Track circuit current calibration device

Abstract

The utility model provides a track circuit current calibration device, which comprises a cable assembly, the cable assembly comprises a first end and a second end, and the first end and the second end are respectively provided with an aviation plug; the antenna assembly comprises an antenna aviation socket. The aviation plug of the first end or the second end of the cable assembly is connected with the antenna aviation socket of the antenna assembly in an inserted mode. The junction box assembly comprises a junction box aviation socket, the first end or the second end of the cable assembly is inserted into the junction box aviation socket of the junction box assembly, and the antenna assembly and the junction box assembly are inserted into different ends of the cable assembly so as to be connected with the antenna assembly and the junction box assembly; the antenna assembly is in lap joint with the top of a steel rail, and voltages of different frequencies are converted to different adjustable divider resistors through the junction box assembly and then output to the load resistor so as to calibrate and measure the measured signal current. Under the specified frequency, the linear precision between the signal current of the steel rail and the detected induced voltage and the linear precision between the signal frequency of the steel rail and the detected induced voltage are ensured to be within the allowable range.

Description

Technical Field

[0001] This application belongs to the field of current signal measurement technology, specifically relating to a track circuit current calibration device. Background Technology

[0002] Track circuits use each section of the railway as a loop for the signal current, with input at one end and short-circuited at the other. Due to differences in the insulation between the track and the ground, and the varying lengths of the sections, the actual track current at different locations within a section will differ from the input and output currents. In other words, the current magnitude on the rails varies at different points within the section. Calibration requires measuring the current at each point within the section, necessitating adjustments to the input power to ensure the current at each location conforms to specifications. Therefore, the induced voltage method is used for measurement. At a specified frequency, the linearity between the rail signal current and the detected induced voltage, as well as between the rail signal frequency and the detected induced voltage, must be within allowable limits. To address this, we propose a track circuit current calibration device. Utility Model Content

[0003] Therefore, this application provides a track circuit current calibration device, which at least solves the technical problem of ensuring linear accuracy in the prior art.

[0004] To address the aforementioned problems, this application provides a track circuit current calibration device, comprising:

[0005] A cable assembly, the cable assembly including a first end and a second end, the first end and the second end respectively being provided with an aviation plug;

[0006] An antenna assembly, the antenna assembly including an antenna aviation socket, wherein the aviation plug at the first end or the second end of the cable assembly is plugged into the antenna aviation socket of the antenna assembly;

[0007] A junction box assembly, the junction box assembly including a junction box aviation socket, a first end or a second end of a cable assembly being plugged into the junction box aviation socket of the junction box assembly, and an antenna assembly and the junction box assembly being plugged into different ends of the cable assembly to connect the antenna assembly and the junction box assembly;

[0008] The antenna assembly is attached to the top of the rail. Voltages of different frequencies are converted by the junction box assembly to different adjustable voltage divider resistors and then output to the load resistor to calibrate and measure the current of the signal being measured.

[0009] Optionally, the antenna assembly further includes a housing, which includes a receiving cavity and a magnetic core. The magnetic core is snapped into the receiving cavity, and a coil is fitted onto the outer peripheral surface of the magnetic core. The antenna aviation socket is disposed on the outer wall of the housing, and the two leads of the coil are connected to the corresponding pins of the antenna aviation socket.

[0010] Optionally, the magnetic core is provided with an insulating film for housing the coil portion.

[0011] Optionally, the cavity of the housing is filled with a filler.

[0012] Optionally, the housing is provided with a plug-in slot, through which the antenna assembly is attached to the top of the rail.

[0013] Optionally, the housing is provided with an opening, and a housing cover is installed at the opening.

[0014] Optionally, the junction box assembly further includes a first wire, a selector switch, and an adjustable resistor assembly. The two ends of the first wire are respectively connected to two of the junction box aviation sockets to connect the two junction box aviation sockets in series. One end of each of the two series-connected junction box aviation sockets is connected to a corresponding antenna assembly to connect the two antenna assemblies in series. The other ends of the two series-connected junction box aviation sockets are respectively connected to the adjustable resistor assembly and a third junction box aviation socket. The two ends of the selector switch are respectively connected to the adjustable resistor assembly and the third junction box aviation socket.

[0015] Optionally, the adjustable resistor assembly includes multiple adjustable voltage divider resistors connected in parallel. One end of each adjustable voltage divider resistor is connected to one of the terminal box aviation sockets connected in series via a wire, and the other end is connected to the selector switch. Adjusting the selector switch to connect to different adjustable voltage divider resistors allows voltages of different frequencies to be converted to different adjustable voltage divider resistors before being output.

[0016] Optionally, the junction box assembly further includes a housing, the selector switch and the adjustable resistor assembly are arranged inside the housing, and the junction box aviation socket is disposed on the side wall of the housing.

[0017] Optionally, the current calibration device further includes a sheath assembly, and the cable assembly is disposed within the sheath assembly.

[0018] Beneficial effects

[0019] The track circuit current calibration device provided in this embodiment actually receives a voltage signal from each of the two rails at the same location during operation. Voltages of different frequencies are converted to different voltage divider resistors by the junction box assembly and then output to the load resistor to calibrate and measure the signal current to be measured. At the specified frequency, the linearity between the rail signal current and the detected induced voltage, as well as between the rail signal frequency and the detected induced voltage, is guaranteed to be within the allowable range. It also has the advantages of small size and light weight. Attached Figure Description

[0020] Figure 1 This is a circuit diagram of the junction box assembly and antenna assembly according to an embodiment of this application;

[0021] Figure 2 This is a simplified schematic diagram of the basic principle of the track circuit current calibration device according to an embodiment of this application;

[0022] Figure 3 This is a front view of the antenna assembly according to an embodiment of this application;

[0023] Figure 4 This is a side view of the antenna assembly according to an embodiment of this application.

[0024] The reference numerals in the attached figures are as follows:

[0025] 1. Antenna assembly; 101. Housing; 102. Magnetic core; 103. Coil; 104. Antenna aviation socket; 105. Filler; 106. Housing cover; 107. Connecting slot;

[0026] 2. Junction box assembly; 201. Junction box aviation socket; 202. First conductor; 203. Selector switch; 204. Adjustable voltage divider resistor;

[0027] 3. Cable assemblies;

[0028] 4. Measure the cable;

[0029] 5. Steel rails. Detailed Implementation

[0030] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0032] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0033] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0034] See also Figures 1 to 4 As shown, according to an embodiment of this application, a track circuit current calibration device is provided, including a cable assembly 3, an antenna assembly 1, and a junction box assembly 2. The cable assembly 3 includes a first end and a second end, and the first end and the second end are respectively provided with aviation plugs. The antenna assembly 1 includes an antenna aviation socket 104, and the aviation plug of the first end or the second end of the cable assembly 3 is plugged into the antenna aviation socket 104 of the antenna assembly 1. The junction box assembly 2 includes a junction box aviation socket 201, and the first end or the second end of the cable assembly 3 is plugged into the junction box aviation socket 201 of the junction box assembly 2. The antenna assembly 1 and the junction box assembly 2 are plugged into different ends of the cable assembly 3 to connect the antenna assembly 1 and the junction box assembly 2. The antenna assembly 1 is attached to the top of the rail 5. Voltages of different frequencies are converted to different voltage divider resistors by the junction box assembly 2 and output to the load resistor connected to the measuring cable 4, and then connected to a digital multimeter to calibrate and measure the current of the signal to be measured.

[0035] Antenna assembly 1 is mounted on rail 5 via its insertion slot 107. When the alternating current of the signal flows through rail 5, it generates an alternating induced magnetic field around rail 5. An alternating electromotive force (EMF) is induced in the coil 103 of antenna assembly 1, and the magnitude of the EMF determines the current on rail 5. Therefore, based on this principle, in actual signal reception, voltage signals are collected from two rails 5 at the same location and superimposed in series. Voltages of different frequencies are converted by junction box assembly 2 to different voltage divider resistors before being output to the load resistor. The load resistor connected to measuring cable 4 has a resistance of 4KΩ and is equipped with a shielded grounding system. The output of measuring cable 4 is connected to a digital multimeter, which measures the voltage drop across the load resistor to calibrate the measured signal current. At a specified frequency, the linearity between the signal current and the detected induced voltage on rail 5, as well as between the signal frequency and the detected induced voltage on rail 5, is maintained within the allowable range. If the measured near-end voltage drop is higher than the far-end voltage drop, insulation needs to be inspected. It also has the advantages of small size and light weight.

[0036] The cable assembly 3 includes a live wire and a neutral wire; pins of an aviation plug are installed at both ends of the live wire and the neutral wire.

[0037] Among them, antenna assembly 1 consists of two parts, namely the first antenna assembly and the second antenna assembly;

[0038] Both the antenna aviation socket 104 and the junction box aviation socket 201 include three pins. The antenna aviation socket 104 has three pins from left to right: pin 3, pin 2, and pin 1. Pin 3 is used to connect to the shielding mesh, pin 2 is used to connect to the neutral wire, and pin 1 is used to connect to the live wire.

[0039] There are three junction box aviation sockets 201: the first junction box aviation socket, the second junction box aviation socket, and the third junction box aviation socket. From left to right, the first and second junction box aviation sockets are pin 3, pin 2, and pin 1, respectively. From bottom to top, the third junction box aviation socket is pin 3, pin 2, and pin 1, respectively.

[0040] The No. 3 pin of the third junction box aviation socket is connected to the No. 3 pin of the first junction box aviation socket and the No. 3 pin of the second junction box aviation socket via a shielded wire; the cable assembly 3 also includes a shielding mesh, wherein the two ends of the shielding mesh of one cable assembly 3 are respectively connected to the No. 3 pin of the antenna aviation socket of the first antenna assembly and the No. 3 pin of the first junction box aviation socket; the two ends of the shielding mesh of the other cable assembly 3 are respectively connected to the No. 3 pin of the antenna aviation socket of the second antenna assembly and the No. 3 pin of the second junction box aviation socket.

[0041] The shielding mesh of measuring cable 4 is connected to pin 3 of the aviation socket in the third junction box; the live wire of measuring cable 4 is connected to pin 1 of the aviation socket in the third junction box; the neutral wire of measuring cable 4 is connected to pin 2 of the aviation socket in the third junction box.

[0042] The first junction box aviation socket corresponds to the antenna aviation socket 104 of the first antenna assembly. The aviation plugs at both ends of the live wire of one cable assembly 3 are inserted between pin 1 of the first junction box aviation socket and pin 1 of the antenna aviation socket 104 of the first antenna assembly. At the same time, the aviation plugs at both ends of the neutral wire of the cable assembly 3 are inserted between pin 2 of the first junction box aviation socket and pin 2 of the antenna aviation socket 104 of the first antenna assembly. Similarly, the second junction box aviation socket corresponds to the antenna aviation socket 104 of the second antenna assembly. The aviation plugs at both ends of the live wire of another cable assembly 3 are inserted between pin 1 of the second junction box aviation socket and pin 1 of the antenna aviation socket 104 of the second antenna assembly. At the same time, the aviation plugs at both ends of the neutral wire of the cable assembly 3 are inserted between pin 2 of the second junction box aviation socket and pin 2 of the antenna aviation socket 104 of the second antenna assembly. Thus, the connection between the two antenna assemblies 1 and the junction box assembly 2 is completed.

[0043] The antenna assembly 1 also includes a housing 101, which includes a receiving cavity and a magnetic core 102. The magnetic core 102 is snapped into the receiving cavity, and a coil 103 is fitted on the outer peripheral surface of the magnetic core 102. An antenna aviation socket 104 is disposed on the outer side wall of the housing 101, and the two leads of the coil 103 are connected to the corresponding pins of the antenna aviation socket 104.

[0044] According to the law of electromagnetic induction, the induced electromotive force is directly proportional to the number of turns of coil 103 and the rate of change of magnetic flux. The magnetic flux at coil 103 is directly proportional to the permeability and area of ​​magnetic core 102, and inversely proportional to the distance from coil 103 to the current-carrying wire. That is, under the same current, the induced electromotive force is larger at higher frequencies.

[0045] Therefore, the magnetic core 102 is a ferrite rod with a diameter of 20mm and a length of 200mm, and the two ends of the magnetic core 102 are snapped into the receiving cavity.

[0046] The coil 103 is made of enameled wire with a diameter of 0.59mm, and is wound with 560 turns at the middle of the magnetic core 102 at a distance of 60mm.

[0047] The magnetic core 102 and coil 103 are arranged according to the above parameters to ensure that the frequency response characteristics meet the requirements while satisfying the resistance and inductance.

[0048] The two leads of coil 103 are connected to pin 1 and pin 2 of antenna aviation socket 104 respectively, thereby connecting coil 103 to antenna aviation socket 104.

[0049] The portion of the magnetic core 102 used to house the coil 103 is provided with an insulating film. Firstly, the coil 103 generates a magnetic field when energized. By providing an insulating film between the coil 103 and the magnetic core 102, potential interference with the magnetic field distribution can be avoided, preventing a reduction in the magnetism of the magnetic core 102. Secondly, if the surface of the magnetic core 102 lacked an insulating film, the insulating film of the enameled wire might slip and rub against the magnetic core 102, leading to insulation failure.

[0050] When installing coil 103, an insulating film must first be placed on magnetic core 102, and then the enameled wire is wound around magnetic core 102 to form coil 103, that is, coil 103 is fitted onto magnetic core 102.

[0051] The cavity of the housing 101 is filled with filler 105.

[0052] The filler 105 is polyurethane foam. After the magnetic core 102 with coil 103 is installed, the polyurethane foam is filled into the gap of the receiving cavity of the housing 101, so that the inside of the receiving cavity is filled with foam, so as to fix the iron core 102 with coil 103 inside the housing 101, achieving the effect of dustproof, waterproof and shockproof.

[0053] The housing 101 is provided with a plug-in slot 107, and the antenna assembly 1 is attached to the top of the rail 5 through the plug-in slot 107.

[0054] The insertion slot 107 is a recessed groove on the housing 101 facing the geometric center of the housing 101. The width of the insertion slot 107 is greater than the width of the rail 5, so as to facilitate the installation of the antenna assembly 1 on the rail 5, while ensuring that the two side walls of the insertion slot 107 of the antenna assembly 1 do not generate hard friction with the rail 5, so as not to damage the housing 101.

[0055] Specifically, the distance between the housing 101 and the rail surface of the rail 5 is determined by the height of the housing 101 to ensure frequency response characteristics. The voltage signal collected by the antenna assembly 1 from the rail 5 flows through the cable assembly 3 to the junction box assembly 2.

[0056] An opening is provided on the housing 101, and a cover 106 is installed at the opening.

[0057] The opening and the antenna aviation socket 104 are arranged on two side walls opposite to the housing 101. After the magnetic core 102 with coil 103 is installed on the housing 101, polyurethane foam is filled into the gap of the housing 101 through the opening. After filling, the cover 106 is installed at the opening of the housing 101 to seal the opening.

[0058] Specifically, the housing 101 and the cover 106 are made of nylon, which ensures that the signal magnetic field can reach the coil 103 smoothly.

[0059] The junction box assembly 2 also includes a first wire 202, a selector switch 203, and an adjustable resistor assembly. The two ends of the first wire 202 are respectively connected to two of the junction box aviation sockets 201, so that the two junction box aviation sockets 201 are connected in series. One end of the two series-connected junction box aviation sockets 201 is respectively connected to the corresponding antenna assembly 1, so that the two antenna assemblies 1 are connected in series. The other end of the two series-connected junction box aviation sockets 201 is respectively connected to the adjustable resistor assembly and the third junction box aviation socket 201. The two ends of the selector switch 203 are respectively connected to the adjustable resistor assembly and the third junction box aviation socket 201.

[0060] The first and second junction box aviation sockets are located on the same side, while the third junction box aviation socket is located on another side. The first and second junction box aviation sockets are perpendicular to the third junction box aviation socket.

[0061] The first wire 202 is connected at both ends to two of the junction box aviation sockets 201, so that the two junction box aviation sockets 201 are connected in series. That is, the first wire 202 is connected at both ends to the first pin of the first junction box aviation socket and the second junction box aviation socket, so as to realize the series connection of the first junction box aviation socket and the second junction box aviation socket.

[0062] In this configuration, one end of each of the two series-connected junction box aviation sockets 201 is connected to the corresponding antenna assembly 1, thereby connecting the two antenna assemblies 1 in series. That is, the first junction box aviation socket and the antenna aviation socket 104 of the first antenna assembly are arranged correspondingly. The two ends of the live wire of one cable assembly 3 are respectively plugged into the first pin of the first junction box aviation socket and the antenna aviation socket 104 of the first antenna assembly, and the two ends of the neutral wire are respectively plugged into the second pin of the first junction box aviation socket and the antenna aviation socket 104 of the first antenna assembly. At the same time, the second antenna assembly is connected to the second junction box aviation socket in the same way, which will not be described in detail here; thus realizing the series connection of the two antenna assemblies 1.

[0063] Among them, the other ends of the two series-connected aviation sockets 201 are connected to the adjustable resistor assembly and the third aviation socket 201, respectively. That is, the first aviation socket is connected to the adjustable resistor assembly through the second wire, one end of the second wire is inserted into the second pin of the first aviation socket; the second aviation socket and the third aviation socket are connected by the third wire, the two ends of the third wire are inserted into the second pin of the second aviation socket and the third aviation socket, respectively.

[0064] The selector switch 203 is connected to the adjustable resistor assembly and the third junction box aviation socket 201 at both ends. That is, one end of the selector switch 203 is connected to the adjustable resistor assembly to connect with voltage divider resistors of different resistance values; the other end of the selector switch 203 is connected to the first pin of the third junction box aviation socket through the fourth wire; the junction box assembly 2 is connected to the measuring cable 4 through the third junction box aviation socket to calibrate the measured signal current.

[0065] To simultaneously meet the frequency response characteristics at different frequencies (i.e., the induced voltage value of the antenna assembly at a specified current), it is difficult to accurately match the relationship between the volume of the magnetic core 102, the number of turns of the coil 103, and the height from the rail surface of the rail 5. Often, after ensuring the characteristic value at one frequency, the characteristic values ​​at other frequencies cannot be guaranteed. To ensure that the frequency response characteristics are met, a junction box assembly 2 with a fine-tuning board is provided. After the induced electromotive forces of the two antenna assemblies 1 are connected in series, the voltages of different frequencies are switched by the selector switch 203 to different adjustable voltage divider resistors 204 and then output to the load resistor connected to the measuring cable 4, so that the frequency response characteristics of the final output end fully meet the usage requirements.

[0066] The adjustable resistor assembly includes multiple adjustable voltage divider resistors 204 connected in parallel. One end of each adjustable voltage divider resistor 204 is connected to one of the series-connected junction box aviation sockets 201 via a wire, and the other end is connected to a selector switch 203. Adjusting the selector switch 203 to connect to different adjustable voltage divider resistors 204 allows voltages of different frequencies to be converted to different adjustable voltage divider resistors 204 for output.

[0067] The adjustable resistor assembly includes multiple adjustable voltage divider resistors 204 connected in parallel. In this embodiment, there are four adjustable voltage divider resistors 204 connected in parallel, which, from top to bottom, are: 500-1000Ω (composed of a 500Ω resistor and a 0-500Ω variable resistor), corresponding to a detection frequency of 2600Hz; 200-700Ω (composed of a 200Ω resistor and a 0-500Ω variable resistor), corresponding to a detection frequency of 2300Hz; 0-500Ω, corresponding to a detection frequency of 2000Hz; and 0-500Ω, corresponding to a detection frequency of 1700Hz. The selection switch 203 switches between the adjustable voltage divider resistors 204 with different resistance values ​​to correspond to different detection frequencies.

[0068] The four parallel-connected adjustable voltage divider resistors 204 and the selection switch 203 are integrated on the micro-adjustment board. One end of the micro-adjustment board is the input end, which is connected to one end of the second wire, and the other end of the second wire is connected to the aviation socket of the first junction box. The other end of the micro-adjustment board is the output end, which is connected to one end of the fourth wire, and the other end of the fourth wire is connected to the aviation socket of the third junction box.

[0069] The junction box assembly 2 also includes a box body, a selector switch 203 and an adjustable resistor assembly arranged inside the box body, and a junction box aviation socket 201 disposed on the side wall of the box body.

[0070] The arrangement of the box serves two purposes: insulation and protection, as well as dust and moisture prevention.

[0071] The current calibration device also includes a sheath assembly, within which the cable assembly 3 is housed. The sheath assembly protects the cable assembly 3 from mechanical damage, corrosion, or contamination, thereby extending its service life.

[0072] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0073] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A track circuit current calibration device, characterized in that, include: Cable assembly (3), the cable assembly (3) includes a first end and a second end, the first end and the second end are respectively provided with aviation plugs; Antenna assembly (1), the antenna assembly (1) includes an antenna aviation socket (104), and the aviation plug of the first end or the second end of the cable assembly (3) is plugged into the antenna aviation socket (104) of the antenna assembly (1); Junction box assembly (2), the junction box assembly (2) includes a junction box aviation socket (201), the first end or the second end of the cable assembly (3) is plugged into the junction box aviation socket (201) of the junction box assembly (2), the antenna assembly (1) and the junction box assembly (2) are plugged into different ends of the cable assembly (3) to connect the antenna assembly (1) and the junction box assembly (2); The antenna assembly (1) is attached to the top of the rail (5). Voltages of different frequencies are converted by the junction box assembly (2) to different adjustable voltage divider resistors (204) and then output to the load resistor to calibrate and measure the current of the signal to be measured.

2. The track circuit current calibration device according to claim 1, characterized in that, The antenna assembly (1) further includes a housing (101), which includes a receiving cavity and a magnetic core (102). The magnetic core (102) is snapped into the receiving cavity. A coil (103) is fitted on the outer peripheral surface of the magnetic core (102). The antenna aviation socket (104) is disposed on the outer wall of the housing (101). The two leads of the coil (103) are connected to the corresponding pins of the antenna aviation socket (104).

3. The track circuit current calibration device according to claim 2, characterized in that, The magnetic core (102) is used to house the coil (103), and the portion of the coil is provided with an insulating film.

4. The track circuit current calibration device according to claim 2, characterized in that, The cavity of the housing (101) is filled with filler (105).

5. A track circuit current calibration device according to claim 2, characterized in that, The housing (101) is provided with a plug-in slot (107), and the antenna assembly is attached to the top of the rail (5) through the plug-in slot (107).

6. A track circuit current calibration device according to claim 2, characterized in that, The housing (101) has an opening, and a cover (106) is installed at the opening.

7. A track circuit current calibration device according to claim 1, characterized in that, The junction box assembly further includes a first wire (202), a selector switch (203), and an adjustable resistor assembly. The two ends of the first wire (202) are respectively connected to two of the junction box aviation sockets (201) so that the two junction box aviation sockets (201) are connected in series. One end of the two series-connected junction box aviation sockets (201) is respectively connected to the corresponding antenna assembly so that the two antenna assemblies are connected in series. The other end of the two series-connected junction box aviation sockets (201) is respectively connected to the adjustable resistor assembly and the third junction box aviation socket (201). The two ends of the selector switch (203) are respectively connected to the adjustable resistor assembly and the third junction box aviation socket (201).

8. A track circuit current calibration device according to claim 7, characterized in that, The adjustable resistor assembly includes multiple adjustable voltage divider resistors (204) connected in parallel. One end of each adjustable voltage divider resistor (204) is connected to one of the terminal box aviation sockets (201) connected in series via a wire, and the other end is connected to the selector switch (203). Adjusting the selector switch (203) to connect to different adjustable voltage divider resistors (204) allows voltages of different frequencies to be converted to adjustable voltage divider resistors (204) with different resistance values ​​before being output.

9. A track circuit current calibration device according to claim 7, characterized in that, The junction box assembly also includes a housing, the selector switch (203) and the adjustable resistor assembly are arranged inside the housing, and the junction box aviation socket (201) is disposed on the side wall of the housing.

10. A track circuit current calibration device according to claim 1, characterized in that, The current calibration device also includes a sheath assembly, and the cable assembly (3) is disposed within the sheath assembly.

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