CN206211979U - A kind of ground nuclear magnetic resonance signal locking amplifying device - Google Patents
A kind of ground nuclear magnetic resonance signal locking amplifying device Download PDFInfo
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- CN206211979U CN206211979U CN201621368197.5U CN201621368197U CN206211979U CN 206211979 U CN206211979 U CN 206211979U CN 201621368197 U CN201621368197 U CN 201621368197U CN 206211979 U CN206211979 U CN 206211979U
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- Prior art keywords
- amplifier
- lock
- signal
- preamplifier
- magnetic resonance
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Abstract
The utility model belongs to nuclear magnetic resonance equipment preparation field, more particularly to a kind of ground nuclear magnetic resonance signal locking amplifying device.Including：Preamplifier, for receiving measured signal, measured signal is amplified；Lock-in amplifier, is connected, signal generator with the output of preamplifier, produces the stable sine wave signal of desired frequency to be connected with the input of the lock-in amplifier as reference signal；NET0824 capture cards, by by connecting the preamplifier and the lock-in amplifier after serial ports；Power module, powers after being connected with the preamplifier, lock-in amplifier, frequency synthesizer, NET0824 capture cards and 74HC595 serial ports；Host computer, display is connected to NET0824 capture cards, originally new to improve the precision of measurement result, and the electronic component for using is few, is capable of achieving to reduce the purpose of volume.
Description
Technical field
The utility model belongs to nuclear magnetic resonance equipment preparation field, more particularly to a kind of ground nuclear magnetic resonance signal locking is put
Big device.
Background technology
Along with the development of modern measure technology, the detection of small-signal is widely applied to every field, traditional
Detection method has synchronous backing space technique and correlation detection etc., and wherein lock-in amplifier has just used correlation detection, using mutual
Relative theory, is in the correlator carried out the reference signal under CF and frequency identical measured signal composition therewith related
Computing, so as to detect the useful signal flooded by noise.Lock-in amplifier has that reliability is high, detectability is strong, general
The features such as property is high.Small-signal can be detected well with lock-in amplifier, be widely applied.What lock mutually amplified
Principle is techniques of phase-sensitive detecting technique.Wherein, the lock-in amplifier of only one of which correlator is referred to as single-phase lock-in amplifier, there is two phases
The lock-in amplifier for closing device turns into two-phase lock-in amplifier.
Ground nuclear magnetic resonance signal (Magnetic Resonance Sounding, MRS) is exactly a kind of faint signal,
General volt level of only receiving.The detection of NMR signal is significant for Underground water.The earth's magnetic field of different geographical
With different size of Larmor frequency fL(it is mainly 1kHz-3kHz in the range of the earth within the border, China is mainly within the border
1.7kHz-2.5kHz)[10-11].So the lock phase amplifying device developed herein is also intended to the letter in this frequency range
Number detected.Usual lock-in amplifier volume all than larger, carries very inconvenient, is only used for testing and tests.And it is a lot
When we will arrive live (field) collection ground NMR signal, so to design a set of more portable lock mutually amplifies dress
Put.
Compared with the country, the external research starting to this technology will more earlier, EG＆G the and ATMETEH companies in the U.S.
It is the leading enterprise of industry.Wherein First lock-in amplifier in the world, Er Qieyi have been invented by SIGNAL RECOVERY companies
The straight top level in the sector.The representative products of the said firm have：Analog lock-in amplifier 5210, digital lock-in amplifier
7225 and 7280.5210 measurement frequency scope is 0.5Hz-120kHz, and dynamic deposit reaches 130dB, is lock-in amplifier
Significant product.Additionally, the achievement that U.S. Stamford SRS companies obtain in the art is also extremely protruded, its production
SR850 digital lock-in amplifiers are the mainstream products of the said firm, this be it is a based on DSP Technology designs and also support waveform show
The lock-in amplifier for showing, dynamic deposit is more than 100dB, and can automatically set gain and phase.
For the country, Nanjing University Tang Hong guest etc. makes internal disorder or usurp starting relatively early to grinding for lock-in amplifier, have developed FS series
Lock-in amplifier.It is exactly in addition that data are surveyed but these device volumes all than larger, inconvenience are brought to the on-the-spot test in field
The accuracy for measuring result has much room for improvement.
Utility model content
Technical problem to be solved in the utility model is to provide a kind of ground nuclear magnetic resonance signal locking amplifying device,
The precision of measurement result can be improved, and the electronic component for using is few, is capable of achieving to reduce the purpose of volume.
The utility model is achieved in that a kind of ground nuclear magnetic resonance signal locking amplifying device, including：
Preamplifier, for receiving measured signal, measured signal is amplified；
Lock-in amplifier, is connected with the output of preamplifier,
Signal generator, produces the stable sine wave signal of desired frequency as reference signal and the lock-in amplifier
Input connection；
NET0824 capture cards, by by connecting the preamplifier and the lock-in amplifier after serial ports；
Power module, with the preamplifier, lock-in amplifier, frequency synthesizer, NET0824 capture cards and
Powered after the connection of 74HC595 serial ports；
Host computer, display is connected to NET0824 capture cards；
Wherein, the preamplifier include sequentially input output connection low-noise amplifier, the first programmable amplifier,
Second programmable amplifier, low pass filter, high-pass filter, the 3rd programmable amplifier and output amplifier, the low noise
Amplifier magnification ratio be 10 times, with first programmable amplifier set a capacitance C, first programmable amplifier,
Second programmable amplifier and the 3rd programmable amplifier pass through address line traffic control multiplication factor.
Further, the lock-in amplifier includes two inputs, and one of input connection signal generator connects
It is input into by reference signal, reference signal is input into zero passage shaping circuit through entering into phase lock circuitry by harmonic circuit, described
The output end of phase lock circuitry is linked on quadrature square wave generator, and two output ends of the quadrature square wave generator are connected respectively
First multiplier and the second multiplier, first multiplier are connected preamplifier with the input of second multiplier
Output end, first multiplier is connected low pass filter I and low pass filter respectively with the output end of second multiplier
II。
Further, the harmonic circuit has 1-15 subharmonic control ends, and the phase lock circuitry connection losing lock indicates two
Pole pipe, connects 90 ° of stepping coarse adjustment ends on the quadrature square wave generator.
Further, the signal generator uses AD9850 chips.
Further, the serial ports expands to 32 I/O mouthfuls using 4 74HC595 chips.
Compared with prior art, beneficial effect is the utility model：Lock-in amplifier can preferably complete nuclear-magnetism and be total to
Shake the detection work of signal, traditional lock-in amplifier is heavier, in order to preferably complete the work of on-the-spot test, profit
Use modular lock-in amplifier：
1. program control preamplifier and lock-in amplifier are utilized, the ground in 1kHz-3kHz that will be simulated as needed
NMR signal amplifies 8-8 × 106Times, reach expected index.Suitable time constant is selected, by testing result and reason
Contrasted by value, demonstrated the accuracy of measurement result.
2., by the use of capture card as the control axis of whole acquisition system, complete to two amplifier modules and AD9850
Parameter configuration work and data acquisition task, whole device is organically combined.
3. the volume and weight of whole device all very littles, with it is portable the characteristics of, can well complete on-the-spot test
Task.
Brief description of the drawings
Fig. 1 is the device structure block diagram that the utility model embodiment is provided；
Fig. 2 is the structured flowchart of the preamplifier that the utility model embodiment is provided；
Fig. 3 is the pin definition figure of the 74HC595 chips that the utility model embodiment is provided；
Fig. 4 is the block diagram of the low pass filter that the utility model embodiment is provided；
Fig. 5 is the block diagram of the high-pass filter that the utility model embodiment is provided；
Fig. 6 is the structured flowchart of the lock-in amplifier that the utility model embodiment is provided.
Specific embodiment
In order that the purpose of this utility model, technical scheme and advantage become more apparent, below in conjunction with accompanying drawing and implementation
Example, is further elaborated to the utility model.It should be appreciated that specific embodiment described herein is only used to explain
The utility model, is not used to limit the utility model.
A kind of block diagram of ground nuclear magnetic resonance signal locking amplifying device shown in Figure 1, including：
Preamplifier, for receiving measured signal, measured signal is amplified；
Lock-in amplifier, is connected with the output of preamplifier,
Signal generator, produces the stable sine wave signal of desired frequency as reference signal and the lock-in amplifier
Input connection；
NET0824 capture cards, by by connecting the preamplifier and the lock-in amplifier after serial ports；
Power module, with preamplifier, lock-in amplifier, frequency synthesizer, NET0824 capture cards and 74HC595
Powered after serial ports connection；
Host computer, display is connected to NET0824 capture cards；
Referring to Fig. 2, wherein, preamplifier includes sequentially inputting the low-noise amplifier K of output connection1, it is first program control
Amplifier K2, the second programmable amplifier K3, low pass filter, high-pass filter, the 3rd programmable amplifier K4And output amplifier
K5, the low-noise amplifier multiplication factor is 10 times, and a capacitance C is set with first programmable amplifier, described the
One programmable amplifier, the second programmable amplifier and the 3rd programmable amplifier pass through address line traffic control multiplication factor.
The input stage K1 of this amplifier is special low-noise amplifier, and input short noise voltage isIt is fixed
Amplify 10 times, i.e. K1=10.
The second programmable amplifier is connected by a capacitance after first programmable amplifier, all programmable amplifiers have
Two kinds of control modes：The first is to carry out gear selection by toggle switch, so as to select this grade of multiplication factor of amplifier；The
Two kinds is by some (each program-controlled unit is different) address line traffic controls.And Program-controlled lock is to do is in the present embodiment and is mutually put
Big system, so the second way will be used, is controlled so as to complete the configuration to amplifier parameter to each address wire
Work.
First programmable amplifier is a high performance amplifier, and multiplication factor K2 can be made by three address line traffic controls
K2=1,2,5,10,20,50,100, having seven grades of multiplication factors can select.
Second programmable amplifier is an attenuator, and its multiplication factor K3 can make K by two address line traffic controls3=
0.01st, 0.1,1, total third gear can be selected.
Next to that low pass filter, low-pass cut-off frequencies fLCBy three address line traffic controls, fLCFor 10kHz, 3kHz,
1kHz, 300Hz, 100Hz, 30Hz, 10Hz, 3Hz, having eight grades can select.
It is again high-pass filter, high pass cut off frequency fHCBy two address line traffic controls, fHCFor 0.1Hz, 1Hz,
10Hz, 30Hz, 100Hz, 300Hz, 1kHz, 3kHz, having eight grades can select.
It is also a high-performance programmable amplifier followed by the 3rd programmable amplifier, multiplication factor K4 passes through three ground
Location line traffic control, can make K4=1,2,5,10,20,50,100, having seven grades of multiplication factors can select.
Afterbody output amplifier is output stage, and multiplication factor is fixed as K5=1 times.
So total magnification K it is total=K1K2K3K4K5, by three reasonable selections of programmable amplifier multiplication factor
Multiplication factor K=0.1-100K can be made and the rule according to 1,2,5,10 changes.The specific structure of above-mentioned programmable amplifier,
To use what structure conventional on the market can just be realized, the specific structure of programmable amplifier is no longer given herein.
Referring to Fig. 4, lock-in amplifier can use HB-292 (V-1) type high-performance two-phase lock-in amplifier, the present embodiment
Include two inputs, one of input connection signal generator receives the input of reference signal, reference signal input
Passed through after to zero passage shaping circuit and phase lock circuitry is entered into by harmonic circuit, the output end of phase lock circuitry is linked into quadrature square wave generation
On device, two output ends of quadrature square wave generator connect the first multiplier and the second multiplier, the first multiplier and respectively
The input of paired multiplier connects the output end of preamplifier, and the first multiplier is distinguished with the output end of second multiplier
Connection low pass filter I and low pass filter II.
And harmonic circuit has 1-15 subharmonic control ends, phase lock circuitry connection losing lock indicates diode, the orthogonal side
90 ° of stepping coarse adjustment ends are connected on wave producer.
The reference signal of signal generator output produces the same frequency square wave of reference signal by zero passage shaping circuit, is sent to humorous
Wave circuit, according to the harmonic wave that harmonic circuit can be controlled to produce 1 time to 15 times the need for measurement.The losing lock indicator lamp of phase lock circuitry
It is initially bright, when reference signal stabilization, losing lock indicator lamp extinguishes, this amplifier requirements reference signal is the cycle letter of stabilization
Number, size is between 200mV-3V.Then 0 °, 90 °, 180 °, 270 ° of phase-shift phase can as needed be selected.Then arrive
Lock-in amplifier most crucial part：Correlator.Correlator carries out relevant treatment to measured signal, in the extremely low feelings of signal to noise ratio
Under condition, useful signal is reduced.Correlator is made up of multiplier and low pass filter, for direct current amplifies 100 times after correlator,
And suppress the interference of noise, it is necessary to select suitable time constant as needed.The present embodiment is two-phase lock-in amplifier, is had
In the same direction with orthogonal two correlators.Therefore, two magnitudes of voltage of output are the in-phase component and quadrature component of measured signal.
Harmonic circuit can select 1 time of reference signal to 15 subharmonic, can be with selected harmonic number by four address wires.
90 ° of stepping coarse adjustment function can select 0 °, 90 °, 180 °, 270 ° by two address line traffic controls, altogether fourth gear.
The selection of time constant by three address line traffic controls, can select 1ms, 3ms, 10ms, 30ms, 100ms,
300ms, 1s, 3s, totally 8 grades.
Signal generator uses AD9850 chips in the present embodiment.
Referring to Fig. 3, serial ports expands to 32 I/O mouthfuls using 4 74HC595 chips.
Referring to Fig. 5 in the present embodiment, low-pass filter circuit includes the first arithmetic device A1 of model LT1885IS, described the
The in-phase input end connection resistance R2 of one arithmetic unit, and be grounded by electric capacity C1, the inverting input of the first arithmetic device connects
Output end is connected after connecting resistance R1 and by adjustable resistance Rf1.
Referring to Fig. 6, high-pass filtering circuit：Second arithmetic device A2 including model LT1885IS, the second arithmetic device
The in-phase input end of A2 is input into by connecting electric capacity C2, and is grounded by resistance R4, the homophase input of the second arithmetic device A2
End is connected to output end after resistance R3 is grounded by adjustable resistance Rf2.
The present apparatus is that triple channel is gathered simultaneously.On device after electricity, the first step will match somebody with somebody to serial ports 74HC595 first
Put so as to be configured to the parameter of preamplifier and lock-in amplifier, AD9850 signal generators are configured and selected
The frequency of reference signal.
First way, capture card produces a trailing edge by itself sending out synchronizing signal, is arrived in trailing edge
Before, whole device does not work, when trailing edge arrives later just as the trigger signal of signal generator AD9850, signal hair
Raw AD9850 starts to produce a sine wave for settable fixed frequency as reference signal, and reference signal enters stabilization quickly
State, the losing lock indicator lamp of lock-in amplifier extinguishes, and lock-in amplifier is started working.Then the A/D chip in capture card is entered at once
Enter working condition, collection terminates rear capture card and produces a rising edge and terminate this collection.It is automatic by number after A/D chip collection
According to being uploaded to host computer and show the in-phase component V of measured signalxWith quadrature component Vy, the signal of also lock-in amplifier is defeated
Enter the input signal Vo at end.
The second way, capture card does not work first, is changed into by the trigger signal outside TRIG_IN waits, when triggering is believed
Number produce a trailing edge, AD9850 signal generators start produce a sine wave for settable fixed frequency as reference
Signal, lock-in amplifier is started working.Then as first way, a gatherer process is completed.
Preferred embodiment of the present utility model is the foregoing is only, is not used to limit the utility model, it is all at this
Any modification, equivalent and improvement made within the spirit and principle of utility model etc., should be included in the utility model
Protection domain within.
Claims (5)
1. a kind of ground nuclear magnetic resonance signal locking amplifying device, it is characterised in that including：
Preamplifier, for receiving measured signal, measured signal is amplified；
Lock-in amplifier, is connected with the output of preamplifier,
Signal generator, produces the stable sine wave signal of desired frequency defeated with the lock-in amplifier as reference signal
Enter end connection；
NET0824 capture cards, by by connecting the preamplifier and the lock-in amplifier after serial ports；
Power module, with the preamplifier, lock-in amplifier, frequency synthesizer, NET0824 capture cards and 74HC595
Powered after serial ports connection；
Host computer, display is connected to NET0824 capture cards；
Wherein, the preamplifier includes sequentially inputting low-noise amplifier, the first programmable amplifier, second of output connection
Programmable amplifier, low pass filter, high-pass filter, the 3rd programmable amplifier and output amplifier, the low noise amplification
Device multiplication factor is 10 times, and a capacitance C is set with first programmable amplifier, first programmable amplifier, described
Second programmable amplifier and the 3rd programmable amplifier pass through address line traffic control multiplication factor.
2. ground nuclear magnetic resonance signal locking amplifying device as claimed in claim 1, it is characterised in that the lock-in amplifier
Including two inputs, one of input connection signal generator receives the input of reference signal, reference signal be input into
Passed through after zero passage shaping circuit and phase lock circuitry is entered into by harmonic circuit, the output end of the phase lock circuitry is linked into quadrature square wave hair
On raw device, two output ends of the quadrature square wave generator connect the first multiplier and the second multiplier, described first respectively
Multiplier is connected the output end of preamplifier, first multiplier and described second with the input of second multiplier
The output end of multiplier connects low pass filter I and low pass filter II respectively.
3. ground nuclear magnetic resonance signal locking amplifying device as claimed in claim 2, it is characterised in that the harmonic circuit tool
There are 1-15 subharmonic control ends, the phase lock circuitry connection losing lock indicates diode, 90 ° are connected on the quadrature square wave generator
Stepping coarse adjustment end.
4. ground nuclear magnetic resonance signal locking amplifying device as claimed in claim 1, it is characterised in that the signal generator
Using AD9850 chips.
5. ground nuclear magnetic resonance signal locking amplifying device as claimed in claim 1, it is characterised in that the serial ports uses 4
Piece 74HC595 chips expand to 32 I/O mouthfuls.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621368197.5U CN206211979U (en) | 2016-12-14 | 2016-12-14 | A kind of ground nuclear magnetic resonance signal locking amplifying device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621368197.5U CN206211979U (en) | 2016-12-14 | 2016-12-14 | A kind of ground nuclear magnetic resonance signal locking amplifying device |
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| Publication Number | Publication Date |
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| CN206211979U true CN206211979U (en) | 2017-05-31 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621368197.5U Expired - Fee Related CN206211979U (en) | 2016-12-14 | 2016-12-14 | A kind of ground nuclear magnetic resonance signal locking amplifying device |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108254794A (en) * | 2018-01-26 | 2018-07-06 | 吉林大学 | A kind of magnetic resonance noise-eliminating method and device based on the anti-recovery technology of modeling |
| CN109633759A (en) * | 2018-12-12 | 2019-04-16 | 吉林大学 | Ground magnetic resonance signal rapidly extracting device and method based on phase lock amplifying technology |
| CN111308401A (en) * | 2020-04-09 | 2020-06-19 | 西安交通大学 | Detection circuit based on impedance sensitive type magnetic sensor and magnetic sensor |
| CN112433187A (en) * | 2019-08-26 | 2021-03-02 | 通用电气精准医疗有限责任公司 | MRI system comprising a patient motion sensor |
-
2016
- 2016-12-14 CN CN201621368197.5U patent/CN206211979U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108254794A (en) * | 2018-01-26 | 2018-07-06 | 吉林大学 | A kind of magnetic resonance noise-eliminating method and device based on the anti-recovery technology of modeling |
| CN108254794B (en) * | 2018-01-26 | 2020-01-14 | 吉林大学 | Magnetic resonance denoising method and device based on modeling reverse recovery technology |
| CN109633759A (en) * | 2018-12-12 | 2019-04-16 | 吉林大学 | Ground magnetic resonance signal rapidly extracting device and method based on phase lock amplifying technology |
| CN112433187A (en) * | 2019-08-26 | 2021-03-02 | 通用电气精准医疗有限责任公司 | MRI system comprising a patient motion sensor |
| CN111308401A (en) * | 2020-04-09 | 2020-06-19 | 西安交通大学 | Detection circuit based on impedance sensitive type magnetic sensor and magnetic sensor |
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Legal Events
| Date | Code | Title | Description |
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20170531 Termination date: 20171214 |