CN106199465B - A kind of twin-stage superconducting quantum interference device amplifying device, method and SQUID Magnetic Sensor - Google Patents

A kind of twin-stage superconducting quantum interference device amplifying device, method and SQUID Magnetic Sensor Download PDF

Info

Publication number
CN106199465B
CN106199465B CN201510225474.0A CN201510225474A CN106199465B CN 106199465 B CN106199465 B CN 106199465B CN 201510225474 A CN201510225474 A CN 201510225474A CN 106199465 B CN106199465 B CN 106199465B
Authority
CN
China
Prior art keywords
magnetic flux
signal
squid
voltage
modulation
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.)
Active
Application number
CN201510225474.0A
Other languages
Chinese (zh)
Other versions
CN106199465A (en
Inventor
王永良
徐小峰
孔祥燕
谢晓明
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shanghai Institute of Microsystem and Information Technology of CAS
Original Assignee
Shanghai Institute of Microsystem and Information Technology of CAS
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Shanghai Institute of Microsystem and Information Technology of CAS filed Critical Shanghai Institute of Microsystem and Information Technology of CAS
Priority to CN201510225474.0A priority Critical patent/CN106199465B/en
Publication of CN106199465A publication Critical patent/CN106199465A/en
Application granted granted Critical
Publication of CN106199465B publication Critical patent/CN106199465B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Landscapes

  • Superconductor Devices And Manufacturing Methods Thereof (AREA)
  • Measuring Magnetic Variables (AREA)

Abstract

The present invention provides a kind of twin-stage superconducting quantum interference device amplifying device, method and SQUID Magnetic Sensor, which includes: that the square-wave modulation signal of a fixed frequency is converted into modulation magnetic flux by modulation module；First order superconducting quantum interference device detects external magnetic flux signal and obtains tested magnetic flux, while the voltage output of tested magnetic flux being modulated by modulated voltage signal using the modulation magnetic flux of coupling；Shaping conversion module will be carried out conversion shaping, output adjustment magnetic flux signal by modulated voltage signal；The 2nd SQUID magnetic flux-voltage transformation module of Self-resetting and transmission characteristic hysteresis couples the second level superconducting quantum interference device being connected with shaping conversion module including one, and response adjustment magnetic flux signal exports the adjustment voltage signal of corresponding amplification；Demodulation module demodulates adjustment voltage signal using square-wave modulation signal, exports the detectable voltage signals of twin-stage amplification corresponding with tested magnetic flux.The present invention solves the problems, such as operating point ambiguity and job stability in twin-stage SQUID amplifying technique.

Description

A kind of twin-stage superconducting quantum interference device amplifying device, method and SQUID Magnetic Sensor
Technical field
The invention belongs to magnetic sensor technologies fields, are related to a kind of amplifying device for SQUID Magnetic Sensor, especially It is related to a kind of twin-stage superconducting quantum interference device amplifying device, method and SQUID Magnetic Sensor.
Background technique
Based superconductive quantum interference device (Superconducting Quantum Interference Device, below Abbreviation SQUID) Magnetic Sensor be the most sensitive magnetic detector being currently known, be widely used in biological magnetic field, earth magnetic field The Weak magentic-fields field of detecting such as abnormal, extremely low field nuclear magnetic resonance, detectivity, which has reached, flies spy (10-15Tesla) amount Grade.SQUID Magnetic Sensor is limit detection, magnetic sensor device important in scientific research, has very high scientific research and application Value.
SQUID device is magnet-sensitive element most crucial in SQUID Magnetic Sensor.Generally use direct current SQUID device (with The lower SQUID refers to direct current SQUID device), which is that one be made of two Josephson junction parallel connections surpasses Lead ring loads certain bias current in the both ends leading-out terminal of Josephson junction, has the voltage at the both ends SQUID with it The changed characteristic of induced magnetic field.That is SQUID incudes extraneous magnetic flux, and the voltage of output response, inputs magnetic flux and voltage is constituted Corresponding transmission characteristic.Typical SQUID magnetic flux-voltage-transfer characteristic curve is as shown in Figure 1.SQUID magnetic flux-voltage transmission is special Property refer to SQUID input and output relationship, that is, input a tested magnetic flux, SQUID accordingly exports a voltage value, with defeated Entering magnetic flux is horizontal axis, and voltage responsive is the longitudinal axis, and input magnetic flux and output voltage correspond, and just constitutes spy shown in FIG. 1 Linearity curve, the curve reflect the magnetic field SQUID-voltage-transfer characteristic.Magnetic flux-the voltage-transfer characteristic is that the period is nonlinear, Period is a flux quantum Φ0(2.07×10-15Weber).It can be seen that from magnetic flux-voltage-transfer characteristic curve of SQUID SQUID response external magnetic flux is nonlinear, and is in mechanical periodicity with input magnetic flux, is one to input magnetic flux as independent variable Periodic function.Period is a flux quantum Φ0.The SQUID is magneto sensor, just refers to that SQUID can respond the magnetic of input It is logical, generate voltage change, i.e., it is sensitive to input magnetic flux.Due to magnetic flux-voltage-transfer characteristic be it is nonlinear, SQUID is to difference Magnetic flux inputs its responding ability difference.Usually introduce the slope of transfer curveSensitivity is characterized, slope gets over Greatly, sensitivity is higher.In the slope of some point of transfer curveIt embodies SQUID and inputs a small magnetic flux in the point Variation generates the ability of voltage responsive, the referred to as magnetic flux of the point-voltage transmission rate.SQUID is bigger in the transmission rate of some point, uses It works, and to constitute linear Magnetic Sensor noise obtained lower.
SQUID Magnetic Sensor is exactly to rely on above-mentioned SQUID magnetic flux-voltage-transfer characteristic application magnetic flux-voltage lockout principle Magnetic flux to realize flux detection, and will test is converted linearly into voltage signal, and it is low to constitute the high sensitivity based on SQUID Noise Magnetic Sensor.Typical structure based on magnetic flux-locked loop SQUID Magnetic Sensor is as shown in Figure 2.Fig. 3 is SQUID magnetic Transfer curve schematic diagram of the sensor at operating point.Can be seen that this from the exemplar schematic figure of SQUID Magnetic Sensor is A kind of negative feedback loop, circuit are in dynamic balance state, i.e., adjust output feedback current by integrator, tracking is offset always Externally input tested magnetic flux, so that SQUID all-the-time stable is in work zero point.The work zero point is exactly in SQUID magnetic flux A characteristic point is chosen on voltage-transfer characteristic curve, the characteristic point magnetic flux-voltage transmission rate is maximum, and operating point both sides have one Fixed section makes SQUID magnetic sensor circuit be able to maintain negative-feedback；When occurring to deviate the fluctuation of operating point, as long as in the area In, negative feedback loop can automatically reply balance, come back to SQUID state on operating point.
Above-mentioned flux locked loop structure is that a kind of non-linear magneto sensor of typically application realizes magnetic flux-voltage linear conversion Scheme, its working principle is that: selection SQUID magnetic flux-one of operating point of voltage-transfer characteristic, at operating point, SQUID Output voltage is zero, and integrator does not integrate, and all outputs are stablized, and reaches the stable state of negative-feedback.When the tested magnetic flux in outside It changes, the magnetic flux of SQUID induction deviates operating point, and according to magnetic flux-voltage-transfer characteristic curve output voltage, the voltage Premenstrual to put big feeding integrator, integrator is according to input voltage size quadrature modulates transmission voltage, modulated output electricity Drive feedback resistance is pressed to generate feedback current If, feedback current pass through feedback inductance LfWith the mutual inductance M of magnet-sensitive element SQUIDfIt produces It is raw to offset magnetic flux, externally input magnetic flux is offset, so that entire feedback loop restores balance, SQUID state returns to operating point It keeps stablizing.From the negative-feedback course of work of flux locked loop it is found that the tested magnetic flux size of input and counteracting magnetic flux phase always Together, therefore tested magnetic flux size generates the proportional relationship of integrator output voltage for offsetting magnetic flux, as long as detection integrator is defeated Voltage out, you can learn that the size of external tested magnetic flux, SQUID Magnetic Sensor are exactly to realize magnetic flux-voltage using the principle Linear transformation.From the working principle of SQUID Magnetic Sensor it is found that sensor is turned using magnetic flux-voltage from the operating point SQUID It changes characteristic and maintains negative-feedback balance, complete magnetic flux-voltage linear transformation.
SQUID device has the following problems in building Magnetic Sensor: SQUID magnetic flux-voltage transmission rateNot enough, Make sensor noise by preamplifier noise dominant.The weak output signal of SQUID device needs to pass through low-noise preamplifier Signal is amplified, then drives integrator and magnetic flux negative feedback loop, forms flux locked loop.Since SQUID works in low temperature ring Under border, there is very low noise, and matched preamplifier is constituted using semiconductor circuit, and is worked in low temperature environment Under, voltage noise is much higher than the intrinsic noise of SQUID, so that SQUID Magnetic Sensor noiseproof feature is dominated by preamplifier, SQUID device low-noise performance is not in full use, and main cause is SQUID device magnetic flux voltage transmission rateNo Foot.SQUID device work at low ambient temperatures (low temperature superconducting material production SQUID be usually operated under 4.2K liquid helium environment, The SQUID of high temperature superconducting materia production is usually operated under the liquid nitrogen environment of 77K), there is very low noise, typical magnetic flux is made an uproar Sound is lower thanThe magnetic flux of SQUID-voltage transmission rateGenerally reach 100 μ V/ Φ0.The preposition amplification of SQUID Device uses semiconductor amplifier, and under room temperature environment, the typical voltage noise of amplifier isTherefore preposition amplification Device introduce equivalent Flux noise beIt can be seen that the noise that amplifier introduces is much larger than SQUID intrinsic noise produces SQUID device and the unmatched problem of preamplifier noise.
In order to solve the problems, such as noise matching, current existing scheme is to introduce the design of two-stage SQUID amplification, that is, uses two A SQUID device, the signal that first SQUID detects tested magnetic field output amplify through second SQUID device again, pass through Two-stage amplification enhances total magnetic flux-voltage transmission rate, to realize with the semiconductor preamplifier matching under room temperature Low noise.Amplified using two-stage SQUID, signal amplification is at low temperature using the second level SQUID with same low noise performance Amplify the noise, it can be achieved that very low to realize, is the scheme of optimal building high-performance SQUID Magnetic Sensor at present.
There are two types of current existing two-stage SQUID magnification schemes:
The first scheme are as follows: two SQUID simple cascades, as shown in Figure 4, wherein SQUID1 and SQUID2 has such as Identical period nonlinear transmission characteristic shown in fig. 5, therefore magnetic flux-voltage-transfer characteristic curve after two SQUID cascades As shown in Figure 6.The program generates the problem that transmission characteristic exists simultaneously the different work zero of multiple characteristics in one cycle Point, only one of them work zero point with optimal magnetic flux-voltage transmission rate.SQUID magnetic flux-voltage-transfer characteristic curve is Period is duplicate, only one lockable operating point in a cycle just can guarantee the consistency of SQUID sensor performance. If having different work zero points in one cycle, and magnetic flux-voltage transmission rate is different at different zero points, then SQUID is passed Performance will cause sensor performance inconsistent because of keyed end difference after sensor locking.In practical applications, since operating point is difficult to Selection, therefore sensor can not be made to reach optimum performance.
Second scheme are as follows: realize that signal is put using the linear magnetic detector that the 2nd grade of SQUID and its amplifying circuit are constituted Greatly, i.e., SQUID amplifying circuit linearisation in the second level is come to the operating point multivalue problem in solution one.Due to the second level SQUID constitutes flux locked loop road, and transmission characteristic is linear, therefore the magnetic flux-voltage-transfer characteristic synthesized can be kept away Exempt from operating point multivalue problem.But since second level amplification is using a SQUID flux locked loop road, output access product Point device and feedback loop form complete sensor circuit, form the degeneration factor of double loop structure, and double loop structure Degeneration factor stability it is poor, flux locked loop road of second level SQUID itself is easy to appear losing lock, and operating point occurs and jumps Become, this will cause entire sensor flux locked loop road losing lock, so that it cannot work normally.Therefore the mistake on flux locked loop road The Operating match problem of lock problem and two feedback loops, so that stability is poor in actual use for the program, it is difficult to practical Change.In addition, second level SQUID is realized transfer linearity using flux locked loop road by the program, bandwidth is limited, it is difficult to Implement Flux modulation mode and carry out 1/f noise inhibition, therefore the Magnetic Sensor low-frequency noise performance constructed is unable to get improvement.
The noise technique that secondary amplification inhibits ambient temperature amplifier is carried out using SQUID at low ambient temperatures, is to give full play to SQUID low-noise characteristic improves the important means of SQUID Magnetic Sensor performance, serious to limit due to facing above-mentioned technical problem The application of the sensor.
Summary of the invention
In view of the foregoing deficiencies of prior art, the purpose of the present invention is to provide a kind of twin-stage superconducting quantum interference devices Amplifying device, method and SQUID Magnetic Sensor work for solving operating point ambiguity in existing twin-stage SQUID amplifying technique The problem of stability difference.
In order to achieve the above objects and other related objects, the present invention provides a kind of twin-stage superconducting quantum interference device amplification dress It sets, the twin-stage superconducting quantum interference device amplifying device includes: modulation module, and the square-wave modulation signal of a fixed frequency is converted At modulation magnetic flux；First order superconducting quantum interference device is connected with modulation module coupling, obtains for detecting external magnetic flux signal It must be tested magnetic flux, while the voltage output of the tested magnetic flux being modulated by modulation voltage using the modulation magnetic flux of coupling Signal；The amplitude by modulated voltage signal is with the first order superconducting quantum interference device to the response voltage phase of tested magnetic flux It closes；It is described by the frequency of modulated voltage signal and phase and the modulation flux synchronous；Shaping conversion module, with the first order Superconducting quantum interference device is connected, and carries out conversion shaping, output adjustment magnetic flux signal by modulated voltage signal for described；Self-resetting and The 2nd SQUID magnetic flux-voltage transformation module of transmission characteristic hysteresis, the to be connected including one with shaping conversion module coupling Second level superconducting quantum interference device responds the adjustment magnetic flux signal, exports the adjustment voltage signal of corresponding amplification；Demodulation module, It is respectively connected with the magnetic flux detector with hysteresis characteristic Self-resetting and modulation module, utilizes the square-wave modulation signal pair The adjustment voltage signal is demodulated, the detectable voltage signals that output twin-stage corresponding with the tested magnetic flux amplifies.
Optionally, the modulation module further comprises: square-wave generator, generates the square-wave frequency modulation letter of the fixed frequency Number；Amplitude adjusting elements are connected with the square-wave generator, and the square-wave modulation signal is converted into modulation electric current；Modulation is single Member is connected with the amplitude adjusting elements, and the modulation electric current is converted into modulation magnetic flux.
Optionally, the shaping conversion module further comprises: the first converting unit, dry with the first order Superconducting Quantum It relates to device to be connected, be converted into described by modulated voltage signal by modulated current signal；Shaping unit, with first converting unit It is connected, shaping is carried out by modulated current signal to described, becomes the raising and lowering transition edges by modulated current signal It is slow, eliminate burr；Second converting unit is connected with the shaping unit, will be converted into adjusting by modulated current signal after shaping Whole magnetic flux signal.
Optionally, the Self-resetting and the 2nd SQUID magnetic flux-voltage transformation module of transmission characteristic hysteresis are using voltage It owes feedback SQUID circuit or electric current owes feedback SQUID circuit to realize the transmission characteristic of Self-resetting hysteresis.
The present invention also provides a kind of twin-stage superconducting quantum interference device amplification method, the twin-stage superconducting quantum interference device amplification Method includes: that the square-wave modulation signal of a fixed frequency is converted into modulation magnetic flux；Utilize a first order superconducting quantum interference device It detects external magnetic flux signal and obtains tested magnetic flux, while coupling the modulation magnetic flux, and by the voltage output of the tested magnetic flux It is modulated by modulated voltage signal；The amplitude by modulated voltage signal is with the first order superconducting quantum interference device to tested The response voltage of magnetic flux is related；It is described by the frequency of modulated voltage signal and phase and the modulation flux synchronous；By the quilt Modulated voltage signal carries out conversion shaping, output adjustment magnetic flux signal；Using a Self-resetting and transmission characteristic hysteresis second SQUID magnetic flux-voltage transformation module responds the adjustment magnetic flux signal, exports the adjustment voltage signal of corresponding amplification；Using institute It states square-wave modulation signal to demodulate the adjustment voltage signal, the inspection that output twin-stage corresponding with the tested magnetic flux amplifies Survey voltage signal.
Optionally, the twin-stage superconducting quantum interference device amplification method further comprises: being generated using a square-wave generator The square-wave modulation signal of the fixed frequency；The square-wave modulation signal is converted into modulation electricity using an amplitude adjusting elements Stream；The modulation electric current is converted into modulation magnetic flux using a modulation unit.
Optionally, the twin-stage superconducting quantum interference device amplification method further comprises: utilizing one first converting unit will It is described to be converted by modulated voltage signal by modulated current signal；It is carried out to described by modulated current signal using a shaping unit Shaping, make it is described slowed down by the raising and lowering transition edges of modulated current signal, eliminate burr；Utilize one second converting unit Adjustment magnetic flux signal will be converted by modulated current signal after shaping.
Optionally, the twin-stage superconducting quantum interference device amplification method further comprises: owing feedback SQUID electricity using voltage Realize the 2nd SQUID magnetic flux-voltage transformation module of the Self-resetting and transmission characteristic hysteresis in road；Or feedback is owed using electric current SQUID circuit realizes the 2nd SQUID magnetic flux-voltage transformation module of the Self-resetting and transmission characteristic hysteresis.
The present invention also provides a kind of SQUID Magnetic Sensor, the SQUID Magnetic Sensor includes: that Claims 1-4 is any Twin-stage superconducting quantum interference device amplifying device, integrator, feedback resistance and feedback inductance described in one；The feedback resistance It is respectively connected with the integrator and the feedback inductance；The input terminal of the twin-stage superconducting quantum interference device amplifying device and institute It states feedback inductance coupling to be connected, the output end of the twin-stage superconducting quantum interference device amplifying device is connected with the integrator.
As described above, twin-stage superconducting quantum interference device amplifying device, method and SQUID Magnetic Sensor of the present invention, It has the advantages that
The present invention not only solves the problems, such as operating point ambiguity and job stability in twin-stage SQUID amplifying technique, The technical issues of 1/f noise inhibits is also solved, the important technological break-through of SQUID high-performance magnetism sensor is realized.
Detailed description of the invention
Fig. 1 is typical SQUID magnetic flux-voltage-transfer characteristic curve schematic diagram.
Fig. 2 is the typical structure schematic diagram based on magnetic flux-locked loop SQUID Magnetic Sensor.
Fig. 3 is transmission characteristic schematic diagram of the SQUID Magnetic Sensor at operating point.
Fig. 4 is the structural schematic diagram of simple twin-stage SQUID magnetic flux-voltage transformation module.
Fig. 5 is the period nonlinear transmission characteristic curve synoptic diagram of single SQUID.
Fig. 6 is magnetic flux-voltage-transfer characteristic curve schematic diagram after two SQUID cascades.
Fig. 7 is using the twin-stage SQUID magnetic flux amplified based on SQUID flux locked loop road as the second level-voltage conversion The structural schematic diagram of module.
Fig. 8 a is the realization structural block diagram of twin-stage superconducting quantum interference device amplifying device described in the embodiment of the present invention.
Fig. 8 b is that a kind of circuit of twin-stage superconducting quantum interference device amplifying device described in the embodiment of the present invention realizes structure Schematic diagram.
Fig. 8 c is the waveform diagram by modulated current signal of the output of shaping conversion module described in the embodiment of the present invention.
Fig. 9 a is Self-resetting described in the embodiment of the present invention and the 2nd SQUID magnetic flux of transmission characteristic hysteresis-voltage conversion A kind of realization structural schematic diagram of module.
Fig. 9 b is Self-resetting described in the embodiment of the present invention and the 2nd SQUID magnetic flux of transmission characteristic hysteresis-voltage conversion The signal detection process schematic diagram of module.
Fig. 9 c is magnetic flux-voltage-transfer characteristic curve schematic diagram of SQUID magnetic detector.
Fig. 9 d is magnetic flux-voltage-transfer characteristic curve schematic diagram of hysteresis Self-resetting.
Figure 10 a is that another circuit of twin-stage superconducting quantum interference device amplifying device described in the embodiment of the present invention realizes knot Structure schematic diagram.
Figure 10 b is Self-resetting described in the embodiment of the present invention and the 2nd SQUID magnetic flux of transmission characteristic hysteresis-voltage conversion The another of module realizes structural schematic diagram.
Figure 10 c is magnetic flux-voltage-transfer characteristic curve schematic diagram of SQUID magnetic detector.
Figure 10 d is magnetic flux-voltage-transfer characteristic curve schematic diagram of hysteresis Self-resetting.
Figure 11 is the waveform diagram of square-wave modulation signal described in the embodiment of the present invention.
Figure 12 is the modulation principle schematic diagram of square-wave modulation signal described in the embodiment of the present invention.
Figure 13 is Self-resetting described in the embodiment of the present invention and the 2nd SQUID magnetic flux of transmission characteristic hysteresis-voltage conversion The magnetic flux of module-voltage-transfer characteristic schematic diagram.
Figure 14 is Self-resetting described in the embodiment of the present invention and the 2nd SQUID magnetic flux of transmission characteristic hysteresis-voltage conversion Response schematic diagram of the module for amplitude less than the magnetic flux signal of a flux quantum.
Figure 15 a is Self-resetting described in the embodiment of the present invention and the 2nd SQUID magnetic flux of transmission characteristic hysteresis-voltage conversion Module is greater than amplitude in the response schematic diagram of the magnetic flux signal of the positive change of one flux quantum or more.
The 2nd SQUID magnetic flux-voltage modulus of conversion of Self-resetting described in Figure 15 b embodiment of the present invention and transmission characteristic hysteresis Block is greater than amplitude in the response schematic diagram of the magnetic flux signal of the inverse change of one flux quantum or more.
The 2nd SQUID magnetic flux-voltage modulus of conversion of Self-resetting described in Figure 15 c embodiment of the present invention and transmission characteristic hysteresis Block is greater than amplitude in the response schematic diagram of the magnetic flux signal of the positive and negative two-way variation of one flux quantum or more.
Figure 16 is Self-resetting described in the embodiment of the present invention and the 2nd SQUID magnetic flux of transmission characteristic hysteresis-voltage conversion Module is directed to the detection feature schematic diagram of exchange flux signal.
Figure 17 is magnetic flux-voltage-transfer characteristic of twin-stage superconducting quantum interference device amplifying device described in the embodiment of the present invention Schematic diagram.
Figure 18 is the realization structural schematic diagram of SQUID Magnetic Sensor described in the embodiment of the present invention.
Figure 19 is a kind of implementation process signal of twin-stage superconducting quantum interference device amplification method described in the embodiment of the present invention Figure.
Component label instructions
800 twin-stage superconducting quantum interference device amplifying devices
810 modulation modules
811 square-wave generators
812 amplitude adjusting elements
813 modulation units
820 first order superconducting quantum interference devices
830 shaping conversion modules
831 first converting units
832 shaping units
833 second converting units
The second of 840 Self-resettings and transmission characteristic hysteresis
SQUID magnetic flux-voltage transformation module
841 second level superconducting quantum interference devices
850 demodulation modules
851 phase adjustment units
852 multipliers
S1~S5 step
Specific embodiment
Illustrate embodiments of the present invention below by way of specific specific example, those skilled in the art can be by this specification Other advantages and efficacy of the present invention can be easily understood for disclosed content.The present invention can also pass through in addition different specific realities The mode of applying is embodied or practiced, the various details in this specification can also based on different viewpoints and application, without departing from Various modifications or alterations are carried out under spirit of the invention.
Please refer to attached drawing.It should be noted that only the invention is illustrated in a schematic way for diagram provided in the present embodiment Basic conception, only shown in schema then with related component in the present invention rather than component count, shape when according to actual implementation Shape and size are drawn, when actual implementation kenel, quantity and the ratio of each component can arbitrarily change for one kind, and its component cloth Office's kenel may also be increasingly complex.
SQUID is the magnet-sensitive element of extremely low noise, since magnetic flux-voltage transmission rate is insufficient, with work under room temperature half Conductor low-noise amplifier mismatches, so that SQUID Magnetic Sensor noiseproof feature is dominated by preamplifier noise, fails to fill SQUID low-noise performance is waved in distribution.In order to play SQUID low-noise performance, need to introduce two kinds of technologies: 1, two-stage SQUID is low Noise amplifying technique promotes magnetic flux-voltage transmission rate.Its difficulty encountered is two SQUID Cascaded amplifications, and transmission characteristic occurs Operating point multivalue problem in period, it is difficult to control working sensor on best operating point.2, Flux modulation signal detection is amplified Technology inhibits the low frequency 1/f noise of preamplifier.Its difficulty encountered is to be amplified the 2nd grade of SQUID with flux locked loop road There is job stability in device transfer linearity, while being also difficult to carry out Flux modulation 1/f noise suppression technology.Cause This, low noise SQUID Magnetic Sensor faces practical technical problem.The present invention realizes two-stage SQUID amplification and magnetic flux tune Technology processed solves the problems, such as operating point multivalue and the operation is stable, while inhibiting the white noise and 1/f noise of preamplifier, So that SQUID performance is not fully exerted, practical high-performance SQUID Magnetic Sensor is realized, is that SQUID Magnetic Sensor closes The technological break-through of key.The present invention is solved the problems, such as twin-stage SQUID amplification, advances and amplified based on twin-stage by technological improvement SQUID Magnetic Sensor functionization.
Below with reference to embodiment and attached drawing, the present invention is described in detail.
Embodiment
The present embodiment provides a kind of twin-stage superconducting quantum interference device amplifying devices, as shown in Figure 8 a, the twin-stage superconduction amount Sub- interferometer amplifying device 800 includes: modulation module 810, first order superconducting quantum interference device 820, shaping conversion module 830, The 2nd SQUID magnetic flux-voltage transformation module 840 of Self-resetting and transmission characteristic hysteresis, demodulation module 850.
The square-wave modulation signal of one fixed frequency is converted into modulation magnetic flux by the modulation module 810.A kind of its specific reality Existing mode are as follows: the square-wave modulation signal is converted into modulation electric current by the square-wave modulation signal for generating a fixed frequency, will be described Modulation electric current is converted into modulation magnetic flux.The frequency of the square-wave modulation signal can such as may be used depending on actual circuit responding ability Select 1k~1MHz.The duty ratio of the square-wave modulation signal can also select according to the actual situation, effect it is optimal be duty ratio For 50% square-wave signal, certain duty ratio is 49%, 48%, 47% etc. square-wave signal also may be implemented the present invention to be reached The purpose arrived, only effect can be somewhat poorer.Therefore, protection scope of the present invention is not limited to the square-wave modulation signal Duty ratio.Following the present embodiment by duty ratio be 50% square-wave modulation signal for specific implementation of the invention do into The description of one step.
Further, as shown in Figure 8 b, a kind of specific implementation structure of the modulation module 810 includes: square-wave generator 811, amplitude adjusting elements 812, modulation unit 813.The square-wave generator 811 generates the fixed frequency that a duty ratio is 50% Square-wave modulation signal.The amplitude adjusting elements 812 are connected with the square-wave generator 811, by the square-wave modulation signal It is converted into modulation electric current.The modulation unit 813 is connected with the amplitude adjusting elements 812, and the modulation electric current is converted into Modulate magnetic flux.
The first order superconducting quantum interference device 820 is connected with the modulation module 810 coupling, for detecting external magnetic flux Signal obtains tested magnetic flux, while the voltage output of the tested magnetic flux is modulated into fixation using the modulation magnetic flux of coupling Frequency by modulated voltage signal；The amplitude by modulated voltage signal is with the first order superconducting quantum interference device to tested The response voltage of magnetic flux is related；It is described by the frequency of modulated voltage signal and phase and the modulation flux synchronous.Square-wave frequency modulation Magnetic flux (the i.e. described modulation magnetic flux) and tested magnetic flux input the first SQUID (i.e. first order superconducting quantum interference device 820) simultaneously, base In magnetic flux-voltage-transfer characteristic of the first SQUID, export by modulated voltage signal (i.e. by modulated voltage signal).The quilt The frequency and phase and modulation flux synchronous of modulated voltage signal, amplitude is with the first SQUID to the response voltage phase of tested magnetic flux It closes.
The shaping conversion module 830 is connected with the first order superconducting quantum interference device 820, by described by modulation voltage Signal carries out conversion shaping, output adjustment magnetic flux signal.Its a kind of specific implementation are as follows: turned described by modulated voltage signal It changes by modulated current signal, and shaping is carried out by modulated current signal to described, make the rising by modulated current signal Slow down with decline saltus step edge, burr is eliminated, referring to shown in Fig. 8 c；It will be converted into adjusting by modulated current signal after shaping again Magnetic flux signal.Shaping conversion module is sent by modulated voltage signal.So-called conversion passes through a resistance and inductance in parallel The first SQUID voltage signal exported is converted into loop current (i.e. by modulated current signal) by circuit.That is, so-called shaping will Loop current is filtered by the network being made of resistance and inductance, by loop current (and by modulated square wave current Signal) raising and lowering transition edges slow down, eliminate burr, in favor of the 2nd SQUID circuit (i.e. Self-resetting and transmission characteristic The 2nd SQUID magnetic flux-voltage transformation module 840 of hysteresis) response.Inductance of the loop current by concatenation in the loop, will be electric Circulation changes magnetic flux output into, exports the amplification intensity of magnetic flux by the coupling mutual inductance M of the conversion inductance and the 2nd SQUID12It determines, It is general to require 10 times of amplification or more；In this way, the first SQUID circuit (i.e. first order superconducting quantum interference device 820 and shaping modulus of conversion The circuit that block 830 is constituted) substantially complete be: tested magnetic flux is detected, and in the case where modulating flux interaction, after output Shaping, amplification By modulation magnetic flux signal (the i.e. described adjustment magnetic flux signal).The magnetic flux output coupling of first SQUID circuit is electric to the 2nd SQUID Lu Zhong realizes magnetic flux-voltage conversion.
Further, as shown in Figure 8 b, a kind of specific implementation structure of the shaping conversion module 830 includes: the first conversion Unit 831, shaping unit 832, the second converting unit 833.First converting unit 831 and the first order Superconducting Quantum are dry It relates to device 820 to be connected, be converted into described by modulated voltage signal by modulated current signal.Shown shaping unit 832 and described the The series connection of one converting unit 831 carries out shaping by modulated current signal to described, eliminates the hair by modulated current signal Thorn makes described to be slowed down by the rising edge of modulated current signal.Second converting unit 833 is connected with the shaping unit 832, Adjustment magnetic flux signal will be converted by modulated current signal after shaping.What Fig. 8 b was provided is turned with the shaping that circuit mode is realized A kind of circuit structure of block 830 is changed the mold, wherein the first converting unit 831 is resistance, shaping unit 832 is coil, the second conversion Unit 833 is also coil.The shaping conversion module 830 can also be with other prior art manners such as digital circuit or software It realizes, therefore protection scope of the present invention is not limited to the specific implementation structure of the shaping conversion module 830.
The 2nd SQUID magnetic flux-voltage transformation module 840 of the Self-resetting and transmission characteristic hysteresis, including with it is described whole The connected second level superconducting quantum interference device 841 of shape conversion module coupling, responds the adjustment magnetic flux signal, exports corresponding amplification Adjustment voltage signal.The 2nd SQUID magnetic flux-voltage transformation module 840 ensure that the second level superconductive quantum interference The stability of the operating point of device.
Further, the Self-resetting and the 2nd SQUID magnetic flux-voltage transformation module of transmission characteristic hysteresis can use electric Pressure owes feedback SQUID circuit or electric current owes feedback SQUID circuit to realize the transmission characteristic of Self-resetting hysteresis, can also use it His prior art realizes the transmission characteristic of Self-resetting hysteresis.
As illustrated in fig. 9, the second of the feedback Self-resetting that SQUID circuit is realized and transmission characteristic hysteresis is owed using voltage SQUID magnetic flux-voltage transformation module circuit structure is: giving SQD2 loading current Ib2, so that SQD2 is provided with magnetic flux-voltage and passes Defeated characteristic, SQD2 output voltage VsProportional amplifier U1 is accessed, proportional amplifier U1 is that the gain of low noise is G0Given amplification The amplifier of multiple.The output end of amplifier U1 connects feedback resistance RfWith feedback inductance Lf, constitute feedback flux circuit.It is adjustable DC voltage VdcDrive resistance RdcGenerate adjustable DC current injection inductance Lf, DC adjustment magnetic flux is generated, SQUID 2 is adjusted The SQUID direct current flux size of magnetic flux detector, so that detector SQUID 2 detects the first order with the center of its transmission characteristic The AC modulation magnetic flux signal of SQUID circuit (including first order superconducting quantum interference device 820 and shaping conversion module 830) output (i.e. adjustment magnetic flux signal), detection process is referring to shown in Fig. 9 b.
The working principle that voltage owes the Self-resetting SQUID magnetic detector of feedback loop realization hysteresis characteristic is: amplifier U1 By drive feedback flux circuit (including feedback resistance R after the voltage amplification of SQD1 outputfWith feedback inductance Lf), generate feedback magnetic Logical to offset input magnetic flux, since amplifier U1 is finite gain, the counteracting magnetic flux generated can only offset part input magnetic Logical, when external input magnetic flux reaches a flux quantum, this undercompensation feedback reaches critical state and unbalance, equalization point jump Next operating point is changed to, deficient feedback equalization is re-established.
Voltage owes parameter of the feedback loop by initialization circuit: including proportional amplifier gain G0, feedback resistance RfAnd Mf, When meeting following critical condition, it can be achieved that magnetic flux-voltage-transfer characteristic curve of hysteresis Self-resetting shown in Fig. 9 d.Critical item Part is as follows:
Wherein, as is shown in fig. 9 c, VppThe voltage of output can be responded for SQUID in SQD2 magnetic flux-voltage-transfer characteristic Maximum value, i.e. peak-to-peak value；ΦppIt is right from minimum peak to peak-peak for voltage in SQD2 magnetic flux voltage transfer curve The magnetic flux that should be inputted.Therefore, foregoing circuit parameter meets this equation, and transmission characteristic as shown in figure 9d can be realized.
As shown in Figure 10 a, the second of the feedback Self-resetting that SQUID circuit is realized and transmission characteristic hysteresis is owed using electric current SQUID magnetic flux-voltage transformation module circuit structure is: SQUID device SQD2 and feedback inductance LfCoupling mutual inductance be Mf, when When SQD2 has electric current to flow through, which also flows through inductance Lf, feedback magnetic flux is generated, by where Mutual Inductance Coupling to SQD2 In SQUID flux locked loop road, forms electric current and owe feedback.SQD2 accesses the negative input end of operational amplifier U1, resistance RfBridging Between the negative input end and output end of operational amplifier U1, the electric current I of SQD2 will be flowed throughsVoltage signal is zoomed into, that is, is amplified Device output voltage VO=Is×Rf.The positive input of operational amplifier U1 terminates adjustable DC power supply Vb, adjust adjustable DC power supply Vb Generate bias voltage.When operational amplifier U1 works, the voltage of positive input terminal and the voltage of negative input end are equal, therefore SQD2 Work is under constant pressure biasing, and bias voltage size is by VbIt adjusts.Adjust suitable bias voltage VbVoltage value, SQUID device SQD2 is provided with magnetic flux-current transmission characteristic under constant pressure biasing, therefore SQD2 inducting flux signal, generates electric current Is, stream Electric current through SQD2 passes through resistance RfAmplification is converted into voltage.The electric current for flowing through SQD2 flows into inductance LfFeedback magnetic flux is generated, is constituted Magnetic flux based on electric current owes feedback loop, based on voltage owes feedback with above-mentioned to form hysteresis magnetic flux-voltage-transfer characteristic similar, when When magnetic flux-current transmission characteristic of SQD2, series inductance reach critical condition with SQD2 mutual inductance matching, so that it may constitute transmission characteristic Magnetic flux-voltage-transfer characteristic of hysteresis Self-resetting.It is inductance L that electric current, which owes the feedback key parameter that SQUID circuit is related to,fWith The mutual inductance M of SQUID2f, when meeting following critical condition, it can be achieved that the magnetic flux of hysteresis Self-resetting shown in Figure 10 d-voltage passes Defeated characteristic curve.Critical condition is as follows:
Φpp+Ipp·Mf=2 Φ0
Wherein, as shown in figure l0c, IppSQUID can be rung in the magnetic flux-current characteristic curve for being SQD2 under voltage bias The peak-to-peak value for the electric current that should be exported；ΦppIt is electric current in SQD2 magnetic flux-current transmission characteristic curve from minimum peak to maximum peak The corresponding magnetic flux inputted of value.Therefore, foregoing circuit parameter meets this equation, and the transmission that can be realized as shown in fig. 10d is special Property.
Adjustable dc voltage V in Figure 10 adcWith D.C. resistance RdcEffect it is identical as scheme shown in Fig. 9 a, generate it is adjustable DC current flows through inductance Lf, DC adjustment magnetic flux is generated, the SQUID direct current flux of 2 magnetic detector of SQUID is adjusted, so that visiting It surveys device SQUID 2 and first order SQUID circuit (including first order superconducting quantum interference device is detected with the center of its transmission characteristic 820 and shaping conversion module 830) output AC modulation magnetic flux signal (i.e. adjustment magnetic flux signal).
The transmission characteristic feature that 2nd SQUID magnetic flux-voltage transformation module is realized is: 1) Self-resetting, i.e. input reaches just Or when negative one flux quantum, operating point is jumped to automatically on operated adjacent point, and transmission characteristic jumps to operated adjacent point automatically Corresponding transmission characteristic.Therefore the measurement range that each operating point corresponds to transmission characteristic covering is ± Φ0.2) hysteresis, due to every The coverage area that a operating point corresponds to transmission characteristic is ± Φ0, and operating point period profile, i.e., an adjacent flux quantum are corresponding One operating point, therefore the corresponding transmission characteristic is period profile, therefore two transmission characteristics are by the detection of overlapping covering Area.Thus for the input magnetic flux (highlight and mark in figure) of different directions variation, response is special by the different transmission of correspondence Property, it is exactly this characteristic, so that being greater than Φ to amplitude0The detections of modulated signals would not occur being zero or reverse phase is asked Topic.
In this way, the cascade by two modules, i.e., cascade first SQUID circuit and the 2nd SQUID circuit, realize biography The magnetic flux of defeated characteristic amplification-voltage conversion, that is to say, that cascade first SQUID circuit and the 2nd SQUID circuit constitute biography Magnetic flux-voltage transformation module of defeated characteristic amplification.
The demodulation module 850 divides with the magnetic flux detector 840 with hysteresis characteristic Self-resetting and modulation module 810 Not Xiang Lian, the adjustment voltage signal is demodulated using the square-wave modulation signal, export it is corresponding with the tested magnetic flux Twin-stage amplification detectable voltage signals.The demodulation module 850 is by two-stage SQUID to the response voltage of the tested magnetic flux of input Demodulation output.
Further, as shown in Figure 8 b, a kind of specific implementation structure of the demodulation module 850 includes: phase adjustment unit 851, multiplier 852.The phase adjustment unit 851 includes phase adjusted resistance and phase adjusted capacitor；Phase adjusted resistance One end be connected with the modulation module, the other end phase of one end of the phase adjusted capacitor and the phase adjusted resistance Even, the other end ground connection of the phase adjusted capacitor.The other end of the multiplier 852 and the phase adjusted resistance and described Self-resetting and the 2nd SQUID magnetic flux-voltage transformation module output end of transmission characteristic hysteresis is respectively connected with, recover with it is described It is tested the detectable voltage signals of the corresponding twin-stage amplification of magnetic flux.What Fig. 8 b was provided is the demodulation module 850 realized with circuit mode A kind of circuit structure, wherein phase adjustment unit 851 is the circuit that resistance and capacitor form.The demodulation module 850 may be used also To be realized with other prior art manners such as digital circuit or software, therefore protection scope of the present invention is not limited to the demodulation The specific implementation structure of module 850.
Specifically, the square-wave modulation signal passes through amplitude adjusting elements RmodGenerate modulation electric current Imod.Modulate electric current Imod Input modulation unit LmodIn, generate modulation magnetic flux Φmod.Modulate magnetic flux ΦmodIt is coupled to signal sensor SQUID 1 (to be abbreviated as SQD1, i.e. first order superconducting quantum interference device 820) in, tested magnetic flux Φ is incuded to modulate SQUID 1inVoltage output Vout, by tested magnetic flux ΦinVoltage output VoutBe modulated into setpoint frequency by modulated voltage signal.It is described to be believed by modulation voltage Number amplitude and the first order superconducting quantum interference device to respond the tested voltage value of magnetic flux related；It is described by modulated voltage signal Frequency and phase and the modulation flux synchronous.Adjust adjustable resistance RmodSize, be adjusted flow into inductance LmodElectric current, Realize modulation magnetic flux ΦmodAmplitude adjusting.Adjust modulation magnetic flux ΦmodAmplitude so as to incude tested magnetic flux defeated by SQUID 1 The modulation amplitude of voltage signal reaches maximum out.
It is added to the modulation magnetic flux Φ of SQUID 1modIt is square-wave signal, duty cycle square wave 50%, i.e., in a cycle, Half the time loads the magnetic flux of 0 state to SQUID 1, the other half time loads the magnetic flux of 1 state, two states to SQUID 1 Under, magnetic flux-voltage-transfer characteristic curve of corresponding two phases of SQUID 1, so that in the state of two differences of SQUID 1 Magnetic flux-voltage-transfer characteristic switch operating, as shown in figure 11.Under the magnetic flux signal modulating action shown in Figure 11,1 sound of SQUID It should outer magnetic flux (i.e. tested magnetic flux Φin) voltage output be just modulated into square wave state, i.e., by modulated voltage signal.By modulation electricity The amplitude for pressing signal is the response input of SQUID 1 magnetic flux (i.e. tested magnetic flux Φin) voltage value, by the frequency of modulated voltage signal With phase and the modulation flux synchronous.Modulation principle is as shown in figure 12, in square-wave frequency modulation magnetic flux ΦmodUnder the action of, SQUID 1 under magnetic flux-voltage-transfer characteristic curve of two outs of phase switch operating, the voltage output modulation in tested magnetic field will be incuded At square-wave signal.Shaping conversion module 830 is sent by modulated voltage signal through SQUID 1 is modulated.
Shaping conversion module 830 passes through resistance Rs(i.e. the first converting unit 831) by SQUID 1 export by modulation voltage Signal is converted to by modulated current signal, and passes through inductance L1(i.e. shaping unit 832) carries out shaping to by modulated current signal, The burr in signal (i.e. by modulated current signal) after eliminating square-wave frequency modulation, and will be become by the rising edge of modulated current signal It is slow, to cooperate second level SQUID amplifying circuit (i.e. Self-resetting and the 2nd SQUID magnetic flux-voltage modulus of conversion of transmission characteristic hysteresis Block) it responds.Shaping conversion module 830 will pass through inductance L by modulated current signal by shaping2(the i.e. second conversion is single 833) member is converted into adjustment magnetic flux signal, be coupled to the adjustment magnetic flux signal in the SQUID amplifying circuit of the second level.Inductance L2 It is M2 with SQUID 2 (referred to as SQD2) mutual inductance coupled.Resistance RsVoltage for incuding SQUID 1 is converted into electric current. In order to ensure the operating point of SQUID 1, the value of SQUID 1 must be with the dynamic electric resistor R of SQUID 1sMatch, SQUID 1 The voltage signal of generation drives resistance RsVoltage is converted to electric current.Inductance L2The electric current flowed through is converted into magnetic flux to be coupled to In the magnetic detector SQUID 2 of rear end.L1With L2The inductance and resistance R of summationsThe low-pass filter of electric current in series, i.e., The current signal of high frequency will be inhibited, and realize filtering and the sine of SQUID detection square-wave signal, avoid frequency glitches, together When enable conversion export signal match with subsequent SQUID magnetic detector bandwidth.
The present invention solves the technical issues of conventional twin-stage SQUID amplification module faces, successfully by twin-stage SQUID amplification and Modulation-demodulation technique realizes combination, solves operating point multivalue problem and magnetic-electricity conversion stability problem, realizes low noise Amplification, improves magnetic flux-voltage transmission rate of module, has reached the matching with preamplifier noise, it is suppressed that preposition amplification The 1/f noise of device has given full play to the characteristic of SQUID low noise.The magnetic flux realized using the present invention-voltage transformation module is constructed SQUID Magnetic Sensor all has better performance in terms of white noise and 1/f noise.
The present invention has magnetic flux detector (i.e. Self-resetting and the transmission characteristic of hysteresis characteristic Self-resetting using SQUID building The 2nd SQUID magnetic flux-voltage transformation module of hysteresis), for detect by front stage circuits generate shaping after adjustment magnetic communication Number, magnetic flux signal will be adjusted and be converted into the adjustment voltage signal amplified.2nd SQUID magnetic of Self-resetting and transmission characteristic hysteresis Magnetic flux-voltage-transfer characteristic of logical-voltage transformation module is as shown in figure 13.2nd SQUID of Self-resetting and transmission characteristic hysteresis Magnetic flux-voltage transformation module is as follows to the Analysis of response of magnetic flux signal:
1) response for amplitude less than the magnetic flux signal of a flux quantum, as shown in figure 14, Self-resetting and transmission spy Property hysteresis the 2nd SQUID magnetic flux-voltage transformation module utilize its continuous transmission within the scope of positive negative one flux quantum Characteristic amplify with frequency with phase to magnetic flux signal.
2) it is greater than the response of the magnetic flux signal of flux quantum or more for amplitude, as shown in Figure 15 a to Figure 15 c, from Reset and transmission characteristic hysteresis the 2nd SQUID magnetic flux-voltage transformation module response output signal occur it is non-linear, but its The amplitude for responding the adjustment voltage signal of output is not zero, and with the adjustment magnetic flux signal of input with the same phase of frequency.Therefore when input The amplitude of adjustment magnetic flux signal when being greater than 1 flux quantum or more, the 2nd SQUID magnetic of Self-resetting and transmission characteristic hysteresis The output of logical-voltage transformation module is not in the case where output is zero or reverse phase amplification.The 2nd SQUID magnetic flux-electricity The transmission characteristic of pressure conversion module is period profile (one flux quantum in interval), and the transmission characteristic in each period is corresponding Maximum input range is 2 flux quantums；More than two flux quantums are inputted, just jumps in adjacent transmission characteristic and is rung It answers.Exactly this characteristic (as soon as i.e. amplitude positive direction or negative direction are more than a flux quantum, transmission characteristic is jumped), produces back Stagnant characteristic just has special effects for the response of modulated signal, shown in Figure 15 a to Figure 15 c.
Therefore, the present invention is using Self-resetting and the 2nd SQUID magnetic flux-voltage transformation module (abbreviation of transmission characteristic hysteresis Detector) detection first order SQUID circuit (including first order superconducting quantum interference device 820 and shaping conversion module 830) output The exchange flux (i.e. adjustment magnetic flux signal) modulated, and magnetic flux signal will be adjusted and convert and zoom into frequently with the exchange of phase Voltage signal (i.e. adjustment voltage signal).Its main feature is that: when the width for the exchange flux (i.e. adjustment magnetic flux signal) that input is modulated When degree is less than a flux quantum, the 2nd SQUID magnetic flux-voltage transformation module of Self-resetting and transmission characteristic hysteresis using its Continuous transmission characteristic within the scope of positive negative one flux quantum mutually amplify with frequently same；One magnetic flux is greater than for amplitude The exchange flux of son, detector can be to AC modulated signals (the i.e. ac voltage signals or adjustment electricity that response exchange flux obtains Press signal) rising edge and failing edge by different transfer curve progress nonlinear amplifications, therefore can export and input Exchange flux, with the voltage signal of phase, although occurring to the amplification of the amplitudes of AC modulated signals non-linear, but not goes out with frequency Existing zero passage or reverse phase, therefore avoid the work zero point multivalue problem of traditional SQUID magnetic detector transmission characteristic.
The Self-resetting and the 2nd SQUID magnetic flux-voltage transformation module of transmission characteristic hysteresis are directed to exchange flux signal Detection feature transmission characteristic shown in Figure 16 describe.The horizontal axis of transfer curve is the exchange flux width of input Degree, the longitudinal axis are the amplitudes for amplifying output signal.By the transmission characteristic figure, the Self-resetting and transmission characteristic hysteresis can reflect out The 2nd SQUID magnetic flux-voltage transformation module characteristic that exchange flux is amplified.
In short, Self-resetting and the 2nd SQUID magnetic flux-voltage transformation module of transmission characteristic hysteresis has a characteristic that
1, the detector automatically resets, and job stability problem is not present.
2, have the characteristics that transmission characteristic hysteresis, it can be according to the exchange flux signal that input is modulated using different transmission Characteristic carries out voltage conversion, and being not in is zero to the exchange flux signal response output for being greater than a flux quantum or phase is anti- The problem of phase.The characteristic solves most intractable work zero point multivalue problem in SQUID Cascaded amplification.
3, the Self-resetting and the 2nd SQUID magnetic flux-voltage transformation module of transmission characteristic hysteresis are not required for having linear Magnetic flux-voltage-transfer characteristic, as long as have amplifying power so that magnetic flux-voltage transmission rate near the operating point SQUID obtains Raising.
Since when the twin-stage superconducting quantum interference device amplifying device final application is in SQUID Magnetic Sensor, SQUID Magnetic Sensor is stablized in the work zero point of first order superconducting quantum interference device after locking.It is dry in first order Superconducting Quantum Device work zero crossings are related to, the modulation magnetic flux signal of very little can be exported for the 2nd SQUID flux detection device (i.e. Self-resetting and transmission The 2nd SQUID magnetic flux-voltage transformation module of characteristic hysteresis) amplification, therefore amplified using the twin-stage superconducting quantum interference device For the SQUID Magnetic Sensor of device when locking work, embodiment is it to less than one flux quantum exchange flux signal of amplitude Detectivity.It is greater than the signal of a flux quantum for modulation amplitude, although nonlinear amplification, as long as avoiding the occurrence of Zero and inversion issue, it does not just influence to apply.Because only that launched into the locking course of work in SQUID Magnetic Sensor, due to SQUID Magnetic Sensor feedback loop does not also make the first SQUID be stabilized to operating point, is adjusted to stable process in operating point In, it may appear that greater than the exchange flux signal of a flux quantum, as long as it is zero and anti-that gain, which occurs, in the 2nd SQUID magnetic detector Phase situation would not be such that SQUID Magnetic Sensor feedback loop locks.Therefore feedback control loop is forced to be locked to unique first In the work zero point of SQUID.Once being stabilized on operating point, which just works communicates in AC magnetism by a small margin Number amplification mode only amplifies the signal of exchange flux by a small margin near operating point.
It is (referred to as tested that twin-stage superconducting quantum interference device amplifying device input of the present invention is detected external magnetic flux signal Magnetic flux), through ovennodulation, amplification, detection, demodulating process, finally export amplified voltage responsive.Input tested magnetic flux and demodulation Magnetic flux-voltage-transfer characteristic as shown in figure 17 is formed between output voltage.As can be seen from Figure 17, twin-stage superconduction of the present invention The magnetic flux voltage transmission characteristic that quantum interfering device amplifying device is realized are as follows: using a flux quantum as the period, in signal period Only unique operating point with maximum magnetic flux-voltage transmission rate, such as W in figureaOr WbIt is shown, WaOr WbSelection depend on The polarity in magnetic flux feedback circuit meets negative-feedback requirement.
Twin-stage superconducting quantum interference device amplifying device of the present invention has a characteristic that
1, transmission characteristic keeps periodicity identical with first order superconducting quantum interference device transmission characteristic, and in the period only Single work zero point.
2, magnetic flux-voltage transmission rate at the zero point that works is amplified, and low noise amplification SQUID detection signal is realized Purpose, reached the requirement with preamplifier noise matching.
3, since the SQUID of rear class detects amplifier (i.e. Self-resetting and the 2nd SQUID magnetic flux-electricity of transmission characteristic hysteresis Press conversion module) losing lock problem is not present, therefore the transmission characteristic stabilization of whole twin-stage superconducting quantum interference device amplifying device can It leans on.
4, it is based on Flux modulation and demodulating process, the 1/f noise of traditional preamplifier is effectively inhibited, obtains more Good low-frequency noise performance.
The present embodiment also provides a kind of SQUID Magnetic Sensor, as shown in figure 18, including the amplification of twin-stage superconducting quantum interference device Device 800, integrator, feedback resistance and feedback inductance.The input terminal of the twin-stage superconducting quantum interference device amplifying device and institute It states feedback inductance coupling to be connected, the output end of the twin-stage superconducting quantum interference device amplifying device is connected with the integrator.Instead Feed resistance is connected with the integrator, and feedback inductance is connected with the feedback resistance.The twin-stage superconducting quantum interference device amplification The specific structure of device 800 and working principle are not repeated herein referring to described previously.
The present invention also provides a kind of twin-stage superconducting quantum interference device amplification method, this method can be by of the present invention double Grade superconducting quantum interference device amplifying device is realized, but the realization structure of twin-stage superconducting quantum interference device amplification method of the present invention The including but not limited to twin-stage superconducting quantum interference device amplifying device enumerated of the present embodiment.
As shown in figure 19, the twin-stage superconducting quantum interference device amplification method includes:
The square-wave modulation signal of one fixed frequency is converted into modulation magnetic flux by S1.The frequency of the square-wave modulation signal can Depending on actual circuit responding ability, 1k~1MHz such as may be selected.The duty ratio of the square-wave modulation signal can also be according to reality The selection of border situation, effect it is optimal be square-wave signal that duty ratio is 50%, certain duty ratio is 49%, 48%, 47% etc. Present invention purpose to be achieved also may be implemented in square-wave signal, and only effect can be somewhat poorer.Therefore, guarantor of the invention Shield range is not limited to the duty ratio of the square-wave modulation signal.
Further, a kind of specific implementation process of the step S1 includes: to generate the fixation using a square-wave generator The square-wave modulation signal of frequency；The amplitude adjusting elements being connected using one with the square-wave generator are by the square-wave modulation signal It is converted into modulation electric current；The modulation electric current is converted into modulating by the modulation unit being connected using one with the amplitude adjusting elements Magnetic flux.Protection scope of the present invention is not limited to the specific implementation structure of device and accounting for for the square-wave modulation signal of step S1 Sky compares size.
S2 detects external magnetic flux signal using a first order superconducting quantum interference device and obtains tested magnetic flux, while coupling institute State modulation magnetic flux, and by the voltage output of the tested magnetic flux be modulated into fixed frequency by modulated voltage signal；It is described to be adjusted The amplitude of voltage signal processed is related to the tested voltage value of magnetic flux of first order superconducting quantum interference device response；It is described to be modulated The frequency and phase of voltage signal and the modulation flux synchronous.
S3 carries out conversion shaping by modulated voltage signal for described, forms adjustment magnetic flux signal.
Further, a kind of specific implementation process of the step S3 include: by it is described by modulated voltage signal be converted by Modulated current signal, and shaping is carried out by modulated current signal to described, make the raising and lowering by modulated current signal Transition edges slow down, and eliminate burr；Adjustment magnetic flux signal will be converted by modulated current signal after shaping again.
Such as: the first converting unit being connected using one with the first order superconducting quantum interference device is by described by modulation voltage Signal is converted by modulated current signal；Electricity is modulated to described with the concatenated shaping unit of the first converting unit using one It flows signal and carries out shaping, eliminate the burr by modulated current signal, become the rising edge by modulated current signal It is slow；Adjustment magnetic will be converted by modulated current signal after shaping with concatenated second converting unit of the shaping unit using one Messenger.Protection scope of the present invention is not limited to the structure of the specific implementation device of step S3.
S4 responds the adjustment using a Self-resetting and the 2nd SQUID magnetic flux of transmission characteristic hysteresis-voltage transformation module Magnetic flux signal exports the adjustment voltage signal of corresponding amplification.The 2nd SQUID magnetic flux-voltage transformation module ensure that itself The stability of the operating point for the second level superconducting quantum interference device for being included.
Further, a kind of specific implementation process of the step S4 includes: and owes feedback SQUID circuit using voltage to realize institute State the 2nd SQUID magnetic flux-voltage transformation module of Self-resetting and transmission characteristic hysteresis；Or feedback SQUID circuit is owed using electric current Realize the 2nd SQUID magnetic flux-voltage transformation module of the Self-resetting and transmission characteristic hysteresis.Protection scope of the present invention is unlimited In the structure of the specific implementation device of step S4.
S5 demodulates the adjustment voltage signal using the square-wave modulation signal, output and the tested magnetic flux The detectable voltage signals of corresponding twin-stage amplification.
The protection scope of twin-stage superconducting quantum interference device amplification method of the present invention, which is not limited to the present embodiment, to be enumerated Step executes sequence, and all those skilled in the art are included in this hair to the deformation of scheme of the present invention using the prior art In bright protection scope.
The present invention realizes only one best operating point in the period, solves operating point in twin-stage SQUID amplifying technique Multivalue problem ensure that lockout feature of the SQUID Magnetic Sensor under any state is consistent.Second level SQUID amplifier There is no losing lock problem, after the locking of SQUID Magnetic Sensor can steady operation, ensure that the stability of signal amplification operating point.? Amplified under Flux modulation using two-stage SQUID, not only inhibits the white noise of preamplifier, it is often more important that inhibit preposition The 1/f noise of amplifier further reduced the low-frequency noise of SQUID Magnetic Sensor.The performance of low-frequency noise is that SQUID magnetic passes The maximum performance advantage of sensor, playing Low Frequency Low Noise performance has important value to the application of SQUID Magnetic Sensor.Cause This, the present invention not only solves the problems, such as operating point ambiguity and job stability in twin-stage SQUID amplifying technique, also solves The technical issues of 1/f noise inhibits, realizes the important technological break-through of SQUID high-performance magnetism sensor.
In conclusion the present invention effectively overcomes various shortcoming in the prior art and has high industrial utilization value.
The above-described embodiments merely illustrate the principles and effects of the present invention, and is not intended to limit the present invention.It is any ripe The personage for knowing this technology all without departing from the spirit and scope of the present invention, carries out modifications and changes to above-described embodiment.Cause This, institute is complete without departing from the spirit and technical ideas disclosed in the present invention by those of ordinary skill in the art such as At all equivalent modifications or change, should be covered by the claims of the present invention.

Claims (9)

1. a kind of twin-stage superconducting quantum interference device amplifying device, which is characterized in that the twin-stage superconducting quantum interference device amplification dress It sets and includes:
The square-wave modulation signal of one fixed frequency is converted into modulation magnetic flux by modulation module；
First order superconducting quantum interference device is connected with modulation module coupling, is tested for detecting external magnetic flux signal Magnetic flux, while the voltage output of the tested magnetic flux being modulated by modulated voltage signal using the modulation magnetic flux of coupling； The amplitude by modulated voltage signal is related with response voltage of the first order superconducting quantum interference device to tested magnetic flux；Institute It states by the frequency of modulated voltage signal and phase and the modulation flux synchronous；
Shaping conversion module is connected with the first order superconducting quantum interference device, is converted described by modulated voltage signal Shaping, output adjustment magnetic flux signal；
The 2nd SQUID magnetic flux-voltage transformation module of Self-resetting and transmission characteristic hysteresis, including one and the shaping conversion module The connected second level superconducting quantum interference device of coupling, responds the adjustment magnetic flux signal, exports the adjustment voltage letter of corresponding amplification Number；
Demodulation module, the 2nd SQUID magnetic flux-voltage transformation module and modulation module with the Self-resetting and transmission characteristic hysteresis It is respectively connected with, the adjustment voltage signal is demodulated using the square-wave modulation signal, output and the tested magnetic flux pair The detectable voltage signals for the twin-stage amplification answered.
2. twin-stage superconducting quantum interference device amplifying device according to claim 1, which is characterized in that the modulation module into One step includes:
Square-wave generator generates the square-wave modulation signal of the fixed frequency；
Amplitude adjusting elements are connected with the square-wave generator, and the square-wave modulation signal is converted into modulation electric current；
Modulation unit is connected with the amplitude adjusting elements, and the modulation electric current is converted into modulation magnetic flux.
3. twin-stage superconducting quantum interference device amplifying device according to claim 1, which is characterized in that the shaping modulus of conversion Block further comprises:
First converting unit is connected with the first order superconducting quantum interference device, by it is described by modulated voltage signal be converted by Modulated current signal；
Shaping unit is connected with first converting unit, carries out shaping by modulated current signal to described, makes described modulated The raising and lowering transition edges of current signal slow down, and eliminate burr；
Second converting unit is connected with the shaping unit, adjustment magnetic communication will be converted by modulated current signal after shaping Number.
4. twin-stage superconducting quantum interference device amplifying device according to claim 1, it is characterised in that: the 2nd SQUID Magnetic flux-voltage transformation module be using voltage owe feedback SQUID circuit or electric current owe feedback SQUID circuit come realize Self-resetting and The characteristic of transmission characteristic hysteresis.
5. a kind of twin-stage superconducting quantum interference device amplification method, which is characterized in that twin-stage superconducting quantum interference device amplification side Method includes:
The square-wave modulation signal of one fixed frequency is converted into modulation magnetic flux；
External magnetic flux signal is detected using a first order superconducting quantum interference device and obtains tested magnetic flux, while coupling the modulation magnetic It is logical, and the voltage output of the tested magnetic flux is modulated by modulated voltage signal；The amplitude by modulated voltage signal is same The first order superconducting quantum interference device is related to the response voltage of tested magnetic flux；The frequency and phase by modulated voltage signal Position and the modulation flux synchronous；
Conversion shaping, output adjustment magnetic flux signal are carried out by modulated voltage signal by described；
The adjustment magnetic communication is responded using a Self-resetting and the 2nd SQUID magnetic flux of transmission characteristic hysteresis-voltage transformation module Number, export the adjustment voltage signal of corresponding amplification；
The adjustment voltage signal is demodulated using the square-wave modulation signal, is exported corresponding with the tested magnetic flux double The detectable voltage signals of grade amplification.
6. twin-stage superconducting quantum interference device amplification method according to claim 5, which is characterized in that the twin-stage superconduction amount Sub- interferometer amplification method further comprises:
The square-wave modulation signal of the fixed frequency is generated using a square-wave generator；
The square-wave modulation signal is converted into modulation electric current using an amplitude adjusting elements；
The modulation electric current is converted into modulation magnetic flux using a modulation unit.
7. twin-stage superconducting quantum interference device amplification method according to claim 5, which is characterized in that the twin-stage superconduction amount Sub- interferometer amplification method further comprises:
It is converted by modulated voltage signal by modulated current signal using one first converting unit by described；
Shaping is carried out by modulated current signal to described using a shaping unit, make it is described by the rising of modulated current signal and under Drop transition edges slow down, and eliminate burr；
Adjustment magnetic flux signal will be converted by modulated current signal after shaping using one second converting unit.
8. twin-stage superconducting quantum interference device amplification method according to claim 5, which is characterized in that the twin-stage superconduction amount Sub- interferometer amplification method further comprises:
Feedback SQUID circuit, which is owed, using voltage realizes that the 2nd SQUID magnetic flux-voltage of the Self-resetting and transmission characteristic hysteresis turns Change the mold block；Or the 2nd SQUID magnetic flux-that feedback SQUID circuit realizes the Self-resetting and transmission characteristic hysteresis is owed using electric current Voltage transformation module.
9. a kind of SQUID Magnetic Sensor, which is characterized in that the SQUID Magnetic Sensor includes: Claims 1-4 any one The twin-stage superconducting quantum interference device amplifying device, integrator, feedback resistance and feedback inductance；The feedback resistance with it is described Integrator and the feedback inductance are respectively connected with；The input terminal of the twin-stage superconducting quantum interference device amplifying device and the feedback Inductive coupling is connected, and the output end of the twin-stage superconducting quantum interference device amplifying device is connected with the integrator.
CN201510225474.0A 2015-05-05 2015-05-05 A kind of twin-stage superconducting quantum interference device amplifying device, method and SQUID Magnetic Sensor Active CN106199465B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201510225474.0A CN106199465B (en) 2015-05-05 2015-05-05 A kind of twin-stage superconducting quantum interference device amplifying device, method and SQUID Magnetic Sensor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201510225474.0A CN106199465B (en) 2015-05-05 2015-05-05 A kind of twin-stage superconducting quantum interference device amplifying device, method and SQUID Magnetic Sensor

Publications (2)

Publication Number Publication Date
CN106199465A CN106199465A (en) 2016-12-07
CN106199465B true CN106199465B (en) 2018-12-14

Family

ID=57458027

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201510225474.0A Active CN106199465B (en) 2015-05-05 2015-05-05 A kind of twin-stage superconducting quantum interference device amplifying device, method and SQUID Magnetic Sensor

Country Status (1)

Country Link
CN (1) CN106199465B (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106597102B (en) * 2016-12-12 2020-05-05 四川大学 Magnetic thin film structure, magnetic sensor device comprising same and application method
CN107733641B (en) * 2017-08-29 2020-12-22 上海循态信息科技有限公司 High-speed high-adjustable-bandwidth quantum balance homodyne detector and control method thereof
CN109597004A (en) * 2018-12-27 2019-04-09 中国科学院上海微***与信息技术研究所 Superconducting quantum interference device and preparation method
CN109765505A (en) * 2018-12-29 2019-05-17 中国船舶重工集团公司第七一0研究所 A kind of magnetic field compensation apparatus
CN110324018B (en) * 2019-07-25 2024-06-14 本源量子计算科技（合肥）股份有限公司 Microwave signal annular transmission structure
CN115015727A (en) * 2022-06-28 2022-09-06 中国科学院上海微***与信息技术研究所 Josephson junction measuring system and measuring method
CN116415675B (en) * 2023-06-09 2023-09-22 中国科学技术大学 System and method for modulating superconducting quantum bit transition frequency

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN203720339U (en) * 2014-02-28 2014-07-16 中国科学院上海微***与信息技术研究所 Superconductive quantum interference device magnetic sensing system
CN203825176U (en) * 2013-12-05 2014-09-10 中国科学院上海微***与信息技术研究所 Reading circuit and applicative two-stage superconductive quantum interference sensor
CN104198961A (en) * 2014-07-18 2014-12-10 中国科学院上海微***与信息技术研究所 SQUID (Superconducting Quantum Interference Device) magnetic sensor with single operational amplifier

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04268471A (en) * 1991-02-22 1992-09-24 Seiko Instr Inc Highly sensitive device for detecting magnetic field

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN203825176U (en) * 2013-12-05 2014-09-10 中国科学院上海微***与信息技术研究所 Reading circuit and applicative two-stage superconductive quantum interference sensor
CN203720339U (en) * 2014-02-28 2014-07-16 中国科学院上海微***与信息技术研究所 Superconductive quantum interference device magnetic sensing system
CN104198961A (en) * 2014-07-18 2014-12-10 中国科学院上海微***与信息技术研究所 SQUID (Superconducting Quantum Interference Device) magnetic sensor with single operational amplifier

Also Published As

Publication number Publication date
CN106199465A (en) 2016-12-07

Similar Documents

Publication Publication Date Title
CN106199465B (en) A kind of twin-stage superconducting quantum interference device amplifying device, method and SQUID Magnetic Sensor
JP6577496B2 (en) SQUID magnetic sensor using a single operational amplifier
CN202083973U (en) Current biasing circuit used for magnetic sensor
CN203825176U (en) Reading circuit and applicative two-stage superconductive quantum interference sensor
CN202614920U (en) Magnetic sensor based on giant magneto-impedance phase response
CN102483444A (en) Squid with coil inductively coupled to squid via mutual inductance
WO2017128706A1 (en) Readout circuit and method for direct-reading flux modulation
US4888558A (en) Phase detector for amplitude modulated radio frequency signals containing a low frequency waveform
CN104345758B (en) A kind of superconducting quantum interference device bias amplifier
CN106556805B (en) SQUID signal amplification module, amplification method and Magnetic Sensor
CN106199464B (en) Twin-stage superconducting quantum interference device magnetic flux-voltage conversion device, method and its application
CN201266892Y (en) Isolation anti-DC magnetic biasing circuit of sine wave inversion power supply
CN108680877A (en) Balance wiring multichannel superconductive quantum interference Magnetic Sensor
CN104569868A (en) Superconducting quantum interference device
CN203480013U (en) Characteristic scanning device of superconducting quantum interference device (SQUID)
CN106100820A (en) Amplitude-frequency is adjustable chaos signal generator
EP0366264B1 (en) High signal to noise ratio amplitude detector
CN205141986U (en) Big current DC filter
CN104808156A (en) SQUID (superconducting quantum interference device) magnetic sensor and best operating point locking method
CN106405205A (en) Zero-crossing detection circuit
US7091718B1 (en) System having unmodulated flux locked loop for measuring magnetic fields
CN105866712B (en) A kind of superconducting quantum interference device
CN109743043A (en) A kind of pulse signal zeroing circuit
CN209432883U (en) A kind of high frequency sound Hall integrated circuit with enlarging function
Jou et al. New three-port DC-AC inverter outputting a single-phase and a set of three-phase AC voltages

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant