JPS59116041A - High frequency transceiver circuit for nuclear magnetic resonance imaging equipment - Google Patents
High frequency transceiver circuit for nuclear magnetic resonance imaging equipmentInfo
- Publication number
- JPS59116041A JPS59116041A JP57230451A JP23045182A JPS59116041A JP S59116041 A JPS59116041 A JP S59116041A JP 57230451 A JP57230451 A JP 57230451A JP 23045182 A JP23045182 A JP 23045182A JP S59116041 A JPS59116041 A JP S59116041A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- magnetic resonance
- nuclear magnetic
- high frequency
- amplifier
- 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
Links
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
- G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
- G01R33/36—Electrical details, e.g. matching or coupling of the coil to the receiver
- G01R33/3614—RF power amplifiers
Landscapes
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Amplifiers (AREA)
- Transceivers (AREA)
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
【発明の詳細な説明】
この発明は、核磁気共鳴＜ Ｎ Ｍ Ｒ＞映ｉ装置用高
周波送受信回路に関し、特に、非送信時にＪ３Ｇ：する
送信機ノイズを主発生源にて梢（や的に抑制したＮ〜Ｉ
Ｒ映像装置用高周波送受信回路に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high frequency transmitting/receiving circuit for nuclear magnetic resonance (NMR) imaging equipment, and in particular, to a high frequency transmitter/receiver circuit for a nuclear magnetic resonance <NMR> imaging device, in particular, the main source of transmitter noise during non-transmission is Suppressed N~I
The present invention relates to a high frequency transmitting/receiving circuit for an R video device.
一般にＮ Ｍ Ｒ映像装置用高周波送受信回路は、第１
図に要部を示すように構成され、高周波信号発生回路（
１）で発生した励起高周波パルス信号を電力増幅回路（
２）で大出力化してタイオード（３ａ）（３ｂ）からな
るスイッチング回路（３）を介してアンテナタンクコイ
ル（４）より発信させ、これによってタンクコイル内に
均一性の良い高周波磁場を作るものである。Generally, a high frequency transmitting/receiving circuit for an NMR video device has a first
The main parts are shown in the figure, and the high-frequency signal generation circuit (
The excitation high-frequency pulse signal generated in 1) is passed through a power amplifier circuit (
In step 2), the output is increased to a high level and transmitted from the antenna tank coil (4) via the switching circuit (3) consisting of diodes (3a) and (3b), thereby creating a highly uniform high-frequency magnetic field within the tank coil. be.
ところで、従来の電力増幅回路は、使用部品とくに半導
体部品の特性上の制約から多数の電力増幅器を並設した
分布増幅回路とされることが多く、かつ電力増幅器とし
ては、′（１級あるいはＢ級増幅器が用いられている。By the way, conventional power amplifier circuits are often distributed amplifier circuits in which a large number of power amplifiers are arranged in parallel due to restrictions on the characteristics of the parts used, especially semiconductor parts. A class amplifier is used.
しかし、Ａ級増幅器は、無人力信号時においても能動素
子がカット・オフにならず、Ｂ級増幅器においても零入
力時の対向回路の非平衡性により、高周波雑音電流を発
生ずる。この９１１音電流は、ダイオードの特性値（い
わゆる肩電圧）より小さい信−号であるが、ダイオード
・スイッチング回路を介１ノでアンテナ・コイルに伝わ
り、微弱な送信機ノイズとなる。ところが、ＮＭＲ信号
が数ｎＷから数ｍＷ程度の小さな信号であるため、ＮＭ
Ｒ信号に対してこの送信機ノイズは無視できないものと
なり、ＮＭＲ信号の観測の妨害となる。However, in a class A amplifier, the active elements do not cut off even when an unmanned signal is applied, and in a class B amplifier, high frequency noise current is generated due to the unbalanced nature of the opposing circuit at the time of zero input. Although this 911 sound current is a signal smaller than the characteristic value of the diode (so-called shoulder voltage), it is transmitted to the antenna coil via the diode switching circuit and becomes weak transmitter noise. However, since the NMR signal is a small signal ranging from several nW to several mW, the NM
This transmitter noise cannot be ignored for the R signal and interferes with the observation of the NMR signal.
この発明は、このような事情に鑑みてなされたもので、
端的にｊホペれば、電力増幅器の構成を工夫することに
よって上記ノイズの発生を発生源にて抑制したＮＭＲ映
像装置用高周波送受信回路を提供するものである。This invention was made in view of these circumstances,
In short, the present invention provides a high frequency transceiver circuit for an NMR imaging device in which the generation of the above noise is suppressed at the source by devising the configuration of the power amplifier.
以下、第２図〜第４図に示すこの発明の一実施例に基い
て、この発明を詳説する。ただし、これによりこの発明
が限定されるものではない。Hereinafter, this invention will be explained in detail based on an embodiment of the invention shown in FIGS. 2 to 4. However, this invention is not limited thereby.
第２図に示す０４）は、この発明のＮ Ｍ Ｒ映像装置
用高周波送受信回路の一実施例であり、外部トリガー（
パルス入力信号）により起動する高周波信号発生回路（
６）、後記、電力増幅回路（８）およびフィルタ回路（
９）で生じる歪をあらかじめを逆補正しておくための歪
発生回路（７）、電力増幅回路（８）、フィルタ回路（
９）、スイッチング回路（１０１（１２１、ＲＦ均一磁
界を発生せしめるアンテナタンクコイル（Ｉｌｌ Ｊ５
よびＮ Ｍ Ｒ信号を効率よく増幅４−るための前置増
幅器０３）からなっている。04) shown in FIG. 2 is an embodiment of the high frequency transmitting/receiving circuit for an NMR video device according to the present invention, and the external trigger (
A high-frequency signal generation circuit (pulse input signal) activated by a
6), Postscript, power amplifier circuit (8) and filter circuit (
9), a distortion generation circuit (7), a power amplifier circuit (8), and a filter circuit (
9), switching circuit (101 (121), antenna tank coil (Ill J5) that generates an RF uniform magnetic field
and a preamplifier 03) for efficiently amplifying the NMR signal.
高周波信号発生回路（６）、スイッチング回路＋ｌｏｔ
（＋２＋ 。High frequency signal generation circuit (6), switching circuit +lot
(+2+.
アンテナタンクコイルｔ１１） 、およびＮＭＲ信号前
置回路０３）は、従来と同様の構成である。The antenna tank coil t11) and the NMR signal pre-circuit 03) have the same configuration as the conventional one.
歪発生回路（７）は、次に説明する電力増幅回路（８）
がＣ級増幅であることから発生づる信号歪をキャンセル
するために予めその歪を逆補正づるような歪を入力信号
に加える回路である。この回路はアナログ的にも構成で
きるが、デジタル的に構成してもよい。The distortion generation circuit (7) is a power amplifier circuit (8) which will be explained next.
This is a circuit that adds distortion to the input signal in advance so as to inversely correct the distortion in order to cancel the signal distortion that occurs because it is a class C amplification. This circuit can be constructed analogously, but may also be constructed digitally.
電力増幅回路（８）は、第３図に示１ように、電力増幅
器（１７）を多数用いた分布増幅回路である。それら電
力増幅器ａ力は、Ｃ級増幅器としてバイアスされた２個
のトランジスタ［＋５１ 、 （１６１にてプッシュプ
ル増幅器を構成したものである。バイアスの深さは、第
４図のように１−ランジスタ（１５） 、 （１６）が
無信号人ツノ時に完全にカット・オフになることおよ６
微小ノイズ入力に対してもカッ１−・オフであることを
条件としてなるべくＢ級に近く設定される。膜言づれば
、実際の使用にあたり適宜定まる範囲の微小入力に対し
無出力で、それを越えて定格人力までの入力に対し線型
どなるＪ：うにバイアスがあたえられる。そこで第３図
の電力増幅器（１７＋の場合、ＥＢＢの値をたとえばＯ
としてもよい場合がある。The power amplifier circuit (8) is a distributed amplifier circuit using a large number of power amplifiers (17), as shown in FIG. These power amplifiers are configured as push-pull amplifiers with two transistors [+51, (161) biased as class C amplifiers. (15) and (16) may be completely cut off when there is no signal.
It is set as close to class B as possible on the condition that it is cut-off even in response to minute noise input. In other words, there is no output for small inputs within a range that is appropriately determined in actual use, and a linear bias is applied for inputs beyond this range up to the rated human power. Therefore, in the case of the power amplifier shown in Fig. 3 (17+), the value of EBB is set to 0, for example.
In some cases, it may be possible to do so.
なんとなれば、トランジスタ０５）、 （１６１のベー
ス電流は、ある稈度以上の入力電圧がな（プれば流れな
いから、ＥＢＢ＝Ｏでも上記条件を満たすことがあるか
らである。This is because the base current of transistors 05) and 161 will not flow if the input voltage is higher than a certain culm, so the above condition may be satisfied even when EBB=O.
フィルタ回路（９）は、通常のバンドパス・フィルタで
ある。上記したＪζうに電力増幅器（１７）はＣ級プッ
シュプル回路であるから、出ツノ信号に歪を生じる。フ
ィルタ回路（９）は、その歪を吸収するもので、換言す
れば、実質的に核スピンを励起する周波数成分のみを通
過させて高周波成分を除去するものであり、ＮＭＲ映像
法としての高周波強度の変調時直線性をも保持ｕしめる
ものである。The filter circuit (9) is a normal bandpass filter. Since the Jζ power amplifier (17) described above is a class C push-pull circuit, distortion occurs in the output signal. The filter circuit (9) absorbs the distortion. In other words, it passes only the frequency components that substantially excite nuclear spins and removes the high frequency components. This also maintains linearity during modulation.
さて、このＮＭＲ映像装置用高周波送受信回路（１４）
によれば、電力増幅回路（８）の電力増幅器（１７）が
Ｃ級増幅であるから、無人力信号時にはトランジスタｆ
１５＋ 、 ＋１６） 、が完全にカッ１〜・オフとな
り出力電流を流さない。そこで熱雑音なとのノイズの発
生が抑制され、ＮＭＲ信号を好適に観測できることとな
る。Now, this high frequency transmitting/receiving circuit (14) for NMR imaging equipment
According to , since the power amplifier (17) of the power amplifier circuit (8) is a class C amplification, the transistor f is
15+, +16) are completely turned off and no output current flows. Therefore, the generation of noise such as thermal noise is suppressed, and the NMR signal can be observed suitably.
他の実施例としては、電力増幅回路にミノｊ増幅機を単
独で用いて分布増幅回路としないもの、電力増幅回路の
出力に同調回路を用いてフィルタ回路の機能をもたせた
もの、ダーリントン接続した２個のトランジスタを一対
用いてＣ級プッシュプル電力増幅回路を構成し人出力化
したものなどが挙げられる。Other examples include one in which a Mino J amplifier is used alone in the power amplifier circuit without making it into a distributed amplifier circuit, one in which a tuning circuit is used for the output of the power amplifier circuit to provide the function of a filter circuit, and one in which a Darlington connection is used. For example, a class C push-pull power amplifier circuit is configured using a pair of two transistors to produce human output.
以上の説明から理解されるように、この発明は、ＮＭＲ
映１！！！装置用高周波送受信回路において、Ｃ級増幅
としてバイアスを加えた一対の能動素子でプッシュプル
増幅器を構成し、これを電力増幅回路に用い、さらにそ
の回路の入出力特性に実質的に直線性をもたせたことを
特徴とするものであり、これによって非送信時のノイズ
がカットされるから、Ｓ／Ｎ比が改善されて、好適にＮ
Ｍ Ｒ信号を観測できるようになる。すなわち、通常
の分析用Ｎ Ｍ Ｒ装置ではさほど問題にならない送信
機ノイズがＮＭＲ映像装置にＪ５いて問題となっていた
点を改良できる。As understood from the above explanation, the present invention is applicable to NMR
Movie 1! ! ! In high-frequency transmitter/receiver circuits for equipment, a push-pull amplifier is configured with a pair of biased active elements as a class C amplifier, and this is used in a power amplifier circuit, and the input/output characteristics of the circuit are made substantially linear. This is characterized by the fact that the noise during non-transmission is cut, the S/N ratio is improved, and the N
You will be able to observe MR signals. That is, it is possible to improve the problem that transmitter noise, which is not a problem in ordinary NMR apparatuses for analysis, is present in NMR imaging apparatuses.
第１図はＮＭＲ映像装四川高用波送受信回路の一般的な
構成説明図、第２図はこの発明のＮ ｆｖｌ Ｒ映像装
置用高周波送受信回路の一実施例の構成説明図、第３図
は第２図に示す回路における電力増幅回路の一例の回路
図である。第４図は第３図に示す回路におりるトランジ
スタの動作特性図である。
［１１（６１・・・高周波信号発生回路、［２１（８）
・・・電ツノ増幅回路、
＋３１００１０２１・・・ダイオード・スイッチング回
路、（４１（１１１・・・アンテナタンクコイル、（５
１（１４）・・・ＮＭＲ映像装置用高周波送受信回路、
（１５］ （１６１・・・トランジスタ、（１７）・・
・電力増幅器、
ＥＢＢ・・・バイアス電源。FIG. 1 is an explanatory diagram of the general configuration of a Sichuan high frequency transmitting and receiving circuit for NMR imaging equipment, FIG. 2 is an explanatory diagram of the configuration of an embodiment of the high frequency transmitting and receiving circuit for Nfvl R imaging equipment of the present invention, and FIG. 3 is a circuit diagram of an example of a power amplifier circuit in the circuit shown in FIG. 2. FIG. FIG. 4 is a diagram showing the operating characteristics of the transistor included in the circuit shown in FIG. 3. [11 (61...high frequency signal generation circuit, [21 (8)
... Electric horn amplifier circuit, +31001021 ... Diode switching circuit, (41 (111 ... Antenna tank coil, (5
1 (14)...High frequency transmitting and receiving circuit for NMR imaging equipment,
(15) (161...transistor, (17)...
・Power amplifier, EBB...bias power supply.
Claims (1)
プッシュプル増幅器を構成してこれを電力増幅回路に用
いると共に、その電力増幅回路の後段にＣ級増幅回路に
Ｊ３ける増幅素子切換え電圧ト１４近にて発生する高調
波成分を取りのぞくためのフィルタ回路を設け、これに
よってパルスＮＭＲ法における非送信時の微少な送信機
ノイズを積極的に制御し、核磁気共鳴信号を良好に取り
出し可能としたことを特徴とする核磁気共鳴映像装置用
高周波送受信回路。 ２、ミノｊ増幅回路の前段に、Ｃ級増幅回路による信号
歪をあらかじめ逆補正させるための歪発生回路が設けら
れてなる特許請求の範囲第１項記載の核磁気共鳴映像装
置用高周波送受信回路。[Claims] 1. A push-pull amplifier is configured with a pair of biased active elements as a class C amplifier, and this is used in a power amplifier circuit. A filter circuit is provided to remove harmonic components generated near the amplification element switching voltage t14, which actively controls minute transmitter noise during non-transmission in the pulsed NMR method, and improves nuclear magnetic resonance. A high-frequency transceiver circuit for a nuclear magnetic resonance imaging apparatus, characterized in that a signal can be extracted satisfactorily. 2. The high-frequency transmitting/receiving circuit for a nuclear magnetic resonance imaging apparatus according to claim 1, wherein a distortion generation circuit for reversely correcting signal distortion caused by the class C amplifier circuit is provided in advance of the Mino J amplifier circuit. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57230451A JPS59116041A (en) | 1982-12-23 | 1982-12-23 | High frequency transceiver circuit for nuclear magnetic resonance imaging equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57230451A JPS59116041A (en) | 1982-12-23 | 1982-12-23 | High frequency transceiver circuit for nuclear magnetic resonance imaging equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS59116041A true JPS59116041A (en) | 1984-07-04 |
Family
ID=16908079
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57230451A Pending JPS59116041A (en) | 1982-12-23 | 1982-12-23 | High frequency transceiver circuit for nuclear magnetic resonance imaging equipment |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59116041A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008298102A (en) * | 2007-05-29 | 2008-12-11 | Jasco Corp | Pressure leak device |
| US12370333B2 (en) | 2018-05-13 | 2025-07-29 | Ventec Life Systems, Inc. | Portable medical ventilator system using portable oxygen concentrators |
| US12440634B2 (en) | 2021-12-21 | 2025-10-14 | Ventec Life Systems, Inc. | Ventilator systems with integrated oxygen delivery, and associated devices and methods |
-
1982
- 1982-12-23 JP JP57230451A patent/JPS59116041A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008298102A (en) * | 2007-05-29 | 2008-12-11 | Jasco Corp | Pressure leak device |
| US12370333B2 (en) | 2018-05-13 | 2025-07-29 | Ventec Life Systems, Inc. | Portable medical ventilator system using portable oxygen concentrators |
| US12434026B2 (en) | 2018-05-13 | 2025-10-07 | Ventec Life Systems, Inc. | Portable medical ventilator system using portable oxygen concentrators |
| US12440634B2 (en) | 2021-12-21 | 2025-10-14 | Ventec Life Systems, Inc. | Ventilator systems with integrated oxygen delivery, and associated devices and methods |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH04352507A (en) | Amplifier | |
| US4039981A (en) | Variable impedance circuit | |
| US4403347A (en) | Antenna tuning circuit for AM radio receiver | |
| US4225827A (en) | Stabilization circuit for transistor RF power amplifiers | |
| US2870267A (en) | Arrangement for scanning and reproducing magnetic fields | |
| JPS59116041A (en) | High frequency transceiver circuit for nuclear magnetic resonance imaging equipment | |
| US6586994B2 (en) | Variable gain and low noise amplifier for received signals in imaging apparata | |
| EP0140430B1 (en) | Frequency multiplying circuit | |
| JPH06188643A (en) | High-frequency low-noise amplifier | |
| US3258695A (en) | Reflex receiver | |
| JPH08289171A (en) | CATV converter | |
| JPS63270036A (en) | magnetic resonance imaging device | |
| CA1086385A (en) | Audio frequency amplifiers | |
| US3383611A (en) | Amplifier with high input impedance | |
| EP4387110A1 (en) | Electric circuit fragment with transmit/receive switch topology | |
| EP2647123A1 (en) | Bias point setting for third order linearity optimization of class a amplifier | |
| Stern et al. | Transistor broadcast receivers | |
| JPH11317629A (en) | System using class D amplifier | |
| JPS60191525A (en) | common mode noise attenuator | |
| JP2001094362A (en) | Transmission amplifier | |
| GB1039407A (en) | Improvements in transistorized ultra high frequency receivers | |
| JPS6119205A (en) | Amplifier circuit | |
| Locanthi | Operational Amplifier Circuit for Hi-Fi | |
| CN119652263A (en) | A nuclear magnetic resonance preamplifier circuit | |
| Bishop | Amplifiers |