Dual-frequency switching circuit and vehicle control system

Abstract

The invention provides a dual-frequency switching circuit and a vehicle control system. The dual-frequency switching circuit comprises a main control unit, an excitation source modulation unit, a first impedance matching circuit, a second impedance matching circuit and an onboard antenna unit, the excitation source modulation unit comprises a first end and a second end, the first impedance matching circuit comprises a third end and a fourth end, and the second impedance matching circuit comprises a fifth end and a sixth end; the main control unit is connected with the first end, and the second end is connected with the third end or the fifth end; the fourth end and the sixth end are connected to the onboard antenna unit; the main control unit is used for generating a first control signal or a second control signal to the excitation source modulation unit, so that the first control signal is transmitted to the first impedance matching circuit, a first radio frequency signal is output through the first impedance matching circuit and the onboard antenna unit, and the second control signal is transmitted to the second impedance matching circuit; and a second radio frequency signal is output through the second impedance matching circuit and the onboard antenna unit. The design cost is reduced, and integration is easy.

Description

Technical Field

[0001] The present application relates to the fields of wireless communication and automotive electronics, and particularly to a dual-frequency switching circuit and a control system for a vehicle. Background Art

[0002] With the development of radio technology, radio frequency technology has been widely applied in signal transmission in the field of commercial vehicles. Among them, low-frequency antennas are usually used for simple ranging or wake-up excitation, and high-frequency antennas are used for complex data transmission such as key authentication or tire pressure detection. The signal transmission path of the vehicle is made more abundant through contactless signal means to promote the intelligent development of the vehicle.

[0003] In the prior art, due to the different lengths of on-board antennas in different frequency bands and the different lengths of the corresponding circuit board traces, for on-board antennas in different frequency bands, circuits are designed separately and corresponding controllers are set to improve the signal stability of the on-board antennas. However, equipping each frequency band with a corresponding electronic control unit increases the design cost and the complexity of wiring harness layout, which is not conducive to the integrated design of the vehicle electronic control unit.

[0004] Based on this, in the prior art, there are problems of high design cost and low integration degree in signal transmission. Summary of the Invention

[0005] The present application provides a dual-frequency switching circuit and a control system for a vehicle, so as to achieve the effects of reducing the design cost and reducing the complexity of wiring harness layout.

[0006] In a first aspect, the present application provides a dual-frequency switching circuit, including a main control unit, an excitation source modulation unit, a first impedance matching circuit, a second impedance matching circuit, and an on-board antenna unit;

[0007] The excitation source modulation unit includes a first end and a second end, the first impedance matching circuit includes a third end and a fourth end, and the second impedance matching circuit includes a fifth end and a sixth end;

[0008] The main control unit is connected to the first end, and the second end is connected to the third end or the fifth end;

[0009] Both the fourth end and the sixth end are connected to the on-board antenna unit;

[0010] The main control unit is configured to generate a first control signal or a second control signal to the excitation source modulation unit, so that the first control signal is transmitted to the first impedance matching circuit, and a first radio frequency signal is output through the first impedance matching circuit and the on-board antenna unit, and the second control signal is transmitted to the second impedance matching circuit, and a second radio frequency signal is output through the second impedance matching circuit and the on-board antenna unit.

[0011] In a possible design, the on-board antenna unit 205 includes an L-shaped on-board antenna.

[0012] In a possible design, the L-shaped on-board antenna includes an impedance matching circuit connection port and an external interaction interface;

[0013] The impedance matching circuit connection port is used to connect to the first impedance matching circuit or the second impedance matching circuit;

[0014] The external interaction interface is used to output the first radio frequency signal or the second radio frequency signal.

[0015] In a possible design, the antenna length of the L-shaped on-board antenna is the larger value of the first antenna length and the second antenna length;

[0016] Wherein, the first antenna length is determined by the board manufacturing parameters of the circuit board of the L-shaped on-board antenna and the wavelength of the first control signal, and the second antenna length is determined by the board manufacturing parameters of the circuit board of the L-shaped on-board antenna and the wavelength of the second control signal.

[0017] In a possible design, the first impedance matching circuit includes a first capacitor and a first inductor, and the second impedance matching circuit includes a second capacitor and a second inductor;

[0018] The first capacitor is connected in parallel to the first impedance matching circuit, and the first inductor is connected in series to the first impedance matching circuit;

[0019] The second capacitor is connected in parallel to the second impedance matching circuit, and the second inductor is connected in series to the second impedance matching circuit.

[0020] In a possible design, the parameters of the first capacitor and the first inductor are obtained by analyzing the impedance trajectory of the first control signal through the Smith chart, and the parameters of the second capacitor and the second inductor are obtained by analyzing the impedance trajectory of the second control signal through the Smith chart.

[0021] In a possible design, the excitation source modulation unit is used to distinguish between the first control signal and the second control signal.

[0022] In a possible design, the dual-frequency switching circuit further includes a selection switch;

[0023] The selection switch includes a first connection end, a second connection end and a third connection end;

[0024] The first connection end is connected to the second end, the second connection end is used to connect to the third end, and the third connection end is used to connect to the fifth end;

[0025] The selection switch is used to connect the second connection end to the third end according to the first control signal, or connect the third connection end to the fifth end according to the second control signal.

[0026] In a possible design, the main control unit is specifically configured to detect the working process of the vehicle and generate a first control signal or a second control signal according to the working process.

[0027] In a second aspect, the present application provides a control system for a vehicle, including a dual-frequency switching circuit and a control circuit of the vehicle as described in the first aspect and / or various possible implementations of the first aspect;

[0028] wherein, the dual-frequency switching circuit is connected to the control circuit of the vehicle, and the dual-frequency switching circuit is configured to transmit a radio frequency signal to the control circuit of the vehicle.

[0029] The dual-frequency switching circuit and the control system for a vehicle provided by the present application include a main control unit, an excitation source modulation unit, a first impedance matching circuit, a second impedance matching circuit, and an on-board antenna unit; the excitation source modulation unit includes a first end and a second end, the first impedance matching circuit includes a third end and a fourth end, and the second impedance matching circuit includes a fifth end and a sixth end; the main control unit is connected to the first end, and the second end is connected to the third end or the fifth end; the fourth end and the sixth end are both connected to the on-board antenna unit; the main control unit is configured to generate a first control signal or a second control signal to the excitation source modulation unit, so that the first control signal is transmitted to the first impedance matching circuit and output a first radio frequency signal through the first impedance matching circuit and the on-board antenna unit, and the second control signal is transmitted to the second impedance matching circuit and output a second radio frequency signal through the second impedance matching circuit and the on-board antenna unit; to achieve dual-frequency switching. Compared with the existing technology that equips corresponding electronic control units for each frequency band, the dual-frequency switching circuit of the present application realizes the functions and signal transmission of two different frequency bands by the scheduling of the main control unit, uses one on-board antenna to complete the functions of the vehicle in the corresponding frequency bands, thereby reducing the design cost and the complexity of the wiring harness layout, and improving the integration degree of the vehicle electronic control unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application and used together with the specification to explain the principles of the present application.

[0031] Figure 1 A single-frequency circuit design diagram provided for the prior art;

[0032] Figure 2 A structural schematic diagram of a dual-frequency switching circuit provided by the present application Figure 1 ;

[0033] Figure 3 A structural schematic diagram of a dual-frequency switching circuit provided by the present application Figure 2 ;

[0034] Figure 4Schematic diagram of the structure of a dual - frequency switching circuit provided by this application Figure 2 ;

[0035] Figure 5 Schematic diagram of the simulation results of the S - parameters (also known as scattering parameters) corresponding to the frequency of 433 MHz;

[0036] Figure 6 Schematic diagram of the simulation results of the S - parameters (also known as scattering parameters) corresponding to the frequency of 315 MHz;

[0037] Figure 7 Schematic diagram of the structure of a control system of a vehicle provided by this application.

[0038] Through the above - mentioned drawings, specific embodiments of this application have been shown, and there will be more detailed descriptions hereinafter. These drawings and written descriptions are not intended to limit the scope of the concept of this application in any way, but to illustrate the concept of this application to those skilled in the art by referring to specific embodiments. Description of reference numerals

[0039] 101: First electronic control unit;

[0040] 102: Second electronic control unit;

[0041] 20: Dual - frequency switching circuit;

[0042] 201: Main control unit;

[0043] 202: Excitation source modulation unit;

[0044] 203: First impedance matching circuit;

[0045] 204: Second impedance matching circuit;

[0046] 205: On - board antenna unit;

[0047] S: Selection switch;

[0048] J1: Impedance matching circuit connection port;

[0049] J2: External interaction interface;

[0050] C1: First capacitor;

[0051] L1: First inductor;

[0052] C2: Second capacitor;

[0053] L2: Second inductor;

[0054] 30: Control circuit. Detailed implementation manners

[0055] Exemplary embodiments will be described in detail herein, and examples thereof are shown in the accompanying drawings. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0056] It should be noted that all the data involved in the present application are information and data that have been authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant laws, regulations, and standards, and corresponding operation entrances are provided for the user to choose to authorize or reject.

[0057] Radio frequency technology is widely used in vehicle signal transmission, and different radio frequency bands support different functions and applications. Among them, the low-frequency band antenna can be used for simple ranging and wake-up excitation of the vehicle, and the high-frequency band antenna can be used for data transmission of various signals, such as specific data transmission for key authentication and tire pressure detection; through this wireless contact signal transmission method, the intelligent development of the vehicle is promoted.

[0058] Figure 1 A single-frequency circuit design diagram provided by the prior art is as Figure 1 shown. For example, the radio frequency high-frequency usage bands of current vehicles are usually 433 MHz and 315 MHz; through the corresponding first electronic control unit 101 and second electronic control unit 102, the antennas of 433 MHz and 315 MHz are respectively controlled to complete the corresponding functions of the frequency bands of 433 MHz and 315 MHz.

[0059] In the prior art, since the lengths of the on-board antennas in different frequency bands are different, and the lengths of the corresponding circuit board traces are also different, it is necessary to design circuits separately for different fixed frequency bands and set corresponding controllers to improve the signal stability. However, this method increases the design cost of the circuit and the complexity of the wiring harness layout, which is not conducive to the integration of vehicle electronic control units.

[0060] To solve the above problems, the core concept of the present application is: to design a dual-frequency switching circuit, through the scheduling of the main control unit, use one on-board antenna to complete the functions and signal transmission of two different frequency bands, so as to realize the functions of the vehicle in the corresponding frequency bands, thereby reducing the design cost and the complexity of the wiring harness layout, and improving the integration degree of the vehicle electronic control unit.

[0061] The technical solution of the present application and how the technical solution of the present application solves the above technical problems will be described in detail below with specific embodiments. The following several specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0062] Figure 2 Schematic structure of a dual-frequency switching circuit provided by the present application Figure 1 , such as Figure 2 shown, the dual-frequency switching circuit 20 includes a main control unit 201, an excitation source modulation unit 202, a first impedance matching circuit 203, a second impedance matching circuit 204, and an on-board antenna unit 205.

[0063] The excitation source modulation unit 202 includes a first end and a second end, the first impedance matching circuit 203 includes a third end and a fourth end, and the second impedance matching circuit 204 includes a fifth end and a sixth end.

[0064] The main control unit 201 is connected to the first end, and the second end is connected to the third end or the fifth end.

[0065] Both the fourth end and the sixth end are connected to the on-board antenna unit 205.

[0066] The main control unit 201 is configured to generate a first control signal or a second control signal to the excitation source modulation unit 202, so that the first control signal is transmitted to the first impedance matching circuit 203, and a first radio frequency signal is output through the first impedance matching circuit 203 and the on-board antenna unit 205, and the second control signal is transmitted to the second impedance matching circuit 204, and a second radio frequency signal is output through the second impedance matching circuit 204 and the on-board antenna unit 205.

[0067] In this embodiment, by generating control signals of different frequency bands through the main control unit 201, the flexibility of the dual-frequency switching circuit is improved. Then, based on the excitation source modulation unit 202, impedance matching is performed on the control signals of different frequency bands through the first impedance matching circuit 203 or the second impedance matching circuit 204 respectively to reduce the loss of the control signals, realize the efficient transmission of signals, and complete the switching of two frequency bands through the on-board antenna unit 205, realizing the application and integrated design of the vehicle for two frequency bands, making the dual-frequency switching circuit miniaturized, facilitating integration, reducing the complexity of the vehicle harness layout, reducing the design cost, and improving the utilization rate of the dual-frequency switching circuit inside the vehicle.

[0068] Optionally, the main control unit 201 is specifically configured to detect the working process of the vehicle and generate a first control signal or a second control signal according to the working process.

[0069] In this embodiment, the working process of the vehicle includes vehicle unlocking, vehicle starting, vehicle status retrieval, and driving mode. Among them, different working processes correspond to different frequency bands. For example, if the main control unit 201 generates a first control signal in response to the first fixed frequency band of 433 MHz, or generates a second control signal in response to the second fixed frequency band of 315 MHz.

[0070] Among them, the first control signal or the second control signal can also be a control signal generated by other frequency bands.

[0071] Optionally, the excitation source modulation unit 202 is used to distinguish the first control signal and the second control signal.

[0072] In this embodiment, the excitation source modulation unit 202 loads different control signals onto different carrier frequencies, phases, or amplitudes through modulation techniques to achieve the identification of the first control signal and the second control signal.

[0073] Optionally, the dual-frequency switching circuit further includes a selection switch S.

[0074] The selection switch S includes a first connection end, a second connection end, and a third connection end.

[0075] The first connection end is connected to the second end, the second connection end is used to connect to the third end, and the third connection end is used to connect to the fifth end.

[0076] The selection switch S is used to connect the second connection end to the third end according to the first control signal, or connect the third connection end to the fifth end according to the second control signal.

[0077] In this embodiment, after the excitation source modulation unit 202 distinguishes the first control signal and the second control signal, the selection switch S is used to connect the second connection end to the third end according to the first control signal, or connect the third connection end to the fifth end according to the second control signal, so that the first control signal and the second control signal can be transmitted to the corresponding impedance matching circuits.

[0078] Figure 3 The structural schematic of a dual-frequency switching circuit provided by the present application Figure 2 , as Figure 3 shown, on the basis of the Figure 2 embodiment, the first impedance matching circuit 203 and the second impedance matching circuit 204 are respectively described in detail. The first impedance matching circuit 203 includes a first capacitor C1 and a first inductor L1, and the second impedance matching circuit 204 includes a second capacitor C2 and a second inductor L2.

[0079] The first capacitor C1 is connected in parallel to the first impedance matching circuit 203, and the first inductor L1 is connected in series to the first impedance matching circuit 203.

[0080] The second capacitor C2 is connected in parallel to the second impedance matching circuit 204, and the second inductor L2 is connected in series to the second impedance matching circuit 204.

[0081] Optionally, the parameters of the first capacitor C1 and the first inductor L1 are obtained by analyzing the impedance trajectory of the first control signal through a Smith chart, and the parameters of the second capacitor C2 and the second inductor L2 are obtained by analyzing the impedance trajectory of the second control signal through a Smith chart.

[0082] In this embodiment, based on the on-board antenna unit 202, the load impedance to be matched and the target impedance are determined. By adjusting the parameters of the capacitor and the inductor, the position of the load impedance to be matched is marked on the Smith chart until the load impedance to be matched matches the target impedance, thereby obtaining the corresponding impedance trajectory.

[0083] For example, the target impedance corresponding to the first control signal can be 51 Ω, and the target impedance corresponding to the second control signal can be 50 Ω; based on the impedance trajectory of the first control signal through the Smith chart and the impedance trajectory of the second control signal through the Smith chart, it is determined that the parameter of the first capacitor C1 is 26 pF and the parameter of the first inductor L1 is 25.5 nH, and the parameter of the second capacitor C2 is 36 pF and the parameter of the second inductor L2 is 72 nH.

[0084] The dual-frequency switching circuit provided in this application transmits the first control signal to the first impedance matching circuit 203 and the second control signal to the second impedance matching circuit 204 respectively, so that the first control signal and the second control signal achieve maximum power transmission, reduce signal reflection, reduce signal transmission loss, and ensure signal integrity and transmission efficiency.

[0085] Figure 4 Schematic diagram of the structure of a dual-frequency switching circuit provided in this application Figure 2 , as Figure 4 shown, this embodiment elaborates on the on-board antenna unit 202 on the basis of the Figure 2 embodiment. Preferably, the on-board antenna unit 205 includes an L-shaped on-board antenna.

[0086] In this embodiment, the L-shaped on-board antenna is a PCB (Printed Circuit Board) on-board antenna. By directly integrating the antenna on the printed circuit board, external factor interference is reduced and the design cost is lowered; the structure of the L-shaped on-board antenna is L-shaped, consisting of a vertical and a horizontal part, occupying less space and being easy to integrate.

[0087] In this embodiment, the L-shaped onboard antenna supports multi-band design and multi-polarization directions. Therefore, dual-band switching can be achieved by adjusting the antenna length of the L-shaped onboard antenna.

[0088] Optionally, the antenna length of the L-shaped onboard antenna is the larger value of the first antenna length and the second antenna length;

[0089] Wherein, the first antenna length is determined by the board manufacturing parameters of the circuit board of the L-shaped onboard antenna and the wavelength of the first control signal, and the second antenna length is determined by the board manufacturing parameters of the circuit board of the L-shaped onboard antenna and the wavelength of the second control signal.

[0090] In this embodiment, the board manufacturing parameters of the circuit board of the L-shaped onboard antenna include the dielectric constant and the board thickness; the calculation formula of the first antenna length or the second antenna length is as follows:

[0091]

[0092] In the formula, L is the first antenna length or the second antenna length; is the wavelength of the first control signal or the wavelength of the second control signal; is the dielectric constant of the circuit board of the L-shaped onboard antenna.

[0093] Wherein, when L is the first antenna length, is the wavelength of the first control signal; when L is the second antenna length, is the wavelength of the second control signal.

[0094] For example, if the frequency band corresponding to the first control signal is 433 MHz and the frequency band corresponding to the second control signal is 315 MHz, then the wavelength of the second control signal is greater than the wavelength of the first control signal. Correspondingly, the second antenna length is greater than the first antenna length, and the antenna length of the L-shaped onboard antenna is the second antenna length.

[0095] When the antenna length of the L-shaped onboard antenna needs to be adjusted to the first antenna length, a passive component is used for adjustment, wherein the passive component includes a variable capacitor, a variable inductor or a resistor.

[0096] In this embodiment, through the matching design of the L-shaped onboard antenna and discrete devices, the volume of the PCB is effectively reduced, so that the dual-band switching circuit is miniaturized and easy to integrate; wherein, the discrete devices include a first capacitor C1, a first inductor L1, a second capacitor C2 and a second inductor L2.

[0097] Optionally, the L-shaped onboard antenna includes an impedance matching circuit connection port J1 and an external interaction interface J2.

[0098] The impedance matching circuit connection port J1 is used to connect to the first impedance matching circuit 203 or the second impedance matching circuit 204.

[0099] In this embodiment, the L-shaped onboard antenna receives, through the impedance matching circuit connection port J1, the first control signal after impedance matching by the first impedance matching circuit 203, or the second control signal after impedance matching by the second impedance matching circuit 204, and converts the first control signal or the second control signal into the corresponding first radio frequency signal or second radio frequency signal.

[0100] The external interaction interface J2 is used to output the first radio frequency signal or the second radio frequency signal.

[0101] Optionally, after the external interaction interface J2 outputs the first radio frequency signal or the second radio frequency signal, in response to the first confirmation signal corresponding to the first radio frequency signal, or the second confirmation signal corresponding to the second radio frequency signal, the first confirmation signal or the second confirmation signal is input in reverse, undergoes signal modulation through the corresponding path, and returns to the main control unit 201 to complete the reception of the radio frequency signal.

[0102] Figure 5 is a schematic diagram of the simulation result of the S-parameters (also known as scattering parameters) corresponding to a frequency of 433 MHz; Figure 6 is a schematic diagram of the simulation result of the S-parameters (also known as scattering parameters) corresponding to a frequency of 315 MHz; where Figure 5 and Figure 6 the abscissa of represents the frequency (unit: MHz), Figure 5 and Figure 6 the ordinate of represents the S-parameters (unit: dB). As can be seen from Figure 5 and Figure 6 the S-parameters corresponding to the frequency of 433 MHz and the S-parameters corresponding to the frequency of 315 MHz are both less than -10 dB. Therefore, the dual-frequency switching circuit of the present application has a high matching degree within the target frequency band; the S-parameters represent the signal ratio reflected at the external interaction interface J2 and reflect the transmission efficiency of the L-shaped onboard antenna.

[0103] Figure 7 is a schematic structural diagram of a vehicle control system provided by the present application, including a dual-frequency switching circuit 20 and a vehicle control circuit 30.

[0104] Among them, the dual-frequency switching circuit 20 is connected to the vehicle control circuit 30, and the dual-frequency switching circuit 20 is used to transmit radio frequency signals to the vehicle control circuit 30.

[0105] In this embodiment, frequency switching is achieved through the dual-frequency switching circuit 20, and the corresponding radio frequency signal is sent to the control circuit 30 of the vehicle to complete different working processes of the vehicle; and the confirmation signal corresponding to the radio frequency signal returned from the control circuit 30 of the vehicle is received, which simplifies the design circuit of the control system of the vehicle and reduces the design cost of the control system of the vehicle, thereby realizing the intelligent integration of the vehicle.

[0106] Finally, it should be noted that those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention, which follow the general principles of the present invention and include the common general knowledge or conventional technical means in the technical field not disclosed in the present invention. It is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A dual-frequency switching circuit, characterized in that: It includes a main control unit, an excitation source modulation unit, a first impedance matching circuit, a second impedance matching circuit and an onboard antenna unit; The excitation source modulation unit includes a first end and a second end, the first impedance matching circuit includes a third end and a fourth end, and the second impedance matching circuit includes a fifth end and a sixth end; The main control unit is connected to the first end, and the second end is connected to the third end or the fifth end; The fourth end and the sixth end are both connected to the onboard antenna unit; The main control unit is used to generate a first control signal or a second control signal to the excitation source modulation unit, so that the first control signal is transmitted to the first impedance matching circuit, and a first radio frequency signal is output through the first impedance matching circuit and the onboard antenna unit, and the second control signal is transmitted to the second impedance matching circuit, and a second radio frequency signal is output through the second impedance matching circuit and the onboard antenna unit.

2. The dual-frequency switching circuit according to claim 1, characterized in that: The onboard antenna unit 205 includes an L-shaped onboard antenna.

3. The dual-frequency switching circuit according to claim 2, characterized in that: The L-shaped onboard antenna includes an impedance matching circuit connection port and an external interaction interface; The impedance matching circuit connection port is used to connect to the first impedance matching circuit or to connect to the second impedance matching circuit; The external interaction interface is used to output a first radio frequency signal or a second radio frequency signal.

4. The dual-frequency switching circuit according to claim 2, characterized in that: The antenna length of the L-shaped onboard antenna is the larger value of the first antenna length and the second antenna length; Among them, the length of the first antenna is determined by the board parameters of the circuit board of the L-shaped board-mounted antenna and the wavelength of the first control signal, and the length of the second antenna is determined by the board parameters of the circuit board of the L-shaped board-mounted antenna and the wavelength of the second control signal.

5. The dual-frequency switching circuit according to claim 1, characterized in that: The first impedance matching circuit includes a first capacitor and a first inductor, and the second impedance matching circuit includes a second capacitor and a second inductor; The first capacitor is connected in parallel to the first impedance matching circuit, and the first inductor is connected in series to the first impedance matching circuit; The second capacitor is connected in parallel to the second impedance matching circuit, and the second inductor is connected in series to the second impedance matching circuit.

6. The dual-frequency switching circuit according to claim 1, characterized in that: The parameters of the first capacitor and the first inductor are obtained by analyzing the impedance trajectory of the first control signal using a Smith chart, and the parameters of the second capacitor and the second inductor are obtained by analyzing the impedance trajectory of the second control signal using a Smith chart.

7. The dual-frequency switching circuit according to claim 1, characterized in that: The excitation source modulation unit is used to distinguish the first control signal from the second control signal.

8. The dual-frequency switching circuit according to any one of claims 1 to 7, characterized in that: Also includes a selector switch; The selection switch includes a first connection terminal, a second connection terminal and a third connection terminal; The first connection end is connected to the second end, the second connection end is used to connect to the third end, and the third connection end is used to connect to the fifth end; The selection switch is used to connect the second connection end to the third end according to the first control signal, or to connect the third connection end to the fifth end according to the second control signal.

9. The dual-frequency switching circuit according to any one of claims 1 to 7, characterized in that: The main control unit is specifically used to detect the working process of the vehicle, and generate a first control signal or a second control signal according to the working process.

10. A vehicle control system, characterized in that: A dual-frequency switching circuit as claimed in any one of claims 1 to 9 and a control circuit of a vehicle; The dual-frequency switching circuit is connected to the control circuit of the vehicle, and the dual-frequency switching circuit is used to transmit a radio frequency signal to the control circuit of the vehicle.

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