[go: up one dir, main page]
More Web Proxy on the site http://driver.im/

JPS5887450A - Nuclear magnetism resonator - Google Patents

Nuclear magnetism resonator

Info

Publication number
JPS5887450A
JPS5887450A JP56185305A JP18530581A JPS5887450A JP S5887450 A JPS5887450 A JP S5887450A JP 56185305 A JP56185305 A JP 56185305A JP 18530581 A JP18530581 A JP 18530581A JP S5887450 A JPS5887450 A JP S5887450A
Authority
JP
Japan
Prior art keywords
converter
free induction
signal
attenuator
value
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.)
Pending
Application number
JP56185305A
Other languages
Japanese (ja)
Inventor
Tadatetsu Hattori
服部 忠鐵
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.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
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 Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP56185305A priority Critical patent/JPS5887450A/en
Publication of JPS5887450A publication Critical patent/JPS5887450A/en
Pending legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00Arrangements or instruments for measuring magnetic variables
    • G01R33/20Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/32Excitation or detection systems, e.g. using radio frequency signals
    • G01R33/36Electrical details, e.g. matching or coupling of the coil to the receiver
    • G01R33/3621NMR receivers or demodulators, e.g. preamplifiers, means for frequency modulation of the MR signal using a digital down converter, means for analog to digital conversion [ADC] or for filtering or processing of the MR signal such as bandpass filtering, resampling, decimation or interpolation

Landscapes

  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)

Abstract

PURPOSE:To perform a rapid and accurate setting of optimum conditions of an A/D converter input level of a free induction attenuator signal, by installing a high-frequency variable attenuator varied by a data processor. CONSTITUTION:A probe 2 consisting of a sample to be measured and a transmitting and receiving coil is placed in a uniform DC magnetic field of a magnet 1. A resonating frequency of a frequency source 3, produced into a pulse shape, is applied to the probe 2 to cause the sample to excite a resonance. A free induction attenuating signal is then inputted to an A/D converter 8 via a variable attenuator 6 and a high-frequency detector 7. The signal is inputted to a data processor 9 and is outputted to a recorder. A value corresponding to a measuring condition is first set in the attenuator 6, and is then set to a lower value by the input of the converter 8 to A/D convert a free induction attenuating signal of a dummy to detect a maximum value of an amplitude. The maximum value is compared with the value of the converter 8 to reset the attenuator 6. A specified free induction attenuating signal is then A/D-converted to input it to a device 9.

Description

【発明の詳細な説明】 本発明はフーリエ変換形核磁気共鳴装置の自由誘導減衰
信号をAD変換して取込む最適条件設定を迅速にかつ正
確に行うことのできる回路に関する。
DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit that can quickly and accurately set optimal conditions for AD converting and capturing a free induction attenuation signal of a Fourier transform type nuclear magnetic resonance apparatus.

従来の核磁気共鳴装置は高周波増幅器の利得、又は、高
周波減衰器の減衰量を操作パネル上のンマミ設定で可変
してダミーの自由誘導減衰信号をAD変換してその信号
の大きさを見て操作する人が判断してAD変換器の入力
レベルが適当になるように設定している。一般に自由誘
導減衰信号は測定条件、測定試料そのもの、試料の濃度
などで犬きく変化し、CRTなどでモニタすると適当な
設定は一度ではできず何度もダミーを取込まねばならな
い。又、自由誘導減衰信号は核磁気共鳴の緩和時間を考
慮してインターバルは充分長い時間が必要でなる5など
AD変換器入力の最適値設定は非常に操作が煩雑である
Conventional nuclear magnetic resonance apparatuses vary the gain of the high-frequency amplifier or the amount of attenuation of the high-frequency attenuator by adjusting the settings on the operation panel, convert the dummy free induction attenuation signal into AD, and check the magnitude of the signal. The input level of the AD converter is set to be appropriate based on the operator's judgment. Generally, the free induction attenuation signal varies considerably depending on the measurement conditions, the measurement sample itself, the concentration of the sample, etc., and when monitoring with a CRT or the like, appropriate settings cannot be made at once and dummy signals must be taken many times. Further, the free induction decay signal requires a sufficiently long interval in consideration of the relaxation time of nuclear magnetic resonance (5), so setting the optimum value of the input to the AD converter is very complicated.

本発明は上記欠点を改良して自由誘導減衰信号のAD変
換器入力レベルの最適条件設定を迅速にしかも正確に行
う回路を提供する。
The present invention improves the above-mentioned drawbacks and provides a circuit that quickly and accurately sets the optimum condition for the AD converter input level of the free induction decay signal.

例えば一般に使用されるAD変換器は12ビツトであり
これは最小ピットは約4000分の1でADの入力レベ
ルが適当で全ビット有効に使用した時はデータの有効桁
数は3桁あるが入力レベルが低くて半分のビットのみ使
用しなければ最小ピットは64分の1で有効桁数は1桁
となる。
For example, commonly used AD converters are 12 bits, which means that the minimum pit is approximately 1/4000th, and when the AD input level is appropriate and all bits are used effectively, the number of effective digits of data is 3 digits. If the level is low and only half of the bits are used, the minimum pit will be 1/64 and the number of effective digits will be 1 digit.

一般に自由誘導減衰信号は観測時間の極ぐ初期の振幅が
一番大キく、その後は減衰して小さくなるので信号の初
期値がAD変換器の入力の大きさが問題になる。一方C
RT上では画面の制約などにより過渡現象の振幅を一度
で、精度よく読みとることは極めてむずかしい。そこで
ダミーの信号をAD変換して振幅の最大値全データ処理
装置が検出して、AD変換器のビット数と比較するすな
わち信号の振幅最大値とあらかじめ解っているAD変換
器の最大入力値を比較する。
Generally, the free induction decay signal has the largest amplitude at the very beginning of the observation time, and then it attenuates and becomes smaller, so the initial value of the signal is the magnitude of the input to the AD converter. On the other hand, C
On RT, it is extremely difficult to accurately read the amplitude of a transient phenomenon at once due to screen limitations and other factors. Therefore, the dummy signal is AD converted, the maximum amplitude value is detected by the total data processing device, and compared with the bit number of the AD converter.In other words, the maximum input value of the AD converter, which is known in advance to be the maximum amplitude value of the signal, is compare.

第1図、第2図に本発明の実施例を示す。直流磁石1に
よってつくられる均一な直流磁場の中に測定試料と送受
コイルとからなるプローブ2が置かれ、周波数源3でつ
くられる共鳴周波数をパルス状にして高周波電力増幅器
4で増幅してプローブ2に印加して試料に共鳴を励起さ
せるっその後の自由誘導減衰信号を低ノイズ高周波増幅
器5で増幅して可変減衰器6を介して高周波検波器7で
検波して低周波数の信号に変換し、観測周波数帯域のフ
ィルタを通し7てAD変換器8に人力する。
Embodiments of the present invention are shown in FIGS. 1 and 2. A probe 2 consisting of a measurement sample and a transmitting/receiving coil is placed in a uniform DC magnetic field created by a DC magnet 1, and the resonant frequency created by a frequency source 3 is made into a pulse and amplified by a high frequency power amplifier 4. is applied to excite resonance in the sample, and the subsequent free induction decay signal is amplified by a low-noise high-frequency amplifier 5, detected by a high-frequency detector 7 via a variable attenuator 6, and converted into a low-frequency signal, The signal is passed through a filter in the observation frequency band 7 and then input to an AD converter 8 .

AD変換された信号はデータ処理装置9に取込まれてフ
ーリエ変換の演算をして周波数領域のスペクトルにして
レコーダなどの記録装置に出方される。
The AD-converted signal is taken into the data processing device 9, subjected to Fourier transform calculations, and output as a frequency domain spectrum to a recording device such as a recorder.

指定された測定のデータ取込の前に下のフローチャート
のごとく高周波可変減衰器6の設定を行なう。先づ測定
条件が設定されるとそれに応じてあらかじめ高めに定め
らt′した値を減衰器6に設定してAD変換器の入力で
低く目に設定してダミーの自由誘導減衰信号(FID)
をADf換して振幅の最大値を検出する。その振幅の最
大値とAD変換器の最大値を比較し、その比に相当する
値を減衰器6に再設定する。その後指定された自由誘導
減衰信号をAD変換してデータ処理装置が取込む。この
取込まnたデータは常にAD変換器のビット数を最も有
効に使用したものとなる。
Before data acquisition for the specified measurement, the high frequency variable attenuator 6 is set as shown in the flowchart below. First, when the measurement conditions are set, a high predetermined value t' is set in the attenuator 6, and a low value is set at the input of the AD converter to generate a dummy free induction attenuation signal (FID).
is converted into ADf and the maximum value of the amplitude is detected. The maximum value of the amplitude is compared with the maximum value of the AD converter, and a value corresponding to the ratio is reset to the attenuator 6. Thereafter, the designated free induction attenuation signal is AD converted and taken in by the data processing device. This captured data always makes the most effective use of the number of bits of the AD converter.

本発明によれば従来装置において測定の都度性なってい
たAD変換器の入力レベルの煩雑な操作はなくなり、常
にAD変換器の入力レベルが最適に設定さ扛装置の性能
が向上する。
According to the present invention, the complicated operation of adjusting the input level of the AD converter, which was required each time a measurement is made in the conventional device, is eliminated, and the input level of the AD converter is always set to the optimum value, thereby improving the performance of the combing device.

複数の試料を自動的に測定したり、複数の測定モードを
自動的に連続して測定する場合は本発明が不可欠なもの
である。
The present invention is indispensable when automatically measuring a plurality of samples or automatically and continuously measuring a plurality of measurement modes.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は本発明の実施U」を示すブロック図、第2図は
動作内容を示すフローチャートである。 1・・・直流磁石、2・・・プローブ、3・・・周波数
源、4・・・高周波電力増幅器、5・・・高周波増幅器
、6山可変減衰器、7・・・検波器、8・・・AD変換
器、9・・・デ第  /  国 2 早 2  胆
FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a flowchart showing the operation details. DESCRIPTION OF SYMBOLS 1... DC magnet, 2... Probe, 3... Frequency source, 4... High frequency power amplifier, 5... High frequency amplifier, 6-peak variable attenuator, 7... Detector, 8...・・AD converter, 9...De No. 2 / Country 2 Early 2 Bile

Claims (1)

【特許請求の範囲】[Claims] 1、均一な直流磁場を発生する磁石と周波数源、高周波
電力増幅器、低ノイズ高周波増幅器、高周波検波器、A
D変換器、データ処理装置で構成さ扛るフーリエ変換形
核磁気共鳴装置において、データ処理装置により可変さ
れる高周波可変減衰器を備えることにより、測定条件設
定後ダミーの自由誘導減衰信号をAE変換してその最大
値とAD変換器の最大値の比を計算して、その比の値を
前記高周波可変減衰器に設定し、その状態で指定さnた
自由誘導減衰信号をデータ処理装置がAD変換して取込
むことを特徴とする核磁気共鳴装置。
1. Magnet and frequency source that generates a uniform DC magnetic field, high frequency power amplifier, low noise high frequency amplifier, high frequency detector, A
In a Fourier transform type nuclear magnetic resonance apparatus consisting of a D converter and a data processing device, a high-frequency variable attenuator that is varied by the data processing device is provided to perform AE conversion of the dummy free induction attenuation signal after setting measurement conditions. calculates the ratio between the maximum value and the maximum value of the AD converter, sets the value of the ratio in the high frequency variable attenuator, and in that state, the data processing device converts the specified free induction attenuation signal to the A nuclear magnetic resonance apparatus characterized by converting and importing.
JP56185305A 1981-11-20 1981-11-20 Nuclear magnetism resonator Pending JPS5887450A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP56185305A JPS5887450A (en) 1981-11-20 1981-11-20 Nuclear magnetism resonator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP56185305A JPS5887450A (en) 1981-11-20 1981-11-20 Nuclear magnetism resonator

Publications (1)

Publication Number Publication Date
JPS5887450A true JPS5887450A (en) 1983-05-25

Family

ID=16168527

Family Applications (1)

Application Number Title Priority Date Filing Date
JP56185305A Pending JPS5887450A (en) 1981-11-20 1981-11-20 Nuclear magnetism resonator

Country Status (1)

Country Link
JP (1) JPS5887450A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4806867A (en) * 1985-02-19 1989-02-21 Kabushiki Kaisha Toshiba Magnetic resonance imaging system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4806867A (en) * 1985-02-19 1989-02-21 Kabushiki Kaisha Toshiba Magnetic resonance imaging system

Similar Documents

Publication Publication Date Title
Hedeen et al. Characterization and prediction of gradient acoustic noise in MR imagers
Chu Comparison of reverberation measurements using Schroeder’s impulse method and decay‐curve averaging method
US5408880A (en) Ultrasonic differential measurement
Cohn Determination of reactor kinetic parameters by pile noise analysis
US4127813A (en) Method for balancing the sensitivity of two channels in a differential detection apparatus
US5432442A (en) Speed sensor including output signal proportional to air gap size
JPS5887450A (en) Nuclear magnetism resonator
JP2662406B2 (en) Data collection device for partial discharge measurement device
US11255900B2 (en) System and method for measuring repetitive complex and pulse modulated RF signals
CN110632535B (en) Noise suppression system and method suitable for proton magnetic precession signal
IL101177A (en) Method and apparatus for obtaining an NMR signal having a preselected frequency domain
JP3096370B2 (en) NQR signal measuring method and NQR device
JPS6252445A (en) Fourier transformation type nuclear magnetic resonance apparatus
JP3354491B2 (en) External noise removal method
SU1755230A1 (en) Seismic oscillation recording method
Tatsis et al. Instrumentation and Measurements of Magnetic Coil Schumann Resonance Receivers
SU1485097A1 (en) Method of recording signals of electron paramagnetic resonance
KR100282700B1 (en) Signal processing circuit of moisture measuring device using hydrogen nuclear magnetic resonance.
JP4811804B2 (en) Method for optimizing NMR measurement conditions
JPH0324991B2 (en)
JP2824765B2 (en) Nuclear magnetic resonance equipment
SU696327A1 (en) Stand for vibration-proofness testing of vehicle to be mounted on a vehicle
JPH085688A (en) Method and apparatus for measuring shield performance
SU1538141A1 (en) Extrapolation method of spectral analysis
SU819709A2 (en) Acoustical method of flaw detection