Transmitting circuit of ground transponder and debugging method thereof

Abstract

The invention provides a transmitting circuit of a ground transponder and a debugging method of the transmitting circuit. In the circuit, all transmitting channels receive FSK signals with different frequency information in a logic control circuit respectively; the output ends of the N sending channels are in one-to-one correspondence with the N input ends of the isolation circuit, and the output end of each sending channel is connected with the corresponding input end in the isolation circuit; the output end of the isolation circuit is connected with the transmitting antenna through the filter circuit. The N transmitting channels, the transmitting antenna, the filter circuit and the isolating circuit form N mutually independent FSK resonant circuits; in other words, the FSK channels do not influence each other, so that the isolation and synthesis technology of multi-channel sending signals is realized, the change of resonance characteristics among multiple channels is avoided, the multiple channels are ensured to independently and parallelly send messages, and the purpose of doubling the message transmission capacity of the ground transponder is realized.

Description

Technical Field

[0001] This invention belongs to the field of railway signaling technology, and more specifically, relates to a ground transponder transmitting circuit and its debugging method. Background Technology

[0002] A transponder transmission system is a secure information transmission system that relies on point-to-point technology to achieve safe information transmission between ground or trackside equipment and onboard equipment. The system mainly consists of three components: ground transponders, transponder transmission units, and trackside electronic units. It can transmit various data information, including signal data, control commands, location and geographical information, train target operation details, route status, track speed limits, and temporary speed limits. The ground transponder is the key component of the transmission system; as a point-to-point device for information transmission between the ground and the train, it plays the role of sending messages to the onboard subsystems. The ground transponder can not only transmit fixed information content but also flexibly transmit variable information through connection with the ground electronic units.

[0003] Current ground transponder devices, while adhering to the European standard FSK message transmission channel, also include an additional PSK message transmission channel. This innovative design allows the FSK and PSK channels to transmit messages simultaneously and independently, thus significantly increasing the transponder's message transmission capacity. This high-capacity ground transponder functionality is achieved through...

[0004] However, PSK (Phase Shift Keying) and FSK (Frequency Shift Keying), as two widely used digital modulation techniques in wireless communication, each have different characteristics. Compared to FSK, PSK performs relatively poorly in nonlinear channels, especially after nonlinear amplification, where PSK signals are prone to phase distortion. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a transmitting circuit for a ground transponder and a debugging method thereof, so as to avoid changes in the resonance characteristics between multiple channels, ensure that multiple channels can independently transmit messages in parallel, and achieve the purpose of doubling the message transmission capacity of the ground transponder.

[0006] The first aspect of this application discloses a transmitting circuit for a ground transponder, comprising: a transmitting antenna, a filtering circuit, an isolation circuit, and N transmitting channels; where N is a positive integer;

[0007] Each of the aforementioned transmission channels receives FSK signals with different frequency information from the logic control circuit;

[0008] The output terminals of the N transmission channels correspond one-to-one with the N input terminals of the isolation circuit, and the output terminal of each transmission channel is connected to its corresponding input terminal in the isolation circuit.

[0009] The output of the isolation circuit is connected to the transmitting antenna through the filter circuit.

[0010] The N transmission channels, together with the transmitting antenna, the filtering circuit, and the isolation circuit, constitute N independent FSK resonant circuits.

[0011] Optionally, the isolation circuit includes: two transformers and two coupling inductors;

[0012] One end of the first coupling inductor is connected to the first end of the first transformer, and the connection point is connected to the first end of the first transmitting channel.

[0013] The other end of the first coupling inductor is connected to the fourth end of the first transformer, and the connection point is connected to the first end of the second transmission channel;

[0014] The third and second terminals of the first transformer are connected, and the connection point is connected to the first input terminal of the filter circuit.

[0015] The first and second ends of the first transformer belong to the first winding, and the third and fourth ends of the first transformer belong to the second winding.

[0016] One end of the second coupling inductor is connected to the first end of the second transformer, and the connection point is connected to the second end of the first transmitting channel.

[0017] The other end of the second coupling inductor is connected to the fourth end of the second transformer, and the connection point is connected to the second end of the second transmitting channel;

[0018] The third terminal of the second transformer is connected to the second terminal, and the connection point is connected to the second input terminal of the filter circuit;

[0019] The first and second ends of the second transformer belong to the first winding, and the third and fourth ends of the second transformer belong to the second winding.

[0020] Optionally, the filtering circuit is disposed on the transmitting antenna.

[0021] Optionally, the filtering circuit includes two 27MHz filters;

[0022] The input terminals of the two 27MHz filters are each used as one input terminal of the filter circuit.

[0023] The outputs of the two 27MHz blocking filters are respectively connected to the transmitting antenna.

[0024] Optionally, the signal of the first transmission channel is a 4.23MHz FSK signal;

[0025] The signal for the second transmission channel is a 9.032MHz FSK signal.

[0026] Optionally, each of the aforementioned transmission channels is used to receive FSK signals with different frequency information to be transmitted;

[0027] The isolation circuit is used to effectively isolate each FSK signal, eliminate coupling between them, and synthesize multiple FSK signals at its own output.

[0028] The filtering circuit is used to filter out vehicle signals;

[0029] The transmitting antenna is used to combine and transmit the FSK signals received from the N transmitting channels.

[0030] The second aspect of this application discloses a method for debugging the transmitting circuit of a ground transponder, including:

[0031] The circuit connected to the transmitting circuit is equivalent to a network port;

[0032] Construct a reflection power model for multiple network ports; the reflection power model for multiple network ports includes: reflection power relationships constructed based on the signal power of the network ports;

[0033] Based on the reflected power model, the equivalent capacitance of each network port is adjusted so that the reflected power of each network port in the reflected power model meets the power threshold of each network port, and the equivalent frequency of each network port is its corresponding target frequency.

[0034] Optionally, the step of converting the circuit connected to the transmitting circuit into a network port includes:

[0035] The radio frequency energy circuit connected to the transmitting circuit is equivalent to the first network port;

[0036] The first circuit connected to the transmitting circuit that transmits FSK signals at the first frequency is equivalent to the second network port;

[0037] The second circuit connected to the transmitting circuit that transmits FSK signals at the second frequency is equivalent to a third network port.

[0038] Optionally, the reflection power model of the multi-network port is:

[0039]

[0040] Wherein, Reflect1 is the reflected power of the first network port; S11 is the reflection coefficient of the first network port; S12 is the transmission coefficient from the second network port to the first network port; S13 is the transmission coefficient from the third network port to the first network port; Reflect2 is the reflected power of the second network port; S21 is the transmission coefficient from the first network port to the second network port; S22 is the reflection coefficient of the second network port; S23 is the transmission coefficient from the third network port to the second network port; Reflect3 is the reflected power of the third network port; S31 is the transmission coefficient from the first network port to the third network port; S32 is the transmission coefficient from the second network port to the third network port; S33 is the reflection coefficient of the third network port; Input1 is the signal power of the first network port; Input2 is the signal power of the second network port; and Input3 is the signal power of the third network port.

[0041] Optional, also includes:

[0042] The reflected power and frequency of each network port are evaluated, and an evaluation report is obtained.

[0043] As can be seen from the above technical solution, the present invention provides a ground transponder transmitting circuit, wherein: each transmitting channel receives FSK signals with different frequency information from the logic control circuit; the output terminals of N transmitting channels correspond one-to-one with the N input terminals of the isolation circuit, and the output terminal of each transmitting channel is connected to its corresponding input terminal in the isolation circuit; the output terminal of the isolation circuit is connected to the transmitting antenna through a filter circuit; the N transmitting channels, the transmitting antenna, the filter circuit, and the isolation circuit constitute N independent FSK resonant circuits; that is, the FSK channels do not affect each other, realizing the isolation and synthesis technology of multi-channel transmitted signals, avoiding changes in the resonance characteristics between multiple channels, ensuring that multiple channels independently transmit messages in parallel, and achieving the purpose of doubling the message transmission capacity of the ground transponder. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the transmitting circuit of a ground transponder provided in an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the transmitting circuit of another ground transponder provided in an embodiment of the present invention;

[0047] Figure 3 This is a flowchart of a ground transponder transmission circuit debugging method provided in an embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of the equivalent network interface of the transmitting circuit of a ground transponder provided in an embodiment of the present invention;

[0049] Figure 5 This is a schematic diagram of a test system for the transmitting circuit of a ground transponder provided in an embodiment of the present invention;

[0050] Figure 6 This is a test flowchart of the transmitting circuit of a ground transponder provided in an embodiment of the present invention. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Furthermore, the terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data used can be interchanged where appropriate so that embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein.

[0053] Explanation of relevant terms:

[0054] Transponder (Balise): A ground transmission unit using magnetic induction technology. Its key function is to transmit data information through an air gap. A transponder is a signaling device installed on the track to communicate with onboard equipment passing overhead. Transponders are a general term for both active and passive transponders.

[0055] 4FSK: 4Frequencyshift keying, is a digital modulation technique that uses changes in the carrier frequency to transmit digital information. It utilizes the discrete value characteristics of baseband digital signals to key the carrier frequency in order to transmit information.

[0056] PSK: Phase Shift Keying, is a phase modulation method that uses changes in the phase of a carrier wave to transmit digital information. It is based on two levels of a digital baseband signal to switch the carrier phase between two different values.

[0057] Adjacent channel interference: The transmission of a signal from one channel to a signal in an adjacent channel through spatial coupling or (and) conduction.

[0058] Tuning capacitor: A device that provides capacitive compensation for the inductive properties of specific frequency signals transmitted through rails, while also short-circuiting adjacent line or section frequency signals.

[0059] Transponder Transmission Module (BTM): An onboard module used for ground-to-vehicle data transmission, which processes uplink signals and messages between the transponder and the onboard host unit device.

[0060] The transponder transmission system consists of ground transponders, transponder transmission units, and trackside electronic units. Interface "S" is the interface between the ground electronic unit and the train control center or other external equipment, serving as the data input for uplink information. Interface "B" is the interface between the transponder transmission module and the onboard host unit; the transponder transmission module transmits uplink information to the host unit and receives information sent by the onboard host unit. Interface "A" is the information transmission interface between the ground transponder and the onboard antenna unit. Interface "C" is the information transmission interface between the ground electronic unit and the active transponder; the ground electronic unit receives messages or information from the train control center or other equipment and transmits them to the active transponder through interface "C," which then transmits the information to passing onboard equipment.

[0061] This application discloses a ground transponder transmission circuit to address the problem that in the prior art, two channels, FSK and PSK, can transmit messages simultaneously and independently, but PSK performs relatively poorly in nonlinear channels, especially when it undergoes nonlinear amplification, where the PSK signal is prone to phase distortion.

[0062] The transmitting circuit of this ground transponder can be used to transmit response signals for multi-channel transponders.

[0063] See Figure 1 The ground transponder's transmitting circuit includes: a transmitting antenna, a filtering circuit, an isolation circuit, and N transmitting channels; N is a positive integer.

[0064] Each transmitting channel receives FSK signals with different frequency information from the logic control circuit.

[0065] Specifically, each transmitting channel has a receiving function, receiving FSK signals carrying different frequency information transmitted from the logic control circuit. Under the precise control of the logic control circuit, these signals are given their own unique frequency characteristics, enabling accurate identification and differentiation during subsequent processing and transmission. Each transmitting channel independently processes its received FSK signal, ensuring the integrity and accuracy of the information.

[0066] Taking N=2 as an example, the FSK signals of different frequencies for each transmission channel are illustrated below: the signal of the first transmission channel is a 4.23MHz FSK signal; the signal of the second transmission channel is a 9.032MHz FSK signal. Of course, other frequencies of FSK signals can also be used, which will not be elaborated here, but can be determined according to the actual situation, and all are within the protection scope of this application.

[0067] In addition, when N is 3 or other values, it is similar to the case of N=2 above, as long as the frequency information of the FSK signal transmitted by each transmission channel is different.

[0068] The outputs of the N transmission channels correspond one-to-one with the N inputs of the isolation circuit, and the output of each transmission channel is connected to its corresponding input in the isolation circuit.

[0069] The outputs of the N transmission channels are connected in a one-to-one correspondence with the N inputs of the isolation circuit. Specifically, the output of the first transmission channel is connected to the first input of the isolation circuit; the output of the second transmission channel is connected to the second input of the isolation circuit, thus ensuring accurate signal transmission and isolation.

[0070] The output of the isolation circuit is connected to the transmitting antenna through a filter circuit.

[0071] The output of the isolation circuit is connected to the transmitting antenna via a filter circuit. The filter circuit plays a crucial role here, effectively filtering out unwanted noise and interference to ensure a pure and stable signal received by the transmitting antenna.

[0072] Specifically, the output of the isolation circuit is connected to the input of the filter circuit, and the output of the filter circuit is connected to the transmission line.

[0073] It should be noted that the isolation circuit has two output terminals. The first output terminal of the isolation circuit is connected to the first input terminal of the filter circuit, and the second output terminal of the isolation circuit is connected to the second input terminal of the filter circuit. The filter circuit can also have two output terminals: the first output terminal of the filter circuit is connected to one end of the transmitting antenna, and the second output terminal of the filter circuit is connected to the other end of the transmitting antenna.

[0074] N transmission channels, along with transmitting antennas, filtering circuits, and isolation circuits, constitute N independent FSK resonant circuits.

[0075] N transmitting channels, transmitting antennas, filtering circuits, and isolation circuits together constitute N independent FSK resonant circuits. For example, taking N=2, the first transmitting channel, transmitting antenna, filtering circuit, and isolation circuit constitute the first FSK resonant circuit; the second transmitting channel, transmitting antenna, filtering circuit, and isolation circuit constitute the second FSK resonant circuit. Although the two FSK resonant circuits have the same components, such as transmitting antennas, filtering circuits, and isolation circuits, they are independent of each other. These circuits work independently without interfering with each other, thus achieving the efficient and stable signal transmission function of the ground transponder.

[0076] In this embodiment, each transmitting channel receives FSK signals with different frequency information from the logic control circuit; the outputs of the N transmitting channels correspond one-to-one with the N inputs of the isolation circuit, and the output of each transmitting channel is connected to its corresponding input in the isolation circuit; the output of the isolation circuit is connected to the transmitting antenna through a filter circuit; the N transmitting channels, the transmitting antenna, the filter circuit, and the isolation circuit constitute N independent FSK resonant circuits; that is, the FSK channels do not affect each other, realizing the isolation and synthesis technology of multi-channel transmitted signals, avoiding changes in the resonance characteristics between multiple channels, ensuring that multiple channels independently transmit messages in parallel, and achieving the goal of doubling the message transmission capacity of the ground transponder.

[0077] It should be noted that because European standard transponder technology transmits information using a single-channel FSK signal, the data transmission capacity of the transponder is relatively small, requiring a large number of transponders to be installed on the track. To increase the transponder's data transmission capacity and reduce the number of transponders installed on-site, a new type of high-capacity multi-channel transponder is needed to send more information to the onboard equipment within the same time frame. However, the transmitting circuit design of European standard transponders cannot effectively isolate and synthesize multi-channel signals, and the multiple channels can interfere with each other's resonant characteristics.

[0078] The ground transponder's transmitting circuit provided in this application uses a multi-channel isolation circuit to isolate the multi-channel signals and avoid the influence of resonance characteristics between the multi-channels, making the output signals of each channel of the transponder stable and reliable.

[0079] Optional, such as Figure 2 As shown, the isolation circuit includes two transformers and two coupled inductors; the two transformers and two coupled inductors work together to achieve signal isolation and transmission.

[0080] One end of the first coupling inductor is connected to the first end of the first transformer, and the connection point is connected to the first end of the first transmitting channel.

[0081] The other end of the first coupling inductor is connected to the fourth end of the first transformer, and the connection point is connected to the first end of the second transmitting channel.

[0082] Specifically, one end of the first coupling inductor is connected to the first terminal of the first transformer, and this connection point is connected to the first terminal of the first transmitting channel, ensuring accurate signal transmission. The other end of the first coupling inductor is connected to the fourth terminal of the first transformer, and this connection point is connected to the first terminal of the second transmitting channel, further widening the signal transmission path.

[0083] The first transmitting channel receives the first FSK signal, and the second transmitting channel receives the second FSK signal. These two FSK signals can be transmitted to the first coupled inductor and the first transformer through their respective transmitting channels. However, the nodes connected to the two FSK signals are different. For example, the first FSK signal is transmitted to the first end of the first coupled inductor and the primary winding of the first transformer; the second FSK signal is transmitted to the second end of the first coupled inductor and the secondary winding of the first transformer, so that the first FSK signal and the second FSK signal are isolated during transmission.

[0084] The third and second terminals of the first transformer are connected, and the connection point is connected to the first input terminal of the filter circuit.

[0085] The first and second ends of the first transformer belong to the first winding, and the third and fourth ends of the first transformer belong to the second winding. Specifically, the first winding can be the primary winding and the second winding can be the secondary winding. No specific limitation is made here, and it can be determined according to the actual situation. All of them are within the protection scope of this application.

[0086] One end of the second coupling inductor is connected to the first end of the second transformer, and the connection point is connected to the second end of the first transmitting channel.

[0087] The other end of the second coupling inductor is connected to the fourth end of the second transformer, and the connection point is connected to the second end of the second transmitting channel.

[0088] The third terminal of the second transformer is connected to the second terminal, and the connection point is connected to the second input terminal of the filter circuit.

[0089] The first and second terminals of the second transformer belong to the first winding, and the third and fourth terminals of the second transformer belong to the second winding.

[0090] Specifically, one end of the second coupling inductor is connected to the first end of the second transformer, and this connection point is connected to the second end of the first transmitting channel, ensuring accurate signal transmission. The other end of the second coupling inductor is connected to the fourth end of the second transformer, and this connection point is connected to the second end of the second transmitting channel, further widening the signal transmission path.

[0091] The first transmitting channel receives the first FSK signal, and the second transmitting channel receives the second FSK signal. These two FSK signals can be transmitted to the second coupled inductor and the second transformer through their respective transmitting channels. However, the nodes connected to these two FSK signals are different. For example, the first FSK signal is transmitted to the first end of the second coupled inductor and the primary winding of the second transformer; the second FSK signal is transmitted to the second end of the second coupled inductor and the secondary winding of the second transformer, thereby isolating the first FSK signal and the second FSK signal during transmission.

[0092] In summary, through careful design, the isolation circuit achieves signal isolation, transmission, and filtering, providing a solid guarantee for the stable operation of the entire system.

[0093] It should be noted that the isolation circuit described above is illustrated using two FSK signals as an example. When there are at least three FSK signals, taps can be added to both the transformer and the coupling inductor. These taps are connected to the transmission channels corresponding to the additional FSK signals, thereby achieving isolation and transmission of multiple FSK signals. The specific process for multiple FSK signals will not be detailed here.

[0094] The purpose of configuring coupling inductors is to decouple different frequencies. This can be used to guide the design and debugging of production circuits, aiming to improve design efficiency and product manufacturing and debugging efficiency. Meanwhile, the transmitting circuit in this application is a multi-frequency transmitting circuit, which not only needs to consider the mutual influence of multiple frequencies but also involves the debugging of antennas with multiple resonant frequencies.

[0095] In this embodiment, the isolation circuit is mainly achieved through a transformer and a coupling inductor. The transformer is used to couple and cancel the input channel signals, ultimately ensuring that the signals between the channels do not interfere with each other.

[0096] Optionally, the filter circuit is located on the transmitting antenna.

[0097] A filter circuit is installed on the transmitting antenna to ensure that the signal is effectively purified and processed before it reaches the antenna. This design not only improves the purity of the signal but also enhances the efficiency of the transmitting antenna in receiving and transmitting signals, thereby ensuring the stability and reliability of the entire communication system.

[0098] Optionally, the filtering circuit includes two 27MHz filters.

[0099] The input terminals of the two 27MHz blocking filters are each used as one input terminal of the filtering circuit; the output terminals of the two 27MHz blocking filters are respectively connected to the transmitting antenna.

[0100] This 27MHz filter is an electronic component specifically designed to filter out signals passing through frequencies near 27MHz. It has wide applications in communications, broadcasting, television, and radio, especially in situations requiring precise control of signal frequency and bandwidth.

[0101] Specifically, the input terminal of the first 27MHz blocking filter serves as the first input terminal of the filtering circuit and is connected to the first output terminal of the isolation circuit; more specifically, the input terminal of the first 27MHz blocking filter is connected to the third and second terminals of the first transformer, respectively. The output terminal of the first 27MHz blocking filter is connected to one end of the transmitting antenna.

[0102] The input terminal of the second 27MHz stop filter serves as the second input terminal of the filter circuit and is connected to the second output terminal of the isolation circuit. More specifically, the input terminal of the second 27MHz stop filter is connected to the third and second terminals of the second transformer, respectively. The output terminal of the second 27MHz stop filter is connected to the other end of the transmitting antenna.

[0103] In this embodiment, the filter circuit is installed on the transmitting antenna to isolate the 27M energy signal coupled to the antenna and ensure the signal quality of the response signal.

[0104] The following explains the operation of the ground transponder's transmitting circuit:

[0105] Each transmission channel is used to receive FSK signals with different frequency information to be transmitted.

[0106] An isolation circuit is used to effectively isolate each FSK signal, eliminate coupling between them, and synthesize multiple FSK signals at its own output.

[0107] The filtering circuit is used to filter out vehicle signals.

[0108] The transmitting antenna is used to combine and transmit the FSK signals received from N transmitting channels.

[0109] In other words, each transmitting channel is responsible for receiving FSK signals carrying different frequency information to be transmitted. To achieve independent signal processing, an isolation circuit is introduced. This isolation circuit can effectively isolate the various FSK signals from each other, eliminate the coupling effect between them, and accurately synthesize the multiple FSK signals at its output.

[0110] In addition, to further improve the purity of the signal, a special filtering circuit is set up. This filtering circuit is focused on filtering out possible interference from vehicle-mounted signals, such as filtering out the vehicle-mounted 27MHz signal, avoiding the influence of the vehicle-mounted 27MHz signal on the transmission signal of the ground transponder, and ensuring the quality of the transmitted signal.

[0111] Ultimately, the carefully processed FSK signal was synthesized and transmitted through the transmitting antenna, enabling the transponder's multi-channel signal to be transmitted smoothly and achieving efficient and stable communication.

[0112] In this embodiment, for the ground transponder, with the background of increasing the capacity of the ground transponder to send messages, a transmission circuit for the 4FSK orbital ground transponder is proposed, and a decoupling design for multiple frequencies such as 4.2MHz, 9.032MHz, and 27.095MHz is designed, and the theoretical derivation basis is given.

[0113] Another embodiment of this application provides a method for debugging the transmitting circuit of a ground transponder.

[0114] join Figure 3 The debugging method includes:

[0115] S101. The circuit connected to the transmitting circuit is equivalent to a network port.

[0116] It should be noted that the transmitting circuit of the ground transponder needs to transmit data with other circuits through an antenna. However, since there are resonant frequencies between the circuits, the transmitting parameters of the antenna will be affected, which in turn will affect the data transmission between the circuits. Therefore, it is necessary to apply the equivalent network port of the circuit connected to the transmitting circuit, and then use the network port for subsequent debugging to ensure that the data transmission between the transmitting circuit and its connected circuits is efficient and accurate.

[0117] Specifically, the different circuits connected to the transmitting circuit are equivalent to different network ports. For example, the antenna in the transmitting circuit is also used as an input terminal, and the circuit that interacts with the antenna (e.g., performs radio frequency energy signal interaction) is equivalent to a third network port. The transmitting circuit receives the first FSK signal through the first input terminal (the input terminal of the first transmitting channel); then the circuit connected to the first input terminal is equivalent to the first network port. The transmitting circuit receives the second FSK signal through the second input terminal (the input terminal of the second transmitting channel); then the circuit connected to the second input terminal is equivalent to the second network port.

[0118] In other words, the specific process of converting the circuit connected to the transmitting circuit into a network port can be as follows:

[0119] The radio frequency energy circuit connected to the transmitting circuit is equivalent to the first network port; the first circuit connected to the transmitting circuit that transmits the first frequency FSK signal is equivalent to the second network port; and the second circuit connected to the transmitting circuit that transmits the second frequency FSK signal is equivalent to the third network port.

[0120] In other words, the RF power transmission circuit connected to the transmitting circuit is considered the first network port, responsible for transmitting RF power; simultaneously, the first circuit connected to the transmitting circuit, specifically used for transmitting the first frequency FSK (Frequency Shift Keying) signal, is equivalent to the second network port; furthermore, the second circuit connected to the transmitting circuit, used for transmitting the second frequency FSK signal, is considered the third network port. This equivalent treatment allows for easier analysis and optimization of the entire transmitting circuit system.

[0121] S102. Construct a reflection power model for multiple network ports.

[0122] The reflection power model for multiple network ports includes: a reflection power relationship constructed based on the signal power of multiple network ports.

[0123] The core of this multi-network-port reflection power model lies in the fact that it includes multiple network ports and constructs corresponding reflection power relationships based on the signal power of these network ports. These relationships can clearly reflect the power reflection situation between each network port.

[0124] Optionally, the reflection power model for multiple network ports is as follows:

[0125]

[0126] Wherein, Reflect1 is the reflected power of the first network port; S11 is the reflection coefficient of the first network port; S12 is the transmission coefficient from the second network port to the first network port; S13 is the transmission coefficient from the third network port to the first network port; Reflect2 is the reflected power of the second network port; S21 is the transmission coefficient from the first network port to the second network port; S22 is the reflection coefficient of the second network port; S23 is the transmission coefficient from the third network port to the second network port; Reflect3 is the reflected power of the third network port; S31 is the transmission coefficient from the first network port to the third network port; S32 is the transmission coefficient from the second network port to the third network port; S33 is the reflection coefficient of the third network port; Input1 is the signal power of the first network port; Input2 is the signal power of the second network port; and Input3 is the signal power of the third network port.

[0127] The reflection coefficient is the ratio of reflected power to incident power.

[0128] It should be noted that although the isolation circuit is designed to reduce the mutual coupling effect between the antennas inside the 4FSK transponder, certain equivalent electrical parameters will inevitably affect other circuit ports, which brings considerable difficulty to circuit debugging. Furthermore, solving this problem using field analysis methods is extremely cumbersome. Therefore, as... Figure 4 As shown, the transmitting and receiving circuits are treated as a multi-port network model. The mutual coupling mechanism between the internal antennas is explored by analyzing the voltage and current at the network ports. In this model, Input1 represents the signal power received by the RF power receiving antenna, Input2 represents the signal power of the 4.234MHz transmitting antenna in the uplink, and Input3 represents the signal power of the 9.032MHz transmitting antenna in the uplink. This approach helps us to more clearly understand and solve the antenna mutual coupling problem.

[0129] S103. Based on the reflection power model, adjust the equivalent capacitance of each network port so that the reflection power of each network port in the reflection power model meets the power threshold of each network port, and the equivalent frequency of each network port is its corresponding target frequency.

[0130] After constructing the reflection power model, the equivalent capacitance of each network port is adjusted based on this model. The goal of the adjustment is to ensure that the reflected power of each network port in the reflection power model meets the preset power threshold, and that the equivalent frequency of each network port is the target frequency. This step ensures that the power reflection of the entire transmitting circuit system is within a controllable range, thereby improving the system's stability and efficiency.

[0131] Among them, reflected power refers to the power that is reflected back when an electromagnetic wave encounters an interface with impedance mismatch.

[0132] The resonant frequency refers to the frequency at which a circuit resonates. At this angular frequency, the inductor reactance and the capacitor reactance are equal, and the circuit exhibits pure resistivity with zero reactive power.

[0133] Impedance matching and reflected power: When a circuit operates at its resonant frequency, if the impedances between the network ports are well matched, the reflected power will be very small. Conversely, if the impedances are mismatched, a large amount of reflected power will be generated.

[0134] Adjusting the resonant frequency to reduce reflected power: In RF and microwave circuit design, the resonant frequency can be changed by adjusting the values ​​of circuit components (such as inductors and capacitors), thereby achieving impedance matching and reducing reflected power.

[0135] It should be noted that the resonant frequency is the core objective in the design of network ports. Given the specific requirements of the transponder transmission system, the frequencies of the network ports must be set to 27.095MHz, 9.032MHz, and 4.234MHz. To ensure the circuit resonates simultaneously at these three target frequencies, the complex effects of coupling between coils must be fully considered. Therefore, this application proposes a tuning method to effectively adjust the frequencies of each network port to precisely match the preset resonant frequency points. In short, this method calibrates the frequencies of each port to the required target resonant frequencies.

[0136] While theoretical calculation methods exist, in actual engineering implementation, process deviations during printed circuit board antenna fabrication and errors caused by the precision of inductors and capacitors must still be considered. This means that the debugging process is not a one-time fix, but requires continuous frequency adjustment to the expected target frequency. Based on the methods described in this article, debugging suggestions can be provided to R&D engineers and production line technicians, thereby assisting them in completing debugging work and production tasks more effectively.

[0137] It is also worth noting that the reflection power adjustment in this application requires testing the reflection power using a designed automated testing system, which can quantify the target range. Furthermore, the reflection power values ​​at the center of the three frequencies differ. A reflection power of 0 is equivalent to negative infinity in the form of logmag for the S11 parameter. Taking 27.095MHz in the system as an example, in the automated testing system, the extreme value of the S11 parameter between 27.135MHz and 27.195MHz is considered acceptable. 27.135 and 27.195 are data derived by considering the product's characteristics, the 0.07MHz reduction in center frequency due to subsequent production and potting processes, and other factors.

[0138] It should be noted that the formula for calculating the resonant frequency is:

[0139]

[0140] When the equivalent L (inductance) and C (capacitance) of different ports are connected to other ports, it is necessary to analyze the relationship between L and C and the circuit of this port, calculate the final L and C, and then adjust to obtain the final resonant frequency.

[0141] Specifically, taking a frequency of 27.095MHz as an example, the resonant frequency of the circuit is adjusted to the expected target of 27.095MHz. Factors affecting L include the fabrication process of the printed circuit board antenna, the inductance in the circuit, and other inductive components. These factors are superimposed to obtain L in the formula. Since f and L in the formula are known quantities, the target C can be calculated. Subtracting the fixed circuit C from the target C leaves the adjustable capacitor in the circuit. The desired capacitor is then soldered at the location of the adjustable capacitor to achieve the expected frequency of 27.095MHz for the resonant circuit. This achieves the required capacitor parameters for the model.

[0142] The same applies to signals with frequencies of 9.032MHz and 4.234MHz, which will not be elaborated here. They can be determined according to the actual situation and are all within the protection scope of this application.

[0143] At any point in the above steps, it may also include:

[0144] The reflected power and frequency of each network port are evaluated, and an evaluation report is obtained.

[0145] In other words, this application can automatically evaluate whether the 4FSK transponder's transmitting circuit and receiving antenna frequency meet the relevant standards.

[0146] Specifically, such as Figure 5As shown, the automated commissioning and testing system for the resonant frequency of a 4FSK transponder operates as follows: The control terminal connects to a network analyzer via a GPIB bus to configure frequency scanning parameters, including the scan bandwidth Bw and power setting P. Subsequently, the network analyzer, using an RF switch and coupling network, measures the current resonant frequency of each network port of the transponder. If the measured frequency fails to meet the target, the system automatically calculates the capacitance value required to adjust to the target frequency based on the formula for the reflected power S and the resonant frequency, and provides corresponding commissioning guidance.

[0147] like Figure 6 As shown, analysis can be performed on each network port. For example: First, the network port with a resonant frequency of 27.095MHz is measured, its power and frequency are evaluated, the capacitance value required for the 27.095MHz frequency offset is calculated, and the analysis results are displayed; Second, the network port with a resonant frequency of 9.032MHz is measured, its power and frequency are evaluated, the capacitance value required for the 9.032MHz frequency offset is calculated, and the analysis results are displayed; Next, the network port with a resonant frequency of 4.234MHz is measured, its power and frequency are evaluated, the capacitance value required for the 4.234MHz frequency offset is calculated, and the analysis results are displayed.

[0148] Each network port can be processed sequentially or synchronously; no specific restrictions are imposed here.

[0149] It should be noted that an independent evaluation report (test report) can be generated for each network port, or the evaluation results of each network port can be generated into a single test report. No specific limitation is made here; it depends on the actual situation.

[0150] In this embodiment, the circuit connected to the transmitting circuit is equivalent to a network port; a multi-network port reflection power model is constructed; the multi-network port reflection power model includes: a reflection power relationship constructed by multiple network ports based on the signal power of the network ports; according to the reflection power model, the equivalent capacitance of each network port is adjusted so that the reflection power of each network port in the reflection power model meets the power threshold of each network port, and the equivalent frequency of each network port is its corresponding target frequency; thus realizing the debugging of the transmitting circuit of the ground transponder, improving debugging efficiency, and optimizing circuit performance.

[0151] The features described in the various embodiments of this specification can be substituted for or combined with each other. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0152] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0153] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A transmitting circuit for a ground transponder, characterized in that, include: Transmitting antenna, filtering circuit, isolation circuit, and N transmission channels; N is a positive integer; Each of the aforementioned transmission channels receives FSK signals with different frequency information from the logic control circuit; The output terminals of the N transmission channels correspond one-to-one with the N input terminals of the isolation circuit, and the output terminal of each transmission channel is connected to its corresponding input terminal in the isolation circuit. The output of the isolation circuit is connected to the transmitting antenna through the filter circuit. The N transmission channels, together with the transmitting antenna, the filtering circuit, and the isolation circuit, constitute N independent FSK resonant circuits.

2. The transmitting circuit of the ground transponder according to claim 1, characterized in that, The isolation circuit includes: two transformers and two coupling inductors; One end of the first coupling inductor is connected to the first end of the first transformer, and the connection point is connected to the first end of the first transmitting channel. The other end of the first coupling inductor is connected to the fourth end of the first transformer, and the connection point is connected to the first end of the second transmission channel; The third and second terminals of the first transformer are connected, and the connection point is connected to the first input terminal of the filter circuit. The first and second ends of the first transformer belong to the first winding, and the third and fourth ends of the first transformer belong to the second winding. One end of the second coupling inductor is connected to the first end of the second transformer, and the connection point is connected to the second end of the first transmitting channel. The other end of the second coupling inductor is connected to the fourth end of the second transformer, and the connection point is connected to the second end of the second transmitting channel; The third terminal of the second transformer is connected to the second terminal, and the connection point is connected to the second input terminal of the filter circuit; The first and second ends of the second transformer belong to the first winding, and the third and fourth ends of the second transformer belong to the second winding.

3. The transmitting circuit of the ground transponder according to claim 1, characterized in that, The filtering circuit is mounted on the transmitting antenna.

4. The transmitting circuit of the ground transponder according to claim 1, characterized in that, The filtering circuit includes two 27MHz filters; The input terminals of the two 27MHz filters are each used as one input terminal of the filter circuit. The outputs of the two 27MHz blocking filters are respectively connected to the transmitting antenna.

5. The transmitting circuit of the ground transponder according to claim 1, characterized in that, The signal for the first transmission channel is a 4.23MHz FSK signal; The signal for the second transmission channel is a 9.032MHz FSK signal.

6. The transmitting circuit of the ground transponder according to claim 1, characterized in that, Each of the aforementioned transmission channels is used to receive FSK signals with different frequency information to be transmitted; The isolation circuit is used to effectively isolate each FSK signal, eliminate coupling between them, and synthesize multiple FSK signals at its own output. The filtering circuit is used to filter out vehicle signals; The transmitting antenna is used to combine and transmit the FSK signals received from the N transmitting channels.

7. A method for debugging the transmitting circuit of a ground transponder, characterized in that, include: The circuit connected to the transmitting circuit is equivalent to a network port; Construct a reflection power model for multiple network ports; The multi-network port reflection power model includes: a reflection power relationship constructed by multiple network ports based on the signal power of the network ports; Based on the reflected power model, the equivalent capacitance of each network port is adjusted so that the reflected power of each network port in the reflected power model meets the power threshold of each network port, and the equivalent frequency of each network port is its corresponding target frequency.

8. The debugging method for the transmitting circuit of a ground transponder according to claim 7, characterized in that, The circuit connected to the transmitting circuit is equivalent to a network port, including: The radio frequency energy circuit connected to the transmitting circuit is equivalent to the first network port; The first circuit connected to the transmitting circuit that transmits FSK signals at the first frequency is equivalent to the second network port; The second circuit connected to the transmitting circuit that transmits FSK signals at the second frequency is equivalent to a third network port.

9. The debugging method for the transmitting circuit of a ground transponder according to claim 7, characterized in that, The reflection power model for the multi-network port is as follows: Wherein, Reflect1 is the reflected power of the first network port; S11 is the reflection coefficient of the first network port; S12 is the transmission coefficient from the second network port to the first network port; S13 is the transmission coefficient from the third network port to the first network port; Reflect2 is the reflected power of the second network port; S21 is the transmission coefficient from the first network port to the second network port; S22 is the reflection coefficient of the second network port; S23 is the transmission coefficient from the third network port to the second network port; Reflect3 is the reflected power of the third network port; S31 is the transmission coefficient from the first network port to the third network port; S32 is the transmission coefficient from the second network port to the third network port; S33 is the reflection coefficient of the third network port; Input1 is the signal power of the first network port; Input2 is the signal power of the second network port; and Input3 is the signal power of the third network port.

10. The debugging method for the transmitting circuit of a ground transponder according to claim 7, characterized in that, Also includes: The reflected power and frequency of each network port are evaluated, and an evaluation report is obtained.

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