JPH0475471B2 - - Google Patents
Info
- Publication number
- JPH0475471B2 JPH0475471B2 JP58031429A JP3142983A JPH0475471B2 JP H0475471 B2 JPH0475471 B2 JP H0475471B2 JP 58031429 A JP58031429 A JP 58031429A JP 3142983 A JP3142983 A JP 3142983A JP H0475471 B2 JPH0475471 B2 JP H0475471B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- component
- magnetic field
- electromagnet
- detected
- 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.)
- Expired - Lifetime
Links
- 238000005481 NMR spectroscopy Methods 0.000 claims description 20
- 238000001514 detection method Methods 0.000 description 8
- 230000005540 biological transmission Effects 0.000 description 7
- 230000010354 integration Effects 0.000 description 7
- 239000000523 sample Substances 0.000 description 7
- 230000005284 excitation Effects 0.000 description 5
- 125000004429 atom Chemical group 0.000 description 4
- 230000000630 rising effect Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical class [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 238000012886 linear function Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
- G01R33/38—Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field
- G01R33/389—Field stabilisation, e.g. by field measurements and control means or indirectly by current stabilisation
Description
【発明の詳細な説明】
この発明は、例えば磁場中に置かれた原子核の
核磁気共鳴現象を利用して、その原子の空間的密
度分布や化学的結合状態の情報を断層画像として
得るNMR−CT装置に用いられ、電磁石が発生
する磁場の強度を自動的に制御するNMR−
LOCK装置に関するものである。DETAILED DESCRIPTION OF THE INVENTION This invention utilizes the nuclear magnetic resonance phenomenon of atomic nuclei placed in a magnetic field to obtain information on the spatial density distribution and chemical bonding state of the atoms as a tomographic image. NMR, which is used in CT equipment and automatically controls the strength of the magnetic field generated by an electromagnet.
It concerns the LOCK device.
＜背景＞
磁場中に置かれたある種の原子（原子番号か質
量数のどちらかが奇数であるような原子）の核磁
気共鳴周波数ｆは、その時の磁気強度Ｈに比例す
ることが知られている。この性質を利用して、従
来から電磁石が発生する磁場強度を知るために、
その磁場中に基準原子核（通常多くの場合、水素
原子核）を置き、その核磁気共鳴信号から、基準
磁場強度に対する偏差を検知して、その偏差を補
正するように前記電磁石の電源を制御するNMR
−LOCK装置が存在している。<Background> It is known that the nuclear magnetic resonance frequency f of a certain type of atom (an atom with an odd atomic number or mass number) placed in a magnetic field is proportional to the magnetic strength H at that time. ing. Using this property, in order to know the magnetic field strength generated by an electromagnet,
NMR that places a reference atomic nucleus (usually a hydrogen nucleus in many cases) in the magnetic field, detects a deviation from the reference magnetic field strength from the nuclear magnetic resonance signal, and controls the power supply of the electromagnet to correct the deviation.
- A LOCK device is present.
従来のNMR−LOCK装置においては、前記基
準原子核（例えば水素原子核）の基準磁場強度
（例えば0.1Tesla）における核磁気共鳴周波数
（前記例においては4.3MHz）で発振している基準
RF（高周波）発振器を用意し、この出力信号で前
記基準原子核から実際に得られた核磁気共鳴信号
（前記例においては、4.3±△fMHz）を検波する。
この検波信号はAC（交流）成分として△ｆの周波
数を持ち、この△ｆが実際の磁場強度と基準磁場
強度との偏差に相当することを利用して電磁石の
電源を制御している。 In a conventional NMR-LOCK device, the reference atomic nucleus (e.g. hydrogen nucleus) is oscillated at the nuclear magnetic resonance frequency (4.3 MHz in the above example) at the reference magnetic field strength (e.g. 0.1 Tesla).
An RF (high frequency) oscillator is prepared, and a nuclear magnetic resonance signal (4.3±△fMHz in the above example) actually obtained from the reference atomic nucleus is detected using this output signal.
This detection signal has a frequency of Δf as an AC (alternating current) component, and the fact that this Δf corresponds to the deviation between the actual magnetic field strength and the reference magnetic field strength is used to control the power supply of the electromagnet.
ところが前記核磁気共鳴信号は、数十ｍsecの
時定数で減衰する性質を有するため、一回の核磁
気共鳴信号からその検波信号の周波数（△ｆ）
を、数Hzのオーダまで直接測定して知ることは極
めて難しい。このため、従来は特開昭57−6346号
公報に示すように変調用AF（低周波）発振器の発
振周波数（例えば5KHz）でゲートをON、OFF
し、核磁気共鳴信号の励起と核磁気共鳴信号の受
信とを周期的（前記例においては100μsecごと）
にくりかえして、信号の減衰をふせいでいる。 However, since the nuclear magnetic resonance signal has the property of attenuating with a time constant of several tens of milliseconds, the frequency (△f) of the detected signal from a single nuclear magnetic resonance signal
It is extremely difficult to directly measure and know down to the order of several Hz. For this reason, conventionally, the gate was turned on and off at the oscillation frequency (for example, 5KHz) of the modulation AF (low frequency) oscillator, as shown in Japanese Patent Application Laid-Open No. 57-6346.
The excitation of the nuclear magnetic resonance signal and the reception of the nuclear magnetic resonance signal are performed periodically (every 100 μsec in the above example).
This repeatedly prevents signal attenuation.
このようは方式の従来のNMR−LOCK装置
を、NMR−CT装置の電磁石制御用に利用した
場合、NMR−CT装置本体が被検体（通常多く
の場合人間）から、核磁気共鳴信号を受信してい
る時間帯（例えば16ｍsec）の中に、NMR−
LOCK装置用の励起用パルスが送信され、しかも
NMR−CT装置、NMR−LOCK装置共に対象核
が水素原子核であるために、信号周波数が重なつ
て、NMR−CT装置の受信信号の中にNMR−
LOCK装置の励起用パルスがノイズとなつて現わ
れる。 When a conventional NMR-LOCK device using this method is used to control the electromagnet of an NMR-CT device, the NMR-CT device itself receives nuclear magnetic resonance signals from the subject (usually a human being in many cases). during the time period (e.g. 16 msec)
An excitation pulse for the LOCK device is transmitted, and
Since the target nucleus for both the NMR-CT device and the NMR-LOCK device is a hydrogen nucleus, the signal frequencies overlap, and the NMR-CT device receives an NMR-CT device.
The excitation pulse of the LOCK device appears as noise.
また特開昭54−155089号公報に示すように、受
信した核磁気共鳴信号を基準信号で検波し、この
検波出力として得られる交流成分を矩形波に変換
し、その矩形波を所定時間計数して、周波数の偏
差△ｆを求めることが提案されている。この場
合、１Hzの偏差を求めるためには最低１秒間の計
数を必要とし、0.5Hzの偏差の場合は最低２秒間
の計数を必要とし、小さな偏差△ｆまで検出しよ
うとすると、検出時間が比較的長い欠点がある。 Furthermore, as shown in Japanese Patent Application Laid-Open No. 54-155089, the received nuclear magnetic resonance signal is detected using a reference signal, the AC component obtained as the detected output is converted into a rectangular wave, and the rectangular wave is counted for a predetermined period of time. It has been proposed to calculate the frequency deviation Δf. In this case, to find a deviation of 1Hz, counting is required for at least 1 second, and for a deviation of 0.5Hz, counting is required for at least 2 seconds, and when trying to detect even a small deviation △f, the detection time is compared. There are long drawbacks.
＜発明の概要＞
この発明の目的はパルス雑音が入るおそれがな
いNMR−LOCK装置を提供することがある。<Summary of the Invention> An object of the present invention is to provide an NMR-LOCK device in which there is no possibility of pulse noise being introduced.
この発明によればNMR−LOCK用の基準原子
核を高周波パルスで励起し、この原子核から得た
核磁気共鳴信号を、基準RF発振器野の信号で検
波する。この検波信号は実際の磁場強度と基準磁
場強度との偏差に相当し、その偏差に相当する周
波数△ｆの交流成分を含む。その検波信号を、高
周波パルスの直後から、その信号が減衰するまで
の時間より短く、つまり磁場強度の自動制御のた
めに通常用いられる磁場強度検出用の原子の核磁
気共鳴信号の減衰時間（スピンスピン緩和時間
T2であつて励起パルスから信号強度がｅ分の１
に減衰するまでの時間）は通常200ミリ秒〜１秒
であるから１時間より十分短い一定の時間△Ｔ
（例えば20ｍsec）の間積分することにより、△ｆ
に対応する情報を得て、磁場制御をする。この
際、前記検波信号からDC（直流）成分を差し引い
て、AC成分のみを信号として積分することによ
り、△ｆに対応する情報の積分精度を上げること
ができる。そして△ｆが零の時に、前記検波信号
のAC成分が零となるように検波器に入力する基
準RF発振器の信号位相が調整される。これによ
つて前記AC成分の立ち上がり微分係数は、△ｆ
の大小・符号に対応して変化し、△ｆが数Hz程度
の十分小さい範囲で、前記AC成分を一定時間積
分した結果が、△ｆすなわち実際の磁場強度と基
準磁場強度との偏差と一対一で対応するわけであ
る。 According to this invention, a reference atomic nucleus for NMR-LOCK is excited with a high-frequency pulse, and a nuclear magnetic resonance signal obtained from this atomic nucleus is detected with a signal from a reference RF oscillator field. This detection signal corresponds to the deviation between the actual magnetic field strength and the reference magnetic field strength, and includes an alternating current component with a frequency Δf corresponding to the deviation. The detection signal is shorter than the time from immediately after the high-frequency pulse until the signal decays, that is, the decay time of the nuclear magnetic resonance signal of the atom (spin spin relaxation time
T 2 and the signal strength from the excitation pulse is 1/e
The time required for the decay to decay) is usually 200 milliseconds to 1 second, so it is a constant time △T that is sufficiently shorter than 1 hour.
(for example, 20 msec), △f
Obtain information corresponding to the magnetic field and control the magnetic field. At this time, by subtracting the DC (direct current) component from the detected signal and integrating only the AC component as a signal, it is possible to improve the integration accuracy of the information corresponding to Δf. Then, the signal phase of the reference RF oscillator input to the detector is adjusted so that when Δf is zero, the AC component of the detected signal becomes zero. As a result, the rising differential coefficient of the AC component is △f
The result of integrating the AC component over a certain period of time within a sufficiently small range of about several Hz is the difference between Δf, that is, the deviation between the actual magnetic field strength and the reference magnetic field strength. So we have to deal with it all at once.
つまり、同期検波出力から直流分を差し引いた
AC成分は、△ｆが１Hzの場合は、高周波パルス
直後の波形は第１図の曲線△ｆ＝１Hzとなる。こ
の曲線の足り上り点は正確に高周波パルスの中心
点であるが、高周波パルスのパルス幅は極めて短
く、例えば300μs程度であるから、このパルス幅
を無視して示している。また△ｆが２Hzの場合は
曲線△ｆ＝２Hzとなり、曲線△ｆ＝１Hzよりも急
速に立ち上り、つまり立ち上り微分係数が大であ
る。△ｆ−２Hzの場合は、曲線△ｆ＝−２Hzとな
り、曲線△ｆ＝２Hzと逆位相、つまり立ち上り微
分係数の絶対値が同一で符号が負となる。従つて
これら曲線を高周波パルスの直後から、１秒間よ
りも十分短い時間△Ｔ、例えば20ミリ秒間だけ積
分すると、曲線△ｆ＝１Hzの場合は第１図の横線
ハツチング部分の面積の大きさが正の値として得
られ、曲線△ｆ＝２Hzの場合は縦線ハツチング部
分の面積の大きさが正の値として得られ、これは
△ｆ＝１Hzのそれよりも大きな値となる。曲線△
ｆ＝−２Hzの場合は斜線ハツチング部分の面積が
負の値として得られ、この値は△ｆ＝２Hzの場合
と同一であり、符号が異なる。このようにAC成
分の積分出力は、△ｆが高い程大きく、かつその
正負に応じた符号となる。 In other words, the DC component is subtracted from the synchronous detection output.
For the AC component, when Δf is 1 Hz, the waveform immediately after the high-frequency pulse becomes the curve Δf=1 Hz in FIG. 1. The rising point of this curve is exactly the center point of the high-frequency pulse, but since the pulse width of the high-frequency pulse is extremely short, for example, about 300 μs, this pulse width is ignored in the figure. Further, when Δf is 2 Hz, the curve Δf=2 Hz, which rises more rapidly than the curve Δf=1 Hz, that is, the rising differential coefficient is larger. In the case of Δf-2Hz, the curve Δf=-2Hz, which has an opposite phase to the curve Δf=2Hz, that is, the absolute value of the rising differential coefficient is the same and the sign is negative. Therefore, if these curves are integrated for a time △T that is sufficiently shorter than 1 second, for example 20 milliseconds, from immediately after the high-frequency pulse, if the curve △f = 1 Hz, the area of the horizontal hatched part in Fig. 1 will be When the curve Δf=2 Hz, the area of the hatched portion of the vertical line is obtained as a positive value, which is larger than that when Δf=1 Hz. Curve △
When f=-2Hz, the area of the hatched portion is obtained as a negative value, and this value is the same as when Δf=2Hz, but the sign is different. In this way, the integral output of the AC component becomes larger as Δf is higher, and has a sign corresponding to its sign.
このようにすることにより、核磁気共鳴信号が
減衰するより、つまり１秒間より十分短い時間内
に、数Hzのオーダの△ｆを識別することが可能と
なり、従来技術の欠点を克服することができる。
さらにこの発明によれば、NMR−LOCK用の送
受信を、間欠的に（例えば１秒に１回ずつ）行な
うだけで、△ｆを十分高い精度で検出することが
可能となり、LOCK用励起パルスを、NMR−
CT用の送受信が行なわれていないタイミングに
同期をとつて送信することもできる。このため
NMR−CT装置からの信号に影響させることな
く正しく制御することができる。 By doing this, it becomes possible to identify Δf on the order of several Hz before the nuclear magnetic resonance signal attenuates, that is, within a time sufficiently shorter than one second, and it is possible to overcome the drawbacks of the conventional technology. can.
Furthermore, according to the present invention, it is possible to detect △f with sufficiently high accuracy by simply performing transmission and reception for NMR-LOCK intermittently (for example, once every second), and the excitation pulse for LOCK can be detected with sufficient accuracy. , NMR−
It is also possible to transmit in synchronization with timing when CT transmission and reception are not being performed. For this reason
Correct control can be achieved without affecting the signal from the NMR-CT device.
しかし、DC成分を差し引いてAC成分を単に積
分するだけで磁場強度の偏差が大き過ぎ△ｆが高
くなり、これが積分時間△Ｔの逆数の半分を越え
ると（△ｆ＞１／２・△Ｔ前記例においては、△Ｔ
＝20ｍsecであるから△ｆ＞25Hz）、積分時間内に
AC成分の正負が逆転した信号、つまりAC成分の
半周期以上の信号を含むようになるため、積分結
果がかえつて減少しはじめて適切な制御ができな
くなるおそれがある。すなわち、磁場強度の偏差
（言い換えれば△ｆ）がある上限を越えると、制
御性が急激に悪化するわけである。この欠点をも
克服するためには、検波信号のAC成分を積分す
る際に、そのAC成分の絶対値をとり、その絶対
値を一定時間積分し、偏差の方向（極性）は検波
時の位相情報から検出すればよい。このようにす
ることによつて磁場偏差の広い範囲に渡つて制御
可能なNMR−LOCK装置が実現できる。 However, if the DC component is subtracted and the AC component is simply integrated, the deviation of the magnetic field strength becomes too large and △f becomes high, and if this exceeds half the reciprocal of the integration time △T (△f>1/2・△T In the above example, since △T = 20msec, △f>25Hz), within the integration time
Since the signal includes a signal in which the polarity of the AC component is reversed, that is, a signal that is longer than half the period of the AC component, there is a risk that the integration result will start to decrease and that appropriate control will not be possible. That is, when the deviation of the magnetic field strength (in other words, Δf) exceeds a certain upper limit, the controllability deteriorates rapidly. In order to overcome this drawback, when integrating the AC component of the detected signal, take the absolute value of the AC component, integrate that absolute value for a certain period of time, and determine the direction (polarity) of the deviation from the phase at the time of detection. It can be detected from information. By doing so, it is possible to realize an NMR-LOCK device that can control the magnetic field deviation over a wide range.
＜実施例＞
以下に、この発明の実施例について説明する。
第２図に示すように基準RF発振器１１の出力は、
送信増幅器１２で増幅された後、送信ゲート１３
において、コンピユータよりなる制御部１４の指
示するタイミングでパルス変調される。電磁石１
５が発生する磁場内にプローブ１６が置かれ、プ
ローブ１６に送信ゲート１３を通過した高周波パ
ルスが供給され、プローブ１６中の原子核スピン
を90゜倒すように励起する。送信ゲート１３が閉
になつた後、プローブ１６から得られる核磁気共
鳴信号は、受信増幅器１７で増幅されて検波器１
８へ供給される。基準RF発振器１１の出力は移
相器１９で移相調整され、基準信号として検波器
１８へ供給され、受信増幅器１７の出力が検波さ
れる。この時、移送器１９は、プローブ１６より
の核磁気共鳴信号の周波数が基準RF発振器１１
の周波数と等しい場合に、検波器１８の検波信号
のAC成分が零になるように調節されている。<Examples> Examples of the present invention will be described below.
As shown in FIG. 2, the output of the reference RF oscillator 11 is
After being amplified by the transmission amplifier 12, the transmission gate 13
At this time, pulse modulation is performed at a timing instructed by a control unit 14 made up of a computer. Electromagnet 1
A probe 16 is placed in the magnetic field generated by the probe 16, and a high frequency pulse that has passed through the transmission gate 13 is supplied to the probe 16 to excite the nuclear spins in the probe 16 so as to incline them by 90 degrees. After the transmission gate 13 is closed, the nuclear magnetic resonance signal obtained from the probe 16 is amplified by the reception amplifier 17 and sent to the detector 1.
8. The output of the reference RF oscillator 11 is phase-shifted and adjusted by a phase shifter 19, and is supplied as a reference signal to a detector 18, where the output of the receiving amplifier 17 is detected. At this time, the transfer device 19 is configured so that the frequency of the nuclear magnetic resonance signal from the probe 16 is set to the reference RF oscillator 11.
The AC component of the detection signal of the wave detector 18 is adjusted to be zero when the frequency is equal to the frequency of .
検波器１８の出力はAD変換器２１でデジタル
信号に変換されて制御部１４に取り込まれる。制
御部１４はこの取り込まれた検波信号のAC成分
に対し、その絶対値についてのみ積分し、更に演
算処理をほどこして、その処理結果の出力が、検
波信号のAC成分の周波数と一対一に対応するよ
うにする。この演算処理の結果は、DA変換器２
２でアナログ信号に変換されて電磁石電源２３に
供給され、電磁石１５の磁場強度の基準磁場強度
に対する偏差がなくなるように電磁石電源２３が
制御される。このようにして広いダイナミツクレ
ンジをもつ磁場制御が可能となる。 The output of the wave detector 18 is converted into a digital signal by an AD converter 21 and input to the control section 14. The control unit 14 integrates only the absolute value of the AC component of the detected signal taken in, and further performs arithmetic processing, so that the output of the processing result corresponds one-to-one to the frequency of the AC component of the detected signal. I'll do what I do. The result of this arithmetic processing is sent to the DA converter 2.
2, it is converted into an analog signal and supplied to the electromagnet power supply 23, and the electromagnet power supply 23 is controlled so that there is no deviation of the magnetic field strength of the electromagnet 15 from the reference magnetic field strength. In this way, magnetic field control with a wide dynamic range becomes possible.
制御部１４の演算処理として、単に検波信号の
AC成分の絶対値を積分するだけでなく、積分結
果がAC成分の周波数の一次関数（あるいは電磁
石制御に最適な関数）になるような補正処理をす
ることにより、磁場制御を広い範囲にわたつて最
適化することもできる。この補正処理は例えばメ
モリの中に書き込まれているテーブルを参照して
行うことができる。 The arithmetic processing of the control unit 14 is simply based on the detection signal.
Magnetic field control can be controlled over a wide range by not only integrating the absolute value of the AC component, but also by performing correction processing so that the integration result becomes a linear function of the frequency of the AC component (or the optimal function for electromagnet control). It can also be optimized. This correction processing can be performed, for example, by referring to a table written in a memory.
＜効果＞
以上説明したように、この発明によれば、磁場
の偏差を短時間で検出し、広い範囲にわたつて最
適制御可能なNMR−LOCK装置を実現すること
ができる。<Effects> As described above, according to the present invention, it is possible to realize an NMR-LOCK device that can detect magnetic field deviations in a short time and can perform optimal control over a wide range.
第１図は偏差交流成分の短時間積分を説明する
ための図、第２図はこの発明によるNMR−
LOCK装置の一例を示すブロツク図である。
１１：基準RF発振器、１３：送信ゲート、１
４：制御部、１５：電磁石、１６：プローブ、１
８：検波器、１９：移送器、２１：AD変換器、
２２：DA変換器、２３：電磁石電源。
Figure 1 is a diagram for explaining short-time integration of the deviation AC component, and Figure 2 is a diagram for explaining the short-time integration of the deviation AC component.
FIG. 2 is a block diagram showing an example of a LOCK device. 11: Reference RF oscillator, 13: Transmission gate, 1
4: Control unit, 15: Electromagnet, 16: Probe, 1
8: Detector, 19: Transfer device, 21: AD converter,
22: DA converter, 23: Electromagnet power supply.
Claims (1)
高周波パルスで励起し、その原子核から、核磁気
共鳴信号を受信し、その信号から前記磁場の強度
変化を検知して、前記磁場強度の変動分を補正す
るように前記電磁石の電源を制御するNMR−
LOCK装置において、前記核磁気共鳴信号を、基
準発振器の信号で検波する検波器と、その検波信
号から直流成分を差し引く手段と、その直流分が
差し引かれた残りの交流成分を、前記高周波パル
スの直後から、１秒間より十分短い一定時間積分
して前記電磁石の電源を制御する信号を得る積分
手段とを具備することを特徴とするNMR−
LOCK装置。1 An atomic nucleus placed in a magnetic field generated by an electromagnet is excited with a high-frequency pulse, a nuclear magnetic resonance signal is received from the atomic nucleus, a change in the strength of the magnetic field is detected from the signal, and the variation in the magnetic field strength is detected. NMR− to control the power supply of the electromagnet so as to correct
In the LOCK device, a detector detects the nuclear magnetic resonance signal using a signal from a reference oscillator, a means for subtracting a DC component from the detected signal, and a means for subtracting the DC component and the remaining AC component from the high-frequency pulse. an integrating means for obtaining a signal for controlling the power source of the electromagnet by immediately integrating for a certain period of time sufficiently shorter than one second.
LOCK device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58031429A JPS59157548A (en) | 1983-02-25 | 1983-02-25 | Nmr-lock device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58031429A JPS59157548A (en) | 1983-02-25 | 1983-02-25 | Nmr-lock device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59157548A JPS59157548A (en) | 1984-09-06 |
| JPH0475471B2 true JPH0475471B2 (en) | 1992-11-30 |
Family
ID=12330993
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58031429A Granted JPS59157548A (en) | 1983-02-25 | 1983-02-25 | Nmr-lock device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59157548A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54155089A (en) * | 1978-04-14 | 1979-12-06 | Varian Associates | Method and device for automatically fixing relation between magnetic field and frequency in nmr spectrometer |
-
1983
- 1983-02-25 JP JP58031429A patent/JPS59157548A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54155089A (en) * | 1978-04-14 | 1979-12-06 | Varian Associates | Method and device for automatically fixing relation between magnetic field and frequency in nmr spectrometer |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59157548A (en) | 1984-09-06 |
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