Weak network tester

Abstract

The invention discloses a weak network tester, which belongs to the technical field of radio frequency test and communication, and comprises an attenuator, an RF (Radio Frequency) signal processing module, a signal processing module, a signal processing module and a power supply module, and is characterized in that the attenuator is provided with an RF attenuation channel for attenuating RF signals; one RF attenuation channel is correspondingly provided with two bias devices, RF ports of the two bias devices are connected to the two ends of the RF attenuation channel, DC ports of the bias devices are communicated with each other to form a DC straight-through channel, RF + DC ports of the bias devices are used for inputting or outputting RF + DC signals respectively, one of the RF + DC ports of the bias devices is connected with a TBOX, and the other of the RF + DC ports of the bias devices is connected with a TBOX. And the RF + DC port of the other bias device is connected with a test antenna externally arranged on the TBOX. A bias device and an attenuator are combined, and an independent direct current transmission path is constructed on the premise that an original radio frequency attenuation channel of the attenuator is not changed by utilizing signal separation and synthesis functions of the bias device.

Description

Technical Field

[0001] The present invention belongs to the technical field of radio frequency testing and communication technology, and particularly relates to a weak network tester. Background Art

[0002] In modern communication systems, especially in the test scenarios of in-vehicle communication terminals, such as in-vehicle communication devices (TBOX), simulating a weak network environment is a key indicator for evaluating the performance of devices. A weak network tester can verify key indicators such as the receiving sensitivity, data transmission stability, and network switching performance of a device under low signal strength by precisely controlling signal attenuation and simulating wireless signal environments of different intensities. In view of the DC isolation problem of traditional attenuators when dealing with signals containing DC feed, the present invention proposes an innovative solution integrating a bias unit to ensure parallel transmission of RF signals and DC signals without replacing the existing attenuator, providing an efficient and compatible solution for the testing of in-vehicle communication terminals. In the field of radio frequency communication testing, as a core device, an attenuator mainly functions to quantitatively attenuate radio frequency (RF) signals through built-in attenuation elements to simulate signal intensities in different distance or obstacle environments. To protect the receiving device at the rear end from DC interference, traditional attenuators usually incorporate a capacitor (DC Block component) to achieve DC isolation, allowing only RF signals to pass through. This design performs well when dealing with pure RF signals, but significant defects are exposed in the test scenarios of active antennas that require DC feed.

[0003] The in-vehicle communication terminal TBOX integrates multiple communication functions such as LTE, 5G, and GNSS. During its testing process, it often needs to be connected to external active antennas (such as GNSS antennas, 4G / 5G antennas, etc.). Such antennas usually contain active devices such as low-noise amplifiers (LNA) inside and require external DC power supply to operate normally. However, the DC isolation characteristic of traditional attenuators will cut off the DC feed path, resulting in the following problems: Failure of active antennas: The interruption of DC power supply makes the active devices inside the antennas unable to work, severely degrading the receiving performance of the antennas and even forcing them to switch to the built-in antenna of the TBOX. Distortion of test results: The signal path of the built-in antenna of the TBOX does not pass through the attenuator, resulting in the actual received signal strength not being controlled by the attenuator, showing an abnormal phenomenon of "the attenuator attenuates but the signal strength remains fixed", and unable to truly simulate a weak network environment. Equipment compatibility issues: If an attenuator without DC isolation characteristics is replaced, not only will the cost increase, but also risks of system incompatibility may be caused, such as impedance matching problems and enhanced signal reflection.

[0004] Since the vast majority of attenuators on the market are DC-blocking attenuators, and non-DC-blocking attenuators have fixed attenuation with uncontrollable attenuation values, it is difficult to meet customer requirements. To address the DC-blocking issue of traditional attenuators, the prior art has attempted to solve it in the following ways: replacing with non-DC-blocking attenuators, but non-DC-blocking attenuators need to be specially customized; and directly using attenuators that allow DC to pass through requires re-selection and verification, increasing the equipment procurement cost and potentially introducing new signal interference problems. External DC feeding module: Connecting a DC feeding line in parallel outside the attenuator, but this will lead to complex cable layout, increasing the risk of electromagnetic interference (EMI), and it is difficult to ensure the isolation between DC signals and RF signals, affecting the test accuracy. Summary of the Invention

[0005] The object of the present invention is to provide a weak network tester, which combines a bias tee and an attenuator, and uses the signal separation and synthesis functions of the bias tee to construct an independent DC transmission path without changing the original RF attenuation channel of the attenuator.

[0006] To achieve the above object of the invention, the technical solutions adopted by the present invention are as follows:

[0007] A weak network tester, comprising:

[0008] An attenuator having an RF attenuation channel for attenuating RF signals;

[0009] A bias tee, two bias tees are correspondingly arranged for one RF attenuation channel, the RF ports of the two bias tees are connected to both ends of the RF attenuation channel, the DC ports of the bias tees are interconnected to form a DC direct-through channel, and the RF+DC ports of the bias tees are respectively used for inputting or outputting RF+DC signals.

[0010] A weak network tester, comprising:

[0011] An attenuator having an RF attenuation channel for attenuating RF signals;

[0012] A bias tee, two bias tees are correspondingly arranged for one RF attenuation channel, the RF ports of the two bias tees are connected to both ends of the RF attenuation channel, the DC ports of the bias tees are interconnected to form a DC direct-through channel, and the RF+DC ports of the bias tees are respectively used for inputting or outputting RF+DC signals, wherein the RF+DC port of one of the bias tees is connected to the TBOX, and the RF+DC port of the other bias tee is connected to a test antenna externally disposed to the TBOX.

[0013] Further, the attenuator is provided with a plurality of RF attenuation channels, and two bias tees are correspondingly arranged for each RF attenuation channel.

[0014] Furthermore, the DC direct-through channel adopts a high-frequency isolation design to suppress the mutual interference between RF signals and DC signals during common-path transmission.

[0015] Furthermore, it further includes a chassis housing, and the attenuator and the bias tee are integrated within the chassis housing.

[0016] Furthermore, it further includes external ports. There are multiple external ports, which are arranged on the chassis housing. The external ports are connected to the RF+DC ports in one-to-one correspondence, and the external ports are respectively used for externally connecting a TBOX and a test antenna.

[0017] Furthermore, it further includes a combiner. Multiple external ports are combined through the combiner and then connected to the TBOX.

[0018] Furthermore, the external ports are interfaces of a unified model or modular adapters.

[0019] Furthermore, the attenuator and the bias tee adopt a symmetric circuit structure, so that the RF attenuation channel can attenuate radio frequency signals bidirectionally.

[0020] Furthermore, it further includes a power supply module and a communication port. The power supply module and the communication port are electrically connected to the attenuator. The power supply module is arranged within the chassis housing and is used to supply power to the attenuator. The communication port is arranged on the chassis housing and is used for the attenuator to communicate and interact with the outside world.

[0021] The beneficial effects of the present invention are as follows:

[0022] (1) By introducing an independent DC channel on the basis of the DC-blocking attenuator through the bias tee, the weak network tester separates the DC (direct current) signal from the RF signal. The DC signal and the RF signal are isolated from each other, preventing interference and at the same time not affecting the attenuation direction design scheme of the attenuator. It ensures that the DC signal is not blocked by the DC-blocking module in the attenuator and is directly transmitted by the DC direct-through channel to the bias tee at the other end, where the DC signal is recombined with the RF signal. This solves the DC-blocking problem existing in the attenuator of the weak network tester, and uses a simple shunt fitting (bias tee) to transform the existing attenuator, enabling users to achieve parallel transmission of multiple signals (RF and DC) without large-scale replacement of the existing attenuator equipment, reducing the additional cost and system incompatibility risk brought by equipment conversion.

[0023] (2) The attenuator and the bias tee of the weak network tester adopt a symmetric circuit structure, that is, no matter which side the RF+DC signal enters or exits, it can not affect the attenuation of the RF signal and the transmission of the DC signal, forming a bidirectional attenuation structure.

[0024] (3) This weak network tester can be adapted to a variety of antennas and device structures. According to the power supply requirements of the external antenna under different test scenarios and the internal recognition mechanism of the TBOX, an interface of a unified model or a modular adapter is set, enabling the weak network tester to be adapted to a variety of antenna devices with different specifications and standards.

[0025] (4) This weak network tester integrates the attenuator and the bias tee inside the chassis shell, solving the problem of excessive cable routing caused by the need to add a bias tee to each channel of the multi-channel attenuator.

[0026] (5) The DC direct-through channel of this weak network tester adopts a high-frequency isolation design to suppress the mutual interference between RF signals and DC signals during common-path transmission, ensuring that the DC signal and the RF signal do not interfere with each other during common-path transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a circuit schematic diagram of the attenuator and the bias tee of the weak network tester provided by the present invention;

[0028] Figure 2 is a perspective view of the weak network tester provided by the present invention with the upper cover omitted;

[0029] Figure 3 is a circuit schematic diagram of the weak network tester provided by the present invention;

[0030] Figure 4 is a circuit schematic diagram of the weak network tester provided by the present invention when testing the TBOX;

[0031] Figure 5 is a circuit schematic diagram of the bias tee provided by the present invention.

[0032] Reference numerals: 1, weak network tester; 11, attenuator; 111, attenuation channel; 12, bias tee; 121, direct-through channel; 13, chassis housing; 14, external port; 15, power supply module; 16, communication port; 2, combiner; 3, TBOX; 4, base station. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

[0034] Embodiment 1

[0035] As Figures 1-5A weak network tester 1 shown in the figure includes: an attenuator 11 and a bias unit 12. The attenuator 11 is a core functional device for implementing signal amplitude regulation in an electronic circuit system. Its core function is to construct a signal attenuation environment that meets specific requirements by precisely adjusting the power parameters of the transmitted signal. The main application scenario of this device focuses on simulating the weak network conditions caused by signal attenuation in the actual communication process. Specifically, it quantitatively attenuates the intensity of the transmitted signal in the circuit, thereby simulating a signal transmission state with low data throughput and low transmission rate.

[0036] From the perspective of the technical implementation principle, the attenuator 11 can accurately reproduce the signal intensity attenuation phenomenon caused by factors such as distance loss, multipath fading, and interference noise in the real communication environment through a controllable power attenuation mechanism. It can even simulate the scenario of complete signal interruption in extreme cases. This simulation ability enables the electronic device under test to establish a connection with the target signal processed by the attenuator 11 in the artificially constructed weak network test environment, and then carry out targeted performance tests.

[0037] In actual test applications, the core value of the attenuator 11 lies in providing repeatable and quantifiable weak network test conditions for the device under test. By precisely setting the attenuation parameters, testers can systematically evaluate key performance indicators such as connection stability, data transmission efficiency, and anti-interference ability of the device under different signal intensities and different transmission rates. The construction of this test environment is of great significance for the research and development and quality verification of products such as communication devices, Internet of Things terminals, and wireless modules. It can effectively expose problems such as abnormal connections, data packet loss, and transmission delays that may occur in the device in a real weak network environment, providing data support for product optimization.

[0038] In summary, as the core component of weak network simulation, the attenuator 11 builds a bridge between the laboratory environment and the real complex communication scenario through a scientific signal power regulation mechanism. Its application in the field of electronic device testing significantly improves the comprehensiveness and reliability of product performance verification, providing important technical support for ensuring the stable operation of devices in the actual weak network environment. However, the existing attenuator 11 usually has a DC blocking function. The DC blocking function can provide positive effects in most application scenarios, but in a test environment that requires power feeding, the DC blocking function affects the power feeding function, resulting in the inability of the components that need power feeding in the test environment to work properly, and thus unable to complete the weak network test. If the attenuator 11 is directly replaced, the cost will increase significantly, and there may also be a risk of system incompatibility.

[0039] As Figure 1 shown, the attenuator 11 of the weak network tester 1 in this embodiment has an RF attenuation channel 111 for attenuating RF signals; a bias unit 12, and the circuit diagram of the bias unit 12 is as Figure 5As shown, the attenuator 11 and the bias tee 12 adopt a symmetric circuit structure, that is, no matter which side the RF+DC signal enters or exits, it will not affect the attenuation of the RF signal and the transmission of the DC signal, forming a two-way attenuation structure. A bias tee 12 has three ports, including an RF port, a DC port, and an RF+DC port. Among them, the DC port consists of a feeding inductor, which is used to add a DC bias to prevent the AC signal at the RF port from leaking into the power supply system. Under ideal conditions, the DC port will not cause any impact on the signal at the RF port. The RF port consists of a DC blocking capacitor, which is used to input the RF signal and can block the DC signal at the same time. The RF&DC port allows the RF+DC signal to be input or output simultaneously. In this solution, two bias tees 12 are correspondingly arranged for one RF attenuation channel 111. The RF ports of the two bias tees 12 are connected to both ends of the RF attenuation channel 111. The DC ports of the bias tees 12 are interconnected to form a DC direct-through channel 121. The RF+DC ports of the bias tees 12 are respectively used to input or output the RF+DC signal.

[0040] In this solution, the RF attenuation channel 111 is still the RF attenuation channel 111 of the original attenuator 11, maintaining the original design and signal path of the attenuator 11 to ensure accurate attenuation effect of the signal after passing through the attenuator 11. Therefore, there is no need to replace the existing DC blocking attenuator 11, which will not increase the cost and the risk of system incompatibility. The DC direct-through channel 121 formed by two bias tees 12 allows the DC signal to be transmitted separately without being affected by the DC blocking function of the attenuator 11. After the RF+DC signal flows in from one side, it is separated into an RF signal and a DC signal under the action of the bias tee 12 on this side. The RF signal normally passes through the RF attenuation channel 111 for attenuation and is transmitted to the bias tee 12 on the other side. The DC signal is directly transmitted to the bias tee 12 on the other side through the DC direct-through channel 121 and is recombined into an RF+DC signal under the action of the bias tee 12 on the other side and is output from the RF+DC port, so that the components that need to be fed on the other side can normally receive the RF+DC signal and thus can work normally.

[0041] Preferably, the DC direct-through channel 121 adopts a high-frequency isolation design to suppress the mutual interference between the RF signal and the DC signal during the common-path transmission, ensuring that the DC signal and the RF signal do not interfere with each other during the common-path transmission. The high-frequency isolation design can be to add a metal shielding cover to the DC direct-through channel 121 to suppress the radiation interference. For example, a copper shielding cover (with a thickness of 0.5 mm) is installed around the DC direct-through channel 121 and the copper shielding cover is grounded to improve the shielding effectiveness of the copper shielding cover, or the distance between the DC direct-through channel 121 and the RF attenuation channel 111 is increased. Preferably, the distance is set to be more than three times the line width. For example, when the line width is 0.5 mm, the distance is set to be greater than or equal to 1.5 mm.

[0042] Therefore, for the existing attenuator 11 with DC blocking function, in the test scenarios that require DC feeding, a symmetric circuit structure formed by two biasers 12 and the attenuator 11 as shown in Figure 1 can be adopted, so that the components that require DC feeding in the test scenario can obtain DC feeding normally. Without large-scale replacement of the existing attenuator 11 equipment, multi-signal (RF and DC) parallel transmission can be achieved, reducing the additional cost and system incompatibility risk caused by equipment conversion.

[0043] Embodiment 2

[0044] As Figures 2-5 shown, a weak network tester 1, on the basis of Embodiment 1, applies the weak network tester 1 to the test of TBOX3, including: an attenuator 11, the attenuator 11 having an RF attenuation channel 111 for attenuating RF signals; a biaser 12, two biasers 12 are correspondingly arranged for one RF attenuation channel 111, the RF ports of the two biasers 12 are connected to both ends of the RF attenuation channel 111, the DC ports of the biasers 12 are interconnected to form a DC through channel 121, and the RF+DC ports of the biasers 12 are respectively used for inputting or outputting RF+DC signals, the RF+DC port of one of the biasers 12 is connected to TBOX3, and the RF+DC port of the other biaser 12 is connected to a test antenna external to TBOX3.

[0045] During the test, the weak network tester 1 is connected between TBOX3 and the test antenna through a radio frequency cable. Due to the existing connected DC through channel 121, TBOX3 can recognize the test antenna, and TBOX3 provides DC signal feeding for the test antenna. The test antenna starts to work and receives RF signals in the environment. With the cooperation of the biaser 12, the RF signal can reach the RF receiving module of TBOX3 through the RF attenuation path of the attenuator 11, and the RF signal is accurately attenuated to the set value. The DC signal is connected to the test antenna and TBOX3 through the DC through channel 121, ensuring that the DC signal can be transmitted to the test antenna, activating the active circuit inside the test antenna, and enabling the components that require feeding of the test antenna to work normally, avoiding antenna recognition problems caused by insufficient feeding, which may lead to signals not being received from the external antenna. Therefore, the test engineer can adjust the attenuation value of the attenuator 11 to simulate weak signal scenarios in different environments, verify the communication stability and network switching performance of TBOX3 under high, medium, low, and interrupted signal strengths, and this solution has strong compatibility. For different antenna types (such as GNSS antennas, 4G, 5G antennas) and test scenarios of TBOX3, through test verification, this solution meets the design objectives in both aspects of signal accuracy attenuation and DC feeding maintenance.

[0046] The attenuator 11 is provided with a plurality of RF attenuation channels 111, and two biasers 12 are arranged in cooperation with each RF attenuation channel 111. As Figures 2-3 shown, in this embodiment, 4 RF attenuation channels 111 are provided, so 8 biasers 12 are correspondingly arranged. The TBOX3 has multiple communication methods, such as LTE, 5G, and GNSS, etc. Through the multiple RF attenuation channels 111, it is convenient to test the multiple communication methods of the TBOX3.

[0047] As Figure 2 and Figure 3 shown, it further includes a chassis housing 13. The attenuator 11 and the biasers 12 are integrated in the chassis housing 13. If only the biasers 12 are added beside the existing attenuator 11, it will cause problems such as too many connection cable routes and difficult wiring. In this application, the attenuator 11 and the biasers 12 are integrated in the chassis housing 13 to protect the attenuator 11, the biasers 12, and their connection lines. And the DC direct-through channel 121 is directly built into the chassis housing 13. Only the input and output lines of the traditional attenuator 11 need to be connected to the chassis housing 13 to connect the built-in attenuator 11 and the biasers 12, ensuring that the characteristic of the two-way attenuation of the attenuator 11 is not affected. In this embodiment, the chassis housing 13 adopts a 19-inch 1U standard chassis to ensure that the existing attenuator 11 can be installed in the chassis housing 13, and there is sufficient space to arrange the biasers 12 and their connection cables with the attenuator 11. The material of the chassis housing 13 is preferably metal, such as aluminum alloy, so that the chassis housing 13 can provide a certain electromagnetic shielding performance and reduce the influence of external electromagnetic interference on the attenuator 11.

[0048] As Figure 2 and Figure 3 shown, it further includes an external connection port 14. A plurality of external connection ports 14 are provided and arranged on the chassis housing 13. The external connection ports 14 are connected to the RF+DC ports one by one. The external connection ports 14 are respectively used to externally connect the TBOX3 and the test antenna. The attenuator 11 and the biasers 12 adopt a symmetric circuit structure, so that the RF attenuation channels 111 can perform two-way attenuation on the radio frequency signal. As Figure 2 and Figure 3 shown, 8 external connection ports 14 are provided in this application, which is the same as the number of biasers 12. There are 4 ports on the left and right respectively. The left four ports are connected to the RF+DC ports of the biasers 12 on one side, and the right four ports are connected to the RF+DC ports of the biasers 12 on the other side. Therefore, when wiring, if the left four ports are connected to the test antenna, the right four ports are connected to the TBOX3, and vice versa, realizing the function of two-way attenuation. Or the external connection ports 14 can be divided into upper four ports and lower four ports, which can conveniently guide the user to wire.

[0049] As Figure 4As shown, it also includes a combiner 2. The lower four-port is combined through the combiner 2 and then connected to the TBOX 3. The combiner 2 combines or separates multiple test signals, reducing the external lines of the TBOX 3. The upper four-port can be connected to GNSS antennas, LTE, 4G, 5G antennas, etc. The LTE, 4G, and 5G antennas can interact with the base station 4 to transmit signals.

[0050] The external port 14 is an interface of a unified model or a modular adapter. For example, Figure 2 As shown, in the embodiment of the present application, an interface with a unified signal is adopted. In addition, a modular adapter solution can also be adopted. The modular adapter uses a pluggable interface module, which can be independently plugged and unplugged for different antenna interfaces (such as the SMA interface of the GNSS antenna and the N-type interface of the 5G antenna), so as to facilitate the replacement of the interface required for testing.

[0051] For example, Figure 2 As shown, it also includes a power module 15 and a communication port 16. The power module 15 and the communication port 16 are electrically connected to the attenuator 11. The power module 15 is arranged in the chassis housing 13. The power module 15 is used to supply power to the attenuator 11 so that the attenuator 11 can work normally with power on. The communication port 16 is arranged on the chassis housing 13. The communication port 16 is used for the attenuator 11 to communicate with the outside. The communication port 16 is connected to the upper computer software to set the attenuation value of each channel, so that the attenuator 11 can attenuate the RF signal according to the external control. The communication port 16 can be a wired interface such as RJ45 and / or a wireless communication module such as a WIFI module, so that the weak network tester 1 can be connected and communicate with the upper computer software in a wired or wireless manner.

[0052] According to the disclosure and teachings of the above specification, those skilled in the art to which the present invention pertains can also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above. Some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present invention.

Claims

1. A weak network tester, characterized in that: Comprising: An attenuator having an RF attenuation channel for attenuating an RF signal; A bias unit, two bias units are correspondingly provided for one RF attenuation channel, the RF ports of the two bias units are connected to both ends of the RF attenuation channel, the DC ports of the bias units are interconnected to form a DC direct-through channel, and the RF+DC ports of the bias units are respectively used for inputting or outputting RF+DC signals.

2. A weak network tester, characterized in that: Comprising: An attenuator having an RF attenuation channel for attenuating an RF signal; A bias unit, two bias units are correspondingly provided for one RF attenuation channel, the RF ports of the two bias units are connected to both ends of the RF attenuation channel, the DC ports of the bias units are interconnected to form a DC direct-through channel, and the RF+DC ports of the bias units are respectively used for inputting or outputting RF+DC signals, wherein the RF+DC port of one of the bias units is connected to the TBOX, and the RF+DC port of the other bias unit is connected to a test antenna external to the TBOX.

3. The weak network tester according to claim 1 or 2, characterized in that: The attenuator is provided with a plurality of RF attenuation channels, and two bias units are correspondingly provided for each RF attenuation channel.

4. The weak network tester according to claim 1 or 2, characterized in that: The DC direct-through channel adopts a high-frequency isolation design to suppress the mutual interference between the RF signal and the DC signal during common-path transmission.

5. The weak network tester according to claim 2, wherein: It further includes a chassis housing, and the attenuator and the bias unit are integrated in the chassis housing.

6. The weak network tester according to claim 5, wherein: It further includes external ports, a plurality of external ports are provided and arranged on the chassis housing, the external ports are connected to the RF+DC ports in a one-to-one correspondence, and the external ports are respectively used for externally connecting the TBOX and the test antenna.

7. The weak network tester according to claim 6, characterized in that: It further includes a combiner, and a plurality of the external ports are combined through the combiner and then connected to the TBOX.

8. The weak network tester according to claim 6, wherein: The external ports are interfaces of a unified model or modular adapters.

9. The weak network tester according to claim 1 or 2, characterized in that: The attenuator and the bias unit adopt a symmetric circuit structure, so that the RF attenuation channel can attenuate the radio frequency signal bidirectionally.

10. The weak network tester according to claim 5, wherein: It further includes a power supply module and a communication port, the power supply module and the communication port are electrically connected to the attenuator, the power supply module is arranged in the chassis housing, the power supply module is used for supplying power to the attenuator, the communication port is arranged on the chassis housing, and the communication port is used for the attenuator to communicate and interact with the outside.

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