CN2896299Y - Novel digital spectrum instrument for nuclear magnetic resonance imaging system - Google Patents
Novel digital spectrum instrument for nuclear magnetic resonance imaging system Download PDFInfo
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- CN2896299Y CN2896299Y CN 200520113780 CN200520113780U CN2896299Y CN 2896299 Y CN2896299 Y CN 2896299Y CN 200520113780 CN200520113780 CN 200520113780 CN 200520113780 U CN200520113780 U CN 200520113780U CN 2896299 Y CN2896299 Y CN 2896299Y
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Abstract
The utility model designs a novel digital apparatus that is used in MRI, which is mainly composed of a RF emission module, a receiver and a gradient module. The apparatus adopts the most advanced digital signal processing technology and module-based design structure, so as to realize the full digitalization, generate any type of pulse sequence, meet the needs of the MRI method and provide a wide scope of working frequency. The apparatus is mainly developed oriented to the medical-used MRI system.
Description
Technical field
The utility model relates to a kind of nuclear magnetic resonance (NMR) instrument, is a kind of novel digital spectrum instrument that is used for Magnetic resonance imaging (MRI) specifically.
Background technology
The NMR technology has application widely as a kind of undamaged detection means in the fields such as structure analysis of MRI, chemical molecular.The NMR spectrometer in the MRI system as radio frequency (RF) pulse and gradient waveform produce, the power amplification of waveform, exciting and gradient pulse of radio frequency (RF) pulse, and to the sequential control system of the transmission courses such as acceptance of acquired signal, its major function is the accuracy of signal waveform in the control MRI system, the accurate sequential control of the undistorted and transmission course of transmission course, guarantee the corresponding signal that the relevant parts of MRI system produce, and these signals can co-ordination in the process of amplifying and transmitting.
Traditional analog spectrometer, the transmission control of its RF pulse, gradient pulse, and the relevant detection signal all is an analog quantity.This spectrometer complex structure, poor stability, easy-maintaining is not eliminated at present.Half digital spectrometer is that some producer partly changes input into digital device, and other parts still are analog device.This spectrometer still can't be eliminated the noise that analog device brings, and the volume and weight of spectrometer is all bigger.In order to overcome the above problems, need design a kind of except that with prime amplifier signal that the signal receiving coil directly links to each other, all controlled quentity controlled variables and detection limit are the digital spectrometer of digital quantity.The utility model provides design and has realized a kind of technology path of this class spectrometer.
Nuclear magnetic resonance spectrometer generally includes pulse-pattern generator, frequency synthesizer, transmission channel and receiving cable.Wherein, receiving cable can adopt single channel phase sensitive detection, simulation orthogonal detection or digital quadrature detection.Present digital spectrometer all adopts Study on Digital Phase Sensitive Detection.But the technology path that is adopted all needs frequency source that sinusoidal and cosine reference signal are provided.Study on Digital Phase Sensitive Detection that digital receiver module of the present utility model is used and common used technology path are different.The Study on Digital Phase Sensitive Detection that we adopt need not frequency source provides reference signal, only needs frequency source and quadrature switching to adopt same external clock as time reference.
Summary of the invention
The purpose of the utility model patent is the weak point at above-mentioned analog spectrometer or half digital spectrometer, a kind of new NMR digital spectrum instrument is provided, the digital receiver of this spectrometer adopts quadrature switching and wave digital lowpass filter that the NMR signal that receives is carried out detection, provides reference signal and need not frequency source.
To achieve these goals, the utility model has adopted following technical scheme:
A kind of novel digital spectrum instrument that is used for Magnetic resonance imaging is characterized in that mainly being made up of radiofrequency emitting module, digital receiver module, gradient modules, and wherein said radiofrequency emitting module comprises:
Be used to control the programmable pulse generator of Direct Digital Frequency Synthesizers, its output connects described Direct Digital Frequency Synthesizers;
Be used to produce the Direct Digital Frequency Synthesizers of radiofrequency signal, its output connects analog filter;
Be used for described radiofrequency emitting module input signal is carried out the described analog filter of filtering, its output is connected with described receiver module by transmitter;
Described digital receiver module comprises:
Be used for to the NMR signal that receiver module receives independently amplify from main amplifier, its output connects analog to digital converter;
Be used to produce the described analog to digital converter of digital signal, its output connects quadrature switching;
Be used for the described quadrature switching to described digital demodulation signal, its output connects digital bandwidth filter;
The described digital bandwidth wave filter that is used for filtering, its output connects system for computer control and interface;
Described gradient modules comprises:
Be used to produce the programmable pulse generator of the gradient waveform digital signal of needs, be connected with described computing machine with interface module by computer system control, its output connects digital analog converter;
Be used for the gradient waveform digital signal is become the described digital simulation converter of voltage pulse signal, its output connects the gradient amplifying unit.
The analog filter of described radiofrequency emitting module can adopt the analog filter group.
The analog to digital converter of described digital receiver module can adopt the high speed analog-digital converter that the NMR signal that receives directly can be changed into digital signal.
The digital bandwidth wave filter of described digital receiver module can adopt the wave digital lowpass filter that can carry out digital phase sensitivity detection with quadrature switching.
Described quadrature switching can be provided with the switch signal generator that it is controlled.
Described switch signal generator can be provided with the timing sequencer that it is controlled.
Described radiofrequency emitting module, digital receiver module, gradient modules can all be connected to same master clock generator.
The utlity model has following advantage:
1, the frequency source of radiofrequency emitting module has partly adopted Direct Digital Frequency Synthesizers, and it has high frequency definition, extremely Duan switching time, and digital modulation function.
2, digital receiver partly adopts Study on Digital Phase Sensitive Detection, can eliminate the shortcoming that simulation orthogonal detection technology exists, and need not the reference signal that frequency source provides simultaneously.
Description of drawings
Fig. 1 is the theory diagram of digital spectrum instrument;
Fig. 2 is the digital phase sensitivity detection sequential chart.
Embodiment
The utility model feature and correlated characteristic thereof are described in further detail by example below in conjunction with accompanying drawing, so that technician's of the same trade understanding:
As shown in Figure 1, the NMR spectrometer of the utility model realization is made up of radiofrequency emitting module, receiver module, gradient modules.Wherein, the digital receiver module adopts quadrature switching and wave digital lowpass filter to carry out detection to received signal, produces reference signal and need not frequency source.
Radiofrequency emitting module of the present utility model comprises programmable pulse compositor, Direct Digital Frequency Synthesizers and analog filter composition.The programmable pulse generator is controlled and data transfer with interface module by system's control by computing machine.Direct Digital Frequency Synthesizers can directly produce the radiofrequency signal through amplitude modulation, frequency modulation and phase modulation, can deliver to transmitter through behind the analog filter.
Receiver module of the present utility model comprises analog-digital converter, quadrature switching and wave digital lowpass filter group.In order to realize total digitalization, at first the signal that receives is carried out analog to digital conversion, therefore need analog-digital converter at a high speed.Quadrature switching and wave digital lowpass filter carry out digital phase sensitivity detection to the digital signal that receives under the control of switch signal generator.Remove the digital signal of carrier wave and deliver to computing machine through system's control and interface module.
Gradient modules of the present utility model comprises digital analog converter group and programmable pulse generator.Computing machine produces the gradient waveform digital signal that needs by system's control and interface module control programmable pulse generator, becomes voltage pulse signal through the analog-digital converter group at last, and delivers to the gradient amplifying unit.
Radiofrequency emitting module in the utility model, receiver module, gradient modules all adopt same master clock generator.
Concrete workflow is: when carrying out pulse train, the programmable pulse generator is carried out corresponding pulse train code according to the requirement of nmr experiments, the control Direct Digital Frequency Synthesizers.At first, stimulating frequency, amplitude and phase place by the computer installation Direct Digital Frequency Synthesizers are sent to pulse producer with data, and are produced the radio-frequency pulse of specified width, which width by pulse producer control direct synthesizer.Radio-frequency pulse is delivered to the radio frequency amplifying unit through the analog filter group.Signal by radio-frequency sending coil forms electromagnetic field.After the radio-frequency pulse that sample is launched coil excites, receiving coil will be sensed FID (free induction decay) signal, deliver to the digital receiver module after amplifying through amplifying unit.After this, radiofrequency signal becomes digital signal through the high speed analog-digital converter, carries out digital phase sensitivity detection through quadrature switching and wave digital lowpass filter group again.Digital signal after demodulation is delivered to computing machine by system's control with interface module, carries out image reconstruction or signal analysis by corresponding software in computing machine.
Direct Digital Frequency Synthesizers can select for use different devices to realize, for example adopts the AD9854 of Analog Devices company.
The programmable pulse generator of radiofrequency emitting module and gradient modules can adopt programmable logic device (PLD) FPGA or CPLD to realize.Pulse train and pulse waveform and gradient waveform at first were converted into the Time And Event table before carrying out, write pulse producer by PC.
The Study on Digital Phase Sensitive Detection that the digital receiver module adopts is as shown in Figure 2: the FID signal of the digital signal that obtains through analog to digital conversion after for modulation, need carry out demodulation by quadrature switching and wave digital lowpass filter, and can obtain required FID signal.Wherein, (a) being quadrature switching, is the sequential chart of the mutually orthogonal switching signal of two-way (d) and (g), and the quadrature switching signal frequency is identical with the received signal carrier frequency.(b) being received signal, (c) is wave digital lowpass filter.(e) and (h) be respectively the signal after the quadrature switching modulation.(f) and (i) be respectively (e) and (h) through wave digital lowpass filter filtered signal.In addition, can also the quadrature switching signal frequency be set to half of received signal carrier frequency, the quadrature switching signal with same frequency is modulated again after the ovennodulation low-pass filtering, can play the effect of demodulation again through low-pass filtering.The digital receiver module can use digital signal processor (DSP) to realize.
Claims (7)
1, a kind of novel digital spectrum instrument that is used for Magnetic resonance imaging is characterized in that mainly being made up of radiofrequency emitting module, digital receiver module, gradient modules, wherein
Described radiofrequency emitting module comprises:
Be used to control the programmable pulse generator of Direct Digital Frequency Synthesizers, its output connects described Direct Digital Frequency Synthesizers;
Be used to produce the Direct Digital Frequency Synthesizers of radiofrequency signal, its output connects analog filter;
Be used for described radiofrequency emitting module input signal is carried out the described analog filter of filtering, its output is connected with described receiver module by transmitter;
Described digital receiver module comprises:
Be used for to the NMR signal that receiver module receives independently amplify from main amplifier, its output connects analog to digital converter;
Be used to produce the described analog to digital converter of digital signal, its output connects quadrature switching;
Be used for the described quadrature switching to described digital demodulation signal, its output connects digital bandwidth filter;
The described digital bandwidth wave filter that is used for filtering, its output connects system for computer control and interface;
Described gradient modules comprises:
Be used to produce the programmable pulse generator of the gradient waveform digital signal of needs, be connected with described computing machine with interface module by computer system control, its output connects digital analog converter;
Be used for the gradient waveform digital signal is become the described digital simulation converter of voltage pulse signal, its output connects the gradient amplifying unit.
2, a kind of novel digital spectrum instrument according to claim 1 is characterized in that the analog filter of described radiofrequency emitting module adopts the analog filter group.
3, a kind of novel digital spectrum instrument according to claim 1 is characterized in that the analog to digital converter of described digital receiver module adopts the high speed analog-digital converter that the NMR signal that receives directly can be changed into digital signal.
4, a kind of novel digital spectrum instrument according to claim 1 is characterized in that the digital bandwidth wave filter of described digital receiver module adopts the wave digital lowpass filter that can carry out digital phase sensitivity detection with quadrature switching.
5, a kind of novel digital spectrum instrument according to claim 1 is characterized in that described quadrature switching is provided with the switch signal generator that it is controlled.
6, a kind of novel digital spectrum instrument according to claim 5 is characterized in that described switch signal generator is provided with the timing sequencer that it is controlled.
7, a kind of novel digital spectrum instrument according to claim 1 is characterized in that described radiofrequency emitting module, digital receiver module, gradient modules all connect same master clock generator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200520113780 CN2896299Y (en) | 2005-07-18 | 2005-07-18 | Novel digital spectrum instrument for nuclear magnetic resonance imaging system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200520113780 CN2896299Y (en) | 2005-07-18 | 2005-07-18 | Novel digital spectrum instrument for nuclear magnetic resonance imaging system |
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| Publication Number | Publication Date |
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| CN2896299Y true CN2896299Y (en) | 2007-05-02 |
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| CN 200520113780 Expired - Lifetime CN2896299Y (en) | 2005-07-18 | 2005-07-18 | Novel digital spectrum instrument for nuclear magnetic resonance imaging system |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102269721A (en) * | 2011-05-16 | 2011-12-07 | 杨晓冬 | Sample broadband detection method applied to nuclear magnetic resonance chemical analyzer |
| CN102551722A (en) * | 2012-01-12 | 2012-07-11 | 辽宁开普医疗系统有限公司 | Full digital spectrometer-based magnetic resonance imaging system |
| CN105891754A (en) * | 2016-03-03 | 2016-08-24 | 哈尔滨医科大学 | Multisource frequency spectrum spectrometer control system for multi-nuclear magnetic resonance |
-
2005
- 2005-07-18 CN CN 200520113780 patent/CN2896299Y/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102269721A (en) * | 2011-05-16 | 2011-12-07 | 杨晓冬 | Sample broadband detection method applied to nuclear magnetic resonance chemical analyzer |
| CN102269721B (en) * | 2011-05-16 | 2014-07-23 | 杨晓冬 | Sample broadband detection method applied to nuclear magnetic resonance chemical analyzer |
| CN102551722A (en) * | 2012-01-12 | 2012-07-11 | 辽宁开普医疗系统有限公司 | Full digital spectrometer-based magnetic resonance imaging system |
| CN105891754A (en) * | 2016-03-03 | 2016-08-24 | 哈尔滨医科大学 | Multisource frequency spectrum spectrometer control system for multi-nuclear magnetic resonance |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Expiration termination date: 20150718 Granted publication date: 20070502 |
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| EXPY | Termination of patent right or utility model |