Signal generating equipment for ballast bed resistance test

Abstract

The utility model belongs to the technical field of rail transit signals, and particularly relates to signal generating equipment for ballast bed resistance testing. The signal generating device at least comprises a working unit. The working unit at least comprises a signal generation module, a power amplification module, a monitoring module and a precision resistance box. The output end of the signal generation module is connected with the input end of the power amplification module. The output end of the power amplification module is connected with the input end of the monitoring module. The monitoring module is provided with two output ends. And the precision resistance box is connected in series with one output end of the monitoring module. The precision resistance box at least comprises a rotary switch and a plurality of sampling resistors connected in series. And a plurality of sampling resistors surround the rotary switch. The frequency of output signals of the signal generating equipment for ballast bed resistance testing covers signal frequency points of all track circuits, sampling resistance values can be adjusted with a 100m omega stepping value, the maximum output power is 20W, the maximum output current is 1A, the peak-to-peak value is not smaller than 28V during no-load, and the signal generating equipment has an output short-circuit protection function.

Description

Technical Field

[0001] The utility model relates to the technical field of rail transit signals, in particular to a signal generating device for testing track bed resistance. Background Art

[0002] The ballast resistance is the leakage resistance from one rail through the ballast to another rail. It is an important basic data for the application of track circuit systems. It is often necessary to test it in engineering applications to determine whether it meets the requirements of standard specifications. The ballast resistance test environment is outdoor. During the test, a sinusoidal signal of a certain frequency needs to be transmitted to the two rails, and then the voltage, current and other parameters are measured. The ballast resistance is obtained by calculation. The signal generator is an important device used in the ballast resistance test process and plays an important role in the accuracy of the test results. The existing signal generator for ballast resistance testing mainly has the following problems: 1) The output frequency is relatively single. 2) The output power is small. When the frequency is high and the test distance is long, the current signal power transmitted to the rail is insufficient, resulting in low accuracy of the test results. 3) The internal sampling resistance of the existing signal generator cannot be continuously and finely changed. When the three-voltmeter method is used for testing, it cannot be determined that the internal sampling resistance is close to the measured impedance, which affects the accuracy of the test results. Utility Model Content

[0003] The invention aims to provide a signal generating device for testing the resistance of a track bed in view of the problems in the prior art of relatively single output frequency, low output power and inability of continuous and fine change of internal sampling resistance.

[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0005] A signal generating device for testing track bed resistance. The signal generating device comprises at least a working unit. The working unit comprises at least a signal generating module, a power amplifying module, a monitoring module and a precision resistor box. The output end of the signal generating module is connected to the input end of the power amplifying module. The output end of the power amplifying module is connected to the input end of the monitoring module. The monitoring module is provided with two output ends. The precision resistor box is connected in series to one output end of the monitoring module. The precision resistor box comprises at least a rotary switch and a plurality of sampling resistors connected in series. The plurality of sampling resistors surround the rotary switch.

[0006] As a preferred solution of the utility model, the signal generation module at least includes a crystal oscillator, a processor and a filter. The crystal oscillator is connected to a clock interface of the processor, and a signal output port of the processor is connected to the filter.

[0007] As a preferred solution of the utility model, the signal generating device further comprises a power supply unit composed of a lithium battery and a DC voltage stabilizing module. The lithium battery is connected to the DC voltage stabilizing module to supply power to the working unit.

[0008] As a preferred solution of the utility model, the rotary switch at least includes a first rotary switch, a second rotary switch and a third rotary switch. Each rotary switch is surrounded by a plurality of sampling resistors connected in series.

[0009] As a preferred solution of the utility model, the rotary switch is provided with a fixed connection point and a movable connection point. After the plurality of sampling resistors are connected in series, connection points are provided at the end points and the series connection points, and the rotary switch is rotated so that the movable connection point contacts different connection points, thereby adjusting the resistance value of the precision resistor box connected to the circuit.

[0010] As a preferred solution of the utility model, the fixed connection point of the first rotary switch is used to connect the rail. The tail end of the series sampling resistor surrounding the first rotary switch is connected to the fixed connection point of the second rotary switch. The tail end of the series sampling resistor surrounding the second rotary switch is connected to the fixed connection point of the third rotary switch. The tail end of the series sampling resistor surrounding the third rotary switch is connected to the monitoring module.

[0011] As a preferred solution of the utility model, the power amplifier module at least includes a transformer, a diode, a triode, a resistor and a capacitor. The power amplifier module is provided with two input ports, two output ports, a power input port and a ground port. The two input ports of the power amplifier module are respectively connected to the two output ports of the signal generation module.

[0012] As a preferred solution of the utility model, the transformer in the power amplifier module at least includes a first transformer. The first transformer is provided with two input ends and two output ends. The two input ends of the first transformer are respectively connected to the two input ports of the power amplifier module.

[0013] As a preferred solution of the utility model, the transformer in the power amplifier module further includes a second transformer, and the second transformer is provided with one input and two outputs. The two outputs of the second transformer are connected in series, so that the four output ends of the second transformer become two edge ends and one middle end. The middle end is the series connection point of the two outputs of the second transformer.

[0014] As a preferred solution of the present invention, the two edge ends are connected to the power input port through a first amplifying unit and a second amplifying unit respectively, and the circuit architecture of the second amplifying unit is the same as the circuit architecture of the first amplifying unit.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the utility model are:

[0016] 1. The frequency of the output signal is adjustable and can cover the signal frequency points of all track circuits;

[0017] 2. The sampling resistance value can be adjusted in a step-by-step manner;

[0018] 3. Larger output power can meet the testing needs of longer distances. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a connection diagram of each module of the signal generating device for testing the resistance of the ballast bed of the utility model;

[0020] Figure 2 It is a circuit diagram of the signal generating module of the utility model;

[0021] Figure 3 It is a circuit diagram of the power amplifier module of the utility model;

[0022] Figure 4 This is a circuit diagram of the precision resistor box of the utility model;

[0023] Figure 5 The utility model is a schematic diagram of the use of the signal generating device for testing the resistance of the ballast bed.

[0024] Reference numerals:

[0025] 110: signal generation module; 120: power amplification module; 130: monitoring module; 140: lithium battery; 160: DC voltage regulation module; 200: precision resistor box; 210: rotary switch; 211: first rotary switch; 212: second rotary switch; 213: third rotary switch; 220: sampling resistor. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with test examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0027] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all expressions based on the orientation or position relationship shown in the drawings, or the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, rather than indicating or implying that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.

[0028] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present invention.

[0029] In addition, the expressions “first”, “second”, “third”, etc. that appear in the terms are merely descriptions used to distinguish the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0030] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0031] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0032] Example 1

[0033] The present embodiment provides a signal generating device for testing the resistance of a track bed. The signal generating device may include a working unit. The working unit may include a signal generating module 110, a power amplifying module 120, a monitoring module 130 and a precision resistance box 200. The output end of the signal generating module 110 is connected to the input end of the power amplifying module 120. The output end of the power amplifying module 120 is connected to the input end of the monitoring module 130. The monitoring module 130 is provided with two output ends. The precision resistance box 200 is connected in series to one output end of the monitoring module 130. The precision resistance box 200 may include a rotary switch 210 and a plurality of sampling resistors 220 connected in series. The plurality of sampling resistors 220 surround the rotary switch 210.

[0034] In the signal generating device for testing track bed resistance provided in this embodiment, the signal generating module 110 can generate a signal that can cover the signal frequency points of all track circuits; the precision resistor box 200 can adjust the value of the sampling resistor 220 in a step-by-step manner; the power amplification module 120 can increase the output power of the signal generating device to meet the testing requirements of longer distances; the monitoring module 130 measures and displays the voltage and current of the output signal of the signal generating device in real time, so as to facilitate users to adjust the output of the device according to their needs.

[0035] Example 2

[0036] This embodiment is a further improvement on Embodiment 1, and repeated contents will not be repeated here.

[0037] In this embodiment, the signal generating module 110 may include a crystal oscillator, a processor and a filter. The crystal oscillator is connected to a clock interface of the processor, and a signal output port of the processor is connected to the filter.

[0038] Preferably, the signal generating device further comprises a power supply unit composed of a lithium battery 140 and a DC voltage stabilizing module 160. The lithium battery 140 and the DC voltage stabilizing module 160 are connected to supply power to the working unit.

[0039] Preferably, the rotary switch 210 may include a first rotary switch 211, a second rotary switch 212 and a third rotary switch 213. Each rotary switch 210 is surrounded by a plurality of sampling resistors 220 connected in series.

[0040] Preferably, the rotary switch 210 is provided with a fixed connection point and a movable connection point. After a plurality of sampling resistors 220 are connected in series, connection points are set at the end points and the series connection points. The rotary switch 210 is rotated to make the movable connection point contact different connection points, thereby adjusting the resistance value of the circuit connected to the precision resistor box 200.

[0041] Preferably, the fixed connection point of the first rotary switch 211 is used to connect to the rail. The tail end of the series-connected sampling resistor 220 surrounding the first rotary switch 211 is connected to the fixed connection point of the second rotary switch 212. The tail end of the series-connected sampling resistor 220 surrounding the second rotary switch 212 is connected to the fixed connection point of the third rotary switch 213. The tail end of the series-connected sampling resistor 220 surrounding the third rotary switch 213 is connected to the monitoring module 130.

[0042] Preferably, the power amplifier module 120 may include a transformer, a diode, a triode, a resistor and a capacitor. The power amplifier module 120 is provided with two input ports, two output ports, a power input port and a ground port. The two input ports of the power amplifier module 120 are respectively connected to the two output ports of the signal generating module 110.

[0043] Preferably, the transformer in the power amplification module 120 may include a first transformer. The first transformer is provided with two input terminals and two output terminals. The two input terminals of the first transformer are connected to the two input ports of the power amplification module 120 respectively.

[0044] Preferably, the transformer in the power amplifier module 120 further includes a second transformer, which is provided with one input and two outputs. The two outputs of the second transformer are connected in series, so that the four output ends of the second transformer become two edge ends and one middle end. The middle end is the series connection point of the two outputs of the second transformer.

[0045] Preferably, the two edge ends are connected to the power input port through a first amplifying unit and a second amplifying unit respectively, and the circuit architecture of the second amplifying unit is the same as that of the first amplifying unit.

[0046] Example 3

[0047] This embodiment provides a signal generating device for testing track bed resistance, and this embodiment is a further improvement of Embodiment 1 and Embodiment 2. The signal generating device for testing track bed resistance provided in this embodiment may include a signal generating module 110, a power amplifying module 120, a monitoring module 130, a precision resistance box 200, a lithium battery 140, and a DC voltage stabilizing module 160.

[0048] Preferably, the signal generating module 110, the power amplifying module 120, the monitoring module 130, the precision resistor box 200, the lithium battery 140 and the DC voltage stabilizing module 160 can be placed in a box housing. Preferably, the box housing can be a top-opening box. Preferably, in this embodiment, the signal generating module, the power amplifying module 120, the precision resistor box 200, the monitoring module 130, the lithium battery 140 and the DC voltage stabilizing module 160 are integrated into the box, which is convenient to carry and has its own power supply, and is suitable for testing scenarios in outdoor environments.

[0049] See also Figure 1 The signal generating module 110, the power amplifying module 120, the monitoring module 130 and the precision resistor box 200 form a working unit. The lithium battery 140 and the DC voltage stabilizing module 160 form a power supply unit.

[0050] Preferably, the working unit is provided with two output terminals, which are used to respectively connect two steel rails of the track when testing the resistance of the track bed. The power supply unit is used to supply power to the working unit.

[0051] The output end of the lithium battery 140 is connected to the input end of the DC voltage regulator module 160, and the output end of the DC voltage regulator module 160 supplies power to the working unit. The output end of the signal generation module 110 is connected to the input end of the power amplifier module 120; the output end of the power amplifier module 120 is connected to the input end of the monitoring module 130. The monitoring module 130 is provided with two output ends; and the precision resistor box 200 is connected in series to one output end of the monitoring module 130.

[0052] Preferably, the monitoring module 130 monitors the output current and output voltage of the power amplifier module 120, with a monitoring accuracy of ±2% for current and ±1% for voltage, and displays the monitoring results in real time. Preferably, the monitoring module 130 can be YB5142DM, AC0-5A direct measurement.

[0053] Preferably, the DC voltage stabilizing module 160 has a wide voltage input range of 18-36V, and the lithium battery 140 has a capacity of 24V6000mAh, which can meet the use of the signal generating device for not less than 24 hours.

[0054] The lithium battery 140 may be a 24V two-in-parallel six-in-one battery with a capacity of 6000mAh. The DC voltage regulator module 160 may be URF2424QB-100WR3A5.

[0055] The output frequency of the existing signal generating device for track resistance testing does not cover the signal frequencies of all track circuits, and generally only covers the ZPW-2000 series track circuits. The signal generating device provided in this embodiment is configured with a signal generating module 110, which is used to generate a sine signal that can cover the signal frequencies of all track circuits, including frequencies of 25Hz, 50Hz, 1700Hz, 2000Hz, 2300Hz, 2600Hz and 10kHz.

[0056] See also Figure 2The signal generation module 110 may include: an active crystal oscillator, a processor, and a filter. The active crystal oscillator is connected to the clock interface of the processor, and the signal output port of the processor is connected to the filter. Preferably, the active crystal oscillator may be 50MHz / OT2EL4C4JI-111OLP-50M, the processor may be FPGA (Field-Programmable Gate Array), and the filter may be an active low-pass filter.

[0057] FPGA is responsible for generating a square wave signal of the corresponding frequency. The filter is an active low-pass filter. After the square wave signal passes through the filter, the high-frequency component is filtered out and the output signal is a sine wave analog signal. The crystal oscillator provides the clock for the FPGA, and the FPGA generates a clock signal for the filter. The COM output is the reference power supply, and the voltage value is half of VDD.

[0058] Preferably, the FPGA is used to generate a square wave signal of the corresponding frequency, and at the same time generate a clock signal CLK_F for the filter U1; R1, R2, C1, and C2 are the reference power supply circuit, which provide the reference level COM for the filter U1; the crystal oscillator JZ, C13, and R12 constitute a crystal oscillator circuit, which provides the clock CLK for the FPGA; C3-C12 are filter capacitors, which filter out the ripple on the power supply VDD; R3-R10 are pull-up resistors; the light-emitting diode D1 and the resistor R11 constitute an indicator light circuit, which lights up (YXD is a high level) or goes out (YXD is a low level) according to the YXD signal driven by the FPGA.

[0059] Preferably, the frequency reference of the signal generating module 110 is an active crystal oscillator with high precision. Direct frequency synthesis technology is used to generate a square wave signal of a corresponding frequency based on an FPGA platform. The square wave signal is filtered out of the harmonic components of the square wave after passing through an active low-pass filter to generate a sinusoidal signal.

[0060] The existing signal generating equipment for testing the resistance of the track bed has a low output power. When the frequency is high and the test distance is long, the power of the current signal transmitted to the rail is insufficient, resulting in low accuracy of the test result. The signal generating equipment provided in this embodiment is equipped with a power amplifier module 120, which can output the current signal at a rated current size under the condition of distortion-free amplification of signals at different frequencies. Preferably, the rated current size can be 1A.

[0061] See also Figure 3 The power amplifier module 120 can be composed of a transformer, a diode, a triode, a resistor, a capacitor and other devices. The power amplifier module 120 is provided with two input ports IN+ and IN-, and two output ports OUT+ and OUT-, a power input port and a ground port. The two input ports IN+ and IN- of the power amplifier module 120 are respectively connected to the two output ports of the signal generation module 110.

[0062] Preferably, the transformer in the power amplifier module 120 includes a first transformer 8B1 and a second transformer 8B2. The first transformer 8B1 is provided with two input terminals and two output terminals. The two input terminals of the first transformer 8B1 are respectively connected to the two input ports IN+ and IN- of the power amplifier module 120. An input terminal of the first transformer 8B1 is connected in series with an input capacitor 5C38. The input capacitor 5C38 is a polar capacitor, and its negative pole is connected to the first transformer 8B1.

[0063] One output end of the first transformer 8B1 is grounded, and the other output end is connected in series with the first capacitor 8C1. The first capacitor 8C1 is a polar capacitor, and its negative electrode is connected to the first transformer 8B1. The positive electrode of the first capacitor 8C1 is connected to the power input port through the first diode 8D1 and the first resistor 8R1. The positive electrode of the first diode 8D1 is connected to the first resistor 8R1. The negative electrode of the first diode 8D1 is connected to the first capacitor 8C1. The positive electrode of the first capacitor 8C1 is also connected to the positive electrode of the second diode 8D2. The negative electrode of the second diode 8D2 is grounded through the second resistor 8R2. The positive electrode of the first diode 8D1 is also connected to the base of the first triode 8V1. The collector of the first triode 8V1 is connected to the power input port. The emitter of the first triode 8V1 is connected to the emitter of the second triode 8V2. The base of the second triode 8V2 is connected to the negative electrode of the second diode 8D2. The collector of the second triode 8V2 is grounded. The emitter of the second triode 8V2 is connected to the second capacitor 8C2. The second capacitor 8C2 is a polar capacitor, whose positive electrode is connected to the emitter of the second triode 8V2, and whose negative electrode is connected to an input end of the second transformer 8B2. The other input end of the second transformer 8B2 is grounded. The second transformer 8B2 is provided with one input and two outputs. The two outputs of the second transformer 8B2 are connected in series, so that the four output ends of the second transformer 8B2 become two edge ends and one middle end. Preferably, the middle end is the series connection point of the two outputs of the second transformer 8B2. After the third diode 8D3 and the fourth diode 8D4 are connected in series in the same direction, the positive electrode is connected to the middle end, and the negative electrode is grounded. The twenty-fifth resistor 8R25 connects the middle end and the power input port.

[0064] The two edge ends are connected to the power input port through the first amplifying unit and the second amplifying unit respectively.

[0065] The first amplifier unit is provided with an input end and two output ends. The input end of the first amplifier unit is connected to an edge end of the second transformer 8B2. The second output end of the first amplifier unit is connected to the power input port. The first output end of the first amplifier unit is connected to the second output end through a current sampling unit. The current sampling unit is composed of three resistors connected in parallel, namely, the twenty-seventh resistor 8R27, the twenty-eighth resistor 8R28, and the twenty-ninth resistor 8R29. One end of the current sampling unit is connected to the first output end of the first amplifier unit, and the other end is connected to the second output end of the first amplifier unit.

[0066] The input end of the first amplifying unit is grounded through the fourth capacitor 8C4. The input end of the first amplifying unit is also connected to the base of the fifth triode 8V5 through the third resistor 8R3. The emitter of the fifth triode 8V5 is connected to the positive electrode of the seventh diode 8D7. The negative electrode of the seventh diode 8D7 is connected to the first end of the ninth resistor 8R9. The collector of the fifth triode 8V5 is respectively connected to the emitter of the third triode 8V3 and the first end of the fifth resistor 8R5. The second end of the fifth resistor 8R5 is connected to the base of the third triode 8V3. The collector of the third triode 8V3 is connected to the second output end of the first amplifying unit. The collector of the third triode 8V3 is also connected to the first end of the seventh resistor 8R7. The second end of the seventh resistor 8R7 is connected to the positive electrode of the fifth diode 8D5. The negative electrode of the fifth diode 8D5 is connected to the base of the third triode 8V3. The second end of the fifth resistor 8R5 is also connected to the collector of the seventh triode 8V7. The emitter of the seventh transistor 8V7 is connected to the second output end of the first amplifying unit through the thirteenth resistor 8R13. The base of the seventh transistor 8V7 is connected to the second end of the ninth resistor 8R9 through the twenty-third resistor 8R23. The second end of the ninth resistor 8R9 is also connected to the collector of the ninth transistor 8V9 through the eleventh resistor 8R11. The base of the ninth transistor 8V9 is connected to the collector of the seventh transistor 8V7. The emitter of the ninth transistor 8V9 is connected to the second output end of the first amplifying unit through the fifteenth resistor 8R15. The collector of the ninth transistor 8V9 is connected to the base of the twelfth transistor 8V12 through the seventeenth resistor 8R17. The emitter of the twelfth transistor 8V12 is connected to the second end of the ninth resistor 8R9. The emitter of the twelfth transistor 8V12 is also connected to the emitter of the eleventh transistor 8V11. The collector of the twelfth transistor 8V12 is connected to the collector of the eleventh transistor 8V11. The base of the eleventh transistor 8V11 is connected to the collector of the ninth transistor 8V9 through the nineteenth resistor 8R19. The collector of the eleventh transistor 8V11 is connected to the collector of the ninth transistor 8V9 through the seventh capacitor 8C7. The collector of the eleventh transistor 8V11 is also connected to the first output end of the first amplifying unit. After the ninth capacitor 8C9 and the twenty-first resistor 8R21 are connected in parallel, one end is connected to the collector of the eleventh transistor 8V11, and the other end is connected to the base of the seventh transistor 8V7.

[0067] The architecture of the second amplifying unit is the same as that of the first amplifying unit. The second amplifying unit is also provided with an input end and two output ends. The input end of the second amplifying unit is connected to the other edge end of the second transformer 8B2. The second output end of the second amplifying unit is connected to the power input port. The first output end and the second output end of the second amplifying unit are also connected through the current sampling unit. One end of the current sampling unit is connected to the first output end of the second amplifying unit, and the other end is connected to the second output end of the second amplifying unit.

[0068] The input end of the second amplifying unit is grounded through the fifth capacitor 8C5. The input end of the second amplifying unit is also connected to the base of the sixth triode 8V6 through the fourth resistor 8R4. The emitter of the sixth triode 8V6 is connected to the positive electrode of the eighth diode 8D8. The negative electrode of the eighth diode 8D8 is connected to the first end of the tenth resistor 8R10. The collector of the sixth triode 8V6 is respectively connected to the emitter of the fourth triode 8V4 and the first end of the sixth resistor 8R6. The second end of the sixth resistor 8R6 is connected to the base of the fourth triode 8V4. The collector of the fourth triode 8V4 is connected to the second output end of the second amplifying unit. The collector of the fourth triode 8V4 is also connected to the first end of the eighth resistor 8R8. The second end of the eighth resistor 8R8 is connected to the positive electrode of the sixth diode 8D6. The negative electrode of the sixth diode 8D6 is connected to the base of the fourth triode 8V4. The second end of the sixth resistor 8R6 is also connected to the collector of the eighth triode 8V8. The emitter of the eighth transistor 8V8 is connected to the second output end of the second amplifying unit through the fourteenth resistor 8R14. The base of the eighth transistor 8V8 is connected to the second end of the tenth resistor 8R10 through the twenty-fourth resistor 8R24. The second end of the tenth resistor 8R10 is also connected to the collector of the tenth transistor 8V10 through the twelfth resistor 8R12. The base of the thirteenth transistor 8V10 is connected to the collector of the eighth transistor 8V8. The emitter of the thirteenth transistor 8V10 is connected to the second output end of the second amplifying unit through the sixteenth resistor 8R16. The collector of the thirteenth transistor 8V10 is connected to the base of the thirteenth transistor 8V13 through the eighteenth resistor 8R18. The emitter of the thirteenth transistor 8V13 is connected to the second end of the tenth resistor 8R10. The emitter of the thirteenth transistor 8V13 is also connected to the emitter of the fourteenth transistor 8V14. The collector of the thirteenth transistor 8V13 is connected to the collector of the fourteenth transistor 8V14. The base of the fourteenth triode 8V14 is connected to the collector of the tenth triode 8V10 through the twentieth resistor 8R20. The collector of the fourteenth triode 8V14 is connected to the collector of the tenth triode 8V10 through the eighth capacitor 8C8. The collector of the fourteenth triode 8V14 is also connected to the first output end of the second amplifying unit. After the tenth capacitor 8C10 and the twenty-second resistor 8R22 are connected in parallel, one end is connected to the collector of the fourteenth triode 8V14, and the other end is connected to the base of the eighth triode 8V8.

[0069] Two ends of the sixth capacitor 8C6 are connected to the bases of the fifth transistor 8V5 and the sixth transistor 8V6 respectively.

[0070] One end of the third capacitor 8C3 is grounded, and the other end is connected to the power input port. The eleventh capacitor 8C11 is a polar capacitor, with its positive electrode connected to the power input port and its negative electrode grounded.

[0071] The output port OUT+ is connected to the emitter of the twelfth transistor 8V12 and the output port OUT- is connected to the emitter of the thirteenth transistor 8V13.

[0072] Preferably, the model of the first transformer 8B1 is CU-26, and the model of the second transformer 8B2 is ZPW.FL.

[0073] The specification of input capacitor 5C38 is 10uF / 16V. The specification of first capacitor 8C1 and second capacitor 8C2 is 10uF / 35V. The specification of third capacitor 8C3 is 0.1uF / 50V. The specification of fourth capacitor 8C4 and fifth capacitor 8C5 is 1nF / 1000V. The specification of sixth capacitor 8C6 is 330pF / 630V. The specification of seventh capacitor 8C7 and eighth capacitor 8C8 is 2nF / 630V. The specification of ninth capacitor 8C9 and tenth capacitor 8C10 is 68nF / 630V. The specification of eleventh capacitor 8C11 is 2200uF / 50V.

[0074] The first diode 8D1, the second diode 8D2, the third diode 8D3, the fourth diode 8D4, the fifth diode 8D5, the sixth diode 8D6, the seventh diode 8D7, and the eighth diode 8D8 are all IN4148 type diodes.

[0075] The resistance of the first resistor 8R1 and the second resistor 8R2 is 39K. The resistance of the third resistor 8R3 and the fourth resistor 8R4 is 10K. The resistance of the fifth resistor 8R5, the sixth resistor 8R6, the seventh resistor 8R7 and the eighth resistor 8R8 is 2.2K. The resistance of the ninth resistor 8R9, the tenth resistor 8R10, the eleventh resistor 8R11 and the twelfth resistor 8R12 is 1K. The resistance of the thirteenth resistor 8R13 and the fourteenth resistor 8R14 is 47R. The resistance of the fifteenth resistor 8R15 and the sixteenth resistor 8R16 is 130R. The resistance of the seventeenth resistor 8R17, the eighteenth resistor 8R18, the nineteenth resistor 8R19 and the twentieth resistor 8R20 is 2R. The resistance of the twenty-first resistor 8R21 and the twenty-second resistor 8R22 is 100R. The resistance of the twenty-third resistor 8R23 and the twenty-fourth resistor 8R24 is 15K. The resistance of the twenty-fifth resistor 8R25 is 220K. The resistance of the twenty-seventh resistor 8R27 and the twenty-ninth resistor 8R29 is 0.1R. The resistance of the twenty-eighth resistor 8R28 is 0.12R.

[0076] The model of the first transistor 8V1, the third transistor 8V3, the fourth transistor 8V4, the fifth transistor 8V5 and the sixth transistor 8V6 is 3DA150C. The model of the second transistor 8V2, the seventh transistor 8V7, the eighth transistor 8V8, the ninth transistor 8V9 and the tenth transistor 8V10 is 3CG170D. The model of the eleventh transistor 8V11, the twelfth transistor 8V12, the thirteenth transistor 8V13 and the fourteenth transistor 8V14 is MJ11032.

[0077] Preferably, the power amplifier module 120 performs power amplification on the sinusoidal signal output by the signal generating module, with a maximum output power of 20W, a maximum output current of 1A, a peak-to-peak value of not less than 28V when no-load, and an output short-circuit protection function.

[0078] The transistors and other components used in the power amplifier module 120 should have a linear range that completely covers the output amplitude range of the signal generating module 110 and should be able to operate reliably in the field temperature range of -40°C-85°C. At the same time, the DC voltage regulator module 160 ensures the stability of the power supply voltage of the power amplifier module 120, thereby ensuring that the power amplifier module 120 can amplify the output signal of the signal generating module 110 without distortion.

[0079] The existing method for testing the resistance of the ballast bed often adopts the three-voltmeter method. When testing the resistance of the ballast bed according to the three-voltmeter method, the closer the internal sampling resistor 220 of the signal generating device is to the impedance being measured, the higher the accuracy of the test result. However, the internal sampling resistor 220 of the existing signal generating device for testing the resistance of the ballast bed cannot be changed continuously and finely, and it is impossible to determine whether the internal sampling resistor 220 is close to the impedance being measured, thereby affecting the accuracy of the test result.

[0080] The precision resistor box 200 may include a rotary switch 210 and a plurality of sampling resistors 220 connected in series. The plurality of sampling resistors 220 surround the rotary switch 210. The rotary switch 210 is provided with a fixed connection point and a movable connection point. After the plurality of sampling resistors 220 are connected in series, connection points are provided at the end points and the series connection points. The rotary switch 210 is rotated so that the movable connection points contact different connection points, thereby adjusting the resistance value of the circuit to which the precision resistor box 200 is connected.

[0081] See also Figure 4, the precision resistor box 200 may include three rotary switches 210, namely a first rotary switch 211, a second rotary switch 212 and a third rotary switch 213, and a plurality of sampling resistors 220 are arranged in series around each rotary switch 210. The fixed connection point of the first rotary switch 211 can be used to connect the rail. The tail end of the sampling resistor 220 in series around the first rotary switch 211 is connected to the fixed connection point of the second rotary switch 212. The tail end of the sampling resistor 220 in series around the second rotary switch 212 is connected to the fixed connection point of the third rotary switch 213. The tail end of the sampling resistor 220 in series around the third rotary switch 213 is connected to the monitoring module 130. Preferably, ten sampling resistors 220 are connected in series and arranged around the rotary switch 210.

[0082] Preferably, the function of the precision resistor box 200 is to measure sampling. Preferably, the precision resistor box 200 has a minimum resistance value of 100 mΩ, a step value of 100 mΩ, an accuracy of 1%, which can meet the sampling resistance value required for measurement, and a rated current of 1 A, which is compatible with the output current of the power amplifier module 120.

[0083] Preferably, the resistors in the precision resistor box 200 can be made using the "multi-turn dense winding" technology. According to the relationship between the cross-sectional area and the current carrying capacity of the constantan wire, the cross-sectional area of ​​1A current is calculated, and a high-precision resistance value is produced by adjusting the number of turns.

[0084] See also Figure 5 When testing the resistance of the track bed, use a short-circuit line to connect the two rails of the track, and then connect the two output ends of the monitoring module 130 of the signal generating device to the two rails of the track, respectively, wherein one output end of the monitoring module 130 is connected to the first rail through the precision resistor box 200, and the other output end of the monitoring module 130 is connected to the second rail. The precision resistor box 200 is preset to 5Ω and then turned on. Then adjust the output amplitude of the signal generating module, confirm that the displayed values ​​of the voltage and current of the monitoring module 130 are close to the test requirements, and use a voltmeter to test the voltages V1, V2, and V3 respectively, and then perform impedance calculations. V1 is the voltage between the two output ends of the monitoring module 130, V2 is the voltage on both sides of the precision resistor box 200, and V3 is the voltage between the two rails.

[0085] The technical solution adopted by the utility model is to use the power amplifier module 120 to amplify the output of the signal generating module 110, the output of the power amplifier module 120 is connected in series with the precision resistor box 200 as the measurement sampling resistor 220, and the monitoring module 130 measures and displays the output voltage and output current of the signal generating device in real time. Preferably, the monitoring module 130 can be a voltage and current meter for monitoring the output voltage and output current of the power amplifier module 120.

[0086] The signal generating device provided by the utility model has an output signal frequency that covers the signal frequency points of all track circuits, and the output power can meet the application scenarios with long test distances. The high precision of the sampling resistor 220 and the 100mΩ step value can effectively ensure the accuracy of the test results. The device uses a lithium battery 140 and a DC voltage regulator module 160 to provide power for the device, meeting the use requirements of outdoor environments without power supply.

[0087] The beneficial effects of the utility model are that the output signal frequency is compatible with all track circuit equipment standards in use; the output current provided is doubled compared to existing equipment, which can meet the test needs of longer distances; the output signal distortion provided is small, which can ensure the correctness of the measurement; the precision resistance box 200 can be as close to the measured impedance value as possible, effectively improving the test accuracy; the monitoring module 130 measures and displays the voltage and current of the output signal of the equipment in real time, which is convenient for users to adjust the output of the equipment according to needs.

[0088] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A signal generating device for testing track bed resistance, characterized in that: The signal generating device comprises at least a working unit; the working unit comprises at least a signal generating module (110), a power amplifying module (120), a monitoring module (130) and a precision resistance box (200); The output end of the signal generating module (110) is connected to the input end of the power amplifying module (120); the output end of the power amplifying module (120) is connected to the input end of the monitoring module (130); The monitoring module (130) is provided with two output terminals; The precision resistance box (200) is connected in series to an output end of the monitoring module (130); The precision resistor box (200) comprises at least a rotary switch (210) and a plurality of sampling resistors (220) connected in series, wherein the plurality of sampling resistors (220) surround the rotary switch (210).

2. The signal generating device for testing the resistance of the track bed according to claim 1, characterized in that: The signal generating module (110) comprises at least a crystal oscillator, a processor and a filter; the crystal oscillator is connected to a clock interface of the processor, and a signal output port of the processor is connected to the filter.

3. The signal generating device for testing the track bed resistance according to claim 1, characterized in that: The signal generating device further comprises a power supply unit composed of a lithium battery (140) and a DC voltage stabilizing module (160); after the lithium battery (140) is connected to the DC voltage stabilizing module (160), power is supplied to the working unit.

4. The signal generating device for testing the resistance of the track bed according to claim 1, characterized in that: The rotary switch (210) comprises at least a first rotary switch (211), a second rotary switch (212) and a third rotary switch (213); A plurality of sampling resistors (220) connected in series are arranged around each of the rotary switches (210).

5. The signal generating device for testing the resistance of the track bed according to claim 4, characterized in that: The rotary switch (210) is provided with a fixed connection point and a movable connection point; After the plurality of sampling resistors are connected in series, connection points are set at the end points and the series connection points, and the rotary switch is rotated to make the movable connection points contact different connection points, thereby adjusting the resistance value of the circuit connected to the precision resistor box (200).

6. The signal generating device for testing the resistance of the track bed according to claim 5, characterized in that: The fixed connection point of the first rotary switch (211) is used to connect to a rail; The tail end of the series-connected sampling resistor surrounding the first rotary switch (211) is connected to a fixed connection point of the second rotary switch (212); The tail end of the series-connected sampling resistor surrounding the second rotary switch (212) is connected to a fixed connection point of the third rotary switch (213); The tail end of the series-connected sampling resistor surrounding the third rotary switch (213) is connected to the monitoring module (130).

7. The signal generating device for testing the resistance of the track bed according to claim 1, characterized in that: The power amplification module (120) comprises at least a transformer, a diode, a triode, a resistor and a capacitor; The power amplification module (120) is provided with two input ports, two output ports, a power input port and a ground port; The two input ports of the power amplification module (120) are respectively connected to the two output ports of the signal generation module (110).

8. The signal generating device for testing the track bed resistance according to claim 7, characterized in that: The transformer in the power amplification module (120) comprises at least a first transformer, the first transformer being provided with two input ends and two output ends, and the two input ends of the first transformer being respectively connected to the two input ports of the power amplification module (120).

9. The signal generating device for testing the track bed resistance according to claim 8, characterized in that: The transformer in the power amplification module (120) further comprises a second transformer, wherein the second transformer is provided with one input and two outputs; The two outputs of the second transformer are connected in series, so that the four output ends of the second transformer become two edge ends and one middle end. The middle end is a series connection point of two outputs of the second transformer.

10. The signal generating device for testing the resistance of the track bed according to claim 9, characterized in that: The two edge ends are connected to the power input port through a first amplifying unit and a second amplifying unit respectively, and a circuit architecture of the second amplifying unit is the same as a circuit architecture of the first amplifying unit.

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