JPH0694815A - Operating point setting system and method of squid magnetic flux meter - Google Patents
Operating point setting system and method of squid magnetic flux meterInfo
- Publication number
- JPH0694815A JPH0694815A JP4244506A JP24450692A JPH0694815A JP H0694815 A JPH0694815 A JP H0694815A JP 4244506 A JP4244506 A JP 4244506A JP 24450692 A JP24450692 A JP 24450692A JP H0694815 A JPH0694815 A JP H0694815A
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- Prior art keywords
- operating point
- point setting
- squid
- signal
- magnetometer
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- 238000000034 method Methods 0.000 title claims abstract description 14
- 230000004907 flux Effects 0.000 title claims abstract description 11
- 241000238366 Cephalopoda Species 0.000 title abstract 6
- 238000001514 detection method Methods 0.000 claims description 12
- 239000002826 coolant Substances 0.000 claims description 3
- 238000005259 measurement Methods 0.000 claims description 3
- 238000006243 chemical reaction Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- RDYMFSUJUZBWLH-UHFFFAOYSA-N endosulfan Chemical compound C12COS(=O)OCC2C2(Cl)C(Cl)=C(Cl)C1(Cl)C2(Cl)Cl RDYMFSUJUZBWLH-UHFFFAOYSA-N 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 208000024827 Alzheimer disease Diseases 0.000 description 1
- 210000004556 brain Anatomy 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 206010015037 epilepsy Diseases 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
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- Measuring Magnetic Variables (AREA)
- Containers, Films, And Cooling For Superconductive Devices (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は極微小磁場の測定を目的
としたＳＱＵＩＤ（超伝導量子干渉素子）を用いた磁束
計に関し、ＳＱＵＩＤ磁束計の動作点設定システム及び
方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetometer using an SQUID (superconducting quantum interference device) for measuring an extremely small magnetic field, and to an operating point setting system and method for the SQUID magnetometer.
【０００２】[0002]
【従来の技術】近年、ＳＱＵＩＤを用いた磁束計により
微弱な磁場の測定が可能となってきた。特に最近では、
てんかんやアルツハイマ病といった脳の機能障害などの
診断支援装置として生体磁場計測装置が注目をあびてい
る。2. Description of the Related Art In recent years, it has become possible to measure a weak magnetic field using a magnetometer using an SQUID. Especially recently
Biomagnetic field measurement devices are attracting attention as a diagnostic support device for brain functional disorders such as epilepsy and Alzheimer's disease.
【０００３】ＳＱＵＩＤは非線形素子のために帰還回路
を用いて動作点を設定し、磁束計として動作させる。従
来、この動作点の設定は任意の位置に行われていたた
め、オフセット電圧が生じていた。また、このオフセッ
ト電圧をキャンセルするため、ＳＱＵＩＤ磁束計を図６
に示すように、ＦＬＬ（フラックス ロックド ループ
（Flux Locked Loop)）回路をクローズループ状態で直
流電圧２９を帰還回路に入力して行っていた（レビュー
オブ サイエンティフィック インスツルメンツ（Ｒ
ｅｖ．Ｓｃｉ．Ｉｎｓｔｒｕｍ．）５５（６），Ｊｕｎ
ｅ １９８４）。Since the SQUID is a non-linear element, a feedback circuit is used to set an operating point and operate as a magnetometer. Conventionally, this operating point has been set at an arbitrary position, so that an offset voltage has been generated. Moreover, in order to cancel this offset voltage, the SQUID magnetometer is shown in FIG.
As shown in Fig. 3, a FLL (Flux Locked Loop) circuit was input in a closed loop state by inputting a DC voltage 29 to a feedback circuit (Review of Scientific Instruments (R
ev. Sci. Instrum. ) 55 (6), Jun
e 1984).
【０００４】[0004]
【発明が解決しようとする課題】上記従来技術では、動
作点の設定により生じるオフセット電圧をキャンセルす
るため、オフセット回路が必要である。しかしながら、
多チャンネルのＳＱＵＩＤ磁束計において、オフセット
回路を各々用意し、調整を各々のチャンネルで行うこと
は困難である。このため、オフセット電圧の調整が行な
えない場合には、チャンネル間のオフセット電圧とＳＱ
ＵＩＤの感度はばらつくという問題があった。In the above-mentioned prior art, an offset circuit is necessary to cancel the offset voltage generated by setting the operating point. However,
In a multi-channel SQUID magnetometer, it is difficult to prepare an offset circuit and adjust each channel. Therefore, if the offset voltage cannot be adjusted, the offset voltage between channels and the SQ
There is a problem that the sensitivity of UID varies.
【０００５】[0005]
【課題を解決するための手段】少なくとも２個のジョセ
フソン接合を持ち、冷却媒体内に配置されるＳＱＵＩＤ
（超伝導量子干渉素子）を用いたＳＱＵＩＤ磁束計の動
作点設定システムであって、このＳＱＵＩＤ磁束計の動
作点の設定を行なう動作点設定手段と、この動作点設定
手段の出力信号である動作点設定用信号の変化に応じて
変化するＳＱＵＩＤ磁束計の出力電圧のレベルを検出す
るレベル検出手段と、さきの出力電圧の特定のレベルに
応じて帰還回路のオープン・クローズの接続切り替えを
行う切り替え手段とを有することを特徴とする。すなわ
ち、上記問題点を解決するため、本発明では、動作点設
定用信号を与える動作点設定手段と、ＳＱＵＩＤ磁束計
の出力のレベルを検出するレベル検出器と、ＦＬＬ（Fl
ux Locked Loop)回路のオープン・クローズ切り替え部
とを設ける。動作としては、まずＦＬＬ（Flux Locked
Loop)回路をオープン状態にして帰還回路系に動作点設
定用信号を入力する。この入力に応じた出力からゼロク
ロス点を求め、ＦＬＬ回路をクローズ状態にし、動作点
設定用信号の入力を停止する。これらの一連の操作によ
り、動作点設定が完了する。SQUID having at least two Josephson junctions and disposed in a cooling medium
An operating point setting system for an SQUID magnetometer using (superconducting quantum interference device), wherein an operating point setting means for setting an operating point of the SQUID magnetometer and an operation which is an output signal of the operating point setting means Level detection means for detecting the level of the output voltage of the SQUID magnetometer that changes according to the change in the point setting signal, and switching for switching the open / close connection of the feedback circuit according to the specific level of the output voltage And means. That is, in order to solve the above problems, in the present invention, operating point setting means for giving an operating point setting signal, a level detector for detecting the output level of the SQUID magnetometer, and FLL (Fl
ux Locked Loop) circuit open / close switching section. As for the operation, first, FLL (Flux Locked
Loop) circuit is opened and the operating point setting signal is input to the feedback circuit system. The zero cross point is obtained from the output corresponding to this input, the FLL circuit is closed, and the input of the operating point setting signal is stopped. The operating point setting is completed by a series of these operations.
【０００６】[0006]
【作用】動作点を安定な位置に設定できるため、容易に
オフセット電圧の調整を行うことができ、安定した位置
にＳＱＵＩＤ磁束計の動作点の設定ができる。また、常
にＳＱＵＩＤの感度の最も良い位置に動作点の設定がで
きるため、低雑音化を図ることが可能である。Since the operating point can be set at a stable position, the offset voltage can be easily adjusted, and the operating point of the SQUID magnetometer can be set at a stable position. Further, since the operating point can always be set at the position where the SQUID sensitivity is highest, it is possible to reduce noise.
【０００７】[0007]
【実施例】本発明の実施例について以下に説明する。本
発明を要約すれば次のようになる。少なくとも２個のジ
ョセフソン接合を持ち、冷却媒体内に配置されるＳＱＵ
ＩＤ（超伝導量子干渉素子）を用いたＳＱＵＩＤ磁束計
の動作点設定システムであって、このＳＱＵＩＤ磁束計
の動作点の設定を行なう動作点設定手段と、この動作点
設定手段の出力信号である動作点設定用信号の変化に応
じて変化するＳＱＵＩＤ磁束計の出力電圧のレベルを検
出するレベル検出手段と、上記の出力電圧の特定のレベ
ルに応じて帰還回路のオープン・クローズの接続切り替
えを行う切り替え手段とを有することを特徴としたＳＱ
ＵＩＤ磁束計の動作点設定システムである。EXAMPLES Examples of the present invention will be described below. The present invention can be summarized as follows. SQU with at least two Josephson junctions placed in the cooling medium
An operating point setting system of an SQUID magnetometer using an ID (superconducting quantum interference device), which is an operating point setting means for setting an operating point of this SQUID magnetometer, and an output signal of this operating point setting means. Level detection means for detecting the level of the output voltage of the SQUID magnetometer that changes according to changes in the operating point setting signal, and open / close connection switching of the feedback circuit according to the specific level of the output voltage. SQ characterized by having switching means
It is an operating point setting system of a UID magnetometer.
【０００８】このような動作点設定システムにおいて、
動作点設定用信号をＳＱＵＩＤ磁束計へ入力し、次にＳ
ＱＵＩＤ磁束計の出力電圧のゼロクロス点を抽出し、次
に帰還回路をクローズ状態にし、最後に動作点設定手段
からの信号を停止する。さらに、ＳＱＵＩＤ磁束計はＳ
ＱＵＩＤへの少なくとも２つの帰還ループを持ち、第１
の帰還ループは常にクローズ状態とし、第２の帰還ルー
プは上記した動作点設定方法に従い、ＳＱＵＩＤ磁束計
の出力電圧レベルによりゼロクロス点を判定し、オープ
ン、クローズの接続切り替えへを行なう。また、動作点
設定手段からの信号と変調信号を加算して、同一のコイ
ルに入力する、あるいは、動作点設定手段からの信号と
帰還信号を加算して、同一のコイルに入力する。動作点
設定用信号の周波数が変調信号の周波数より低く、ＳＱ
ＵＩＤ磁束計の測定周波数帯域内とする。動作点設定用
信号の振幅は、ＳＱＵＩＤへ入力される動作点設定用信
号の磁束が１量子磁束（Φ０）以下になるように設定さ
れる。In such an operating point setting system,
Input the operating point setting signal to the SQUID magnetometer, then S
The zero cross point of the output voltage of the QUID magnetometer is extracted, then the feedback circuit is closed, and finally the signal from the operating point setting means is stopped. Furthermore, the SQUID magnetometer is S
Has at least two feedback loops to the QUID, the first
The feedback loop of 1 is always closed, and the second feedback loop determines the zero-cross point according to the output voltage level of the SQUID magnetometer according to the above-mentioned operating point setting method, and performs connection switching between open and closed. Further, the signal from the operating point setting means and the modulation signal are added and input to the same coil, or the signal from the operating point setting means and the feedback signal are added and input to the same coil. If the frequency of the operating point setting signal is lower than the frequency of the modulation signal, SQ
Within the measurement frequency band of the UID magnetometer. The amplitude of the operating point setting signal is set so that the magnetic flux of the operating point setting signal input to the SQUID is 1 quantum magnetic flux (Φ0) or less.
【０００９】図１に基づいて第１の実施例について説明
する。ＳＱＵＩＤ磁束計は図のように、ＳＱＵＩＤ１、
入力コイル２、検出コイル３、帰還変調コイル４、電圧
−電流変換器５、電流源６、検出回路７、スイッチ回路
８、動作点設定用発振器９、ゼロクロス検出器１０から
構成されている。ここで示す検出回路７は、増幅器、位
相検波器、積分器等を含んだ構成で実現できる。A first embodiment will be described with reference to FIG. As shown in the figure, the SQUID magnetometer is SQUID1,
The input coil 2, the detection coil 3, the feedback modulation coil 4, the voltage-current converter 5, the current source 6, the detection circuit 7, the switch circuit 8, the operating point setting oscillator 9, and the zero-cross detector 10. The detection circuit 7 shown here can be realized by a configuration including an amplifier, a phase detector, an integrator, and the like.
【００１０】初期状態としてスイッチ回路８で帰還回路
をオープン状態にしておく。同時に動作点設定用発振器
９からの低周波または直流電圧をスイッチ回路８によっ
て電圧−電流変換器５に入力する。これによってＳＱＵ
ＩＤ１に帰還変調コイル４から低周波の擬似信号が入力
されることになる。また、擬似信号の周波数は帰還回路
のクローズ状態での磁束計としての測定可能な帯域内と
する。この擬似信号をＳＱＵＩＤ１は電圧に変換し検出
回路７に伝達する。この検出回路後の出力電圧Voutのゼ
ロクロス点（出力電圧が零になる点）をゼロクロス検出
器１０によって求める。このゼロクロス点抽出時に制御
信号１１をスイッチ回路８に伝え、帰還回路系をクロー
ズループにし、次に動作点設定用発振器９の電圧−電流
変換器５への入力を切断する。これらの操作により、通
常のＳＱＵＩＤ磁束計動作時（クローズループ時）の出
力電圧Voutにはオフセット電圧が表れず、安定した磁束
計を得ることができる。すなわち、帰還回路系に動作点
設定用信号を入力する装置と、レベル検出器と、スイッ
チ回路とを有し、動作点設定はまず、ＦＬＬ（FluxLock
ed Loop)回路をオープン状態にして帰還回路系に低周波
信号を入力しこれによって得られた出力からゼロクロス
点を抽出する。このゼロクロス点抽出時にＦＬＬ回路を
クローズ状態にし、低周波信号入力を停止する。これら
の一連の操作により、動作点設定が完了する。As an initial state, the feedback circuit is kept open by the switch circuit 8. At the same time, the low frequency or DC voltage from the operating point setting oscillator 9 is input to the voltage-current converter 5 by the switch circuit 8. This makes SQU
A low-frequency pseudo signal is input from the feedback modulation coil 4 to ID1. The frequency of the pseudo signal is within the measurable band of the magnetometer when the feedback circuit is closed. The SQUID 1 converts this pseudo signal into a voltage and transmits it to the detection circuit 7. The zero-cross detector 10 obtains the zero-cross point (the point where the output voltage becomes zero) of the output voltage Vout after the detection circuit. At the time of extracting the zero-cross point, the control signal 11 is transmitted to the switch circuit 8, the feedback circuit system is closed loop, and then the input of the operating point setting oscillator 9 to the voltage-current converter 5 is cut off. By these operations, the offset voltage does not appear in the output voltage Vout during the normal SQUID magnetometer operation (during closed loop), and a stable magnetometer can be obtained. That is, the feedback circuit system has a device for inputting an operating point setting signal, a level detector, and a switch circuit. The operating point is set first by FLL (FluxLock).
ed Loop) circuit is opened and a low-frequency signal is input to the feedback circuit system, and the zero-cross point is extracted from the output obtained by this. At the time of this zero-cross point extraction, the FLL circuit is closed and the low frequency signal input is stopped. The operating point setting is completed by a series of these operations.
【００１１】図２と図３に基づいて第２の実施例につい
て説明する。磁束計の構成としては、ＳＱＵＩＤ１、入
力コイル２、検出コイル３、帰還変調コイル４、増幅器
１３、位相検波器１４、変調信号発振器１７、位相器１
８、スイッチ回路１９、帰還抵抗２１から構成されてい
る。第１の実施例と同様、初期状態は図２に示すように
スイッチ回路１９の＃ａがＯＦＦ状態で、＃ｂがＯＮ状
態である。この時、動作点設定用発振器２０の入力と出
力Voutの関係は図３のようになる。図３は横軸２２が動
作点設定用の入力信号で縦軸が出力Voutある。この図上
のゼロクロス点２３をゼロクロス検出器１０で検出す
る。この点が検出されたとき、制御信号１１によってス
イッチ回路の＃ａをＯＮ状態に＃ｂをＯＦＦ状態に遷移
させる。これによってＦＬＬ回路はクローズ状態にな
り、磁束計として動作することになる。これらの操作に
より、オフセット電圧が発生せず、安定した磁束計を得
ることができる。A second embodiment will be described with reference to FIGS. 2 and 3. The configuration of the magnetic flux meter is as follows: SQUID 1, input coil 2, detection coil 3, feedback modulation coil 4, amplifier 13, phase detector 14, modulation signal oscillator 17, phaser 1
8, a switch circuit 19, and a feedback resistor 21. As in the first embodiment, in the initial state, as shown in FIG. 2, #a of the switch circuit 19 is OFF and #b is ON. At this time, the relationship between the input and output Vout of the operating point setting oscillator 20 is as shown in FIG. In FIG. 3, the horizontal axis 22 is the input signal for setting the operating point, and the vertical axis is the output Vout. The zero-cross detector 23 detects the zero-cross point 23 on this figure. When this point is detected, the control signal 11 causes the switch circuit #a to transition to the ON state and #b to the OFF state. As a result, the FLL circuit is closed and operates as a magnetometer. By these operations, an offset voltage is not generated and a stable magnetometer can be obtained.
【００１２】次に図４に動作点設定手順をフローチャー
トで示す。第１段階２４としてＦＬＬ回路をオープン状
態にする。次に第２段階２５として、帰還変調コイルに
動作点設定用の低周波信号を入力し、この時の検出回路
の出力をモニターする。そして、第３段階２６として出
力のゼロクロス点を抽出する。この出力電圧がゼロにな
ったところで第４段階２７としてＦＬＬ回路をクローズ
状態にする。そして第５段階として、低周波信号の入力
を停止する。これにより、ＦＬＬ回路の変調信号の動作
点を安定な位置に持っていくことができ、安定したＳＱ
ＵＩＤ磁束計を得ることができる。上述したゼロクロス
点検出器は、コンパレータを用いることで実現できる。
また、さらに動作を安定させるための本発明の第３の実
施例を図５に示す。本実施例において、出力電圧Ｖout
と帰還変調コイル４の間に電流−電圧変換回路３０が電
流−電圧変換回路５に並列に接続され、磁束計はクロー
ズ状態となっている。この状態で、上記方法によりロッ
クをかける。電流−電圧変換回路３０によりクローズル
ープ状態とすることにより動作の安定化を図ることがで
きる。Next, FIG. 4 shows a flow chart of the operating point setting procedure. As the first stage 24, the FLL circuit is opened. Next, in the second step 25, a low frequency signal for setting the operating point is input to the feedback modulation coil, and the output of the detection circuit at this time is monitored. Then, as a third stage 26, the zero-cross point of the output is extracted. When this output voltage becomes zero, the FLL circuit is closed as the fourth step 27. Then, as a fifth step, the input of the low frequency signal is stopped. As a result, the operating point of the modulation signal of the FLL circuit can be brought to a stable position, and the stable SQ
A UID magnetometer can be obtained. The zero-cross point detector described above can be realized by using a comparator.
Further, FIG. 5 shows a third embodiment of the present invention for further stabilizing the operation. In this embodiment, the output voltage Vout
The current-voltage conversion circuit 30 is connected in parallel with the current-voltage conversion circuit 5 between the feedback modulation coil 4 and the feedback modulation coil 4, and the magnetometer is in a closed state. In this state, the lock is applied by the above method. The operation can be stabilized by setting the closed loop state by the current-voltage conversion circuit 30.
【００１３】[0013]
【発明の効果】本発明により、ＳＱＵＩＤ磁束計の出力
のオフセット電圧を解除することができる。また、ＳＱ
ＵＩＤの磁束−電圧特性の安定な位置に帰還を掛けて動
作点を決めることにより、安定したＳＱＵＩＤ磁束計が
得られ、常にＳＱＵＩＤの最も感度の良い位置で磁束計
として動作することができる。According to the present invention, the offset voltage of the output of the SQUID magnetometer can be canceled. Also, SQ
A stable SQUID magnetometer can be obtained by feeding back a stable position of the magnetic flux-voltage characteristic of the UID to determine the operating point, and can always operate as a magnetometer at the most sensitive position of the SQUID.
【図１】本発明の実施例１であるＳＱＵＩＤ磁束計の動
作点設定方法を示す図。FIG. 1 is a diagram showing a method for setting an operating point of an SQUID magnetometer, which is Embodiment 1 of the present invention.
【図２】本発明の実施例２であるＳＱＵＩＤ磁束計の動
作点設定方法示す図。FIG. 2 is a diagram showing a method for setting an operating point of an SQUID magnetometer, which is Embodiment 2 of the present invention.
【図３】擬似信号入力と出力との関係を示す図。FIG. 3 is a diagram showing a relationship between pseudo signal input and output.
【図４】ＳＱＵＩＤ磁束計の動作点設定手順を示すフロ
ーチャート。FIG. 4 is a flowchart showing an operating point setting procedure of the SQUID magnetometer.
【図５】本発明の実施例３であるＳＱＵＩＤ磁束計の動
作点設定方法を示す図。FIG. 5 is a diagram showing a method for setting an operating point of an SQUID magnetometer, which is Embodiment 3 of the present invention.
【図６】ＳＱＵＩＤ磁束計の従来技術による動作点設定
方法を示す図。FIG. 6 is a diagram showing an operating point setting method of a SQUID magnetometer according to a conventional technique.
１…ＳＱＵＩＤ、２…入力コイル、３…検出コイル、４
…帰還変調コイル、５…電圧−電流変換回路、６…電流
源、７…検出回路、８…スイッチ回路、９、２０…動作
点設定用発振器、１０…ゼロクロス点検出器、１１…制
御信号、１２…積分器またはローパスフィルタ、１３…
増幅器、１４…位相検波器、１５…クロック、１６…変
調信号、１７…変調信号発振器、１８…位相器、１９…
スイッチ回路、２１…帰還抵抗、２２…入力信号、２３
…ゼロクロス点、２４…第１段階、２５…第２段階、２
６…第３段階、２７…第４段階、２８…第５段階、２９
…オフセット回路、３０…電圧−電流変換回路。1 ... SQUID, 2 ... Input coil, 3 ... Detection coil, 4
... Feedback modulation coil, 5 ... Voltage-current conversion circuit, 6 ... Current source, 7 ... Detection circuit, 8 ... Switch circuit, 9, 20 ... Operating point setting oscillator, 10 ... Zero cross point detector, 11 ... Control signal, 12 ... Integrator or low-pass filter, 13 ...
Amplifier, 14 ... Phase detector, 15 ... Clock, 16 ... Modulation signal, 17 ... Modulation signal oscillator, 18 ... Phaser, 19 ...
Switch circuit, 21 ... Feedback resistor, 22 ... Input signal, 23
… Zero cross point, 24… 1st stage, 25… 2nd stage, 2
6 ... 3rd stage, 27 ... 4th stage, 28 ... 5th stage, 29
... offset circuit, 30 ... voltage-current conversion circuit.
Claims (7)
ち、冷却媒体内に配置されるＳＱＵＩＤ（超伝導量子干
渉素子）を用いたＳＱＵＩＤ磁束計の動作点設定システ
ムであって、このＳＱＵＩＤ磁束計の動作点の設定を行
なう動作点設定手段と、この動作点設定手段の出力信号
である動作点設定用信号の変化に応じて変化するＳＱＵ
ＩＤ磁束計の出力電圧のレベルを検出するレベル検出手
段と、前記出力電圧の特定のレベルに応じて帰還回路の
オープン・クローズの接続切り替えを行う切り替え手段
とを有することを特徴としたＳＱＵＩＤ磁束計の動作点
設定システム。1. An operating point setting system for an SQUID magnetometer having at least two Josephson junctions and using an SQUID (superconducting quantum interference device) arranged in a cooling medium. An operating point setting means for setting an operating point and an SQU that changes according to a change in an operating point setting signal which is an output signal of the operating point setting means.
The SQUID magnetometer is characterized by having level detection means for detecting the level of the output voltage of the ID magnetometer and switching means for switching the open / close connection of the feedback circuit according to the specific level of the output voltage. Operating point setting system.
いて、前記動作点設定用信号をＳＱＵＩＤ磁束計へ入力
し、次にＳＱＵＩＤ磁束計の出力電圧のゼロクロス点を
抽出し、次に帰還回路をクローズ状態にし、最後に前記
動作点設定手段からの信号を停止することを特徴とする
ＳＱＵＩＤ磁束計の動作点設定方法。2. The operating point setting system according to claim 1, wherein the operating point setting signal is input to an SQUID magnetometer, a zero cross point of an output voltage of the SQUID magnetometer is extracted, and then a feedback circuit is provided. Is closed, and finally the signal from the operating point setting means is stopped, and the operating point setting method of the SQUID magnetometer.
いて、上記ＳＱＵＩＤ磁束計はＳＱＵＩＤへの少なくと
も２つの帰還ループを持ち、第１の帰還ループは常にク
ローズ状態とし、第２の帰還ループは請求項２に記載の
動作点設定方法に従い、ＳＱＵＩＤ磁束計の出力電圧レ
ベルによりゼロクロス点を判定し、オープン、クローズ
の接続切り替えへを行なうことを特徴とするＳＱＵＩＤ
磁束計の動作点設定方法。3. The operating point setting system according to claim 1, wherein the SQUID magnetometer has at least two feedback loops to the SQUID, the first feedback loop is always closed, and the second feedback loop is According to the operating point setting method according to claim 2, a zero-cross point is determined based on the output voltage level of the SQUID magnetometer, and the connection is switched between open and closed.
How to set the operating point of the magnetometer.
いて、前記動作点設定手段からの信号と変調信号を加算
して、同一のコイルに入力することを特徴とするＳＱＵ
ＩＤ磁束計の動作点設定システム。4. The SQU of the operating point setting system according to claim 1, wherein the signal from the operating point setting means and the modulation signal are added and input to the same coil.
Operating point setting system for ID magnetometer.
いて、前記動作点設定手段からの信号と帰還信号を加算
して、同一のコイルに入力することを特徴とするＳＱＵ
ＩＤ磁束計の動作点設定システム。5. The SQU according to claim 1, wherein the signal from the operating point setting means and the feedback signal are added and input to the same coil.
Operating point setting system for ID magnetometer.
いて、前記動作点設定用信号の周波数が変調信号の周波
数より低く、ＳＱＵＩＤ磁束計の測定周波数帯域内であ
ることを特徴とするＳＱＵＩＤ磁束計の動作点設定方
法。6. The operating point setting system according to claim 1, wherein the frequency of the operating point setting signal is lower than the frequency of the modulation signal and is within the measurement frequency band of the SQUID magnetometer. How to set the operating point of the meter.
いて、ＳＱＵＩＤへ入力される動作点設定用信号の磁束
が１量子磁束（Φ０）以下になるように、動作点設定用
信号の振幅を設定することを特徴とするＳＱＵＩＤ磁束
計の動作点設定方法。7. The operating point setting system according to claim 1, wherein the amplitude of the operating point setting signal is adjusted so that the magnetic flux of the operating point setting signal input to the SQUID is 1 quantum flux (Φ0) or less. A method for setting an operating point of a SQUID magnetometer characterized by setting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4244506A JPH0694815A (en) | 1992-09-14 | 1992-09-14 | Operating point setting system and method of squid magnetic flux meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4244506A JPH0694815A (en) | 1992-09-14 | 1992-09-14 | Operating point setting system and method of squid magnetic flux meter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0694815A true JPH0694815A (en) | 1994-04-08 |
Family
ID=17119693
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4244506A Pending JPH0694815A (en) | 1992-09-14 | 1992-09-14 | Operating point setting system and method of squid magnetic flux meter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0694815A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100478067B1 (en) * | 1996-10-17 | 2005-07-08 | 스미토모덴키고교가부시키가이샤 | Magnetic sensor drive circuit device |
| CN106793979A (en) * | 2014-08-28 | 2017-05-31 | 日立麦克赛尔株式会社 | Motor function evaluation system and motor function measurement apparatus |
-
1992
- 1992-09-14 JP JP4244506A patent/JPH0694815A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100478067B1 (en) * | 1996-10-17 | 2005-07-08 | 스미토모덴키고교가부시키가이샤 | Magnetic sensor drive circuit device |
| CN106793979A (en) * | 2014-08-28 | 2017-05-31 | 日立麦克赛尔株式会社 | Motor function evaluation system and motor function measurement apparatus |
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