ", then control unit parses to obtain the preset phase angle just for " cutter " according to the instruction
Parameter and preset wave-shape amplitude threshold value.
Alternatively, preset phase angular dimensions and preset wave-shape amplitude threshold value can also be according to different metal products
The data that the experiment of multipass safety check apparatus obtains, and it is pre-stored in control unit local.
Which kind of prompt information central processing unit 1 generates when can need according to user and set and detect which kind of metal object.Example
Such as, in the safety check scene of some races, event watching person with carrying mobile phone admission but can cannot carry other metal admissions, then
When central processing unit 1 determines that metal object is mobile phone, warning message is not generated.And in the safety check scene at some stations, ginseng
Meeting person cannot carry cutter and other items into station, but can carry the article of such as pop can class, then when central processing unit 1
High level alarm prompt information is generated when metal object is cutter and, which is determined, has cutter to fill by safety check for prompting user currently
It sets, it is necessary to further be checked.And low level is generated when central processing unit 1 determines that metal object is aluminum tank body shape object
Prompt messages have aluminum tank body shape by safety check apparatus, conditional can be checked for prompting user currently.
Preferably, magnet exciting coil 4 and 5 groups of induction coil can be correspondingly arranged as two sets of left and right, be respectively used to a detection human body left side
Border region and right area.Wherein, right set magnet exciting coil and induction coil group are responsible for visiting the space of entire search coverage 2/3, left
Set magnet exciting coil and induction coil group are responsible for visiting the space of entire search coverage 1/3.
Also, left and right two sets of induction coil groups 5 be provided with five groups of induction coil groups 5, this five groups of induction coil groups 5
Position, size and arrangement mode in magnet exciting coil 4 is corresponding with the detecting location of human body, is respectively used to detection human body head
Portion, chest, waist, huckle and calf region.Every group of generated detection data of induction coil group includes induction coil
Location information.When central processing unit 1 parses detection data, induction coil location information can also be obtained.Finally, centre
Reason device can 1 with according to the location information of induction coil determine currently by the object of induction coil group be carried with human body which
Position, and user is shown in prompt information.
A kind of waveform detection circuit provided by the embodiment of the utility model detects metal object according to electromagnetic induction principle,
And the collected analog signal of institute is filtered by way of setting filter and amplifying circuit, is amplified, shaping and modulus
Conversion, obtains digital signal, and digital signal is further screened, judges and analyzed, and final accurate judgement is detected
Whether object is metal object and which kind of metal object detected object is, and waveform provided by the embodiment of the utility model detection is electric
The sensitivity on road is high, and performance is stablized.
Above-described specific embodiment, to the purpose of this utility model, technical scheme and beneficial effects carried out into
One step is described in detail, it should be understood that being not used to limit the foregoing is merely specific embodiment of the present utility model
Determine the protection scope of the utility model, within the spirit and principle of the utility model, any modification for being made equally is replaced
It changes, improve, should be included within the scope of protection of this utility model.
Claims (8)
1. a kind of waveform detection circuit, which is characterized in that the waveform detection circuit include: central processing unit, signal generator,
Magnet exciting coil, induction coil group, first filter and analog-digital converter；
The central processing unit is connected with the signal generator；The enabled instruction that the central processing unit is inputted according to user to
The signal generator sends enabling signal；
The signal generator is electrically connected with the induction coil group；The signal generator is generated according to the enabling signal and is handed over
Time-dependent current, and the alternating current is sent to the magnet exciting coil；The magnet exciting coil generates spy according to the alternating current
Survey magnetic field；
The induction coil group is placed in the magnet exciting coil, and is electrically connected with the first filter；
When metal object passes through the detection magnetic field, the detection magnetic field changes；The induction coil group is according to variation
Detection magnetic field afterwards generates the first detection data, and first detection data is sent to first filter；
The first filter is connected with the analog-digital converter；The first filter filters first detection data
Wave processing, obtains the second detection data, and second detection data is sent to the analog-digital converter；
The analog-digital converter is connected with the central processing unit；The analog-digital converter carries out modulus to third detection data and turns
Processing is changed, obtains the 4th detection data, and the 4th detection data is sent to central processing unit；
The central processing unit parses the 4th detection data, generates prompt information according to parsing result, and show.
2. waveform detection circuit according to claim 1, which is characterized in that the circuit further includes the first amplifying circuit；
First amplifying circuit is connected with the first filter and the analog-digital converter respectively；First amplifying circuit
Signal enhanced processing is carried out to second detection data, obtains third detection data, and the third detection data is sent
To analog-digital converter.
3. waveform detection circuit according to claim 1, which is characterized in that the circuit further includes the second amplifying circuit；
Second amplifying circuit is connected with the signal generator and the magnet exciting coil respectively；
Second amplifying circuit receives the alternating current that the signal generator is sent, and puts to most alternating currents
Greatly, and by amplified alternating current it is sent to the magnet exciting coil；The magnet exciting coil is according to the amplified alternation electricity
The raw detection magnetic field of miscarriage.
4. waveform detection circuit according to claim 1, which is characterized in that the circuit further includes second filter；Institute
Second filter is stated to be connected with the analog-digital converter and the central processing unit respectively；
4th detection data is sent to second filter by the analog-digital converter；
The second filter samples the 4th detection data in statistical time, obtains multiple 4th detection datas；
Mean value calculation is carried out to the multiple 4th detection data group, obtains the average wave number of the 4th detection data, and will be described
The average wave number of 4th detection data is sent to the central processing unit.
5. waveform detection circuit according to claim 4, which is characterized in that the average wave number packet of the 4th detection data
Include waveform phase angular data and wave-shape amplitude data.
6. waveform detection circuit according to claim 4, which is characterized in that the circuit further includes the first infrared sensor
With the second infrared sensor；
The second filter passes sequentially through first infrared sensor and the second infrared biography according to the metal object
The time of sensor obtains the statistical time.
7. waveform detection circuit according to claim 2, which is characterized in that first amplifying circuit is put for multi-level differential
Big circuit.
8. waveform detection circuit according to claim 3, which is characterized in that second amplifying circuit is put for multi-level differential
Big circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820231060.8U CN209707695U (en) | 2018-02-09 | 2018-02-09 | Waveform detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820231060.8U CN209707695U (en) | 2018-02-09 | 2018-02-09 | Waveform detection circuit |
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| Publication Number | Publication Date |
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| CN209707695U true CN209707695U (en) | 2019-11-29 |
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ID=68634961
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| CN201820231060.8U Active CN209707695U (en) | 2018-02-09 | 2018-02-09 | Waveform detection circuit |
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