CN117559935A - Double-tuning matching circuit and device - Google Patents
Double-tuning matching circuit and device Download PDFInfo
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- CN117559935A CN117559935A CN202311506940.3A CN202311506940A CN117559935A CN 117559935 A CN117559935 A CN 117559935A CN 202311506940 A CN202311506940 A CN 202311506940A CN 117559935 A CN117559935 A CN 117559935A
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- 238000005481 NMR spectroscopy Methods 0.000 claims abstract description 32
- 239000003990 capacitor Substances 0.000 claims description 16
- 238000001514 detection method Methods 0.000 claims description 14
- 238000012544 monitoring process Methods 0.000 claims description 4
- 238000004804 winding Methods 0.000 claims description 3
- 238000004458 analytical method Methods 0.000 abstract description 7
- 230000009977 dual effect Effects 0.000 description 12
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- 230000005540 biological transmission Effects 0.000 description 6
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- 238000003199 nucleic acid amplification method Methods 0.000 description 2
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
- G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
- G01R33/36—Electrical details, e.g. matching or coupling of the coil to the receiver
- G01R33/3628—Tuning/matching of the transmit/receive coil
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
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- H03H7/38—Impedance-matching networks
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Abstract
The invention relates to the technical field of nuclear magnetic resonance analysis, and discloses a double-tuning matching circuit and a device, wherein the circuit comprises: the receiving and transmitting control circuit comprises a receiving and transmitting control circuit and a double-tuning circuit, wherein the input end of the receiving and transmitting control circuit receives a receiving and transmitting mode switching signal, and the output end of the receiving and transmitting control circuit is connected with the control end of the double-tuning circuit; the first end of the double-tuning circuit is connected with the radio frequency transceiving common coil; after the double-tuning circuit is switched to a receiving mode, the radio frequency receiving and transmitting common coil receives nuclear magnetic resonance signals through the double-tuning circuit, and receives frequency modulation through adjusting the capacitance value of the circuit; after the double-tuning circuit is switched to a transmitting mode, the radio frequency receiving and transmitting common coil transmits radio frequency signals through the double-tuning circuit, and the transmitting frequency modulation is realized through adjusting the capacitance value of the circuit. According to the invention, the double tuning circuits can be used for respectively carrying out transmitting tuning and receiving tuning, the mutual influence is avoided, frequent replacement of the frequency modulation cable is not required, the debugging time is shortened, and the working efficiency is improved.
Description
Technical Field
The invention relates to the technical field of nuclear magnetic resonance analysis, in particular to a double-tuning matching circuit and a double-tuning matching device.
Background
Nuclear magnetic resonance technology is a nondestructive testing technology widely applied to the fields of analysis and imaging, and when atomic nuclei are in a static magnetic field, a two-stage magnet is subjected to the action of magnetic field force and is uniformly oriented with the magnetic field. The nuclei are self-charged and therefore produce a magnetic moment during the spin process, but the nuclear spins do not perfectly align with the magnetic field, but rather an angle of tilt occurs, at which the dipole magnet precesses around the magnetic field. The atomic nucleus can meet radio frequency pulses with the same frequency in the movement process, the radio frequency pulses can transmit energy to the atomic nucleus, and the atomic nucleus can absorb the energy of the radio frequency pulses in a resonance mode and remove the radio frequency pulses. The nuclei then emit part of the absorbed energy in the form of radio waves, which process is resonance emission, and resonance absorption and resonance emission constitute nuclear magnetic resonance, the principle of which is a way of examination of the nuclear signals in a magnetic field, by means of computer reconstruction. The radio frequency system of the nuclear magnetic resonance equipment consists of an electronic control cabinet radio frequency transmitting system, a radio frequency coil, a signal receiving system and the like. The nuclear magnetic resonance radio frequency system is the most basic and important part of nuclear magnetic resonance equipment, and the main function is to implement radio frequency excitation and receive nuclear magnetic resonance signals. The radio frequency coil is not only an excitation source for generating magnetic resonance of atomic nuclei, but also a detector for magnetic resonance signals. The coil used for establishing a radio frequency field in the radio frequency coil is called a transmitting coil, the coil used for detecting magnetic resonance (Magnetic Resonance, MR) signals is called a receiving coil, and the transmitting and receiving coil share one coil and the single-channel transceiving coil. The field of nuclear magnetic analysis has high requirements on radio frequency fields, and the field of low-field nuclear magnetic analysis generally uses a transmit-receive common solenoid coil.
Because of impedance difference of the radio frequency coil in a low power receiving state and a high power transmitting state, an emission excitation signal is not matched, a break point phenomenon is generated by a pulse train (CPMG) signal during receiving, the CPMG signal is not smooth, the influence on signal analysis errors is extremely large, and a simple and reliable debugging scheme is needed to solve the problem. The traditional method is to replace coaxial cables with different lengths, repeatedly replace and try to find out the coaxial cable with the optimal length for matching and solving, and the replacement of the length of the cable mainly depends on experience and has weak guidance.
Disclosure of Invention
Therefore, the invention aims to solve the technical problem that the receiving and transmitting common solenoid coil in the prior art needs to be subjected to receiving tuning and transmitting tuning by replacing a cable, thereby providing a double-tuning matching circuit and a double-tuning matching device.
In order to achieve the above purpose, the present invention provides the following technical solutions:
in a first aspect, the present invention provides a double-tuned matching circuit comprising: the receiving and transmitting control circuit comprises a receiving and transmitting control circuit and a double-tuning circuit, wherein the input end of the receiving and transmitting control circuit receives a receiving and transmitting mode switching signal, and the output end of the receiving and transmitting control circuit is connected with the control end of the double-tuning circuit; the first end of the double-tuning circuit is connected with the radio frequency transceiving common coil; when the double-tuning circuit is required to be switched to a receiving mode, the receiving and transmitting control circuit outputs a receiving mode driving signal based on the receiving mode switching signal, and after the double-tuning circuit is switched to the receiving mode based on the receiving mode driving signal, the radio frequency receiving and transmitting common coil receives nuclear magnetic resonance signals through the double-tuning circuit, at the moment, the capacity value of the double-tuning circuit is a first capacity value, and the first capacity value is used for realizing receiving tuning; when the double-tuning circuit is required to be switched to a transmitting mode, the receiving and transmitting control circuit outputs a transmitting mode driving signal based on the transmitting mode switching signal, and after the double-tuning circuit is switched to the transmitting mode based on the transmitting mode driving signal, the radio frequency receiving and transmitting common coil transmits radio frequency signals through the double-tuning circuit, at the moment, the capacitance value of the double-tuning circuit is a second capacitance value, and the second capacitance value is used for realizing transmitting tuning.
The double-tuning matching circuit provided by the invention is used for carrying out receiving tuning and transmitting tuning on the receiving and transmitting common coil under the condition of receiving and transmitting by using the same coil, the double-tuning matching circuit can work in a transmitting mode and a receiving mode according to a mode switching signal of a receiving and transmitting control circuit, the corresponding transmitting tuning circuit and the receiving tuning circuit in the two working modes are electrically connected, the receiving end of the double-tuning circuit is grounded in the transmitting mode, and the receiving tuning circuit stops working; in the receiving mode, the transmitting end of the double-tuning circuit is disconnected, the transmitting tuning circuit stops working, the transmitting tuning circuit and the receiving tuning circuit do not interfere with each other when working, the transmitting tuning or receiving tuning of the radio frequency receiving and transmitting common coil can be carried out without depending on experience of operators and frequent replacement of cables, tuning debugging time is shortened, the complexity of tuning work is improved, and working efficiency is improved.
In an alternative embodiment, the double tuning circuit comprises: the device comprises a transmitting tuning circuit, a receiving tuning circuit, a parallel tuning circuit, a first switch circuit and a second switch circuit, wherein a first end of the transmitting tuning circuit is connected with an output end of a receiving and transmitting control circuit and a first end of the first switch circuit, and a radio frequency receiving and transmitting common coil transmits radio frequency signals through a transmitting end of the transmitting tuning circuit; the receiving tuning circuit is connected with the first end of the parallel tuning circuit and the second end of the first switch circuit, the receiving end of the receiving tuning circuit is connected with the first end of the second switch circuit, and the radio frequency receiving and transmitting common coil receives nuclear magnetic resonance signals through the receiving end of the receiving tuning circuit; a second switch circuit, the second end of which is grounded; the first end of the parallel tuning circuit is connected with the radio frequency transceiving common coil, and the second end of the parallel tuning circuit is grounded; when the double-tuning circuit is required to be switched to a transmitting mode, the receiving and transmitting control circuit outputs a transmitting mode driving signal, and after the first switch circuit and the second switch circuit are conducted based on the transmitting mode driving signal, the capacitance value of the double-tuning circuit is a second capacitance value which is used for realizing transmitting tuning; when the double-tuning circuit is required to be switched to a receiving mode, the receiving and transmitting control circuit outputs a receiving mode driving signal, and after the first switch circuit and the second switch circuit are switched off based on the receiving mode driving signal, the capacity value of the double-tuning circuit is a first capacity value, and the first capacity value is used for realizing receiving tuning.
According to the double-tuning matching circuit provided by the invention, the receiving and transmitting control circuit enables the double-tuning circuit to be switched to a receiving mode or a transmitting mode by switching the on-off states of the first switch circuit and the second switch circuit, and the receiving tuning of the radio frequency receiving and transmitting common coil is realized by adjusting the first capacitance value; the corresponding transmitting tuning circuit in the transmitting mode realizes the transmitting tuning of the radio frequency receiving and transmitting common coil by adjusting the second capacitance value, and the receiving tuning and the transmitting tuning of the radio frequency receiving and transmitting common coil can be respectively realized without mutual interference and cable replacement during working, so that the operation is simple.
In an alternative embodiment, a transmit tuning circuit includes: the first end of the adjustable inductor is a transmitting end, and the second end of the adjustable inductor is connected with the first end of the first adjustable capacitor and the first end of the first switch circuit; the second end of the first adjustable capacitor is grounded.
The double-tuning matching circuit provided by the invention can realize the transmitting tuning of the radio frequency transmitting-receiving common coil only by adjusting the capacitance value of the first adjustable capacitor, and has a simple circuit structure.
In an alternative embodiment, the parallel tuning circuit includes: the first inductor is wound on the radio frequency receiving and transmitting common coil, the first end of the first inductor is connected with the second end of the first switch circuit, and the second end of the first inductor is grounded; and the second adjustable capacitor is connected with the first inductor in parallel.
In an alternative embodiment, the receive tuning circuit includes: and the first end of the second inductor is connected with the first end of the parallel tuning circuit, the second end of the second inductor is connected with the first end of the second switching circuit, and the second end of the second inductor is a receiving end.
The double-tuning matching circuit provided by the invention can realize the receiving tuning of the radio frequency receiving and transmitting common coil only by adjusting the capacitance value of the second adjustable capacitor, and has a simple circuit structure.
In an alternative embodiment, the first switching circuit comprises a first diode, the anode of which is connected to the first terminal of the transmit tuning circuit and the cathode of which is connected to the first terminal of the receive tuning circuit; the second switching circuit comprises a second diode, the anode of which is connected with the receiving end of the receiving tuning circuit, and the cathode of which is grounded.
In an alternative embodiment, the double-tuned matching circuit further comprises: the input end of the frequency detection circuit is connected with the transmitting end of the transmitting tuning circuit, the transmitting end of the frequency detection circuit transmits radio frequency signals, and the detection end of the frequency detection circuit outputs the frequency signals and is used for monitoring whether the working frequency of the radio frequency receiving and transmitting common coil exceeds the preset frequency.
The double-tuning matching circuit provided by the invention can monitor whether the working frequency of the radio frequency transceiving shared coil is consistent with the frequency of the external magnet or not by monitoring the working frequency of the radio frequency transceiving shared coil, and if not, an operator manually adjusts the working frequency of the radio frequency transceiving shared coil to be consistent with the frequency of the external magnet, so that the receiving capacity and the transmitting capacity of the radio frequency transceiving shared coil are improved.
In an alternative embodiment, the double-tuned matching circuit further comprises: and the first end of the pre-amplifying circuit is connected with the receiving end of the receiving tuning circuit, and the second end of the pre-amplifying circuit is used for receiving the nuclear magnetic resonance signal and eliminating noise in the nuclear magnetic resonance signal.
The double-tuning matching circuit provided by the invention has the advantages that the gain of the preamplifier is adjustable, and the double-tuning matching circuit can be applied to measurement of nuclear magnetic resonance analysis samples with different contents and large differences.
In an alternative embodiment, the double-tuned matching circuit further comprises: and the input end of the coil identification circuit is connected with the receiving end of the receiving tuning circuit, and the output end of the coil identification circuit outputs the identity information of the radio frequency receiving and transmitting common coil.
According to the double-tuning matching circuit provided by the invention, the model is automatically identified after the radio frequency transceiver shared coil is connected to the operating system, software in the operating system automatically displays the current coil model, and the parameters of the current radio frequency coil configuration file are called, so that the equipment operator is prevented from manually selecting the current radio frequency coil model, the identification accuracy is improved, and the working efficiency is improved.
In a second aspect, the present invention provides a double-tuned matching device comprising: the shielding box, the radio frequency receiving and transmitting shared coil and the double-tuning matching circuit of the first aspect, wherein the shielding box comprises a first sub-cavity and a second sub-cavity; the radio frequency receiving and transmitting common coil is arranged in the first sub-cavity, isolates external noise signals through a waveguide tube, and transmits radio frequency signals or receives nuclear magnetic resonance signals through an interface socket on the shielding box; the double-tuning matching circuit is arranged in the second sub-cavity; the first end of the double-tuning circuit is arranged in the first sub-cavity and is connected with the radio frequency transceiving common coil in a winding way; when the double-tuning circuit is required to be switched to a receiving mode, the receiving and transmitting control circuit outputs a receiving mode driving signal based on a receiving mode switching signal, and after the double-tuning circuit is switched to the receiving mode based on the receiving mode driving signal, the radio frequency receiving and transmitting common coil receives nuclear magnetic resonance signals through the double-tuning circuit, and receiving tuning is realized by adjusting the capacitance in the double-tuning circuit; when the double-tuning circuit is required to be switched to a transmitting mode, the transmitting-receiving control circuit outputs a transmitting mode driving signal based on the transmitting mode switching signal, and after the double-tuning circuit is switched to the transmitting mode based on the transmitting mode driving signal, the radio frequency transmitting-receiving common coil transmits radio frequency signals through the double-tuning circuit, and transmitting tuning is realized through adjusting the capacitance in the circuit.
According to the double-tuning matching device provided by the invention, the two sub-cavities are arranged to isolate the radio frequency receiving and transmitting common coil from the double-tuning circuit, so that the interference of radio frequency signals transmitted by the radio frequency receiving and transmitting common coil and received nuclear magnetic resonance signals on the double-tuning circuit is avoided, various circuits are integrated on the circuit board, and the volume of the double-tuning matching device is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
Fig. 1 is a composition diagram of one specific example of a double-tuned matching circuit according to an embodiment of the present invention;
fig. 2 is a composition diagram of another specific example of a double-tuned matching circuit according to an embodiment of the present invention;
FIG. 3 is a block diagram of one particular circuit of a double-tuned matching circuit according to an embodiment of the present invention;
fig. 4 is a composition diagram of another specific example of a double-tuned matching circuit according to an embodiment of the present invention;
FIG. 5 is a block diagram of another specific circuit of a double-tuned matching circuit according to an embodiment of the present invention;
fig. 6 is a block diagram of one specific circuit of an amplifier according to an embodiment of the present invention;
fig. 7 is a block diagram of one specific circuit of an amplifier according to an embodiment of the present invention;
fig. 8 is a composition diagram of one specific example of a double-tuned matching device according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; the two components can be directly connected or indirectly connected through an intermediate medium, or can be communicated inside the two components, or can be connected wirelessly or in a wired way. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
In addition, the technical features of the different embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
The present embodiment provides a double-tuned matching circuit, as shown in fig. 1, including: the device comprises a receiving and transmitting control circuit 1 and a double-tuning circuit 2, wherein the input end of the receiving and transmitting control circuit 1 receives a receiving and transmitting mode switching signal generated by an operating system, and the output end of the receiving and transmitting control circuit is connected with the control end of the double-tuning circuit 2; the first end of the double-tuning circuit 2 is connected with the radio frequency transmitting and receiving common coil.
As shown in fig. 1, when the dual tuning circuit 2 is required to switch to the receiving mode, the transceiver control circuit 1 outputs a receiving mode driving signal based on the receiving mode switching signal, and after the dual tuning circuit 2 switches to the receiving mode based on the receiving mode driving signal, the radio frequency transceiver common coil receives a nuclear magnetic resonance signal through the dual tuning circuit 2, and at this time, the capacitance value of the dual tuning circuit 2 is a first capacitance value, and the first capacitance value is used for realizing receiving tuning.
As shown in fig. 1, when the dual-tuning circuit 2 is required to switch to the transmitting mode, the transceiver control circuit 1 outputs a transmitting mode driving signal based on the transmitting mode switching signal, and after the dual-tuning circuit 2 switches to the transmitting mode based on the transmitting mode driving signal, the radio frequency transceiver common coil transmits a radio frequency signal through the dual-tuning circuit 2, and at this time, the capacitance value of the dual-tuning circuit 2 is a second capacitance value, where the second capacitance value is used to implement transmitting tuning.
Specifically, as shown in fig. 1, the double-tuning circuit 2 of the radio frequency transceiver shared coil is connected, a radio frequency signal is transmitted through a transmitting end of the double-tuning circuit 2, and a nuclear magnetic resonance signal is received through a receiving end of the double-tuning circuit 2. When the receiving tuning is needed to be carried out on the radio frequency receiving and transmitting shared coil, the receiving and transmitting control circuit 1 outputs a receiving mode driving signal, the double-tuning circuit 2 is in a receiving tuning circuit state after the internal switch state of the double-tuning circuit 2 is switched according to the receiving mode driving signal, and the capacitance and inductance resonance frequency of the double-tuning circuit 2 in the receiving mode is adjusted by adjusting the first capacitance value of the double-tuning circuit 2 at the moment, so that the receiving tuning on the radio frequency receiving and transmitting shared coil is realized.
As shown in fig. 1, when the radio frequency transceiver shared coil needs to be tuned, the transceiver control circuit 1 outputs a transmission mode driving signal, the double-tuning circuit 2 is in a transmission tuning circuit state after the double-tuning circuit 2 switches the internal switch state according to the transmission mode driving signal, and the second capacitance value of the double-tuning circuit 2 is adjusted at this time to adjust the resonance frequency of the capacitor and the inductor in the transmission mode of the double-tuning circuit 2, so as to realize the transmission tuning of the radio frequency transceiver shared coil.
The double-tuning matching circuit is used for receiving tuning and transmitting tuning to the receiving and transmitting common coil, the double-tuning circuit can work in a transmitting mode and a receiving mode according to mode switching signals of the receiving and transmitting control circuit, the corresponding transmitting tuning circuit and the receiving tuning circuit in the two working modes are electrically connected, interference is avoided during working, the receiving and transmitting common coil can be transmitted and tuned or received without depending on experience of operators and frequent replacement of cables, tuning debugging time is shortened, complexity of tuning work is improved, and working efficiency is improved.
In some alternative embodiments, as shown in fig. 2, the double tuning circuit includes: a transmit tuning circuit 21, a receive tuning circuit 22, a parallel tuning circuit 23, a first switching circuit 24, and a second switching circuit 25.
As shown in fig. 2, a first end of the transmitting tuning circuit 21 is connected with the output end of the transceiver control circuit 1 and the first end of the first switch circuit 24, and the rf transceiver common coil transmits an rf signal through the transmitting end of the transmitting tuning circuit 21; a receiving tuning circuit 22, a first end of which is connected to a first end of the parallel tuning circuit 23 and a second end of the first switch circuit 24, and a receiving end of which is connected to a first end of the second switch circuit 25, the rf transceiver common coil receiving the nmr signal through the receiving end of the receiving tuning circuit 22; a second switch circuit 25, the second end of which is grounded; the parallel tuning circuit 23 has a first end connected to the radio frequency transmission/reception common coil and a second end grounded.
As shown in fig. 2, when the dual-tuning circuit is required to switch to the transmitting mode, the transceiver control circuit outputs a transmitting mode driving signal, the first switch circuit 24 and the second switch circuit 25 are turned on based on the transmitting mode driving signal, the receiving end of the dual-tuning circuit is grounded, the rf transceiver common coil transmits the rf signal through the parallel tuning circuit 23, the first switch circuit 24 and the transmitting tuning circuit 21, and at this time, the capacitance of the dual-tuning circuit is a second capacitance, and the second capacitance is used for realizing transmitting tuning; when the dual tuning circuit is required to switch to the receiving mode, the transceiver control circuit outputs a receiving mode driving signal, and after the first switch circuit 24 and the second switch circuit 25 are turned off based on the receiving mode driving signal, the receiving tuning circuit 22 and the transmitting tuning circuit 21 of the dual tuning circuit are disconnected, and the rf transceiver common coil receives the nmr signal through the parallel tuning circuit 23 and the receiving tuning circuit 22, and at this time, the capacity value of the dual tuning circuit is a first capacity value, and the first capacity value is used for realizing receiving tuning.
Specifically, as shown in fig. 3, the first switching circuit 24 includes a first diode D1, and the second switching circuit 25 includes a second diode D2; the transmit tuning circuit 21 includes: the first end of the adjustable inductor L1 is a transmitting end, and the second end of the adjustable inductor L1 is connected with the first end of the first adjustable capacitor C1 and the anode of the first diode D1; the second end of the first adjustable capacitor C1 is grounded.
Specifically, as shown in fig. 3, the parallel tuning circuit 23 includes: the first inductor L2 and the second adjustable capacitor C2, wherein the first inductor L2 is wound on the radio frequency transceiver shared coil, the first end of the first inductor L2 is connected with the cathode of the first diode D1, and the second end of the first inductor L2 is grounded; a second adjustable capacitor C2 connected in parallel with the first inductor L2; the reception tuning circuit 21 includes: the first end of the second inductor L3 is connected to the first end of the parallel tuning circuit 23, the second end is connected to the anode of the second diode D2, and the second end is the receiving end.
Specifically, as shown in fig. 3, when the dual-tuning circuit is required to switch to the transmitting mode, the transceiver control circuit 1 outputs a transmitting mode driving signal, the first diode D1 and the second diode D2 are turned on based on the transmitting mode driving signal, the receiving end is shorted by the second diode D2, the radio frequency transceiver common coil stops receiving the nuclear magnetic resonance signal, and the transmitting tuning is performed by adjusting the capacitance value of the first adjustable capacitor C1; when the dual-tuning circuit is required to switch to the receiving mode, the transceiver control circuit 1 outputs a receiving mode driving signal, after the first diode D1 and the second diode D2 are turned off based on the receiving mode driving signal, the transmitting end and the parallel tuning circuit 23 are disconnected, the radio frequency signal transmission is stopped by the radio frequency transceiver common coil, and the receiving tuning is performed by adjusting the capacitance value of the second adjustable capacitor C2.
In some alternative embodiments, as shown in fig. 4, the double-tuned matching circuit further includes: the frequency detection circuit 3, the pre-amplifying circuit 4 and the coil identification circuit 5, wherein the input end of the frequency detection circuit 3 is connected with the transmitting end of the transmitting tuning circuit 21, the transmitting end transmits a radio frequency signal, and the detecting end outputs a frequency signal which is used for monitoring whether the working frequency of the radio frequency receiving and transmitting common coil exceeds a preset frequency; a pre-amplifier circuit 4 having a first end connected to the receiving end of the receiving tuning circuit 21 and a second end receiving the nuclear magnetic resonance signal for eliminating noise in the nuclear magnetic resonance signal; the coil identification circuit 5 has an input terminal connected to the receiving terminal of the receiving tuning circuit 21 and an output terminal for outputting the identity information of the radio frequency transmitting/receiving common coil.
Specifically, as shown in fig. 5, the frequency detection circuit 3 adopts an S11 reflection coefficient detection circuit to measure the resonant frequency of the radio frequency transceiver coil, the circuit is composed of T1, C5 and C6, and the induction signal of T1 and the divided signal of C5 and C6 are added and output through the detection end, wherein the turn ratio of T1 is 1:20.
Specifically, as shown in fig. 5, the pre-amplifying circuit 4 is composed of amplifiers U3, C4 and L5, wherein the specific circuit structure of the amplifier U3 is shown in fig. 6, and is composed of three-stage Q3, Q4 and Q5 amplifiers and a digital attenuator U4, C10 and L10 are input matching circuits of the first-stage amplifier, C12 and L12 are output matching circuits of the first-stage amplifier, and U4 is a 31.5dB digital attenuator, and the steps are 0.5dB. The front power supply is coaxial power supply, and shares a coaxial cable with the output signal, so that the noise interference is small, the structure is simple, and a power supply port is not required to be additionally arranged.
Specifically, as shown in fig. 5, the coil identification circuit 5 adopts a design of a non-magnetic low-power-consumption erasable programmable read-only memory, and the power supply circuit is provided by the voltage stabilizer 78L03, so that the power consumption can be reduced, meanwhile, the circuit interface is compatible with the mainstream 3.3V circuit interface, the address code information of the radio frequency receiving and transmitting common coil can be read, and the type of the radio frequency receiving and transmitting common coil can be identified.
Specifically, as shown in fig. 7, the driving circuits of the first diode D1 and the second diode D2 respectively adopt NPN and PNP triode designs, or can adopt N-communication and P-channel MOS transistor designs, and positive and negative dual power supplies supply power to output positive and negative pulse square waves, the rising edge and the falling edge are smaller than 1us, and the driving current capacity is larger than 500mA. The gate control signal is divided into two paths through U4 for output, wherein the first path is R2, U5, R4, U6, R6 and Q1, and the second path is R3, U7, R5, U8, R7 and Q2. The first path is a Q1 driving circuit, and the Q1 is driven after two-stage amplification; the second path is a Q2 driving circuit, and the Q2 is driven after two-stage amplification. The transmit-receive mode switching signal is a TTL signal, the transmit mode is a high level, and the receive mode is a low level. In the transmitting mode, Q1 is conducted, Q2 is closed, and +5V is output; in the receiving mode, Q1 is closed, Q2 is conducted, and-5V is output. The first diode D1 and the second diode D2 operate on the principle that they are turned on when a forward voltage is applied, and turned off when a reverse voltage is applied, i.e., a negative voltage.
The present embodiment provides a double-tuned matching device, as shown in fig. 8, including: the shielding box 6, the radio frequency transceiver shared coil 7, the double-tuning matching circuit of any of the above embodiments and any of the alternative embodiments thereof, and the interface socket 9, wherein the shielding box comprises a first subchamber 61 and a second subchamber 62; the radio frequency receiving and transmitting common coil 7 is arranged in the first sub-cavity 61, isolates external noise signals through the waveguide tube 8, and transmits radio frequency signals or receives nuclear magnetic resonance signals through an interface socket on the shielding box; the interface socket 9 comprises two coaxial interfaces and a plurality of low-frequency connectors, the two coaxial interfaces are respectively used for transmitting radio-frequency signals and receiving nuclear magnetic resonance signals, and the plurality of low-frequency connectors are respectively used for realizing operations such as frequency detection, identity recognition, transceiving control and the like of the radio-frequency transceiving shared coil through the operating system after being connected with the operating system; the double-tuning matching circuit is arranged in the second sub-cavity; the first end of the double-tuning circuit is arranged in the first sub-cavity and is in winding connection with the radio frequency transceiving common coil 7.
Specifically, referring to fig. 8, when the dual tuning circuit 2 is required to switch to the receiving mode, the transceiver control circuit 1 outputs a receiving mode driving signal based on the receiving mode switching signal, and after the dual tuning circuit 2 switches to the receiving mode based on the receiving mode driving signal, the radio frequency transceiver shared coil 7 receives a nuclear magnetic resonance signal through the dual tuning circuit 2, and the receiving tuning is realized by adjusting the capacitance in the dual tuning circuit 2; when the double-tuning circuit 2 is required to be switched to a transmitting mode, the transmitting-receiving control circuit 1 outputs a transmitting mode driving signal based on the transmitting mode switching signal, and after the double-tuning circuit 2 is switched to the transmitting mode based on the transmitting mode driving signal, the radio frequency transmitting-receiving common coil 7 transmits radio frequency signals through the double-tuning circuit 2, and transmitting tuning is realized through adjusting the capacitance in the circuit.
According to the double-tuning matching device provided by the embodiment, the two sub-cavities are arranged to isolate the radio frequency receiving and transmitting common coil from the double-tuning circuit, so that the interference of radio frequency signals transmitted by the radio frequency receiving and transmitting common coil and received nuclear magnetic resonance signals on the double-tuning circuit is avoided, various circuits are integrated on the circuit board, and the size of the double-tuning matching device is reduced.
Although embodiments of the present invention have been described in connection with the accompanying drawings, various modifications and variations may be made by those skilled in the art without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope of the invention as defined by the appended claims.
Claims (10)
1. A double-tuned matching circuit, comprising: a receiving and transmitting control circuit and a double tuning circuit, wherein,
the input end of the receiving and transmitting control circuit receives a receiving and transmitting mode switching signal, and the output end of the receiving and transmitting control circuit is connected with the control end of the double-tuning circuit;
the first end of the double-tuning circuit is connected with the radio frequency transceiving common coil;
when the double-tuning circuit is required to be switched to a receiving mode, the receiving and transmitting control circuit outputs a receiving mode driving signal based on a receiving mode switching signal, and after the double-tuning circuit is switched to the receiving mode based on the receiving mode driving signal, the radio frequency receiving and transmitting common coil receives a nuclear magnetic resonance signal through the double-tuning circuit, and at the moment, the capacitance value of the double-tuning circuit is a first capacitance value, and the first capacitance value is used for realizing receiving tuning;
when the double-tuning circuit is required to be switched to a transmitting mode, the receiving and transmitting control circuit outputs a transmitting mode driving signal based on the transmitting mode switching signal, and after the double-tuning circuit is switched to the transmitting mode based on the transmitting mode driving signal, the radio frequency receiving and transmitting common coil transmits radio frequency signals through the double-tuning circuit, at the moment, the capacitance value of the double-tuning circuit is a second capacitance value, and the second capacitance value is used for realizing transmitting tuning.
2. The double-tuned matching circuit according to claim 1, wherein the double-tuned circuit comprises: a transmitting tuning circuit, a receiving tuning circuit, a parallel tuning circuit, a first switch circuit and a second switch circuit, wherein,
the first end of the transmitting tuning circuit is connected with the output end of the receiving and transmitting control circuit and the first end of the first switch circuit, and the radio frequency receiving and transmitting common coil transmits radio frequency signals through the transmitting end of the transmitting tuning circuit;
a receiving tuning circuit, a first end of which is connected with a first end of the parallel tuning circuit and a second end of the first switch circuit, a receiving end of which is connected with a first end of the second switch circuit, and a radio frequency receiving and transmitting common coil receives nuclear magnetic resonance signals through a receiving end of the receiving tuning circuit;
a second switch circuit, the second end of which is grounded;
the first end of the parallel tuning circuit is connected with the radio frequency transceiving common coil, and the second end of the parallel tuning circuit is grounded;
when the double-tuning circuit is required to be switched to a transmitting mode, the receiving and transmitting control circuit outputs a transmitting mode driving signal, and after the first switch circuit and the second switch circuit are conducted based on the transmitting mode driving signal, the capacitance value of the double-tuning circuit is a second capacitance value, and the second capacitance value is used for realizing transmitting tuning;
when the double-tuning circuit is required to be switched to a receiving mode, the receiving and transmitting control circuit outputs a receiving mode driving signal, and after the first switch circuit and the second switch circuit are turned off based on the receiving mode driving signal, the capacitance value of the double-tuning circuit is a first capacitance value, and the first capacitance value is used for realizing receiving tuning.
3. The double-tuned matching circuit according to claim 2, wherein the transmit tuning circuit comprises: an adjustable inductance and a first adjustable capacitance, wherein,
the first end of the adjustable inductor is a transmitting end, and the second end of the adjustable inductor is connected with the first end of the first adjustable capacitor and the first end of the first switch circuit;
the second end of the first adjustable capacitor is grounded.
4. The double-tuned matching circuit according to claim 2, wherein the parallel-tuned circuit comprises: a first inductor and a second tunable capacitor, wherein,
the first inductor is wound on the radio frequency transceiving common coil, the first end of the first inductor is connected with the second end of the first switch circuit, and the second end of the first inductor is grounded;
and a second adjustable capacitor connected in parallel with the first inductor.
5. The double-tuned matching circuit according to claim 2, wherein the receiving tuning circuit comprises:
and the first end of the second inductor is connected with the first end of the parallel tuning circuit, the second end of the second inductor is connected with the first end of the second switching circuit, and the second end of the second inductor is a receiving end.
6. The double-tuned matching circuit according to claim 2, wherein,
the first switch circuit comprises a first diode, the anode of the first diode is connected with the first end of the transmitting tuning circuit, and the cathode of the first diode is connected with the first end of the receiving tuning circuit;
the second switching circuit comprises a second diode, the anode of the second diode is connected with the receiving end of the receiving tuning circuit, and the cathode of the second diode is grounded.
7. The double-tuned matching circuit of claim 2, further comprising:
and the input end of the frequency detection circuit is connected with the transmitting end of the transmitting tuning circuit, the transmitting end of the frequency detection circuit transmits a radio frequency signal, and the detection end of the frequency detection circuit outputs a frequency signal and is used for monitoring whether the working frequency of the radio frequency receiving and transmitting common coil exceeds a preset frequency.
8. The double-tuned matching circuit of claim 2, further comprising:
and the first end of the pre-amplifying circuit is connected with the receiving end of the receiving tuning circuit, and the second end of the pre-amplifying circuit is used for receiving the nuclear magnetic resonance signal and eliminating noise in the nuclear magnetic resonance signal.
9. The double-tuned matching circuit of claim 2, further comprising:
and the input end of the coil identification circuit is connected with the receiving end of the receiving tuning circuit, and the output end of the coil identification circuit outputs the identity information of the radio frequency receiving and transmitting common coil.
10. A double-tuned matching device, comprising: the shielding box, the radio frequency transceiver shared coil and the double-tuning matching circuit as claimed in any one of claims 1 to 9, wherein,
the shielding box comprises a first sub-cavity and a second sub-cavity;
the radio frequency receiving and transmitting common coil is arranged in the first sub-cavity, isolates external noise signals through a waveguide tube, and transmits radio frequency signals or receives nuclear magnetic resonance signals through an interface socket on the shielding box;
the double-tuning matching circuit is arranged in the second sub-cavity;
the first end of the double-tuning circuit is arranged in the first sub-cavity and is in winding connection with the radio frequency transceiving common coil;
when the double-tuning circuit is required to be switched to a receiving mode, the receiving and transmitting control circuit outputs a receiving mode driving signal based on a receiving mode switching signal, and after the double-tuning circuit is switched to the receiving mode based on the receiving mode driving signal, the radio frequency receiving and transmitting common coil receives nuclear magnetic resonance signals through the double-tuning circuit and realizes receiving tuning by adjusting the capacitance in the double-tuning circuit;
when the double-tuning circuit is required to be switched to a transmitting mode, the receiving and transmitting control circuit outputs a transmitting mode driving signal based on the transmitting mode switching signal, and after the double-tuning circuit is switched to the transmitting mode based on the transmitting mode driving signal, the radio frequency receiving and transmitting common coil transmits radio frequency signals through the double-tuning circuit, and transmitting tuning is realized through adjusting the capacitance in the circuit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311506940.3A CN117559935A (en) | 2023-11-13 | 2023-11-13 | Double-tuning matching circuit and device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311506940.3A CN117559935A (en) | 2023-11-13 | 2023-11-13 | Double-tuning matching circuit and device |
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| CN117559935A true CN117559935A (en) | 2024-02-13 |
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| CN202311506940.3A Pending CN117559935A (en) | 2023-11-13 | 2023-11-13 | Double-tuning matching circuit and device |
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- 2023-11-13 CN CN202311506940.3A patent/CN117559935A/en active Pending
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