A signal acquisition apparatus, method and magnetic resonance apparatus

Abstract

The embodiment of the specification discloses a signal acquisition device, method and magnetic resonance equipment. The device comprises a signal acquisition module, a signal matching module, an analog-to-digital converter and a control module. The signal acquisition module acquires a magnetic resonance signal, at least part of the magnetic resonance signal being generated by excitation of multiple specific nuclei. The signal matching module comprises an adjustable capacitor unit and a radio frequency transformer. The adjustable capacitor unit adjusts the capacitance value according to the control signal to cooperate with the radio frequency transformer to receive the magnetic resonance signal and convert it into an analog differential signal. The analog-to-digital converter converts the analog differential signal into a digital signal. The control module processes the digital signal to generate K-space data corresponding to the magnetic resonance signal. The control module comprises an analysis unit which analyzes the instruction of the host computer and generates the control signal. The embodiment of the specification designs a receiving link based on the direct sampling architecture of the analog-to-digital converter. The signal demodulation can be performed in the digital domain, thereby shortening the receiving link and improving the integration.

Description

Technical Field

[0001] This specification relates to the field of signal acquisition, and in particular to a signal acquisition device, method and magnetic resonance device. Background Technology

[0002] Signal acquisition devices typically acquire specific signals and perform analog-to-digital conversion and demodulation on these signals for analysis or experimentation. For example, in medical magnetic resonance (MRI) or nuclear magnetic resonance (NMR) equipment, multi-nucleoside MRI signal acquisition devices can acquire one or more MRI signals and output demodulated information corresponding to those signals.

[0003] However, current magnetic resonance or nuclear magnetic resonance equipment signal acquisition devices typically use traditional superheterodyne architecture to design the receiving link, which often demodulates the signal in the analog domain. This results in the receiving link needing to be equipped with many devices (such as mixers, compensation circuits, etc.) in the analog domain. The long receiving link can easily waste hardware resources, causing the overall design of the signal acquisition device to be uncoordinated and occupy too much space.

[0004] Therefore, it is necessary to propose a highly integrated signal acquisition device. Summary of the Invention

[0005] One embodiment of this specification provides a signal acquisition device. The device includes a signal acquisition module, a signal matching module, an analog-to-digital converter (ADC), and a control module. The signal acquisition module acquires a magnetic resonance signal, at least a portion of which is generated by the excitation of various specific nuclides. The signal acquisition module is connected to the signal matching module, which includes an adjustable capacitor unit and an RF transformer connected to each other. The adjustable capacitor unit adjusts its capacitance value according to a control signal to cooperate with the RF transformer in receiving the magnetic resonance signal and converting it into an analog differential signal. The signal matching module is connected to the ADC, which converts the analog differential signal into a digital signal. The ADC is connected to the control module, which processes the digital signal to generate K-space data corresponding to the magnetic resonance signal. The control module includes a parsing unit that parses instructions from a host computer and generates control signals.

[0006] In some embodiments, the signal acquisition module includes multiple sets of radio frequency receiving units, each set of radio frequency receiving units including a radio frequency receiving coil and an anti-aliasing filter, wherein the radio frequency receiving coil receives radio frequency signals of a specific nuclide frequency, and the anti-aliasing filter filters the radio frequency signals of the specific nuclide frequency to obtain a magnetic resonance signal.

[0007] In some embodiments, the signal acquisition device further includes a gain amplifier located between the anti-aliasing filter and the signal matching module, which is used to amplify the magnetic resonance signal according to the control signal.

[0008] In some embodiments, the adjustable capacitor unit includes one or more varactor components, wherein one varactor component includes two varactor diodes connected in parallel or in series.

[0009] In some embodiments, the radio frequency transformer includes one or more coreless balun transformers connected in series.

[0010] In some embodiments, the signal acquisition device further includes a clock generation module, which is disposed between the control module and the analog-to-digital converter. The clock generation module is used to generate a clock signal according to the instructions of the host computer. The analog-to-digital converter samples the analog differential signal according to the clock signal to obtain a digital signal. In some embodiments, the control module includes multiple data processing paths, each including a digital down-converter (DDC) module for decimating, filtering, and demodulating digital signals to obtain K-space data. The signal acquisition device also includes a switching module disposed between the analog-to-digital converter and the data processing paths. This switching module selects the data processing path corresponding to the clock signal, connects the data processing path to the analog-to-digital converter, and ensures that the data rate is equal after passing through any data processing path.

[0011] In some embodiments, the signal acquisition device further includes a counter module and a drive circuit. The counter module outputs digital pulses under the control of a control signal, which are then used by the drive circuit to generate a signal for adjusting the adjustable capacitor unit.

[0012] One embodiment of this specification provides a magnetic resonance imaging (MRI) device. The device includes: a scanner for generating a main magnetic field and exciting the nuclear spins of various specific nuclides of a detection object within the main magnetic field to generate a magnetic resonance signal; a radio frequency (RF) receiving coil connected to the scanner to receive the MRI signal; a receiving link including a gain amplifier, a signal matching module, and an analog-to-digital converter (ADC); the gain amplifier is connected to the receiving coil to amplify the MRI signal; the signal matching module includes an adjustable capacitor unit and an RF transformer connected to each other; the adjustable capacitor unit is connected to the gain amplifier, and its capacitance value is adjustable to cooperate with the RF transformer in receiving the amplified MRI signal and converting it into an analog differential signal; the ADC is connected to the RF transformer and is used to convert the analog differential signal into a digital signal; and a control module connected to the ADC, which processes the digital signal to generate K-space data corresponding to the MRI signal. The control module includes a parsing unit that parses instructions from a host computer and generates control signals.

[0013] One embodiment of this specification provides a signal acquisition method. This method is applied to the aforementioned signal acquisition device and includes: acquiring a magnetic resonance signal, at least a portion of which is generated by the excitation of multiple specific nuclides; parsing instructions from a host computer and generating a control signal, the control signal being used to adjust the capacitance value of an adjustable capacitor unit to cooperate with an radio frequency transformer in processing the magnetic resonance signal; and processing the magnetic resonance signal to generate K-space data corresponding to the magnetic resonance signal.

[0014] In the embodiments of this specification, the receiving link is designed based on the direct sampling architecture of the analog-to-digital converter. The receiving link does not require a mixer and can perform signal demodulation in the digital domain to generate K-space data corresponding to the magnetic resonance signal, thereby shortening the receiving link, reducing the overall size of the signal acquisition device, and improving the integration.

[0015] In addition, the signal matching module, through the cooperation of the adjustable capacitor unit and the RF transformer, can select a specific narrowband signal for transmission under broadband conditions, thereby achieving broadband tuning matching. The architecture is simple, and it can also reduce the intrusion of RF interference by using a narrower receiving frequency band, so that the signal acquisition device can work stably.

[0016] Furthermore, when it is necessary to acquire magnetic resonance signals generated by the excitation of other specific nuclides, the signal acquisition device does not need to replace the entire receiving link. By replacing the signal acquisition module and adjusting the capacitance value of the adjustable capacitor unit, the adjustable capacitor unit can work with the radio frequency transformer to adjust the receiving frequency band, thereby achieving the goal of receiving multiple different magnetic resonance signals with the same link architecture. Attached Figure Description

[0017] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0018] Figure 1 These are schematic diagrams of the medical device shown in some embodiments of this specification;

[0019] Figure 2 This is a schematic diagram of the signal acquisition device shown in some embodiments of this specification;

[0020] Figure 3 This is a schematic diagram of the signal acquisition device shown in some embodiments of this specification;

[0021] Figure 4A This is a schematic diagram of the structure of a parallel adjustable capacitor unit according to some embodiments of this specification;

[0022] Figure 4BThis is a schematic diagram of the structure of a series adjustable capacitor unit according to some embodiments of this specification;

[0023] Figure 5 This is a schematic flowchart illustrating a signal acquisition method according to some embodiments of this specification. Detailed Implementation

[0024] To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0025] It should be understood that the terms “system,” “device,” “unit,” and / or “module” used herein are one way to distinguish different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0026] As indicated in this specification and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0027] Flowcharts are used in this specification to illustrate the operations performed by the system according to embodiments of this specification. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the steps can be processed in reverse order or simultaneously. Furthermore, other operations can be added to these processes, or one or more steps can be removed from them.

[0028] The signal acquisition device of one or more embodiments of this specification can acquire one or more magnetic resonance signals for application in various scenarios requiring signal analysis. For example, in medical devices, it can provide information corresponding to the magnetic resonance signals (such as K-space data, images, etc.) for disease assessment or scientific research analysis; in detection devices, it can provide detection information such as material composition and distribution corresponding to the magnetic resonance signals. In some embodiments, the signal acquisition device can be applied not only to magnetic resonance imaging (MRI) devices and / or nuclear magnetic resonance (NMR) devices, but also to other devices requiring magnetic resonance signal analysis (e.g., geological exploration equipment, chemical substance analysis equipment, etc.). In some embodiments, the signal acquisition device of one or more embodiments of this specification can acquire not only magnetic resonance signals, but also other radio frequency signals, such as communication signals for data transmission and radio electromagnetic waves for energy transmission. The type of radio frequency signal acquired can be selected according to requirements.

[0029] In some embodiments, the signal acquisition device adopts a traditional superheterodyne architecture to design the receiving link. When demodulating the magnetic resonance signal in the analog domain, an analog mixer needs to be set up in the receiving link to cooperate, which results in a long receiving link, which is easy to waste hardware resources, causing the overall design of the signal acquisition device to be uncoordinated and occupying too much volume.

[0030] The signal acquisition device provided in this specification includes a signal acquisition module, a signal matching module, an analog-to-digital converter (ADC), and a control module. The signal acquisition module acquires a magnetic resonance signal, at least a portion of which is generated by the excitation of various specific nuclides. The signal matching module includes an adjustable capacitor unit and an RF transformer. The adjustable capacitor unit changes its capacitance value according to a control signal corresponding to an instruction from a host computer, cooperating with the RF transformer to receive the magnetic resonance signal and convert it into an analog differential signal. The ADC converts the analog differential signal into a digital signal. The control module processes the digital signal to generate K-space data corresponding to the magnetic resonance signal. Thus, by designing the receiving link based on the direct sampling architecture of the ADC, a mixer is not required in the receiving link; instead, signal demodulation is performed in the digital domain to generate K-space data corresponding to the magnetic resonance signal, thereby shortening the receiving link, reducing the overall size of the signal acquisition device, and improving integration.

[0031] In addition, the signal matching module, through the cooperation of the adjustable capacitor unit and the RF transformer, can select a specific narrowband signal for transmission under broadband conditions, thereby achieving broadband tuning matching. The architecture is simple, and it can also reduce the intrusion of RF interference by using a narrower receiving frequency band, so that the signal acquisition device can work stably.

[0032] Furthermore, when it is necessary to acquire magnetic resonance signals generated by the excitation of other specific nuclides, the signal acquisition device does not need to replace the entire receiving link. By replacing the signal acquisition module and adjusting the capacitance value of the adjustable capacitor unit, the adjustable capacitor unit can work with the radio frequency transformer to adjust the receiving frequency band, thereby achieving the goal of receiving multiple different magnetic resonance signals with the same link architecture.

[0033] Figure 1 This is a schematic diagram of the structure of a medical device according to some embodiments of this specification. In some embodiments, such as Figure 1 As shown, the medical device 10 includes a signal acquisition device 100 and an imaging device 200. The signal acquisition device 100 is connected to the imaging device 200. The signal acquisition device 100 is used to acquire magnetic resonance signals and output K-space data corresponding to the magnetic resonance signals. The imaging device 200 is used to output image information corresponding to the K-space data.

[0034] The signal acquisition device 100 is a device for acquiring magnetic resonance signals. In some embodiments, the magnetic resonance signal can be an electromagnetic wave reflected from the object under test. The magnetic resonance signal undergoes different attenuations in different structural environments within the material, thereby reflecting the internal structure of the object under test. For example, a magnetic resonance signal reflected from human tissue can reflect the internal structure of the human body. In some embodiments, the magnetic resonance signal can be a filtered radio frequency signal. In some embodiments, at least a portion of the magnetic resonance signal is generated by the excitation of multiple specific nuclides, thereby the magnetic resonance signal can carry specific nuclide information, which may include information such as the resonance frequency (i.e., nuclide frequency) corresponding to the nuclide and the signal amplitude.

[0035] In some embodiments, the signal acquisition device 100 can acquire and filter radio frequency signals at specific nuclide frequencies to obtain magnetic resonance signals carrying specific nuclide information. For example, the signal acquisition device 100 can acquire... 1 H nuclide frequency, 3 H nuclide frequency and 19 Radio frequency signals corresponding to the frequencies of multiple nuclides, such as the F nuclide frequency. In some embodiments, the signal acquisition device 100 can perform decimation, filtering, and demodulation on the magnetic resonance signal to output K-space data corresponding to the magnetic resonance signal.

[0036] K-space data can be spatial data obtained from the echo (e.g., magnetic resonance signal) of a measured object. In some embodiments, K-space data may include spatial data of one or more image slices of the measured object, such that the K-space data can be arranged in an array, e.g., K-space. Each K-space data entry (or referred to as a K-space data point) can provide frequency and phase information of the magnetic resonance signal.

[0037] In some embodiments, the signal acquisition device 100 can output not only K-space data, but also other image data, such as grayscale data, three-dimensional image data, etc. The specific type of image data can be selected according to requirements. For a detailed implementation of the signal acquisition device 100, please refer to the following... Figures 2-4B The relevant descriptions in the document will not be repeated here.

[0038] Imaging device 200 is an electronic device for constructing images. In some embodiments, imaging device 200 can reconstruct images based on K-space data and output image information corresponding to magnetic resonance signals. In some embodiments, imaging device 200 can be an electronic device such as a host computer or terminal device with image processing capabilities. In some embodiments, imaging device 200 can perform image reconstruction using image processing techniques such as projection reconstruction, shape restoration, stereo vision reconstruction, and laser ranging reconstruction. The specific type of image processing technique can be selected according to the type of acquired radio frequency signal. For example, imaging device 200 can generate an image based on K-space data arranged in K-space using inverse Fourier transform.

[0039] In some embodiments, the medical device 10 is a magnetic resonance (MR) device. The MR device may include one or more components such as a main magnet, gradient coils, radio frequency coils, control equipment, a spectrometer, and a patient bed. In some embodiments, the MR device may include one or more of an MRI device, an NMR device, a magnetic resonance spectroscopy (MRS) device, and a magnetic resonance spectroscopy imaging (MRSI) device. In some embodiments, the medical device 10 can utilize the chemical shift differences of the magnetic resonance signal carrying nuclide information to identify the spectral components of different chemical components and output image information corresponding to the magnetic resonance signal.

[0040] In some embodiments, for acquiring magnetic resonance signals of any nuclide, different intensities of the main static magnetic field (BO field) of the medical device 10 can correspond to different operating frequencies. For example, the intensity of the main static magnetic field of the medical device 10 can be linearly proportional to the operating frequency. The intensity of the BO field of the NMR device can include 4.7T, 7T, 9.4T, 11.7T, 14.1T, etc., correspondingly... 1 The H nuclide frequencies can be around 200MHz, 300MHz, 400MHz, 500MHz, and 600MHz, respectively.

[0041] It should be noted that the signal acquisition device 100 can be applied not only to medical device 10, but also to other systems that require signal acquisition. For example, the signal acquisition device 100 can be used in geological exploration equipment to acquire multiple magnetic resonance signals and output geological distribution information corresponding to the magnetic resonance signals. As another example, the signal acquisition device 100 can be used in chemical substance analysis equipment to acquire magnetic resonance signals returned from multiple substances to be analyzed and output information such as the substance composition and distribution corresponding to the magnetic resonance signals.

[0042] Figure 2 This is a schematic diagram of the structure of a signal acquisition device 100 according to some embodiments of this specification.

[0043] In some embodiments, such as Figure 2 As shown, the signal acquisition device 100 may include: a signal acquisition module 110, a signal matching module 120, an analog-to-digital converter 130, and a control module 140. The signal acquisition module 110 is connected to the signal matching module 120, and acquires magnetic resonance signals carrying specific nuclide information. The signal matching module 120 may include an adjustable capacitor unit and a radio frequency transformer connected to each other. The adjustable capacitor unit adjusts its capacitance value according to a control signal to cooperate with the radio frequency transformer in receiving the magnetic resonance signal corresponding to the specific nuclide information and converting it into an analog differential signal. The signal matching module 120 is connected to the analog-to-digital converter 130, which converts the analog differential signal into a digital signal. The analog-to-digital converter 130 is connected to the control module 140, which processes the digital signal to generate K-space data corresponding to the magnetic resonance signal. The control module 140 includes a parsing unit that parses instructions from the host computer and generates control signals.

[0044] In some embodiments, the receiving link may include a signal acquisition module 110, a signal matching module 120, and an analog-to-digital converter 130. In the embodiments of this specification, the receiving link receives a magnetic resonance signal carrying specific nuclide information, and performs signal demodulation in the digital domain to generate K-space data corresponding to the magnetic resonance signal. This makes the receiving link built based on the analog-to-digital converter 130 shorter, thereby reducing the overall size of the signal acquisition device 100 and improving its integration.

[0045] In addition, the signal matching module 120, through the cooperation of the adjustable capacitor unit and the radio frequency transformer, can select a specific narrow band signal for transmission under broadband conditions, thereby achieving broadband tuning matching. The architecture is simple, and it can also reduce the intrusion of radio frequency interference by using a narrower receiving frequency band, so that the signal acquisition device 100 can work stably.

[0046] Furthermore, when it is necessary to acquire magnetic resonance signals corresponding to other nuclide information, the signal acquisition device 100 does not need to replace the entire receiving link. By replacing the signal acquisition module and adjusting the capacitance value of the adjustable capacitor unit, the adjustable capacitor unit can work with the radio frequency transformer to complete the adjustment of the receiving frequency band, thereby achieving the goal of receiving multiple magnetic resonance signals with different nuclide information using the same link architecture.

[0047] The signal acquisition module 110 is a circuit structure for receiving radio frequency signals. In some embodiments, the signal acquisition module 110 can acquire one or more magnetic resonance signals carrying nuclide information, which may include the resonance frequency (i.e., nuclide frequency) corresponding to the nuclide, signal amplitude, and other information. Further, in some embodiments, the signal acquisition module 110 can acquire a radio frequency signal of a specific nuclide frequency, and obtain a magnetic resonance signal after processing. The specific implementation of the nuclide can be referred to the above. Figure 1 The relevant descriptions in the document will not be repeated here.

[0048] In some embodiments, the signal acquisition module 110 includes multiple sets of radio frequency (RF) receiving units, each set of RF receiving units including an RF receiving coil and an anti-aliasing filter. The RF receiving coil receives RF signals at a specific nuclide frequency, and the anti-aliasing filter filters the RF signals at the specific nuclide frequency to obtain a magnetic resonance signal.

[0049] Radio frequency (RF) receiving units are used to receive RF signals at specific nuclide frequencies. Different RF receiving units with different parameters can be used to receive RF signals at different nuclide frequencies, with each group of RF receiving units corresponding to a specific nuclide frequency. For example, for receiving... 1 A set of radio frequency receiving units for the H nuclide's nuclide frequency, wherein the signal receiving frequency of the radio frequency receiving coil in the radio frequency receiving unit and the passband frequency range of the anti-aliasing filter can be determined according to... 1 The frequency of H nuclide is set.

[0050] A radio frequency (RF) receiving coil (probe), also known as a local coil or probe, receives the RF signal corresponding to the frequency of a specific nuclide by sensing the radiation of electromagnetic waves at that nuclide frequency. In some embodiments, the signal receiving frequency of the RF receiving coil may correspond to the specific nuclide frequency of the RF signal to be received.

[0051] An anti-aliasing filter (AAF) includes a low-pass filter that can be used to reduce aliasing frequency components in a signal, such as suppressing image noise in a radio frequency signal. In some embodiments, the anti-aliasing filter can be constructed using resistor-capacitor (RC) components or inductor-capacitor (LC) components. In some embodiments, the passband frequency range of the anti-aliasing filter can be set according to the sampling rate of the analog-to-digital converter 130 (i.e., the frequency of the clock signal described below) and a specific nuclide frequency to avoid signal-to-noise ratio degradation caused by image noise aliasing in the signal acquisition device 100. For example, the passband frequency range of the anti-aliasing filter may include the nuclide frequencies corresponding to the group of radio frequency receiving units but may not include the sampling rate of the analog-to-digital converter 130.

[0052] In some embodiments, an anti-aliasing filter can filter radio frequency signals at specific nuclide frequencies, allowing radio frequency signals in the passband frequency range to pass through while suppressing image noise in the stopband frequency range, thereby obtaining a magnetic resonance signal carrying specific nuclide information. An exemplary signal acquisition device 100 is provided below, detailing the specific implementation of the radio frequency receiving unit.

[0053] Figure 3 This is a schematic diagram of the signal acquisition device 100 shown according to some embodiments of this specification. In some embodiments, such as Figure 3 As shown, the signal acquisition module 110 can be configured with one or more radio frequency receiving units, wherein the anti-aliasing filter AAF can be positioned adjacent to the receiving coil Probe. Each radio frequency receiving unit is used to receive a radio frequency signal of a specific nuclide frequency and output a magnetic resonance signal corresponding to that radio frequency signal, the magnetic resonance signal carrying specific nuclide information.

[0054] In the embodiments of this specification, compared with the traditional signal acquisition device 100, the anti-aliasing filter is set close to the radio frequency receiving coil, which can make the entire receiving link move forward and closer to the radio frequency receiving coil, suppressing image noise at the source of signal reception. This reduces the radio frequency interconnection cable from the radio frequency receiving coil to the receiving link, optimizes the signal-to-noise ratio of the signal acquisition device 100, and simplifies the circuit structure.

[0055] In some embodiments, the signal acquisition device 100 further includes a gain amplifier located between the signal acquisition module 110 and the signal matching module 120, which is used to amplify the magnetic resonance signal according to the control signal.

[0056] A gain amplifier (VGA) is a circuit structure that amplifies the amplitude of a signal. In some embodiments, the gain amplifier can be used to amplify the magnetic resonance signal transmitted from the signal acquisition module 110. In some embodiments, the gain amplifier can be a fixed-gain amplifier or a variable-gain amplifier, or other devices capable of amplifying signals. In some embodiments, when the gain amplifier is a fixed-gain amplifier, a suitable amplification factor can be selected based on the signal amplitude of the nuclear magnetic resonance line to be acquired. For example, in a magnetic resonance spectroscopy device, a variable-gain amplifier with a large amplification range can be selected for signal amplification.

[0057] In some embodiments, when the gain amplifier is a variable gain amplifier, the amplification factor of the variable gain amplifier can be set according to the signal amplitude of the magnetic resonance signal. For example, the larger the signal amplitude, the smaller the amplification factor of the gain amplifier can be, and vice versa, the smaller the signal amplitude, the larger the amplification factor of the gain amplifier can be, thereby achieving magnetic resonance signal adjustment and control. Correspondingly, in some embodiments, the control signal can come from the control module 140, and the control signal can be used to adjust the amplification factor of the variable gain amplifier. The specific implementation of the control signal can be referred to the content of the control module 140 below, and will not be repeated here. The following is in conjunction with the above... Figure 3 The signal acquisition device 100 shown describes in detail the specific implementation of the variable gain amplifier.

[0058] In some embodiments, such as Figure 3 As shown, the variable gain amplifier VGA can be set between the signal acquisition module 110 and the signal matching module 120 to amplify the magnetic resonance signal output by the anti-aliasing filter AAF, thereby stabilizing the signal amplitude of the input signal matching module 120.

[0059] In the embodiments described in this specification, a variable gain amplifier is used to adapt to signals of different amplitudes. The variable gain amplifier has a high amplification factor when the input signal is small and a low amplification factor when the input signal is large, so that the signal amplitude is stable and the dynamic range of the digital-to-analog converter is utilized as much as possible.

[0060] The signal matching module 120 is a circuit structure that utilizes differential transformation for signal processing. In some embodiments, the signal matching module 120 can convert an input single-ended signal (e.g., the aforementioned magnetic resonance signal) into an analog differential signal for signal processing by the analog-to-digital converter 130. In some embodiments, the signal matching module 120 can be constructed based on architectures such as high-speed operational amplifiers, RF transformers, and inductor-capacitor (LC) components. The following uses an RF transformer as an example to illustrate the specific implementation of the signal matching module 120.

[0061] In some embodiments, the signal matching module 120 may include an adjustable capacitor unit and an RF transformer. The adjustable capacitor unit adjusts the capacitance value according to the control signal to cooperate with the RF transformer to receive the magnetic resonance signal corresponding to specific nuclide information and convert it into an analog differential signal.

[0062] A radio frequency (RF) transformer is a transformer that operates within the radio frequency range. It can be used to transmit radio frequency energy and convert single-ended signals into analog differential signals. In some embodiments, the RF transformer may include one or more balun transformers to cooperate with the analog differential input interface of a digital-to-analog converter. Furthermore, when applied in the field of magnetic resonance imaging, the receiving link of the signal acquisition device 100 needs to be demagnetized. The balun transformer can be an air-core or ceramic-core non-magnetic balun transformer, and the type of balun transformer can be selected according to the actual application scenario.

[0063] In some embodiments, the radio frequency transformer comprises one or more coreless balun transformers connected in series. In some embodiments, such as... Figure 3 As shown, the RF transformer can include a coreless balun transformer T1 and a coreless balun transformer T2. The secondary side of the coreless balun transformer T1 is connected to the primary side of the coreless balun transformer T2. The primary side of the coreless balun transformer T1 receives the magnetic resonance signal, and the secondary side of the coreless balun transformer T2 outputs an analog differential signal, thus realizing the cascading of coreless balun transformers. Balun cascading can increase the output voltage of the RF transformer, improve the amplitude and phase balance characteristics of the positive and negative terminals of the analog differential signal, thereby increasing the gain of the receiving link. At the same time, it can optimize the suppression of signals outside the passband frequency range (i.e., out-of-band rejection), improving the anti-aliasing filtering effect.

[0064] It should be noted that, since the coreless balun transformer lacks a magnetic core, it can only operate within a narrow frequency band. However, it can be used in conjunction with an adjustable capacitor unit. By adjusting the capacitance value of the adjustable capacitor unit, the RF transformer can select specific narrowband signals for transmission within a wide bandwidth. This allows it to maintain certain wideband characteristics within a limited frequency range, such as low-loss signal transmission and wideband resonant matching. The RF transformer's simple architecture also mitigates RF interference by using a narrow receiving frequency band, ensuring stable operation of the signal acquisition device 100.

[0065] An adjustable capacitor unit is a collection of components including variable capacitors (e.g., varactor diodes) and other capacitors. In some embodiments, the adjustable capacitor unit may include one or more variable capacitors and one or more fixed capacitors, configured in a series-parallel arrangement. In some embodiments, the adjustable capacitor unit is located at the input of an RF transformer; further, the adjustable capacitor unit is located on the primary side of a balun transformer.

[0066] In some embodiments, the adjustable capacitor unit can change the applied voltage of the variable capacitor according to the control signal from the drive circuit, thereby adjusting its own capacitance value to cooperate with the RF transformer to complete the adjustment of the receiving frequency band and receive the magnetic resonance signal corresponding to specific nuclide information. Correspondingly, the control module can send a control signal to the adjustable capacitor unit through the drive circuit according to the instructions of the host computer, so that the adjustable capacitor unit cooperates with the RF transformer to complete the adjustment of the receiving frequency band. For the specific implementation of the drive circuit and the control module, please refer to the relevant content of the control module 140 below.

[0067] In some embodiments, the capacitance value of the adjustable capacitor unit can affect the tuning range of the RF transformer, i.e., the receiving frequency band of the received signal. Correspondingly, the control module 140 can determine the tuning range of the RF transformer and the capacitance value of the adjustable capacitor unit based on the nuclide frequency corresponding to the magnetic resonance signal to be acquired. For example, adjusting the capacitance value of the adjustable capacitor unit and the tuning range of the RF transformer ensures that the nuclide frequency corresponding to the magnetic resonance signal is located at the optimal matching point of the adjustable capacitor and the balun transformer, achieving broadband resonance matching. The tuning result can also act as a bandpass filter for the signal of that specific nuclide, and replace the anti-aliasing filter connected to the analog-to-digital converter 130.

[0068] In the embodiments described in this specification, when the capacitance value is properly adjusted (e.g., the nuclide frequency is at the optimal matching point between the adjustable capacitor and the balun transformer), the RF transformer can select a specific narrowband signal for transmission within a wide bandwidth, achieving optimal wideband resonant matching. This reduces energy loss during transmission, allowing the RF energy of the signal to be transmitted to the analog-to-digital converter 130 as much as possible. For example, the analog differential signal received at the analog input of the analog-to-digital converter 130 can maintain the peak value of the maximum AC voltage peak.

[0069] Furthermore, when it is necessary to acquire magnetic resonance signals corresponding to other nuclide information, the signal acquisition device does not need to replace the entire receiving link. By replacing the signal acquisition module and adjusting the capacitance value of the adjustable capacitor unit, the adjustable capacitor unit can work with the radio frequency transformer to adjust the receiving frequency band, thereby achieving the goal of receiving multiple magnetic resonance signals with different nuclide information using the same link architecture.

[0070] It should be noted that, since the frequency band of the electromagnetic induction signal of a specific nuclide is narrow and close to a single frequency point, during the pre-scan preparation stage, the signal acquisition device 100 can ensure that the nuclide frequency is exactly at the optimal matching point of the adjustable capacitor and balun through a precise automatic tuning and calibration workflow, so as to ensure minimal link attenuation and reduce energy loss during transmission.

[0071] In some embodiments, the adjustable capacitor unit may include one or more varactor components, wherein one varactor component includes two varactor diodes connected in parallel or series, the two varactor diodes having opposite DC bias directions. In some embodiments, the two varactor diodes have the same AC bias direction.

[0072] A varactor assembly is a collection of working units of varactor diodes, and the capacitance of the varactor diodes can change with the applied voltage. In some embodiments, the capacitance value of an adjustable capacitor unit can be changed by adjusting the applied voltage of the two varactor diodes in the varactor assembly. In some embodiments, the DC bias directions of the two varactor diodes are opposite, but their AC bias directions are the same.

[0073] Two exemplary adjustable capacitor units are provided below, detailing the specific structure of the varactor assembly.

[0074] Figure 4A This is a schematic diagram of the structure of a parallel adjustable capacitor unit according to some embodiments of this specification. In some embodiments, such as Figure 4A As shown, the adjustable capacitor unit C1 may include a varactor assembly 410, which includes varactor diodes VD1 and VD2 connected in parallel. The cathode of varactor diode VD1 is connected to the anode of varactor diode VD2 via capacitor C11, and the cathode of varactor diode VD2 is connected to the anode of varactor diode VD2 via capacitor C12. The cathode of varactor diode VD1 is connected to the cathode of varactor diode VD2 via resistors R11 and R12 connected in series. The DC bias directions of varactor diodes VD1 and VD2 are opposite, but their AC bias directions are the same.

[0075] In some embodiments, such as Figure 4A As shown, the connection point of resistors R11 and R12 is connected to the output of the driver amplifier stage Opamp, receiving control signals from the control module 140. The connection point of the cathode of varactor diode VD1 and the anode of varactor diode VD2 is also connected to the output of the variable gain amplifier VGA through capacitor C13. This connection point is also connected to the input terminal of the primary side of the coreless balun transformer T1. The anode of varactor diode VD1 and the output terminal of the primary side of the coreless balun transformer T1 are both grounded.

[0076] In the embodiments described in this specification, when the variable gain amplifier VGA outputs a magnetic resonance signal with a large amplitude, Figure 4A The parallel architecture of the varactor component 410 in the adjustable capacitor unit C1 shown can reduce the nonlinear distortion generated by the varactor diodes VD1 and VD2 and optimize the quality of the magnetic resonance signal.

[0077] Figure 4B This is a schematic diagram of the structure of a series adjustable capacitor unit according to some embodiments of this specification. In some embodiments, such as Figure 4B As shown, the adjustable capacitor unit C2 may include a varactor component 420, which may include varactor diodes VD3 and VD4 connected in series. The cathodes of varactor diodes VD3 and VD4 are connected together, and the DC bias directions of varactor diodes VD3 and VD4 are opposite, but their AC bias directions are the same.

[0078] In some embodiments, the positive terminal of varactor diode VD4 is grounded, the positive terminal of varactor diode VD3 is connected to the output terminal of variable gain amplifier VGA through capacitor C14, the positive terminal of varactor diode VD3 is also connected to the input terminal of the primary side of coreless balun transformer T1, and the connection point between the negative terminals of varactor diode VD3 and varactor diode VD4 is connected to the output terminal of drive amplifier stage Opamp through resistor R13 to receive control signals from control module 140.

[0079] In the embodiments described in this specification, when the variable gain amplifier VGA outputs a magnetic resonance signal with a large amplitude, Figure 4B The series architecture of the varactor component 420 in the adjustable capacitor unit C2 shown can reduce the nonlinear distortion generated by the varactor diodes VD3 and VD4, thus optimizing the quality of the magnetic resonance signal. However, compared to Figure 4A The parallel architecture of the varactor component 410 in the adjustable capacitor unit C1 shown has a smaller tuning range and lower adjustability compared to the series architecture of the varactor component 420 in the adjustable capacitor unit C22.

[0080] In some optional embodiments, the two varactor diodes in the varactor assembly can also be configured as an asymmetrical structure. In some optional embodiments, the two varactor diodes in the varactor assembly can be arranged symmetrically, as described above. Figures 4A-4B The two varactor diodes shown are symmetrically arranged in the circuit structure.

[0081] In some embodiments, the adjustable capacitor unit may further include a DC blocking module and / or an AC blocking module. The DC blocking module can be used to isolate DC signals, and the AC blocking module can be used to isolate AC signals. In some embodiments, the DC blocking module may include one or more capacitors. Exemplary examples are as described above. Figure 4AAs shown, the DC blocking module may include capacitors C11 to C13. (As described above...) Figure 4B As shown, the DC blocking module may include capacitor C14. Furthermore, the DC blocking module may include a DC blocking capacitor (such as...) connected in series with the variable gain amplifier VGA. Figure 4A The capacitor C13 shown is as follows: Figure 4B The capacitor C14 shown (etc.) can be used to prevent the bias voltage of the variable gain amplifier VGA from being directly short-circuited to ground by the source of the balun transformer T1.

[0082] In some embodiments, the isolation module may include one or more resistors or inductors. Examples are as described above. Figure 4A As shown, the isolation module may include resistor R11 and resistor R12. (As described above...) Figure 4B As shown, the AC isolation module may include resistor R13. Furthermore, the resistor of the AC isolation module can be connected in series with the driver amplifier stage Opamp, thereby achieving DC-DC blocking to prevent the magnetic resonance signal from the VGA output of the variable gain amplifier from damaging the low-pass filter and / or the driver amplifier stage.

[0083] Because the reverse current of the varactor diode is very small, in some embodiments, the adjustable capacitor unit can be connected in series with the varactor diode by setting a large resistor, thereby isolating the magnetic resonance signal from the output of the variable gain amplifier VGA and turning on the control signal that drives the Opamp amplifier stage.

[0084] It should be noted that when the signal acquisition device 100 retains the nonlinear distortion caused by the adjustable capacitor unit, most of the odd harmonics generated by the nonlinear distortion characteristics can be filtered out by the characteristics of the RF transformer, thereby achieving amplitude compression and improving the dynamic range of the received signal amplitude in the receiving link. In some embodiments, the signal amplitude and phase distortion generated by the adjustable capacitor unit can be compensated by the amplitude and phase nonlinear distortion compensation module (AP-Correct) of the control module 140. The specific implementation method can be referred to the relevant content in the control module 140 below, and will not be repeated here. Several optional embodiments are provided below to illustrate the specific implementation of retaining the nonlinear distortion characteristics.

[0085] In some alternative embodiments, the signal acquisition device 100 can replace the two varactor diodes in the varactor assembly with a DC blocking capacitor module to retain nonlinear distortion characteristics. For example, Figure 4A As shown, varactor diode VD1, capacitor C11, and resistor R11 can be removed, or varactor diode VD2, capacitor C13, and resistor R12 can be removed. Figure 4B As shown, capacitor C14 can be used to replace varactor diode VD3 or varactor diode VD4.

[0086] In some optional embodiments, the signal acquisition device 100 can utilize a combination of two varactor diodes of different models to retain nonlinear distortion characteristics through the difference in the parameter specifications of the two varactor diodes. In some optional embodiments, the signal acquisition device 100 can also retain the nonlinear distortion characteristics of the adjustable capacitor unit by setting a combination of an even number of varactor diodes, based on a symmetrical topology of parallel or series architecture, and then connecting them in parallel with one or more varactor diodes.

[0087] In the embodiments of this specification, by adjusting the resistance value of the adjustable capacitor unit, the adjustable capacitor unit can cooperate with peripheral devices (such as RF transformers, variable gain amplifiers, etc.) to achieve broadband reception of multi-core frequency bands through the same link architecture. It can also improve the dynamic range of the signal amplitude of the receiving link through nonlinear distortion. At the same time, the circuit structure is simple, the integration is high, and it is convenient for miniaturization of the signal acquisition device 100.

[0088] Furthermore, compared to the traditional method of using high-speed operational amplifiers to convert single-ended signals to analog differential signals, the signal matching module 120 in this embodiment can achieve broadband resonant matching through the cooperation of the RF transformer and the adjustable capacitor unit. As a result, the signal matching module 120 can have certain anti-aliasing characteristics, which indirectly reduces the design requirements of the anti-aliasing filter in the signal acquisition module 110 and simplifies the circuit of the signal acquisition module 110.

[0089] Meanwhile, compared to traditional single-ended to differential balun modules built with discrete inductors and capacitors, the combination of the RF transformer and the adjustable capacitor unit in the embodiments of this specification enables the signal matching module 120 to have better out-of-band component suppression, in-band flatness, and amplitude and phase balance characteristics of single-ended to differential conversion. The circuit architecture is also simpler, with higher integration, which facilitates the miniaturization of the signal acquisition device 100.

[0090] An analog-to-digital converter (ADC) 130 is an electronic device that converts an input analog signal into a discrete, amplitude-digitized signal in the time domain according to a sampling rate (such as the frequency of the clock signal described below). In some embodiments, the ADC 130 can be a high-speed ADC 130 with a high sampling rate to facilitate the design of the anti-aliasing filter in the signal acquisition module 110, and to facilitate the optimization of the anti-aliasing characteristics of the adjustable capacitor unit and the RF transformer. For example, the sampling rate of the high-speed ADC 130 can be 100 MSPS, 120 MSPS, etc.

[0091] In some embodiments, the analog-to-digital converter 130 may be disposed between the signal matching module 120 and the control module 140, and the analog-to-digital converter 130 may be used to convert analog differential signals into digital signals. For example, Figure 3 As shown, the analog-to-digital converter (ADC) can be set at the output of the balun transformer T2. Further, the ADC 130 can sample the analog differential signal according to one or more clock signals to obtain a digital signal. The clock signal can come from a clock generation module. In some embodiments, the ADC 130 can set the sampling rate according to the frequency of one or more clock signals. For example, as... Figure 3 As shown, the analog-to-digital converter (ADC) can receive and sample either the frequency of clock signal CLK1 or the frequency of clock signal CLK2. The specific implementation of the clock signal can be found in the relevant description in the clock generation module below, and will not be repeated here.

[0092] In some embodiments, the analog input terminal of the analog-to-digital converter 130 can adopt a high-speed differential interface, and the digital output terminal of the analog-to-digital converter 130 can select a high-speed serial interface. The analog-to-digital converter 130 can convert parallel digital data corresponding to multiple data processing paths through data packetization and serial-to-parallel protocols, and then output differential high-speed digital signals through one or a few high-speed serial interfaces. In some embodiments, the analog-to-digital converter 130 can select the corresponding data processing path for digital output according to the control module 140. Correspondingly, the control module 140 will also perform subsequent digital signal processing for the selected data processing path. In the embodiments of this specification, the analog-to-digital converter 130 selects a high-speed serial interface and bus output so that the switching module can complete the multiplexing function for differential high-speed digital signals. Compared with the parallel bus, the high-speed serial bus in the embodiments of this specification has fewer lines, thereby saving resources of the control module 140 and the circuit board, resulting in high integration and facilitating the miniaturization of the signal acquisition device 100.

[0093] In some embodiments, the signal acquisition device 100 may further include a clock generation module, which is disposed between the control module 140 and the analog-to-digital converter 130. The clock generation module is used to generate a clock signal according to the instructions of the host computer. The analog-to-digital converter 130 samples the analog differential signal according to the clock signal to obtain a digital signal.

[0094] The clock generation module is an electronic device that outputs a unified clock signal to enable other electronic devices to function properly. In some embodiments, the clock generation module can output a signal of a specific frequency based on the phase-locked loop (PLL) in the control module 140. The PLL can utilize the voltage generated by phase synchronization to tune the voltage-controlled oscillator (VCO) of the clock generation module to generate a signal at the target frequency.

[0095] In some embodiments, the clock generation module can generate a clock signal corresponding to an instruction from the host computer based on the voltage received from the control module 140, wherein the frequency of the clock signal corresponds to the instruction from the host computer. Further, the clock generation module can provide one or more clock signals, and the frequencies of the different clock signals can be different. For example, as shown... Figure 3 As shown, the clock generation module PLL can provide clock signal CLK1 or clock signal CLK2 for the analog-to-digital converter (ADC), and the clock generation module PLL can also provide clock signal CLK1, clock signal CLK2 and clock signal CLK3 for the control module 140.

[0096] Image frequency interference is often encountered during signal acquisition. If the difference between the nuclide frequency and the image frequency of the magnetic resonance signal to be acquired is too small, the analog-to-digital converter 130 is easily aliased by image noise during sampling, making it difficult to design an anti-aliasing filter and affecting the quality of signal acquisition. The image frequency is generally an integer multiple of half the sampling rate of the analog-to-digital converter 130. For example, assuming the sampling rate of the analog-to-digital converter 130 is 200 MSPS, the corresponding image frequency could be 50MHz, 100MHz, 200MHz, 300MHz, etc. If the nuclide frequency of the magnetic resonance signal to be acquired is 98MHz, then the difference between the nuclide frequency of 98MHz and the image frequency of 100MHz is less than 5% of the nuclide frequency, which can easily affect the quality of signal acquisition.

[0097] To avoid mirror frequency interference, in some embodiments, the control module 140 can control the clock generation module to output a clock signal corresponding to the nuclide frequency, such as clock signals CLK1 and CLK2, based on the nuclide frequency required by the host computer's instructions. In some embodiments, the difference between the nuclide frequency of the magnetic resonance signal and any harmonic of half the clock signal frequency can be within a preset difference range. Further, the preset difference range can be 5% of the nuclide frequency. The analog-to-digital converter 130 can determine the sampling rate based on the clock signal frequency. The clock signal frequency and the sampling rate have different units but the same numerical value. For example, assuming the nuclide frequency of the magnetic resonance signal to be acquired is 200MHz, the clock signal frequency can be 120MHz, the sampling rate of the analog-to-digital converter 130 can be 120MSPS, and any harmonic of half the clock signal frequency is 60nMHz, where n is a positive integer greater than or equal to 1. When n=3, the third harmonic of half the clock signal frequency is 180MHz, which is closest to the nuclide frequency. The difference between 180MHz and the nuclide frequency of 200MHz is 20MHz, and the difference is greater than 5% of the image frequency or the nuclide frequency. Under the action of the anti-aliasing filter, the analog-to-digital converter 130 can avoid the aliasing of image noise from any image frequency in the operating frequency band near 200MHz, ensuring the stability of the signal quality (signal-to-noise ratio) of the signal acquisition device 100.

[0098] In some optional embodiments, the control module 140 may also select a clock signal from a preset set of clock signals and control the clock generation module to output that clock signal. For example, for a medical device with a B0 field intensity of 9.4T, the control module 140 may control the clock generation module to output a clock signal CLK1 with a frequency of 100MHz, or a clock signal CLK2 with a frequency of 120MHz. An exemplary table showing the correspondence between the nuclide frequencies of the magnetic resonance signal and the sampling rate of the analog-to-digital converter 130 is provided below to illustrate the specific implementation of the clock signal. Table 1. Correspondence between nuclide frequency and analog-to-digital converter sampling rate

[0099] Table 1 shows the correspondence between the available nuclide frequencies and the sampling rate of the analog-to-digital converter 130 at a B0 field strength of 9.4T. As shown in Table 1, for medical devices with a B0 field strength of 9.4T, the clock signal output by the clock generation module has a frequency of 100MHz or 120MHz, which ensures that the signal acquisition device 100 is not affected by image noise in most multi-core frequency bands. Furthermore, an anti-aliasing filter can be built within the signal acquisition module 110 using conventional LC components to further reduce image noise interference.

[0100] In some embodiments, clock signals (such as clock signals CLK1-2) can be used to provide a reference for the control module 140 to select a receiving path, and clock signals (such as clock signal CLK3) can also be used to provide a carrier for the control signal output by the control module 140. The specific implementation of the clock signals in the control module 140 can be found in the relevant description of the control module 140 below, and will not be repeated here.

[0101] In this embodiment, the clock generation module can output a clock signal with an appropriate frequency to adjust the sampling rate of the analog-to-digital converter 130, thereby improving the problem that the image frequency is too close to the nuclide frequency. While reducing the image noise of the signal acquisition device 100, it also facilitates the design of anti-aliasing filters and improves the quality of signal acquisition.

[0102] The control module 140 can be a circuit unit with data processing and control functions. In some embodiments, the control module 140 can be a circuit module such as an integrated circuit ASIC, a field programmable gate array (FPGA), a complex programmable logic device (CPLD), a microcontroller unit (MCU), a central processing unit (CPU), a digital signal processor (DSP), or a graphics processing unit (GPU). The control module 140 may include functional units such as logic gate circuits, registers, hard-core multipliers and accumulators, RAM, phase-locked loops, and high-speed serial-to-parallel converters.

[0103] In some embodiments, the control circuit can process the digital signal output by the analog-to-digital converter 130 and output K-space data corresponding to the nuclide information to the host computer. The K-space data can be one type of image data, and the host computer (e.g., ...) can output the K-space data to the host computer. Figure 1 The imaging device shown can use K-space data to reconstruct images and output image information corresponding to nuclide information.

[0104] In some embodiments, the control module 140 may include multiple data processing paths, each of which includes a digital down-conversion (DDC) module for extracting, filtering, and demodulating the digital signal to obtain the K-space data.

[0105] The data processing path is a line that receives and processes digital signals from the analog-to-digital converter 130, such as a high-speed serial input of an FPGA. In some embodiments, each data processing path can process a digital signal corresponding to a nuclide frequency. In some embodiments, the digital down-conversion (DDC) module is a circuit module that performs mixing in the digital domain, such as decimating, filtering, and demodulating the digital signal to obtain analysis data (such as K-space data) corresponding to the nuclide frequency.

[0106] In some embodiments, the decimation factor of the digital down-converter modules in different data processing paths is different. For example, such as... Figure 3 As shown, the control module 140 may include a digital downconverter module DDC1 and a digital downconverter module DDC2, wherein the decimation factor of the digital downconverter module DDC1 is k1, and the decimation factor required by the digital downconverter module DDC2 is k2.

[0107] To ensure that the data rate of the K-space data is the same, in some embodiments, the control module 140 can determine the data processing path and decimation factor corresponding to the digital signal based on the sampling rate corresponding to the digital signal. The data rate is the ratio of the sampling rate to the decimation factor, which can be used to reflect the difference between the amount of data after digital down-conversion processing and the amount of data in the digital signal. For example, if the sampling rate of the analog-to-digital converter 130 is selected from the clock signal CLK1, then the digital down-conversion module DDC1 is selected to complete a k1-fold decimation; if the sampling rate of the analog-to-digital converter 130 is selected from the clock signal CLK2, then the digital down-conversion module DDC2 is selected to complete a k2-fold decimation, so that the data rate of the K-space data obtained after different data processing paths is equal.

[0108] In this embodiment, when it is necessary to obtain magnetic resonance signals corresponding to other nuclide information, the control module 140 does not need to change the data path. It can select one of the multiple data processing paths to make the data rate of the K-space data the same, thereby achieving the purpose of the same control module 140 being able to process multiple digital signals with different nuclide frequencies.

[0109] In some optional embodiments, the control module 140 may include only one data processing path, the decimation factor of which may correspond to the sampling rate of the analog-to-digital converter 130. Correspondingly, the clock generation module may also control the analog-to-digital converter 130 to provide a clock signal corresponding to the nuclide frequency according to the nuclide frequency required in the instructions from the host computer. In this way, the circuit structure of the control module 140 can be simplified and the production cost reduced while achieving signal acquisition.

[0110] In some embodiments, the signal acquisition device 100 further includes a switch module disposed between the analog-to-digital converter 130 and the data processing path. The switch module is used to select a data processing path corresponding to the clock signal and connect the data processing path to the analog-to-digital converter 130.

[0111] A switching module can be a circuit module that opens a circuit, interrupts current, or directs current to other circuits. In some embodiments, such as Figure 3 As shown, the switching module may include a multi-channel high-speed differential data switch (CPS) for changing the data processing path connected to the analog-to-digital converter (ADC), i.e., selecting the path where the digital down-converter module (DDC1) is located, or selecting the path where the digital down-converter module (DDC2) is located. In some embodiments, the switching module can switch between multiple data processing paths according to the instructions issued by the control module 140, thereby changing the data processing path connected to the analog-to-digital converter 130.

[0112] In some embodiments, the control module 140 may further include a serial-to-parallel conversion module, which may be disposed between the switching module and the data processing path. The serial-to-parallel conversion module may be used to convert serial data in digital signals into parallel data, which facilitates digital down-conversion processing.

[0113] In some embodiments, such as Figure 3 As shown, the control module 140 may further include a multiplexer S2, each of which can be positioned between the data processing path and the host computer. Similarly, the multiplexer can be used to select a data processing path corresponding to the clock signal, connecting the data processing path to the host computer. In some embodiments, one switch can correspond to one high-speed differential data switch and be associated with the same data processing path. For a detailed description of the multiplexer implementation, please refer to the above description of the multiple high-speed differential data switch; it will not be repeated here.

[0114] In some embodiments, such as Figure 3 As shown, the control module 140 may include a parsing unit (Translate), which can parse instructions from the host computer and generate control signals. The host computer instructions can be Host instructions sent by the user through the host computer. In some embodiments, the host computer instructions may carry nuclide information of the magnetic resonance signal to be acquired, such as nuclide frequency and name, and can be used to instruct the signal acquisition device 100 to currently acquire the magnetic resonance signal.

[0115] In some embodiments, the parsing unit can generate control signals based on the nuclide information that needs to be received, in order to configure the parameters of circuit modules, functional units, or devices. For example, the parsing unit can determine the frequency of the clock signal that the clock generation module needs to output based on the nuclide frequency, and adjust the sampling rate of the analog-to-digital converter 130; or control the switch module and multiplexer to determine the data processing path that needs to be connected; or determine the amplification factor of the variable gain amplifier; or configure the parameters of the digital down-converter in the data processing path; or control the counter module to adjust the capacitance value of the adjustable capacitor unit.

[0116] Furthermore, in some embodiments, the control module 140 can control the clock generation module to generate a clock signal of a specific frequency via a phase-locked loop. The control module 140 can select a clock signal (such as clock signal CLK1 or CLK2) corresponding to the frequency of the nuclide that needs to be received for the data processing path.

[0117] In some embodiments, the parsing unit and the host computer can communicate via high-speed optical fiber. Correspondingly, the parsing unit internally performs parallel-to-serial conversion, followed by photoelectric conversion, and finally connects to the host computer via optical fiber. In the embodiments of this specification, using optical fiber for data transmission, compared to electrical connections, can significantly save system wiring space, eliminate EMI interference introduced by long-distance electrical interconnections, and reduce costs.

[0118] In some embodiments, the signal acquisition device 100 further includes a counter module (DC Counter) and a drive circuit. The counter module outputs digital pulses under the control of a control signal, which are then used by the drive circuit to generate a signal for adjusting the adjustable capacitor unit.

[0119] The counter module is a circuit module that outputs adjustable periodic digital pulses. In some embodiments, the counter module can adjust the parameters of the digital pulses, such as frequency and duty cycle, according to a control signal. Further, the counter module can adjust the duty cycle of the digital pulses to control the magnitude of the analog voltage output by the drive circuit. For example, the duty cycle of the digital pulses can be proportional to the magnitude of the analog voltage. In some embodiments, the drive circuit may include a low-pass filter (LPF) and an opamp stage, wherein the low-pass filter and the opamp stage can filter the digital pulses, and the output signal adjusts the capacitance value of the adjustable capacitor unit.

[0120] Furthermore, the counter module can be based on a clock signal from the clock generation module (such as...). Figure 3The clock signal CLK3 shown is divided by m1 and its duty cycle is controlled by logic to generate a digital pulse. For example, the frequency of the digital pulse is... Duty cycle is Where m0 and m1 are different frequency division multiples of the counter module.

[0121] In some embodiments, the difference between the nuclide frequency of the magnetic resonance signal and any harmonic frequency of the digital pulse is not less than 5% of the nuclide frequency. That is, no harmonic of the digital pulse can fall within the frequency band of the corresponding nuclide frequency in the current analog-to-digital processing path, and the difference between the digital pulse and the nuclide frequency has a margin. In this way, the magnetic resonance signal can avoid radio frequency interference coupling problems. If the frequency of the digital pulse is not set according to the nuclide frequency of the nuclear magnetic resonance, even if the digital pulse is filtered by the drive circuit, there is a possibility of leakage to the adjustable capacitor unit C1, and the leaked high-frequency components will still be captured by the receiving link. If the high-frequency components are mixed into the multi-core frequency band of the magnetic resonance signal, it is easy to confuse the receiving link of the signal acquisition device 100 in recognizing the magnetic resonance signal, leading to inaccurate signal acquisition.

[0122] For example, the clock signal CLK3 has a frequency of 200MHz, the counter module's division factor m1 = 40, the counter module's division factor m0 = 0~40, and the digital pulse frequency is 5MHz. If the frequency range of the MR (Magnetic Resonance Imaging) device with a B0 = 3T intensity is between 127.5MHz and 128.5MHz, then the additive interference of any harmonic of the 5MHz digital pulse will not fall within the MR's imaging range. Furthermore, since the signal frequency band of the MR device with a B0 = 3T intensity is generally less than 1MHz, and much less than 5MHz, the multiplicative interference modulated into the link by the adjustable capacitor unit will also not fall within the MR's imaging range. Moreover, the low-pass filter LPF can avoid excessively deep filtering, retaining the DC voltage in the digital pulse through low-pass filtering. In some embodiments, the DC voltage amplitude is proportional to m0 / m1.

[0123] In this embodiment, the layout and wiring of the single-board circuit of the parsing unit do not require special design considerations for suppressing the coupling of the AC pulse signal output by the counter. This reduces the design difficulty, facilitates a more compact circuit layout, and thus saves space and cost. In addition, since the adjustable capacitor unit is located after the variable gain amplifier, the out-of-band harmonic interference coupled into the output of the variable gain amplifier is necessarily much smaller than the amplified maximum magnetic resonance signal, and therefore there is no out-of-band blocking distortion.

[0124] It should be noted that the spatial positions of the low-pass filter LPF and the drive amplifier stage Opamp in the drive circuit can be interchanged, or they can be replaced by an active filter that integrates the filtering mechanism into the op-amp closed-loop feedback network.

[0125] In some embodiments, the signal acquisition device 100 further includes a digital-to-analog converter (DAC) disposed between the resolution unit and the adjustable capacitor unit. The DAC is used to output a signal for adjusting the adjustable capacitor unit under the control of a control signal. In some embodiments, the DAC can convert the signal output from the driving amplifier stage Opamp into an analog voltage signal, so that the adjustable capacitor unit can adjust its capacitance value according to the analog voltage signal.

[0126] In some embodiments, the control module 140 further includes an amplitude-phase nonlinear distortion compensation module (AP-Correct) for compensating for the amplitude-phase distortion of the signal generated by the adjustable capacitor unit. For example, as... Figure 3 As shown, the amplitude-phase nonlinear distortion compensation module AP-Correct can be set between the multiplexer S2 and the host computer.

[0127] In some embodiments, the distortion curve can be obtained first through testing, and then a pre-distortion mechanism for amplitude and phase can be introduced to compensate for the distortion curve on the baseband data in the control module 140. The linear distortion caused by the adjustable capacitor unit is accompanied by amplitude compression. The overall amplitude compression and decompression process also improves the dynamic range of the receiving link. The high-order harmonics caused by linear distortion can be filtered out by the digital downconverter.

[0128] The following provides an exemplary magnetic resonance imaging device, and describes in detail the specific implementation of the signal acquisition device 100 described above.

[0129] In some embodiments, the magnetic resonance device may include: a scanner for generating a main magnetic field and capable of exciting the nuclear spins of various specific nuclides of the object being detected within the main magnetic field to generate a magnetic resonance signal; a radio frequency (RF) receiving coil connected to the scanner to receive the magnetic resonance signal; and a receiving link including a gain amplifier, a signal matching module 120, and an analog-to-digital converter 130. The gain amplifier is connected to the receiving coil to amplify the magnetic resonance signal. The signal matching module 120 includes an adjustable capacitor unit and an RF transformer connected to each other. The adjustable capacitor unit is connected to the gain amplifier, and its capacitance value is adjustable to cooperate with the RF transformer in receiving the amplified magnetic resonance signal and converting it into an analog differential signal. The RF converter 130 is connected to the RF transformer for converting the analog differential signal into a digital signal. A control module 140 may be used to process the digital signal to generate K-space data corresponding to the magnetic resonance signal. The control module 140 may include a parsing unit that parses instructions from a host computer and generates control signals.

[0130] In some embodiments, the scanner may be configured as an electronic device that generates a magnetic field to excite the nuclear spins of various specific nuclides to emit magnetic resonance signals, thereby facilitating acquisition by the aforementioned signal acquisition device 100. In some embodiments, the modules or components in the magnetic resonance device may be derived from the aforementioned... Figures 2-4B The signal acquisition device 100 shown is implemented by it or its modules or components. For specific implementation methods, please refer to the above. Figures 2-4B The relevant descriptions will not be repeated here.

[0131] Figure 5 This is a schematic flowchart illustrating a signal acquisition method according to some embodiments of this specification. In some embodiments, process 500 may be implemented by signal acquisition device 100.

[0132] In some embodiments, process 500 may include:

[0133] Step 510: The signal acquisition device can acquire a magnetic resonance signal. At least a portion of the magnetic resonance signal is generated by the excitation of various specific nuclides.

[0134] In some embodiments, the signal acquisition device can use an RF receiving coil to receive RF signals at a specific nuclide frequency, and then filter the RF signals at the specific nuclide frequency using an anti-aliasing filter to obtain a magnetic resonance signal. In some embodiments, the magnetic resonance signal can carry specific nuclide information. In some embodiments, the control module of the signal acquisition device can receive multiple magnetic resonance signals with different nuclide information by replacing the signal acquisition module.

[0135] In some embodiments, the signal acquisition device can also amplify the magnetic resonance signal using a gain amplifier based on a control signal. Furthermore, in some embodiments, the signal acquisition device can adapt to signals of different amplitudes by adjusting the gain of a variable gain amplifier, thereby stabilizing the signal amplitude and maximizing the application of the dynamic range of the digital-to-analog converter.

[0136] In some embodiments, step 510 can be implemented by the signal acquisition module of the signal acquisition device. The specific implementation of the signal acquisition module can be found above. Figures 2-3 The relevant descriptions in the document will not be repeated here.

[0137] Step 520: Parse the instructions from the host computer and generate control signals. These control signals are used to adjust the capacitance value of the adjustable capacitor unit to cooperate with the radio frequency transformer in processing the magnetic resonance signal corresponding to specific nuclide information.

[0138] In some embodiments, the calculator module of the signal acquisition device can output digital pulses under the control of a control signal, which, after passing through a drive circuit, generate a signal for adjusting the adjustable capacitor unit. In some embodiments, step 520 can be implemented by the control module of the signal acquisition device. The specific implementation of the control module can be found above. Figures 2-3 The relevant descriptions in the document will not be repeated here.

[0139] Step 530: Process the magnetic resonance signal to generate K-space data corresponding to the magnetic resonance signal.

[0140] In some embodiments, the signal acquisition device can utilize an adjustable capacitor unit to adjust the capacitance value according to a control signal, in conjunction with an RF transformer, to receive magnetic resonance signals corresponding to specific nuclide information and convert them into analog differential signals. In some embodiments, the signal acquisition device can adjust the receiving frequency band of its receiving link by adjusting the capacitance value of the adjustable capacitor unit in conjunction with the RF transformer, thereby receiving multiple magnetic resonance signals with different nuclide information using the same link.

[0141] In some embodiments, the signal acquisition device can sample the analog differential signal according to a clock signal using an analog-to-digital converter to obtain a digital signal. In some embodiments, the signal acquisition device can also select a data processing path corresponding to the specific nuclide information of the magnetic resonance signal from multiple data processing paths, and perform decimation, filtering, and demodulation on the digital signal to obtain K-space data. In the embodiments of this specification, the signal acquisition device can design the receiving link based on the direct sampling architecture of the analog-to-digital converter, which reduces the overall size of the signal acquisition device while enabling signal demodulation in the digital domain to obtain K-space data.

[0142] In some embodiments, step 530 can be implemented by the signal matching module, analog-to-digital converter, and control module of the signal acquisition device. Specific implementation methods of the signal matching module, analog-to-digital converter, and control module can be found above. Figures 2-4B The relevant descriptions in the document will not be repeated here.

[0143] It should be noted that the above description of process 500 is for illustrative purposes only and does not limit the scope of this specification. Those skilled in the art can make various modifications and changes to process 500 under the guidance of this specification. However, these modifications and changes are still within the scope of this specification. For example, step 520 can be performed before step 510 or before step 530 to change the receiving frequency band of the signal acquisition module in a timely manner according to the instructions of the host computer, and to acquire magnetic resonance signals with other specific nuclide frequencies.

[0144] The beneficial effects that the embodiments of this specification may bring include, but are not limited to: (1) The receiving link is designed based on the direct sampling architecture of the analog-to-digital converter. There is no need to set up a mixer in the receiving link. The signal demodulation can be performed in the digital domain to generate K-space data corresponding to the nuclide information, thereby shortening the receiving link, reducing the overall size of the signal acquisition device, and improving the integration. (2) The signal matching module can select a specific narrowband signal for transmission in the broadband range through the cooperation of the adjustable capacitor unit and the RF transformer, realizing broadband tuning matching. The architecture is simple and can also reduce the RF interference intrusion through the narrower receiving frequency band, so that the signal acquisition device can work stably. (3) When it is necessary to obtain magnetic resonance signals corresponding to other nuclide information, the signal acquisition device does not need to replace the entire receiving link. By replacing the signal acquisition module and adjusting the capacitance value of the adjustable capacitor unit, the adjustable capacitor unit can cooperate with the RF transformer to complete the adjustment of the receiving frequency band, thereby achieving the purpose of receiving multiple magnetic resonance signals with different nuclide information in the same link architecture.

[0145] The basic concepts have been described above. It is clear that the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, various modifications, improvements, and corrections may be made to this specification by those skilled in the art. Such modifications, improvements, and corrections are suggested in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

[0146] Furthermore, this specification uses specific terms to describe embodiments thereof. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Moreover, certain features, structures, or characteristics in one or more embodiments of this specification can be appropriately combined.

[0147] Furthermore, unless expressly stated in the claims, the order of processing elements and sequences, the use of numbers and letters, or other names described in this specification are not intended to limit the order of the processes and methods described herein. Although various examples have been discussed in the foregoing disclosure of some embodiments of the invention that are currently considered useful, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments; rather, the claims are intended to cover all modifications and equivalent combinations that conform to the spirit and scope of the embodiments described herein. For example, while the system components described above can be implemented using hardware devices, they can also be implemented solely using software solutions, such as installing the described system on existing servers or mobile devices.

[0148] Similarly, it should be noted that, in order to simplify the description disclosed herein and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of embodiments in this specification may sometimes combine multiple features into a single embodiment, drawing, or description thereof. However, this method of disclosure does not imply that the subject matter of this specification requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of a single embodiment disclosed above.

[0149] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this specification are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0150] For each patent, patent application, patent application publication, and other material such as articles, books, specifications, publications, and documents referenced in this specification, the entire contents of which are incorporated herein by reference. This excludes historical application documents that are inconsistent with or conflict with the content of this specification, as well as documents that limit the broadest scope of the claims in this specification (currently or subsequently appended to this specification). It should be noted that in the event of any inconsistency or conflict between the descriptions, definitions, and / or terminology used in the supplementary materials to this specification and the content of this specification, the descriptions, definitions, and / or terminology used in this specification shall prevail.

[0151] Finally, it should be understood that the embodiments described in this specification are merely illustrative of the principles of the embodiments described herein. Other variations may also fall within the scope of this specification. Therefore, alternative configurations of the embodiments described herein are intended to be illustrative rather than limiting, and should be considered consistent with the teachings of this specification. Accordingly, the embodiments described herein are not limited to those explicitly introduced and described herein.

Claims

1. A signal acquisition device (100), characterized in that, include: The signal acquisition module (110), signal matching module (120), analog-to-digital converter (130), and control module (140) are included. The signal acquisition module (110) acquires a magnetic resonance signal, at least a portion of which is generated by the excitation of one or more specific nuclides; The signal acquisition module (110) is connected to the signal matching module (120). The signal matching module (120) includes an adjustable capacitor unit and an RF transformer connected to each other. The adjustable capacitor unit adjusts the capacitance value according to the control signal to cooperate with the RF transformer to receive the magnetic resonance signal and convert it into an analog differential signal. The signal matching module (120) is connected to the analog-to-digital converter (130), which converts the analog differential signal into a digital signal. The analog-to-digital converter (130) is connected to the control module (140), which is used to process the digital signal to generate K-space data corresponding to the magnetic resonance signal. The control module (140) includes a parsing unit, which parses the instructions from the host computer and generates the control signal.

2. The signal acquisition device (100) according to claim 1, characterized in that, The signal acquisition module (110) includes multiple sets of radio frequency receiving units, each set of radio frequency receiving units including a radio frequency receiving coil and an anti-aliasing filter, wherein, The radio frequency receiving coil receives radio frequency signals at a specific nuclide frequency, and the anti-aliasing filter filters the radio frequency signals at the specific nuclide frequency to obtain the magnetic resonance signal.

3. The signal acquisition device (100) according to claim 2, characterized in that, The signal acquisition device (100) further includes a gain amplifier located between the signal acquisition module (110) and the signal matching module (120), which is used to amplify the magnetic resonance signal according to the control signal.

4. The signal acquisition device (100) according to claim 1, characterized in that, The adjustable capacitor unit includes one or more varactor components, wherein one varactor component includes two varactor diodes connected in parallel or in series.

5. The signal acquisition device (100) according to claim 1, characterized in that, The radio frequency transformer includes one or more coreless balun transformers connected in series.

6. The signal acquisition device (100) according to claim 5, characterized in that, The signal acquisition device (100) further includes a clock generation module, which is located between the control module (140) and the analog-to-digital converter (130). The clock generation module is used to generate a clock signal according to the instructions of the host computer. The analog-to-digital converter (130) samples the analog differential signal according to the clock signal to obtain the digital signal.

7. The signal acquisition device (100) according to claim 6, characterized in that, The control module (140) includes multiple data processing paths, each of which includes a digital down-conversion module, which is used to extract, filter and demodulate the digital signal to obtain the K-space data; The signal acquisition device (100) further includes a switch module, which is disposed between the analog-to-digital converter (130) and the data processing path. The switch module is used to select a data processing path corresponding to the clock signal, connect the data processing path to the analog-to-digital converter (130), and ensure that the data rate is equal after passing through any data processing path.

8. The signal acquisition device (100) according to claim 1, characterized in that, The signal acquisition device (100) further includes a counter module and a drive circuit. The counter module outputs digital pulses under the control of the control signal, which are then used by the drive circuit to generate a signal for adjusting the adjustable capacitor unit.

9. A magnetic resonance imaging device, characterized in that, include: A scanner is used to generate a main magnetic field and to excite the nuclear spins of various specific nuclides of the object being detected within the main magnetic field in order to produce a magnetic resonance signal. A radio frequency receiving coil is connected to the scanner to receive the magnetic resonance signal; The receiving link includes a gain amplifier, a signal matching module (120), and an analog-to-digital converter (130); The gain amplifier is connected to the receiving coil to amplify the magnetic resonance signal; The signal matching module (120) includes an adjustable capacitor unit and an RF transformer that are interconnected; The adjustable capacitor unit is connected to the gain amplifier, and the adjustable capacitor unit adjusts the capacitance value according to the control signal to cooperate with the radio frequency transformer to receive the amplified magnetic resonance signal and convert it into an analog differential signal. The analog-to-digital converter (130) is connected to the radio frequency transformer and is used to convert the analog differential signal into a digital signal; A control module (140) is connected to the analog-to-digital converter (130). The control module (140) is used to process the digital signal to generate K-space data corresponding to the magnetic resonance signal. The control module (140) includes a parsing unit, which parses the instructions from the host computer and generates the control signal.

10. A signal acquisition method, characterized in that, Applied to the signal acquisition device as described in any one of claims 1-8, the method comprises: Acquire a magnetic resonance signal, at least a portion of which is generated by the excitation of a variety of specific nuclides; The instructions from the host computer are parsed and control signals are generated. These control signals are used to adjust the capacitance value of the adjustable capacitor unit in order to cooperate with the radio frequency transformer to process the magnetic resonance signal. The magnetic resonance signal is processed to generate K-space data corresponding to the magnetic resonance signal.

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