Optical fiber receiver and magnetic resonance imaging system

Abstract

The invention relates to an optical fiber receiver and a magnetic resonance imaging system, the optical fiber receiver comprises a single-ended to differential module, an anti-aliasing filtering module, an analog-to-digital conversion module and an optical fiber transceiver module, and the single-ended to differential module, the anti-aliasing filtering module, the analog-to-digital conversion module and the optical fiber transceiver module all adopt a non-magnetization design; wherein the single-ended to differential module is used for converting a received magnetic resonance signal into a differential signal, and outputting the differential signal to the anti-aliasing filtering module; the anti-aliasing filtering module is used for filtering the differential signal and outputting the filtered signal to the analog-to-digital conversion module; the analog-to-digital conversion module is used for performing analog-to-digital conversion on the filtered signal and outputting a digital signal obtained after conversion to the optical fiber transceiver module; and the optical fiber transceiver module is used for sending the digital signal to the spectrometer host through an optical fiber, so that the spectrometer host generates a magnetic resonance image based on the digital signal, thereby reducing the attenuation of the magnetic resonance signal in the transmission process and improving the quality of the magnetic resonance image.

Description

Technical Field

[0001] The present application relates to the field of signal processing technology, and in particular to an optical fiber receiver and a magnetic resonance imaging system. Background Art

[0002] The magnetic resonance imaging system is a device that performs medical diagnosis based on the principle of magnetic resonance imaging. The principle of magnetic resonance imaging is to use strong magnetic fields and radio frequency pulses of specific frequencies to act on the hydrogen nuclei in the human body, thereby stimulating the human body to produce magnetic resonance signals in a strong magnetic field environment. Since the magnetic resonance imaging system has a strong magnetic field, and many electronic devices cannot work in a strong magnetic field environment, the magnetic resonance imaging system is generally divided into two areas: the shielded room and the equipment room. The shielded room stores magnets with strong magnetic fields, and the equipment room stores electronic equipment, such as the spectrometer host that generates radio frequency signals and gradient signals, radio frequency signal amplifiers, and gradient signal amplifiers. The electronic equipment in the equipment room is connected to the radio frequency transmitting coil, gradient coil, and radio frequency receiving coil on the magnet in the shielded room through coaxial cables.

[0003] Since the magnetic resonance signal induced on the RF receiving coil is relatively weak, and the distance it is transmitted from the shielding room to the equipment through the coaxial cable is long, there are signal attenuation and external interference, which can easily lead to the problem of low quality of the final magnetic resonance image. Summary of the invention

[0004] The present application provides an optical fiber receiver and a magnetic resonance imaging system to solve the problem of low quality of magnetic resonance images finally formed by a traditional magnetic resonance imaging system.

[0005] In a first aspect, an embodiment of the present application provides an optical fiber receiver, the optical fiber receiver comprising: a single-ended differential conversion module, an anti-aliasing filter module, an analog-to-digital conversion module, and an optical fiber transceiver module, wherein the single-ended differential conversion module, the anti-aliasing filter module, the analog-to-digital conversion module, and the optical fiber transceiver module all adopt a non-magnetized design;

[0006] Wherein, the single-ended to differential module is used to convert the received magnetic resonance signal into a differential signal, and output the differential signal to the anti-aliasing filtering module;

[0007] The anti-aliasing filter module is used to filter the differential signal and output the filtered signal to the analog-to-digital conversion module;

[0008] The analog-to-digital conversion module is used to perform analog-to-digital conversion on the filtered signal, and output the digital signal obtained after the conversion to the optical fiber transceiver module;

[0009] The optical fiber transceiver module is used to send the digital signal to the spectrometer host through the optical fiber, so that the spectrometer host can generate a magnetic resonance image based on the digital signal.

[0010] Optionally, the single-ended to differential module includes a first capacitor, a second capacitor, a third capacitor, a first inductor and a second inductor, the first capacitor, the second capacitor and the third capacitor are all ceramic capacitors, and the first inductor and the second inductor are both non-magnetic winding inductors;

[0011] The first end of the first capacitor and the first end of the first inductor are used together as the first end of the single-ended to differential module to receive the magnetic resonance signal;

[0012] The second end of the first capacitor is connected to the first end of the second capacitor and the first end of the second inductor respectively, the second end of the first inductor is connected to the first end of the third capacitor, and the second end of the second inductor and the second end of the third capacitor are both connected to the ground end;

[0013] The second end of the second capacitor and the first end of the third capacitor serve together as the second end of the single-ended to differential conversion module, and are used to output the differential signal.

[0014] Optionally, the capacitance value of the first capacitor is equal to the capacitance value of the third capacitor, the inductance value of the first inductor is equal to the inductance value of the second inductor, and the capacitance value of the second capacitor is predetermined based on the phase adjustment amount required for the differential signal.

[0015] Optionally, the anti-aliasing filtering module includes a first low-pass filter and a band-pass filter cascaded to each other;

[0016] Wherein, the first low-pass filter is a third-order Chebyshev low-pass filter, and the band-pass filter is a second-order elliptic band-pass filter.

[0017] Optionally, the optical fiber receiver further includes a digital down-conversion module;

[0018] Wherein, the first end of the digital down-conversion module is connected to the second end of the analog-to-digital conversion module, and the second end of the digital down-conversion module is connected to the first end of the optical fiber transceiver module;

[0019] The digital down-conversion module is used to perform digital down-conversion processing on the digital signal converted by the analog-to-digital conversion module, and output the processed digital signal to the optical fiber transceiver module.

[0020] Optionally, the digital down-conversion module includes a first digital controlled oscillator, a first multiplier, a second multiplier and a second low-pass filter, and the first digital controlled oscillator, the first multiplier, the second multiplier and the second low-pass filter all adopt a field programmable logic gate array;

[0021] The first end of the first multiplier and the first end of the second multiplier are used together as the first end of the digital down-conversion module, for receiving the digital signal output by the analog-to-digital conversion module;

[0022] The first digital controlled oscillator is connected to the second end of the first multiplier and the second end of the second multiplier respectively, and the first digital controlled oscillator is used to output a first demodulation signal to the first multiplier and output a second demodulation signal to the second multiplier, and the frequencies of the first demodulation signal and the second demodulation signal are both equal to the frequency of the magnetic resonance signal;

[0023] The third end of the first multiplier and the third end of the second multiplier are respectively connected to the first end of the second low-pass filter, the first multiplier is used to multiply the digital signal with the first demodulated signal to obtain an I-channel orthogonal demodulated signal; the second multiplier is used to multiply the digital signal with the second demodulated signal to obtain a Q-channel orthogonal demodulated signal;

[0024] The second end of the second low-pass filter serves as the second end of the digital down-conversion module, and the second low-pass filter is used to filter the I-channel orthogonal demodulation signal and the Q-channel orthogonal demodulation signal to obtain a zero-frequency digital signal.

[0025] Optionally, the second low-pass filter includes a first cascaded integrator comb filter, a second cascaded integrator comb filter and a non-recursive filter;

[0026] The first cascaded integrator comb filter, the second cascaded integrator comb filter and the non-recursive filter are cascaded in sequence.

[0027] In a second aspect, an embodiment of the present application further provides a magnetic resonance imaging system, the magnetic resonance imaging system comprising the optical fiber receiver according to the first aspect, the magnetic resonance imaging system further comprising a spectrometer host, a radio frequency amplifier, a gradient amplifier, and a radio frequency transmitting coil, a gradient coil, and a radio frequency receiving coil located around the magnet;

[0028] Wherein, the spectrometer host is connected to the optical fiber receiver, the radio frequency amplifier and the gradient amplifier through optical fibers respectively;

[0029] The spectrometer host is used to send a radio frequency waveform generation command to the radio frequency amplifier, and the radio frequency amplifier is used to generate an analog radio frequency signal according to the radio frequency waveform generation command, and amplify the analog radio frequency signal and output it to the radio frequency transmitting coil;

[0030] The spectrometer host is also used to send a digital gradient waveform signal to the gradient amplifier, and the gradient amplifier is used to generate an analog gradient signal according to the digital gradient waveform signal, and amplify the analog gradient signal and output it to the gradient coil;

[0031] The optical fiber receiver is used to receive the magnetic resonance signal induced by the radio frequency receiving coil, and transmit the magnetic resonance signal to the spectrometer host through the optical fiber, so that the spectrometer host generates a magnetic resonance image based on the magnetic resonance signal.

[0032] Optionally, the spectrometer host has a built-in radio frequency transceiver module, the radio frequency amplifier has a built-in optical fiber radio frequency module, and the radio frequency transceiver module and the optical fiber radio frequency module are connected via an optical fiber;

[0033] Wherein, the RF transceiver module comprises a first optical fiber transceiver, and the RF transceiver module is used to send the RF waveform generation command to the optical fiber through the first optical fiber transceiver;

[0034] The optical fiber RF module includes a second optical fiber transceiver, a second digitally controlled oscillator, an RF waveform generator, a third multiplier and a first digital-to-analog converter. The first end of the second optical fiber transceiver is connected to the optical fiber, and the second end of the second optical fiber transceiver is respectively connected to the first end of the second digitally controlled oscillator and the first end of the RF waveform generator. The second optical fiber transceiver is used to receive the RF waveform generation command from the optical fiber, and transmit the RF waveform generation command to the second digitally controlled oscillator and the RF waveform generator; the second digitally controlled oscillator is used to generate a sinusoidal signal based on the RF waveform generation command, and the RF waveform generator is used to generate a RF waveform profile based on the RF waveform generation command;

[0035] The second end of the second digitally controlled oscillator and the second end of the RF waveform generator are both connected to the first end of the third multiplier, and the third multiplier is used to multiply the sinusoidal signal and the RF waveform profile to obtain a digital RF waveform signal;

[0036] The second end of the third multiplier is connected to the first end of the first digital-to-analog converter, the second end of the first digital-to-analog converter is connected to the RF transmitting coil, and the first digital-to-analog converter is used to perform digital-to-analog conversion on the digital RF waveform signal and send the converted analog RF signal to the RF transmitting coil.

[0037] Optionally, the spectrometer host is equipped with a built-in gradient generation module, the radio frequency amplifier is equipped with a built-in optical fiber gradient module, and the gradient generation module and the optical fiber gradient module are connected via an optical fiber;

[0038] Wherein, the gradient generation module includes a gradient waveform generator and a third optical fiber transceiver, the gradient waveform generator is connected to the third optical fiber transceiver, the gradient waveform generator is used to generate a digital gradient waveform signal, and send it to the optical fiber through the third optical fiber transceiver; the optical fiber gradient module includes a fourth optical fiber transceiver, a buffer and a second digital-to-analog converter, the first end of the fourth optical fiber transceiver is connected to the optical fiber, and is used to receive the digital gradient waveform signal from the optical fiber;

[0039] The second end of the fourth optical fiber transceiver is connected to the first end of the buffer, and the buffer is used to cache the digital gradient waveform signal;

[0040] The second end of the buffer is connected to the first end of the second digital-to-analog converter, the second end of the second digital-to-analog converter is connected to the gradient coil, and the second digital-to-analog converter is used to perform digital-to-analog conversion on the digital gradient waveform signal to obtain an analog gradient signal, and send the analog gradient signal to the gradient coil.

[0041] The above technical solution provided by the embodiment of the present application has the following advantages over the prior art: the optical fiber receiver provided by the embodiment of the present application includes: a single-ended to differential module, an anti-aliasing filter module, an analog-to-digital conversion module and an optical fiber transceiver module, wherein the single-ended to differential module, the anti-aliasing filter module, the analog-to-digital conversion module and the optical fiber transceiver module all adopt a non-magnetized design; wherein the first end of the single-ended to differential module is used to receive a magnetic resonance signal, the second end of the single-ended to differential module is connected to the first end of the anti-aliasing filter module, and the single-ended to differential module is used to convert the magnetic resonance signal into a differential signal, and output the differential signal to the anti-aliasing filter module; the second end of the anti-aliasing filter module is connected to the first end of the analog-to-digital conversion module, and the anti-aliasing filter module is used to filter the differential signal and output the filtered signal to the analog-to-digital conversion module; the second end of the analog-to-digital conversion module is connected to the first end of the optical fiber transceiver module, and the analog-to-digital conversion module is used to perform analog-to-digital conversion on the filtered signal and output the converted digital signal to the optical fiber transceiver module; the second end of the optical fiber transceiver module is used to send the digital signal to the spectrometer host through the optical fiber, so that the spectrometer host generates a magnetic resonance image based on the digital signal. In this way, since the single-ended differential module, anti-aliasing filter module, analog-to-digital conversion module and optical fiber transceiver module in the optical fiber receiver all adopt a non-magnetized design, the optical fiber receiver can also work normally in a strong magnetic field environment, so that the received magnetic resonance signal can be converted into analog-to-digital in the shielded room, and then transmitted to the spectrometer host through the optical fiber, thereby reducing the signal attenuation and external interference of the magnetic resonance signal during the transmission process, and improving the quality of the magnetic resonance image. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0043] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0044] Figure 1 A structural block diagram of an optical fiber receiver provided in an embodiment of the present application;

[0045] Figure 2 A circuit diagram of a single-ended to differential module provided in an embodiment of the present application;

[0046] Figure 3A circuit diagram of an anti-aliasing filter module provided in an embodiment of the present application;

[0047] Figure 4 A schematic diagram of the frequency characteristics of an anti-aliasing filter module provided in an embodiment of the present application;

[0048] Figure 5 A structural block diagram of another optical fiber receiver provided in an embodiment of the present application;

[0049] Figure 6 A structural block diagram of a digital down-conversion module provided in an embodiment of the present application;

[0050] Figure 7 A structural block diagram of a magnetic resonance imaging system provided in an embodiment of the present application;

[0051] Figure 8 A structural block diagram of a radio frequency transceiver module and an optical fiber radio frequency module provided in an embodiment of the present application;

[0052] Fig. 9 A structural block diagram of a gradient generating module and the optical fiber gradient module provided in an embodiment of the present application.

[0054] 100, optical fiber receiver; 110, single-ended to differential module; 120, anti-aliasing filter module; 130, analog-to-digital conversion module; 140, optical fiber transceiver module; C1, first capacitor; C2, second capacitor; C3, third capacitor; L1, first inductor; L2, second inductor; 1201, first low-pass filter; 1202, band-pass filter; 150, digital down-conversion module; 160, gain amplifier module; 1501, first digital controlled oscillator; 1502, first multiplier; 1503, second multiplier; 1504, second low-pass filter; 15041, first cascaded integral comb filter; 15042, second cascaded integral comb filter; 15043, non-recursive filter; 200, spectrometer host; 300, RF amplifier; 400, gradient amplifier; 500, RF transmitting coil; 600, gradient coil; 700, RF receiving coil; 210, RF transceiver module; 310, fiber RF module; 2101, first fiber transceiver; 3101, second fiber transceiver; 3102, second digital controlled oscillator; 3103, RF waveform generator; 3104, third multiplier; 3105, first digital-to-analog converter; 220, gradient generating module; 410, fiber gradient module; 2201, gradient waveform generator; 2202, third fiber transceiver; 4101, fourth fiber transceiver; 4102, buffer; 4103, second digital-to-analog converter. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0056] See also Figure 1 , Figure 1 This is a structural block diagram of an optical fiber receiver provided in an embodiment of the present application. Figure 1 As shown, the optical fiber receiver 100 includes: a single-ended differential conversion module 110, an anti-aliasing filter module 120, an analog-to-digital conversion module 130 and an optical fiber transceiver module 140, and the single-ended differential conversion module 110, the anti-aliasing filter module 120, the analog-to-digital conversion module 130 and the optical fiber transceiver module 140 all adopt a non-magnetized design;

[0057] The first end of the single-ended to differential module 110 is used to receive the magnetic resonance signal, the second end of the single-ended to differential module 110 is connected to the first end of the anti-aliasing filter module 120, and the single-ended to differential module 110 is used to convert the magnetic resonance signal into a differential signal, and output the differential signal to the anti-aliasing filter module 120;

[0058] The second end of the anti-aliasing filter module 120 is connected to the first end of the analog-to-digital conversion module 130, and the anti-aliasing filter module 120 is used to filter the differential signal and output the filtered signal to the analog-to-digital conversion module 130;

[0059] The second end of the analog-to-digital conversion module 130 is connected to the first end of the optical fiber transceiver module 140. The analog-to-digital conversion module 130 is used to perform analog-to-digital conversion on the filtered signal and output the converted digital signal to the optical fiber transceiver module 140.

[0060] The second end of the optical fiber transceiver module 140 is used to send the digital signal to the spectrometer host through the optical fiber, so that the spectrometer host generates a magnetic resonance image based on the digital signal.

[0061] Specifically, the above-mentioned single-ended to differential module 110, anti-aliasing filter module 120, analog-to-digital conversion module 130 and optical fiber transceiver module 140 all adopt a non-magnetized design. The non-magnetized design here refers to the removal of components such as magnetic beads and magnetic inductors, and the use of non-magnetic winding inductors, ceramic capacitors and other components to achieve the design.

[0062] After the fiber optic receiver 100 receives the simulated magnetic resonance signal, it can be transmitted and processed in sequence through the single-ended differential module 110, the anti-aliasing filter module 120, the analog-to-digital conversion module 130 and the optical fiber transceiver module 140, wherein the single-ended differential module 110 can be used to convert the single-ended magnetic resonance signal into a differential signal (i.e., two signals with a phase difference of 180°), which can not only meet the input requirements of most current high-speed analog-to-digital conversion modules for differential signals, but also ensure that the subsequent digital circuits can be laid out in the form of high-speed differential routing to improve the anti-interference ability. The anti-aliasing filter module 120 can be used to filter the differential signal to filter out the high-frequency component and the low-frequency component in the differential signal so that it meets the requirements of the sampling theorem, thereby preventing the occurrence of aliasing. The analog-to-digital conversion module 130 can be used to perform analog-to-digital conversion on the filtered signal to obtain the converted digital signal. The optical fiber transceiver module 140 can be used to send the digital signal to the spectrometer host through the optical fiber, so that the spectrometer host can generate a magnetic resonance image based on the digital signal.

[0063] Compared with the traditional magnetic resonance imaging system, since the receiver of the traditional magnetic resonance imaging system does not adopt a non-magnetized design, it must be installed in the equipment room, and the simulated magnetic resonance signal needs to be transmitted through a coaxial cable. This results in the simulated magnetic resonance signal needing to be transmitted through a longer coaxial cable, resulting in more serious signal attenuation and greater impact from external interference.

[0064] In the embodiment of the present application, since the single-ended to differential module 110, the anti-aliasing filter module 120, the analog-to-digital conversion module 130 and the optical fiber transceiver module 140 in the optical fiber receiver 100 all adopt a non-magnetized design, the optical fiber receiver 100 can work normally even in a strong magnetic field environment. Therefore, the received magnetic resonance signal can be converted into an analog-to-digital signal in a shielded room and then transmitted to the spectrometer host through the optical fiber, thereby reducing the signal attenuation and external interference of the magnetic resonance signal during the transmission process, thereby improving the quality of the magnetic resonance image.

[0065] In an alternative embodiment, see Figure 2 The single-ended to differential module 110 includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a first inductor L1 and a second inductor L2. The first capacitor C1, the second capacitor C2 and the third capacitor C3 are all ceramic capacitors, and the first inductor L1 and the second inductor L2 are both non-magnetic winding inductors;

[0066] The first end of the first capacitor and the first end of the first inductor are used together as the first end of the single-ended to differential module for receiving the magnetic resonance signal;

[0067] The second end of the first capacitor is connected to the first end of the second capacitor and the first end of the second inductor respectively, the second end of the first inductor is connected to the first end of the third capacitor, and the second end of the second inductor and the second end of the third capacitor are both connected to the ground end;

[0068] The second end of the second capacitor and the first end of the third capacitor serve together as the second end of the single-ended to differential conversion module, and are used to output a differential signal.

[0069] Specifically, since the first capacitor C1 , the second capacitor C2 and the third capacitor C3 are all ceramic capacitors, and the first inductor L1 and the second inductor L2 are all non-magnetic winding inductors, the single-ended to differential module 110 is not affected by a strong magnetic field environment.

[0070] It should be noted that the first capacitor C1, the third capacitor C3, the first inductor L1 and the second inductor L2 can be regarded as a traditional balun circuit design. Since it cannot output a completely ideal differential signal with a phase difference of 180° in actual applications, and since the capacitor has a lag effect on the AC signal (that is, the capacitor will change the phase of the AC signal), the second capacitor C2 is connected in series to adjust the capacitance value of the entire circuit, so as to output a precise differential signal with a phase difference of 180°.

[0071] Therefore, the single-ended to differential module 110 can output a differential signal with a precise phase difference of 180°, which can not only meet the input requirements of most current high-speed analog-to-digital conversion modules 130 for differential signals, but also ensure that the subsequent digital circuits can be laid out in the form of high-speed differential routing to improve anti-interference capabilities.

[0072] In an optional embodiment, the capacitance value of the first capacitor C1 is equal to the capacitance value of the third capacitor C3, the inductance value of the first inductor L1 is equal to the inductance value of the second inductor L2, and the capacitance value of the second capacitor C2 is predetermined based on the phase adjustment amount required for the differential signal.

[0073] Specifically, since the capacitance value of the first capacitor C1 is equal to the capacitance value of the third capacitor C3, the inductance value of the first inductor L1 is equal to the inductance value of the second inductor L2, the first capacitor C1, the third capacitor C3, the first inductor L1 and the second inductor L2 can be regarded as a traditional balun circuit design. Here, a second capacitor C2 is connected in series on the basis of it to output a differential signal with a precise phase difference of 180°. Among them, the capacitance value of the second capacitor C2 can be predetermined based on the phase adjustment amount required for the differential signal, and can be determined specifically by the following formula:

[0074] φ=-ωtC;

[0075] Wherein, φ represents the phase adjustment amount required for the differential signal, ω represents the angular frequency of the magnetic resonance signal, t represents time, and C represents the capacitance value of the second capacitor C2.

[0076] In this way, the capacitance value of the second capacitor C2 can be accurately determined according to the phase adjustment amount required for the differential signal, so that the single-ended to differential module 110 can output a differential signal with an accurate phase difference of 180°.

[0077] In an alternative embodiment, see Figure 3 , the anti-aliasing filtering module 120 includes a first low-pass filter 1201 and a band-pass filter 1202 which are cascaded to each other;

[0078] The first low-pass filter 1201 is a third-order Chebyshev low-pass filter, and the band-pass filter 1202 is a second-order elliptic band-pass filter 1202 .

[0079] Specifically, the first low-pass filter 1201 and the band-pass filter 1202 are both designed with non-magnetic winding inductors and ceramic capacitors. As an optional implementation, the first low-pass filter 1201 includes capacitor C4, capacitor C5, inductor L3 and inductor L4. The cut-off frequency of the first low-pass filter 1201 can be 16.4MHz. The band-pass filter 1202 includes capacitor C6, capacitor C7, capacitor C8, inductor L5, inductor L6 and inductor L7. The center frequency of the band-pass filter 1202 can be 13.89MHz, and the passband bandwidth can be 5MHz. In this way, the anti-aliasing filter module 120 can realize the function of the band-pass filter 1202 with a center frequency of 13.89MHz and a passband bandwidth of 5MHz, and its frequency characteristics are as follows: Figure 4 shown.

[0080] Therefore, the differential signal output by the single-ended to differential module 110 can be filtered by the anti-aliasing filtering module 120 to filter out high-frequency components and low-frequency components in the differential signal so that it meets the requirements of the sampling theorem, thereby preventing the occurrence of aliasing.

[0081] In an alternative embodiment, see Figure 5 , the optical fiber receiver 100 further includes a digital down-conversion module 150;

[0082] The first end of the digital down-conversion module 150 is connected to the second end of the analog-to-digital conversion module 130, and the second end of the digital down-conversion module 150 is connected to the first end of the optical fiber transceiver module 140;

[0083] The digital down-conversion module 150 is used to perform digital down-conversion processing on the digital signal converted by the analog-to-digital conversion module 130 , and output the processed digital signal to the optical fiber transceiver module 140 .

[0084] Specifically, the digital down-conversion module 150 can be connected in series between the analog-to-digital conversion module 130 and the optical fiber transceiver module 140. The digital down-conversion module 150 can be used to perform digital down-conversion processing on the digital signal output by the analog-to-digital conversion module 130, demodulate the frequency of the digital signal output by the analog-to-digital conversion module 130 to zero frequency, filter the zero-frequency digital signal, and then send the filtered zero-frequency digital signal to the optical fiber through the optical fiber transceiver module 140, and transmit it to the spectrometer host through the optical fiber. In this way, it helps to simplify the signal processing process and improve the anti-interference ability of the signal.

[0085] As an optional implementation, the optical fiber receiver 100 may further include a gain amplifier module 160, which may specifically be a digitally controlled variable gain amplifier. The gain amplifier module 160 may be connected in series between the single-ended to differential module 110 and the anti-aliasing filter module 120. The gain amplifier module 160 may be used to perform gain amplification on the differential signal output by the single-ended to differential module 110, and provide the gain-amplified differential signal to the anti-aliasing filter module 120. In this way, the differential signal may be gain amplified, which is helpful for signal processing.

[0086] In an alternative embodiment, see Figure 6 The digital down-conversion module 150 includes a first digital controlled oscillator 1501, a first multiplier 1502, a second multiplier 1503 and a second low-pass filter 1504, and the first digital controlled oscillator 1501, the first multiplier 1502, the second multiplier 1503 and the second low-pass filter 1504 all adopt field programmable logic gate arrays;

[0087] The first end of the first multiplier 1502 and the first end of the second multiplier 1503 are used together as the first end of the digital down-conversion module 150 to receive the digital signal output by the analog-to-digital conversion module 130;

[0088] The first digital controlled oscillator 1501 is connected to the second end of the first multiplier 1502 and the second end of the second multiplier 1503 respectively. The first digital controlled oscillator 1501 is used to output a first demodulation signal to the first multiplier 1502 and output a second demodulation signal to the second multiplier 1503. The frequencies of the first demodulation signal and the second demodulation signal are both equal to the frequency of the magnetic resonance signal.

[0089] The third end of the first multiplier 1502 and the third end of the second multiplier 1503 are respectively connected to the first end of the second low-pass filter 1504, the first multiplier 1502 is used to multiply the digital signal with the first demodulated signal to obtain an I-channel orthogonal demodulated signal; the second multiplier 1503 is used to multiply the digital signal with the second demodulated signal to obtain a Q-channel orthogonal demodulated signal;

[0090] The second end of the second low-pass filter 1504 serves as the second end of the digital down-conversion module 150 . The second low-pass filter 1504 is used to filter the I-channel orthogonal demodulation signal and the Q-channel orthogonal demodulation signal to obtain a zero-frequency digital signal.

[0091] Specifically, the first digital controlled oscillator 1501, the first multiplier 1502, the second multiplier 1503 and the second low-pass filter 1504 are all implemented by field programmable gate array (FPGA). The first digital controlled oscillator 1501 can be used to output the first demodulation signal to the first multiplier 1502, and output the second demodulation signal to the second multiplier 1503. The first multiplier 1502 can be used to multiply the digital signal with the first demodulation signal to obtain an I-way orthogonal demodulation signal, and the second multiplier 1503 can be used to multiply the digital signal with the second demodulation signal to obtain a Q-way orthogonal demodulation signal. In this way, I and Q two-way orthogonal demodulation signals are input to the second low-pass filter 1504, and I and Q two-way orthogonal demodulation signals are filtered via the second low-pass filter 1504 to obtain a digital signal of zero frequency. Finally, the digital signal of zero frequency is sent to the optical fiber by the optical fiber transceiver module 140, and transmitted to the spectrometer host by optical fiber. This helps simplify the signal processing process and improve the signal's anti-interference ability.

[0092] In an optional embodiment, the second low-pass filter 1504 includes a first cascaded integrator comb filter 15041, a second cascaded integrator comb filter 15042 and a non-recursive filter 15043;

[0093] Among them, the first cascaded integrator comb filter 15041, the second cascaded integrator comb filter 15042 and the non-recursive filter 15043 are cascaded in sequence.

[0094] Specifically, the second low-pass filter 1504 includes a first cascade integrator comb (Cascade Integrator Comb, referred to as CIC) filter, a second cascade integrator comb filter 15042 and a non-recursive (Finite Impulse Response, referred to as FIR) filter, which are cascaded in sequence. In this way, the second low-pass filter 1504 can be used to filter the zero-frequency digital signal.

[0095] In addition, the present application also provides a magnetic resonance imaging system. Figure 7The magnetic resonance imaging system includes a fiber optic receiver 100, and the magnetic resonance imaging system also includes a spectrometer host 200, a radio frequency amplifier 300, a gradient amplifier 400, and a radio frequency transmitting coil 500, a gradient coil 600 and a radio frequency receiving coil 700 located around the magnet;

[0096] The spectrometer host 200 is connected to the optical fiber receiver 100, the radio frequency amplifier 300 and the gradient amplifier 400 through optical fibers respectively;

[0097] The spectrometer host 200 is used to send a radio frequency waveform generation command to the radio frequency amplifier 300, and the radio frequency amplifier 300 is used to generate an analog radio frequency signal according to the radio frequency waveform generation command, and amplify the analog radio frequency signal and output it to the radio frequency transmitting coil 500;

[0098] The spectrometer host 200 is also used to send a digital gradient waveform signal to the gradient amplifier 400, and the gradient amplifier 400 is used to generate an analog gradient signal according to the digital gradient waveform signal, and amplify the analog gradient signal and output it to the gradient coil 600;

[0099] The optical fiber receiver 100 is used to receive the magnetic resonance signal sensed by the radio frequency receiving coil 700, and transmit the magnetic resonance signal to the spectrometer host 200 through the optical fiber, so that the spectrometer host 200 generates a magnetic resonance image based on the magnetic resonance signal.

[0100] Specifically, since the optical fiber receiver 100 adopts a non-magnetized design, it can be placed in a shielded room, and the optical fiber receiver 100 can usually be set next to the magnet. The radio frequency amplifier 300 and the gradient amplifier 400 can also be placed in a shielded room when the non-magnetized design is adopted. Of course, they can also be placed in an equipment room together with the spectrometer host 200, which is not specifically limited in the embodiment of the present application.

[0101] In the magnetic resonance imaging system, the spectrometer host 200 can send a radio frequency waveform generation command to the radio frequency amplifier 300, so that the radio frequency amplifier 300 can generate an analog radio frequency signal according to the radio frequency waveform generation command, and amplify the analog radio frequency signal and output it to the radio frequency transmitting coil 500. In addition, the spectrometer host 200 can also send a digital gradient waveform signal to the gradient amplifier 400, so that the gradient amplifier 400 can generate an analog gradient signal according to the digital gradient waveform signal, and amplify the analog gradient signal and output it to the gradient coil 600. Under the action of the analog gradient signal and the analog radio frequency signal, the radio frequency receiving coil 700 can sense the magnetic resonance signal generated by the human body, and the optical fiber receiver 100 can receive the magnetic resonance signal sensed by the radio frequency receiving coil 700, and transmit the magnetic resonance signal to the spectrometer host 200 through the optical fiber, so that the spectrometer host 200 can generate a magnetic resonance image based on the magnetic resonance signal.

[0102] Since the spectrometer host 200 is connected to the optical fiber receiver 100, the RF amplifier 300 and the gradient amplifier 400 respectively through optical fibers, and optical fibers have the advantages of low transmission loss, wide transmission bandwidth, strong anti-interference, and no influence of magnetic fields compared to coaxial cables, they are particularly suitable for data transmission in strong magnetic field environments. Using optical fiber to transmit signals can further enhance the signal's anti-interference ability.

[0103] In an alternative embodiment, see Figure 8 , the spectrometer host 200 has a built-in radio frequency transceiver module 210, the radio frequency amplifier 300 has a built-in optical fiber radio frequency module 310, and the radio frequency transceiver module 210 and the optical fiber radio frequency module 310 are connected via an optical fiber;

[0104] The RF transceiver module 210 includes a first optical fiber transceiver 2101, and the RF transceiver module 210 is used to send the RF waveform generation command to the optical fiber through the first optical fiber transceiver 2101;

[0105] The optical fiber RF module 310 includes a second optical fiber transceiver 3101, a second digitally controlled oscillator 3102, an RF waveform generator 3103, a third multiplier 3104 and a first digital-to-analog converter 3105. The first end of the second optical fiber transceiver 3101 is connected to the optical fiber, and the second end of the second optical fiber transceiver 3101 is respectively connected to the first end of the second digitally controlled oscillator 3102 and the first end of the RF waveform generator 3103. The second optical fiber transceiver 3101 is used to receive an RF waveform generation command from the optical fiber, and transmit the RF waveform generation command to the second digitally controlled oscillator 3102 and the RF waveform generator 3103; the second digitally controlled oscillator 3102 is used to generate a sinusoidal signal based on the RF waveform generation command, and the RF waveform generator 3103 is used to generate an RF waveform profile based on the RF waveform generation command;

[0106] The second end of the second digitally controlled oscillator 3102 and the second end of the RF waveform generator 3103 are both connected to the first end of the third multiplier 3104, and the third multiplier 3104 is used to multiply the sinusoidal signal and the RF waveform profile to obtain a digital RF waveform signal;

[0107] A second end of the third multiplier 3104 is connected to a first end of the first digital-to-analog converter 3105, a second end of the first digital-to-analog converter 3105 is connected to the RF transmitting coil 500, and the first digital-to-analog converter 3105 is used to perform digital-to-analog conversion on the digital RF waveform signal and send the converted analog RF signal to the RF transmitting coil 500.

[0108] Specifically, the RF waveform generation command can be generated and sent by the RF transceiver module 210, and the RF waveform generation command can be received by the optical fiber RF module 310 and digital-to-analog conversion can be performed to output an analog RF signal. The RF transceiver module 210 and the optical fiber RF module 310 are connected and communicated through optical fiber. This design can separate the RF generation function from the traditional spectrometer host 200 and generate RF waveform signals in a shielded room. The RF generation function can also be built into the RF amplifier 300 to achieve digital communication between the spectrometer host 200 and the RF amplifier 300.

[0109] like Figure 8 As shown, the left side of the figure is the FPGA in the fiber RF module 310, and the right side is the FPGA in the RF transceiver module 210 on the spectrometer host 200. The FPGA in the RF transceiver module 210 sends the RF waveform generation command to the optical fiber through the first optical fiber transceiver 2101, and transmits it to the fiber RF module 310 through the optical fiber. The FPGA in the optical fiber RF module 310 includes a second optical fiber transceiver 3101, a second numerically controlled oscillator 3102 (Numerically Controlled Oscillator, referred to as NCO), an RF waveform generator 3103, a third multiplier 3104 and a first digital-to-analog converter 3105. After receiving the RF waveform generation command transmitted from the optical fiber, the second optical fiber transceiver 3101 in the optical fiber RF module 310 transmits the command to the second digitally controlled oscillator 3102 and the RF waveform generator 3103. The second digitally controlled oscillator 3102 and the RF waveform generator 3103 generate a fixed-frequency sinusoidal signal and an RF waveform profile, respectively, and then pass through the third multiplier 3104 to output a fixed-frequency digital RF waveform signal with an RF waveform profile. Finally, the digital RF waveform signal is sent to the first digital-to-analog converter 3105 for digital-to-analog conversion, and finally an analog RF signal is output.

[0110] Through the above method, the RF generation function can be set inside the RF amplifier 300, optical fiber distributed RF generation can be achieved, and the anti-interference ability of the RF signal can be improved.

[0111] In an alternative embodiment, see Fig. 9 , the spectrometer host 200 has a built-in gradient generation module 220, the RF amplifier 300 has a built-in fiber gradient module 410, and the gradient generation module 220 and the fiber gradient module 410 are connected via an optical fiber;

[0112] Among them, the gradient generation module 220 includes a gradient waveform generator 2201 and a third optical fiber transceiver 2202, the gradient waveform generator 2201 is connected to the third optical fiber transceiver 2202, the gradient waveform generator 2201 is used to generate a digital gradient waveform signal, and send it to the optical fiber through the third optical fiber transceiver 2202; the optical fiber gradient module 410 includes a fourth optical fiber transceiver 4101, a buffer 4102 and a second digital-to-analog converter 4103, the first end of the fourth optical fiber transceiver 4101 is connected to the optical fiber, and is used to receive the digital gradient waveform signal from the optical fiber;

[0113] The second end of the fourth optical fiber transceiver 4101 is connected to the first end of the buffer 4102, and the buffer 4102 is used to buffer the digital gradient waveform signal;

[0114] The second end of the buffer 4102 is connected to the first end of the second digital-to-analog converter 4103, and the second end of the second digital-to-analog converter 4103 is connected to the gradient coil 600. The second digital-to-analog converter 4103 is used to perform digital-to-analog conversion on the digital gradient waveform signal to obtain an analog gradient signal, and send the analog gradient signal to the gradient coil 600.

[0115] Specifically, the gradient generating module 220 can generate a digital gradient waveform signal, and the optical fiber gradient module 410 converts the digital gradient waveform signal received through the optical fiber into an analog gradient signal by the second digital-to-analog converter 4103. This design can separate the gradient waveform generating function from the spectrometer host 200, so that the gradient waveform can be generated in the shielded room, and the gradient waveform generating module can also be built into the gradient amplifier 400 to realize digital communication between the spectrometer host 200 and the gradient amplifier 400.

[0116] like Fig. 9 As shown, the left side of the figure is the FPGA in the fiber gradient module 410, and the right side is the FPGA in the gradient emission module on the spectrometer host 200. The FPGA in the gradient emission module may include a gradient waveform generator 2201 and a third fiber transceiver 2202. The gradient waveform generator 2201 can generate three digital gradient waveform signals of X, Y and Z, and send them to the optical fiber through the third fiber transceiver 2202, and transmit them to the fiber gradient module 410 through the optical fiber. The FPGA in the fiber gradient module 410 includes a fourth fiber transceiver 4101, a buffer 4102 and a second digital-to-analog converter 4103. After the fourth fiber transceiver 4101 in the fiber gradient module 410 receives the three digital gradient waveform signals transmitted from the optical fiber, the three digital gradient waveform signals are first buffered in the buffer 4102, and then output in a certain timing sequence, and finally the three digital gradient waveform signals are sent to the second digital-to-analog converter 4103 for digital-to-analog conversion, and finally the three analog gradient signals of X, Y and Z are output.

[0117] Through the above method, the gradient waveform generation function can be built into the gradient amplifier 400, the fiber-distributed gradient generation can be realized, and the anti-interference ability of the gradient signal can be improved.

[0118] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0119] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. An optical fiber receiver, characterized in that: The optical fiber receiver comprises: a single-ended to differential module, an anti-aliasing filter module, an analog-to-digital conversion module and an optical fiber transceiver module, wherein the single-ended to differential module, the anti-aliasing filter module, the analog-to-digital conversion module and the optical fiber transceiver module all adopt a non-magnetized design; Wherein, the single-ended to differential module is used to convert the received magnetic resonance signal into a differential signal, and output the differential signal to the anti-aliasing filtering module; The anti-aliasing filter module is used to filter the differential signal and output the filtered signal to the analog-to-digital conversion module; The analog-to-digital conversion module is used to perform analog-to-digital conversion on the filtered signal, and output the digital signal obtained after the conversion to the optical fiber transceiver module; The optical fiber transceiver module is used to send the digital signal to the spectrometer host through the optical fiber, so that the spectrometer host can generate a magnetic resonance image based on the digital signal.

2. The optical fiber receiver according to claim 1, characterized in that: The single-ended to differential module includes a first capacitor, a second capacitor, a third capacitor, a first inductor and a second inductor, the first capacitor, the second capacitor and the third capacitor are all ceramic capacitors, and the first inductor and the second inductor are both non-magnetic winding inductors; The first end of the first capacitor and the first end of the first inductor are used together as the first end of the single-ended to differential module to receive the magnetic resonance signal; The second end of the first capacitor is connected to the first end of the second capacitor and the first end of the second inductor respectively, the second end of the first inductor is connected to the first end of the third capacitor, and the second end of the second inductor and the second end of the third capacitor are both connected to the ground end; The second end of the second capacitor and the first end of the third capacitor serve together as the second end of the single-ended to differential conversion module, and are used to output the differential signal.

3. The optical fiber receiver according to claim 2, characterized in that: The capacitance value of the first capacitor is equal to the capacitance value of the third capacitor, the inductance value of the first inductor is equal to the inductance value of the second inductor, and the capacitance value of the second capacitor is predetermined based on the phase adjustment amount required for the differential signal.

4. The optical fiber receiver according to claim 1, characterized in that: The anti-aliasing filtering module includes a first low-pass filter and a band-pass filter cascaded to each other; Wherein, the first low-pass filter is a third-order Chebyshev low-pass filter, and the band-pass filter is a second-order elliptic band-pass filter.

5. The optical fiber receiver according to claim 1, characterized in that: The optical fiber receiver also includes a digital down-conversion module; Wherein, the first end of the digital down-conversion module is connected to the second end of the analog-to-digital conversion module, and the second end of the digital down-conversion module is connected to the first end of the optical fiber transceiver module; The digital down-conversion module is used to perform digital down-conversion processing on the digital signal converted by the analog-to-digital conversion module, and output the processed digital signal to the optical fiber transceiver module.

6. The optical fiber receiver according to claim 5, characterized in that: The digital down-conversion module comprises a first digital controlled oscillator, a first multiplier, a second multiplier and a second low-pass filter, wherein the first digital controlled oscillator, the first multiplier, the second multiplier and the second low-pass filter all adopt a field programmable logic gate array; The first end of the first multiplier and the first end of the second multiplier are used together as the first end of the digital down-conversion module, for receiving the digital signal output by the analog-to-digital conversion module; The first digital controlled oscillator is connected to the second end of the first multiplier and the second end of the second multiplier respectively, and the first digital controlled oscillator is used to output a first demodulation signal to the first multiplier and output a second demodulation signal to the second multiplier, and the frequencies of the first demodulation signal and the second demodulation signal are both equal to the frequency of the magnetic resonance signal; The third end of the first multiplier and the third end of the second multiplier are respectively connected to the first end of the second low-pass filter, the first multiplier is used to multiply the digital signal with the first demodulated signal to obtain an I-channel orthogonal demodulated signal; the second multiplier is used to multiply the digital signal with the second demodulated signal to obtain a Q-channel orthogonal demodulated signal; The second end of the second low-pass filter serves as the second end of the digital down-conversion module, and the second low-pass filter is used to filter the I-channel orthogonal demodulation signal and the Q-channel orthogonal demodulation signal to obtain a zero-frequency digital signal.

7. The optical fiber receiver according to claim 6, characterized in that: The second low-pass filter comprises a first cascaded integrator comb filter, a second cascaded integrator comb filter and a non-recursive filter; The first cascaded integrator comb filter, the second cascaded integrator comb filter and the non-recursive filter are sequentially cascaded.

8. A magnetic resonance imaging system, characterized in that: The magnetic resonance imaging system comprises the optical fiber receiver according to any one of claims 1 to 7, and the magnetic resonance imaging system further comprises a spectrometer host, a radio frequency amplifier, a gradient amplifier, and a radio frequency transmitting coil, a gradient coil and a radio frequency receiving coil located around the magnet; Wherein, the spectrometer host is connected to the optical fiber receiver, the radio frequency amplifier and the gradient amplifier through optical fibers respectively; The spectrometer host is used to send a radio frequency waveform generation command to the radio frequency amplifier, and the radio frequency amplifier is used to generate an analog radio frequency signal according to the radio frequency waveform generation command, and amplify the analog radio frequency signal and output it to the radio frequency transmitting coil; The spectrometer host is also used to send a digital gradient waveform signal to the gradient amplifier, and the gradient amplifier is used to generate an analog gradient signal according to the digital gradient waveform signal, and amplify the analog gradient signal and output it to the gradient coil; The optical fiber receiver is used to receive the magnetic resonance signal induced by the radio frequency receiving coil, and transmit the magnetic resonance signal to the spectrometer host through the optical fiber, so that the spectrometer host can generate a magnetic resonance image based on the magnetic resonance signal.

9. The magnetic resonance imaging system according to claim 8, characterized in that: The spectrometer host has a built-in radio frequency transceiver module, the radio frequency amplifier has a built-in optical fiber radio frequency module, and the radio frequency transceiver module and the optical fiber radio frequency module are connected via an optical fiber; Wherein, the RF transceiver module comprises a first optical fiber transceiver, and the RF transceiver module is used to send the RF waveform generation command to the optical fiber through the first optical fiber transceiver; The optical fiber RF module includes a second optical fiber transceiver, a second digitally controlled oscillator, an RF waveform generator, a third multiplier and a first digital-to-analog converter. The first end of the second optical fiber transceiver is connected to the optical fiber, and the second end of the second optical fiber transceiver is respectively connected to the first end of the second digitally controlled oscillator and the first end of the RF waveform generator. The second optical fiber transceiver is used to receive the RF waveform generation command from the optical fiber, and transmit the RF waveform generation command to the second digitally controlled oscillator and the RF waveform generator; the second digitally controlled oscillator is used to generate a sinusoidal signal based on the RF waveform generation command, and the RF waveform generator is used to generate a RF waveform profile based on the RF waveform generation command; The second end of the second digitally controlled oscillator and the second end of the RF waveform generator are both connected to the first end of the third multiplier, and the third multiplier is used to multiply the sinusoidal signal and the RF waveform profile to obtain a digital RF waveform signal; The second end of the third multiplier is connected to the first end of the first digital-to-analog converter, the second end of the first digital-to-analog converter is connected to the RF transmitting coil, and the first digital-to-analog converter is used to perform digital-to-analog conversion on the digital RF waveform signal and send the converted analog RF signal to the RF transmitting coil.

10. The magnetic resonance imaging system according to claim 8, characterized in that The spectrometer host is equipped with a gradient generation module, the radio frequency amplifier is equipped with a fiber gradient module, and the gradient generation module and the fiber gradient module are connected via an optical fiber; Wherein, the gradient generation module includes a gradient waveform generator and a third optical fiber transceiver, the gradient waveform generator is connected to the third optical fiber transceiver, the gradient waveform generator is used to generate a digital gradient waveform signal, and send it to the optical fiber through the third optical fiber transceiver; the optical fiber gradient module includes a fourth optical fiber transceiver, a buffer and a second digital-to-analog converter, the first end of the fourth optical fiber transceiver is connected to the optical fiber, and is used to receive the digital gradient waveform signal from the optical fiber; The second end of the fourth optical fiber transceiver is connected to the first end of the buffer, and the buffer is used to cache the digital gradient waveform signal; The second end of the buffer is connected to the first end of the second digital-to-analog converter, the second end of the second digital-to-analog converter is connected to the gradient coil, and the second digital-to-analog converter is used to perform digital-to-analog conversion on the digital gradient waveform signal to obtain an analog gradient signal, and send the analog gradient signal to the gradient coil.

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