Tester for rail transit LTE (Long Term Evolution) mobile communication system

Abstract

The utility model discloses a rail transit LTE mobile communication system tester comprising a cabinet, a plurality of function plugboard units and a mother board used for connecting the function plugboard units are arranged in the cabinet, and the top of the cabinet is provided with a plurality of slots. Each functional plugboard unit is installed in a corresponding slot in a pluggable manner and is connected with a connector at a corresponding position on the mother board; a display screen and a flip type keyboard door are arranged on the front face of the machine box, the flip type keyboard door is connected with the machine box through a hinge, a clamping and locking piece is further arranged on the front face of the machine box, and the flip type keyboard door is locked with the machine box through the clamping and locking piece. An ARM industrial control board used for operating the test system is arranged between the plurality of function plugboard units and the display screen. The ARM industrial control board is connected with the mother board, the display screen and the flip type keyboard door through interfaces. Integrated testing is achieved through the case integrating all functional units, carrying and operation are convenient, the plug board type unit is easy to upgrade and maintain, and the flexibility and efficiency of testing of the mobile communication system are effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of LTE communication testing, in particular to a rail transit LTE mobile communication system tester. Background Art

[0002] Mobile broadband trunking technology, mainly LTE, has been widely promoted and applied in urban rail transit in recent years. The dedicated mobile communication network for rail transit carries not only train operation control information, but also trunking dispatching services and operational safety information. To ensure the communication stability and reliability of rail transit, the dedicated mobile communication system needs to conduct periodic daily inspections and tests, including interconnection tests of communication systems on different lines.

[0003] The dynamic test of the dedicated mobile communication system needs to be carried out in a locomotive environment, with a fixed operating line and high requirements for the test time limit. The general mobile communication network test usually uses a computer operating platform to connect a mobile test terminal, which is more complicated to operate and inconvenient for testers to carry and operate, thus affecting the efficiency of mobile communication testing. Utility Model Content

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a rail transit LTE mobile communication system tester, aiming to improve the flexibility and efficiency of rail transit dedicated mobile communication network testing.

[0005] The technical solution of the utility model is as follows:

[0006] A rail transit LTE mobile communication system tester comprises a chassis, wherein a plurality of function plug-in board units and a motherboard for connecting the function plug-in board units are arranged in the chassis, a plurality of slots are opened on the top of the chassis, each function plug-in board unit is installed in a corresponding slot in a pluggable manner and connected to a connector at a corresponding position on the motherboard; a display screen and a flip-type keyboard door are arranged on the front of the chassis, the flip-type keyboard door is connected to the chassis through a hinge, a locking piece is also arranged on the front of the chassis, and the flip-type keyboard door is locked with the chassis through the locking piece; an ARM industrial control board for running a test system is also arranged between the plurality of function plug-in board units and the display screen, and the ARM industrial control board is connected to the motherboard, the display screen and the flip-type keyboard door through an interface.

[0007] In one embodiment, each functional board unit includes a panel and a PCBA board. The functional board unit is fixed to the upper and lower beams of the slot by captive screws on the panel. One end of the PCBA board is connected to the panel, and the other end is connected to the motherboard through the connector.

[0008] In one embodiment, the several functional plug-in board units include a power supply unit for power supply, an audio unit for processing input and output audio data, a first LTE unit for transmitting communication data, a second LTE unit for receiving communication data, and a satellite positioning unit for obtaining positioning information, and the motherboard is provided with a power supply interface, an audio interface, a MIC interface, a UART interface and a GPIO interface; the power supply interface is connected to the power supply unit, the audio interface and the MIC interface are connected to the audio unit, the UART interface is connected to the first LTE unit, the second LTE unit and the satellite positioning unit, and the GPIO interface is connected to the first LTE unit, the second LTE unit and the satellite positioning unit.

[0009] In one embodiment, a battery is further arranged between the plurality of functional plug-in board units and the display screen, and the battery is connected to the power supply unit.

[0010] In one embodiment, a speaker is further arranged between the plurality of function plug-in board units and the display screen, a microphone is arranged on one side of the display screen, and the speaker and the microphone are both connected to the audio unit.

[0011] In one embodiment, the power supply unit is specifically used to convert the input voltage and output two voltages of 12V and 5V respectively.

[0012] In one embodiment, the power supply unit includes a first inductor, a second inductor, a third inductor, a fourth inductor, a fifth inductor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first resistor, a second resistor, a first diode, a second diode, a buck chip and a voltage regulator;

[0013] One end of the first inductor is connected to the voltage input end, and the other end of the first inductor is connected to the positive electrode of the first diode; the negative electrode of the first diode is connected to the positive electrode of the first capacitor and the first pin of the buck chip; the negative electrode of the first capacitor is grounded through the second inductor; one end of the third inductor is connected to the second pin of the buck chip and the negative electrode of the second diode, and the other end of the third inductor is a 12V voltage output end, connecting one end of the first resistor, one end of the second capacitor and one end of the fourth inductor; the other end of the first resistor is connected to one end of the second resistor and the fourth pin of the buck chip; the positive electrode of the second diode, the other end of the second resistor and the other end of the second capacitor are all grounded; the other end of the fourth inductor is connected to one end of the third capacitor and the input end of the regulator; the other end of the third capacitor is grounded through the fifth inductor; one end of the fourth capacitor is a 5V voltage output end, connected to the output end of the regulator, and the other end of the fourth capacitor is grounded.

[0014] In one embodiment, the step-down chip uses a DC-DC step-down chip with model number x17015.

[0015] In one embodiment, the voltage regulator uses a three-terminal voltage regulator chip of model 7805.

[0016] In one embodiment, the chassis is further provided with a plurality of USB interfaces, and the USB interfaces are connected to the ARM industrial control board.

[0017] Beneficial effects: The utility model discloses a rail transit LTE mobile communication system tester. Compared with the prior art, the utility model realizes integrated testing by integrating a chassis of various functional units, which is convenient for carrying and operation, and the plug-in unit is easy to upgrade and maintain, effectively improving the flexibility and efficiency of mobile communication system testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0019] Figure 1 A three-dimensional diagram of the rail transit LTE mobile communication system tester provided by the utility model;

[0020] Figure 2 A component layout diagram of the rail transit LTE mobile communication system tester provided by the utility model from a top-down perspective;

[0021] Figure 3 A schematic diagram of the motherboard layout of the rail transit LTE mobile communication system tester provided by the utility model;

[0022] Figure 4 A structural diagram of a functional plug-in unit in a rail transit LTE mobile communication system tester provided by the utility model;

[0023] Figure 5 A schematic diagram of a panel of a functional plug-in unit in a rail transit LTE mobile communication system tester provided by the utility model;

[0024] Figure 6 The schematic diagram of the rail transit LTE mobile communication system tester provided by the utility model;

[0025] Figure 7 This is a schematic diagram of the architecture of the ARM industrial control board in the rail transit LTE mobile communication system tester provided by the utility model;

[0026] Figure 8 A schematic diagram of the architecture of a motherboard in a rail transit LTE mobile communication system tester provided by the utility model;

[0027] Fig. 9 and Fig.10 A schematic diagram of a power supply unit in a rail transit LTE mobile communication system tester provided by the utility model;

[0028] Fig.11 A schematic diagram of the architecture of the first LTE unit in the rail transit LTE mobile communication system tester provided by the utility model;

[0029] Fig.12 This is a schematic diagram of the architecture of the satellite positioning unit in the rail transit LTE mobile communication system tester provided by the utility model;

[0030] Fig.13 The present invention provides a schematic diagram of the architecture of the audio unit in the rail transit LTE mobile communication system tester. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and effect of the utility model clearer and more specific, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0032] See also Figure 1 , Figure 2 and Figure 3 The rail transit LTE mobile communication system tester provided by the utility model includes a chassis 1, the front of the chassis 1 is provided with a display screen 5 and a flip-type keyboard door 6, the flip-type keyboard door 6 is connected to the chassis 1 through a hinge, and the front of the chassis 1 is also provided with a locking member 7, the flip-type keyboard door 6 is locked with the chassis 1 through the locking member 7, that is, the front of the tester is a hinged keyboard door, and the operation keyboard adopts an embedded compact keyboard, such as a keyboard with a size of about 270mm*130mm, which is installed in the door cover to form a flip-type keyboard door 6, and the keyboard door and the chassis 1 can be locked by the locking member 7 to cover the display screen 5, and the tester can operate the keyboard by opening the door cover of the display screen 5. The display screen 5 can adopt a 12.1-inch LCD screen with an LVDS interface, and of course, display screens 5 of other sizes or screen materials or transmission interfaces can also be adopted, which is not limited in this embodiment.

[0033] The chassis 1 is provided with a plurality of function board units 2 and a motherboard 3 for connecting the function board units 2. The top of the chassis 1 is provided with a plurality of slots. Each function board unit 2 is pluggable and installed in the corresponding slot and connected to the connector 4 at the corresponding position on the motherboard 3. An ARM industrial control board 8 for running the test system is also provided between the plurality of function board units 2 and the display screen 5. The ARM industrial control board 8 is connected to the motherboard 3, the display screen 5 and the flip-type keyboard door 6 through an interface. This embodiment provides necessary functions in the test process, such as power supply, positioning, communication and the like, by adopting a pluggable function board unit 2. The plug-in structure makes the maintenance and upgrade of each function board unit 2 more convenient. For example, a unit can be unplugged for maintenance and upgrade according to needs without completely disassembling the chassis 1, thereby improving the convenience of operation of the tester. In addition, this embodiment runs the test system on the low-power ARM industrial control board 8, and the ARM industrial control board 8 can be connected to the motherboard 3 through an interface, thereby realizing communication and control with each functional plug-in unit 2. During the test, the mobile terminal can be controlled to perform automatic dialing, hanging up and other operations, read the mobile terminal network signal, signaling and transmission data, calculate and determine the communication quality index between the mobile network and the terminal device, realize flexible and convenient mobile communication testing, and effectively improve the flexibility and efficiency of mobile communication system testing.

[0034] The rail transit LTE mobile communication system tester provided in this embodiment, the tester only needs to open the door cover of the display screen 5, press the "power" button to turn on the machine, and the software will automatically run after turning on the machine, detect the connected functional units, enter the test interface and perform test operations through the keyboard, and the test items can include two categories: network service quality test and cluster service quality test. Among them, the network service quality test interface test items include attachment test, RRC connection test, service request test, switching test and tracking area update test, etc. The cluster service quality indicators include connection establishment delay, connection establishment failure rate, packet loss rate, transmission delay, etc., and the service types include individual call, group call, video, data, etc. Through the portable box structure integrating various functional plug-in units 2, the integrated design makes the structure compact, small in size, easy to carry, suitable for mobile operation, and solves the testing problems such as external equipment and inconvenient module upgrade and maintenance.

[0035] Furthermore, the chassis 1 is also provided with a plurality of USB interfaces 15, which are connected to the ARM industrial control board 8. The USB interfaces 15 can be connected to storage devices such as a mouse and a U disk, so as to facilitate operation and data processing.

[0036] For further information, please also refer to Figure 4 and Figure 5, each functional plug-in board unit 2 includes a panel 9 and a PCBA board 10, the functional plug-in board unit 2 is fixed to the upper and lower beams of the slot by the captive screws 11 on the panel 9, one end of the PCBA board 10 is connected to the panel 9, and the other end is connected to the motherboard 3 through the connector 4. In this embodiment, the top surface opening of the tester is a plurality of functional plug-in board units 2 installed with plug-in boards, each functional plug-in board unit 2 is fixed to the upper and lower beams of the slot by the captive screws 11 on the panel 9, each functional plug-in board unit 2 is retracted into the chassis 1, and the cover can be closed when the opening is not in use. The panel 9 of each unit has a width of 10TE, one end of the circuit board (PCBA) is connected to the panel 9 by screws, and the other end is connected to the motherboard 3 by a DIN96 connector. Thereby, multiple functional plug-in board units 2 can be flexibly installed in the chassis 1, which is convenient for subsequent upgrades and maintenance.

[0037] In one embodiment, please refer to Figure 6 , Figure 7 and Figure 8 The several function plug-in board units 2 include a power supply unit 21 for power supply, an audio unit 22 for processing input and output audio data, a first LTE unit 23 for transmitting communication data, a second LTE unit 24 for receiving communication data and a satellite positioning unit 25 for obtaining positioning information. The motherboard 3 is provided with a power interface, an audio interface, a MIC interface, a UART interface and a GPIO interface; the power interface is connected to the power supply unit 21, the audio interface and the MIC interface are connected to the audio unit 22, the UART interface is connected to the first LTE unit 23, the second LTE unit 24 and the satellite positioning unit 25, and the GPIO interface is connected to the first LTE unit 23, the second LTE unit 24 and the satellite positioning unit 25.

[0038] In this embodiment, the function board unit 2 includes a power supply unit 21, an audio unit 22, a first LTE unit 23, a second LTE unit 24 and a satellite positioning unit 25, etc. Each board function unit is directly connected to the motherboard 3 through a DIN96 connector 4, and the motherboard 3 is provided with a power interface, an audio interface, a MIC interface, a UART interface and a GPIO interface. The ARM industrial control board 8 provides a UART interface, an IO interface, a LVDS display interface, an audio interface and a USB interface 15, etc., so the power supply unit 21, the audio unit 22, the first LTE unit 23, the second LTE unit 24 and the satellite positioning unit 25 can be connected to the ARM industrial control board 8 through the corresponding interface on the motherboard 3, so as to realize the control of each function board unit 2 through the ARM industrial control board 8.

[0039] Furthermore, a battery 12 is arranged between several functional plug-in board units 2 and the display screen 5. The battery 12 is connected to the power supply unit 21 through the power interface of the motherboard 3. This embodiment configures the battery 12 and manages the charging and discharging of the battery 12 through the power supply unit 21. The battery 12 can maintain normal power supply of the tester for 1-2 hours when fully charged, meet the needs of emergency power supply, and improve test reliability.

[0040] Furthermore, a speaker 13 is arranged between several functional plug-in board units 2 and the display screen 5, and a microphone 14 is arranged on one side of the display screen 5. The speaker 13 and the microphone 14 are both connected to the audio unit 22. Specifically, the audio unit 22 is connected to the speaker 13 and the microphone 14 through the interface of the motherboard 3, thereby realizing the input and output of audio data during the test process, and realizing functions such as sending and receiving voice during calls.

[0041] Specifically, the power supply unit 21 is used to convert the input voltage and output two voltages of 12V and 5V respectively. The external power supply interface adopts a two-core socket, and the voltage input range is 12.6V to 13.8V. Fig. 9 and Fig.10 As shown, the power supply unit 21 includes a first inductor L1, a second inductor L2, a third inductor L3, a fourth inductor L4, a fifth inductor L5, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a first resistor R1, a second resistor R2, a first diode D1, a second diode D2, a buck chip U1, and a voltage regulator U2;

[0042] One end of the first inductor L1 is connected to the voltage input end, and the other end of the first inductor L1 is connected to the positive electrode of the first diode D1; the negative electrode of the first diode D1 is connected to the positive electrode of the first capacitor C1 and the first pin of the buck chip U1; the negative electrode of the first capacitor C1 is grounded through the second inductor L2; one end of the third inductor L3 is connected to the second pin of the buck chip U1 and the negative electrode of the second diode D2, and the other end of the third inductor L3 is a 12V voltage output end, which is connected to one end of the first resistor R1, one end of the second capacitor C2 and the fourth one end of the inductor L4; the other end of the first resistor R1 is connected to one end of the second resistor R2 and the 4th pin of the buck chip U1; the positive electrode of the second diode D2, the other end of the second resistor R2 and the other end of the second capacitor C2 are all grounded; the other end of the fourth inductor L4 is connected to one end of the third capacitor C3 and the input end of the regulator U2; the other end of the third capacitor C3 is grounded through the fifth inductor L5; one end of the fourth capacitor C4 is a 5V voltage output end, connected to the output end of the regulator U2, and the other end of the fourth capacitor C4 is grounded.

[0043] In this embodiment, the input voltage is stepped down by the step-down chip U1 to output a DC low voltage (+12V in this embodiment), and then the DC low voltage is stabilized by the voltage regulator U2 to output another voltage, i.e., +5V. The display screen 5 and each functional unit are powered by two voltages to meet the power supply requirements of different components and provide reliable guarantee for the stable power supply of the display screen 5 and each unit. The step-down chip U1 can be a DC-DC step-down chip U1 with a model of xl7015, and the voltage regulator U2 can be a three-terminal voltage regulator chip with a model of 7805. Of course, in other embodiments, other step-down chips or voltage regulator chips with the same functions can also be used, and this embodiment does not limit this.

[0044] Further, such as Fig.11 As shown, the first LTE unit 23 includes an LTE wireless module, a UART interface circuit, a control and status interface circuit, an audio circuit and a power supply circuit. The second LTE unit 24 has the same structure as the first LTE unit 23. Two LTE units are installed at the same time to meet different test requirements. For example, one LTE unit is used to receive signals and the other LTE unit is used to send signals, so that a one-transmit-one-receive working mode can be realized. The industrial control board realizes communication and control of the LTE module through the UART interface and the GPIO interface circuit. The SIM card holder is installed on the LTE circuit board. The panel 9 is a BNC holder. When working, a SIM card needs to be installed and a whip or suction cup antenna needs to be connected.

[0045] Further, such as Fig.12 As shown, the satellite positioning unit 25 circuit composition includes a processor (MCU), a UART interface circuit, a control and status interface circuit, a clock chip, a memory, a Beidou / GPS module, and a power supply circuit. The satellite positioning unit 25 is mainly used to extract standard clock and geographic location information, and supports Beidou and GPS two working modes. In addition, the satellite positioning unit 25 can store line geographic information data and output running line positioning information. The industrial control board is connected to the satellite positioning unit 25 through the UART interface and the GPIO interface circuit. The panel 9 of the satellite positioning unit 25 is provided with a satellite positioning antenna BNC interface for connecting an outdoor satellite positioning antenna.

[0046] Further, such as Fig.13 As shown, the audio unit 22 includes an input and output audio switching circuit, an audio combiner and a power amplifier. The audio switching circuit selects and switches multiple audio signals such as the industrial control board and the LTE module through an analog switch chip. The power amplifier can drive the speaker 13 to output. The audio unit 22 connects the speaker 13 and the microphone 14 (MIC) through the motherboard 3 interface. The audio combiner sends the call receiving and sending voice to the input end of the industrial control board to realize the voice recording function and support functions such as voice playback.

[0047] In summary, the rail transit LTE mobile communication system tester disclosed by the utility model includes a chassis, a plurality of function plug-in units and a motherboard for connecting each function plug-in unit are arranged in the chassis, a plurality of slots are provided on the top of the chassis, each function plug-in unit is installed in a corresponding slot and connected to a connector at a corresponding position on the motherboard; a display screen and a flip-type keyboard door are arranged on the front of the chassis, the flip-type keyboard door is connected to the chassis through a hinge, a card lock is also arranged on the front of the chassis, and the flip-type keyboard door is locked with the chassis through the card lock; an ARM industrial control board for running the test system is also arranged between the plurality of function plug-in units and the display screen, and the ARM industrial control board is connected to the motherboard, the display screen and the flip-type keyboard door through an interface. Integrated testing is achieved by integrating the chassis of each functional unit, which is convenient for carrying and operation, and the plug-in unit is easy to upgrade and maintain, which effectively improves the flexibility and efficiency of mobile communication system testing.

[0048] The embodiments described above are merely illustrative, in which the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0049] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a general hardware platform, and of course can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the relevant technology can be embodied in the form of a software product, and the computer software product can exist in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer electronic device (which can be a personal computer, a server, or a network electronic device, etc.) to execute the methods of each embodiment or some parts of the embodiment.

[0050] Conditional language such as "can," "can," "might," or "may," among other things, unless specifically stated otherwise or otherwise understood within the context as used, is generally intended to convey that a particular embodiment can include (while other embodiments do not) a particular feature, element, and / or operation. Thus, such conditional language is also generally intended to imply that a feature, element, and / or operation is required for one or more embodiments anyway or that one or more embodiments must include logic for determining whether such features, elements, and / or operations are included or will be performed in any particular embodiment, with or without input or prompting.

[0051] What has been described herein in this specification and the accompanying drawings includes examples that can provide a rail transit LTE mobile communication system tester. Of course, it is not possible to describe every conceivable combination of elements and / or methods for the purpose of describing the various features of the present disclosure, but it can be recognized that many other combinations and permutations of the disclosed features are possible. Therefore, it is obvious that various modifications can be made to the present disclosure without departing from the scope or spirit of the present disclosure. In addition, or in an alternative, other embodiments of the present disclosure may be apparent from consideration of this specification and the accompanying drawings and from the practice of the present disclosure as presented herein. It is intended that the examples set forth in this specification and the accompanying drawings are considered to be illustrative and not restrictive in all respects. Although specific terms are employed herein, they are used in a general and descriptive sense and are not used for limiting purposes.

Claims

1. A rail transit LTE mobile communication system tester, characterized in that: The invention comprises a chassis, wherein a plurality of function plug-in board units and a motherboard for connecting the function plug-in board units are arranged in the chassis, a plurality of slots are opened on the top of the chassis, each function plug-in board unit is installed in a corresponding slot in a pluggable manner and connected to a connector at a corresponding position on the motherboard; a display screen and a flip-type keyboard door are arranged on the front of the chassis, the flip-type keyboard door is connected to the chassis through a hinge, a locking piece is also arranged on the front of the chassis, and the flip-type keyboard door is locked with the chassis through the locking piece; an ARM industrial control board for running a test system is also arranged between the plurality of function plug-in board units and the display screen, and the ARM industrial control board is connected to the motherboard, the display screen and the flip-type keyboard door through an interface.

2. The rail transit LTE mobile communication system tester according to claim 1, characterized in that: Each functional plug-in board unit includes a panel and a PCBA board. The functional plug-in board unit is fixed to the upper and lower beams of the slot by captive screws on the panel. One end of the PCBA board is connected to the panel, and the other end is connected to the motherboard through the connector.

3. The rail transit LTE mobile communication system tester according to claim 1, characterized in that: The several functional plug-in board units include a power supply unit for power supply, an audio unit for processing input and output audio data, a first LTE unit for transmitting communication data, a second LTE unit for receiving communication data and a satellite positioning unit for obtaining positioning information. The motherboard is provided with a power supply interface, an audio interface, a MIC interface, a UART interface and a GPIO interface; the power supply interface is connected to the power supply unit, the audio interface and the MIC interface are connected to the audio unit, the UART interface is connected to the first LTE unit, the second LTE unit and the satellite positioning unit, and the GPIO interface is connected to the first LTE unit, the second LTE unit and the satellite positioning unit.

4. The rail transit LTE mobile communication system tester according to claim 3, characterized in that: A storage battery is also arranged between the plurality of function plug-in board units and the display screen, and the storage battery is connected to the power supply unit.

5. The rail transit LTE mobile communication system tester according to claim 3, characterized in that: A loudspeaker is also arranged between the plurality of function plug-in board units and the display screen, a microphone is arranged on one side of the display screen, and the loudspeaker and the microphone are both connected to the audio unit.

6. The rail transit LTE mobile communication system tester according to claim 3, characterized in that: The power supply unit is specifically used to convert the input voltage and output two voltages of 12V and 5V respectively.

7. The rail transit LTE mobile communication system tester according to claim 6, characterized in that: The power supply unit includes a first inductor, a second inductor, a third inductor, a fourth inductor, a fifth inductor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first resistor, a second resistor, a first diode, a second diode, a buck chip and a voltage stabilizer; One end of the first inductor is connected to the voltage input end, and the other end of the first inductor is connected to the positive electrode of the first diode; the negative electrode of the first diode is connected to the positive electrode of the first capacitor and the first pin of the buck chip; the negative electrode of the first capacitor is grounded through the second inductor; one end of the third inductor is connected to the second pin of the buck chip and the negative electrode of the second diode, and the other end of the third inductor is a 12V voltage output end, connecting one end of the first resistor, one end of the second capacitor and one end of the fourth inductor; the other end of the first resistor is connected to one end of the second resistor and the fourth pin of the buck chip; the positive electrode of the second diode, the other end of the second resistor and the other end of the second capacitor are all grounded; the other end of the fourth inductor is connected to one end of the third capacitor and the input end of the regulator; the other end of the third capacitor is grounded through the fifth inductor; one end of the fourth capacitor is a 5V voltage output end, connected to the output end of the regulator, and the other end of the fourth capacitor is grounded.

8. The rail transit LTE mobile communication system tester according to claim 7, characterized in that: The step-down chip adopts a DC-DC step-down chip with model xl7015.

9. The rail transit LTE mobile communication system tester according to claim 7, characterized in that: The voltage stabilizer adopts a three-terminal voltage stabilizer chip of model 7805.

10. The rail transit LTE mobile communication system tester according to claim 1, characterized in that: The chassis is also provided with a plurality of USB interfaces, and the USB interfaces are connected to the ARM industrial control board.

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