Double-frequency single-port intermodulation tester

Abstract

The invention provides a dual-frequency single-port intermodulation tester, and the tester comprises an intermodulation control module which comprises an intermodulation controller, a first frequency source and a second frequency source, and the intermodulation controller controls the first frequency source and the second frequency source to generate two carrier signals with different frequencies through receiving a configuration instruction; and the multiplexer module comprises a plurality of power amplifier modules and a multiplexer, the plurality of power amplifier modules are used for amplifying the two paths of carrier signals, synthesizing the two paths of carrier signals through the multiplexer, outputting the synthesized two paths of carrier signals to a tested piece, and receiving and processing intermodulation products reflected back from the tested piece at the same time. According to the invention, the accuracy, the integration level and the field applicability of the intermodulation test are effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of mobile communication technology, and specifically relates to a dual-frequency single-port intermodulation tester. Background Technology

[0002] With the rapid development of mobile communication technology, communication systems are constantly evolving towards higher frequency bands, multiple frequency bands, and higher power. Especially in 4G, 5G, and subsequent mobile communication systems, base station antenna systems, combiners, power dividers, filters, and various passive radio frequency (RF) connection devices are widely used in network deployment. Under the influence of high-power RF signals, these passive devices are prone to passive intermodulation (PIM) if they have material defects, poor contact, oxidation corrosion, or mechanical stress. PIM generates interference signals in the receiving frequency band, affecting the receiving sensitivity of the communication system, reducing system capacity, and in severe cases, even leading to a decline in base station coverage quality. Therefore, passive intermodulation testing of communication passive devices has become a crucial part of network construction and maintenance.

[0003] Existing passive intermodulation testing techniques typically employ a dual-frequency excitation method, where two carrier signals of different frequencies are simultaneously injected into the device under test (DUT). Under the nonlinear influence of the DUT, third-order and fifth-order intermodulation products are generated, and the resulting intermodulation signals are then detected and analyzed. Traditional test equipment often uses a discrete structure, such as separately configuring the dual-frequency signal source, power amplifier, combiner, and receiver modules, which are then combined via external RF cables. While this structure can perform basic intermodulation testing, it suffers from problems such as structural complexity, large size, cumbersome field connections, numerous interfaces, and significant signal link loss.

[0004] Furthermore, under high-power conditions, if there is poor isolation or superposition effect of nonlinear devices during the amplification or combining stages of the dual-frequency signals, residual intermodulation components can easily be generated within the equipment. These intermodulation signals generated by the equipment itself may superimpose with the intermodulation signals generated by the device under test (DUT), leading to deviations in test results and affecting test accuracy and reliability. Therefore, how to reduce the system's own intermodulation interference while ensuring high-power dual-frequency output is a significant technical challenge facing existing technologies.

[0005] On the other hand, traditional dual-port intermodulation test structures typically have separate transmit and receive ports, which not only increases the number of RF interfaces but also raises structural complexity and cost. For field testing, equipment often needs to be portable, rapidly deployable, and operable by a single person. Existing split or multi-port structures have shortcomings in practical applications, such as large size, heavy weight, and limited power supply options, which are not conducive to field maintenance and network optimization.

[0006] Meanwhile, with the increasing number of communication frequency bands, test equipment needs to support rapid switching and flexible configuration across different bands. If the internal frequency source or power amplifier path structure is fixed, switching bands may require replacing modules or reconnecting lines, which not only reduces test efficiency but may also affect test consistency. Therefore, achieving stable output of dual-frequency signals and adaptive band switching is also a key factor in improving the practicality of test equipment.

[0007] In summary, existing passive intermodulation testing equipment still has certain shortcomings in terms of structural integration, system self-intermodulation suppression capability, frequency band switching flexibility, and field applicability. There is an urgent need to provide a dual-frequency single-port intermodulation testing device that is compact, has stable dual-frequency output, performs single-port reflective testing, and can reduce residual intermodulation interference in the system, so as to meet the needs of modern communication system construction and maintenance. Summary of the Invention

[0008] The primary objective of this invention is to solve the aforementioned problems by providing a dual-frequency single-port intermodulation tester.

[0009] To achieve the various objectives of this invention, the following technical solution is adopted: A dual-frequency single-port intermodulation tester includes: The intermodulation control module includes an intermodulation controller, a first frequency source, and a second frequency source. The intermodulation controller controls the first frequency source and the second frequency source to generate two carrier signals of different frequencies respectively by receiving configuration instructions. The multiplexer module includes multiple power amplifier modules and a multiplexer. The multiple power amplifier modules are used to amplify the two carrier signals and combine the two carrier signals through the multiplexer before outputting them to the device under test. At the same time, the multiple power amplifier modules receive and process the intermodulation products reflected back from the device under test.

[0010] Preferably, the plurality of power amplifier modules include a first to a fourth power amplifier module; the first frequency source and the second frequency source respectively have a first output port and a second output port; when the configuration command selects a first frequency band, the first output port of the first frequency source is connected to the first power amplifier module, and the first output port of the second frequency source is connected to the second power amplifier module; when the configuration command selects a second frequency band, the second output port of the first frequency source is connected to the third power amplifier module, and the second output port of the second frequency source is connected to the fourth power amplifier module.

[0011] Preferably, the plurality of power amplifier modules are respectively connected to the transmit port of the multiplexer, so as to amplify the two carrier signals through the plurality of power amplifier modules and then combine them with the help of the multiplexer before outputting them to the device under test from a single radio frequency port.

[0012] More preferably, the intermodulation control module further includes a frequency converter and a digital receiver; the multiplexer module further includes a receiver; the multiplexer has a receiving port connected to the receiver to filter and amplify the intermodulation products and output them to the frequency converter and digital receiver, the frequency converter and digital receiver being used to perform frequency conversion, filtering and amplification of the intermodulation products and sampling analysis to extract intermodulation values ​​of at least third-order, fifth-order, seventh-order, and ninth-order passive intermodulation products.

[0013] A signal is coupled to the output of the plurality of power amplifier modules for power detection, and the detected data is transmitted to the intermodulation controller to monitor the carrier power in real time.

[0014] Preferably, the system further includes a display and control module for displaying test configuration parameters and test results during the operation of the intermodulation control module. More preferably, the display and control module includes an LCD touchscreen display and a control unit; the LCD touchscreen display displays parameters, including at least two carrier frequencies, output power, and intermodulation order, and the control unit generates configuration commands by operating the LCD touchscreen display and sends them to the intermodulation control module.

[0015] In addition, the display and control module is connected to the intermodulation controller via an FPC cable to enable communication of configuration commands and feedback of intermodulation test results.

[0016] Preferably, it further includes: a battery and power supply module, which includes an external adapter, an internal lithium battery, an automatic switching circuit and an internal power supply module, wherein the internal power supply module is used to regulate the voltage of the internal lithium battery and the voltage of the external adapter and then supply power to each module.

[0017] Compared with existing technologies, the present invention has many advantages, including but not limited to: In the technical solution described in this invention, the intermodulation control module receives configuration commands through the intermodulation controller and controls the first and second frequency sources to generate two carrier signals respectively. Since the two carriers are generated independently by different frequency sources and output under the unified scheduling of the controller, the carrier frequency setting and output state switching can be linked with the test frequency band selection (e.g., selecting the corresponding output path under different frequency bands), thereby achieving stable output and independent adjustment of the dual-frequency signals. This better adapts to the intermodulation testing needs of different frequency band devices / antenna systems in the field, avoiding the problems of decreased test consistency and operational complexity caused by the need to replace external modules or rewire due to frequency band switching in traditional solutions.

[0018] Furthermore, this invention combines two carrier waves using a multiplexer and outputs them to the device under test (DUT) via a single port. Simultaneously, the same multiplexer receives and processes the intermodulation products reflected from the DUT, forming a single-port reflective link for both transmission and reception. On one hand, this structure reduces the number of RF interfaces and external connections, minimizing errors in field operation and port switching. On the other hand, the multiplexer provides necessary channel isolation during combining and retrieval, enabling effective separation and acquisition of the transmitted and retrieved intermodulation signals even under the same port conditions. This achieves reflective intermodulation detection within a compact structure. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a system principle block diagram of a dual-frequency single-port intermodulation tester according to a typical embodiment of the present invention.

[0020] Figure 2 This is a flowchart of a passive intermodulation testing method according to a typical embodiment of the present invention. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0022] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or components, nor does it exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or wireless coupling. The term “and / or” as used herein includes all or any units and all combinations of one or more associated listed items.

[0023] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0024] The following is combined with Figure 1 The specific embodiments of the present invention will be described in detail below. Those skilled in the art should understand that the following embodiments are only used to illustrate the technical concept and implementation of the present invention, and are not intended to limit the scope of protection of the present invention.

[0025] In a typical embodiment of the present invention, a dual-frequency single-port intermodulation tester 100 is provided. This tester is used to perform reflective passive intermodulation testing on passive communication devices under high-power dual-frequency excitation conditions. The tester as a whole includes an intermodulation control module 2, a multiplexer module 3, a display and control module 1, and a battery and power supply module 4. The display and control module 1 and the battery and power supply module 4 are optional modules.

[0026] According to a preferred embodiment, the intermodulation control module 2 includes an intermodulation controller 201, a first frequency source 202, a second frequency source 203, and a frequency converter and digital receiver 204. Here, the intermodulation controller 201 can be any suitable type of device, such as an embedded microprocessor, a DSP processor, an FPGA logic control unit, or a combination thereof, thereby enabling high-speed digital signal control, frequency scheduling, power control, data acquisition, and algorithm processing.

[0027] In one embodiment, the first frequency source 202 and the second frequency source 203 are independent radio frequency synthesized signal source modules. Their internal structure may include a phase-locked loop (PLL) circuit, a voltage-controlled oscillator (VCO), a frequency divider, electrically adjustable attenuator, an RF switch, a low-noise amplifier circuit, and a filter circuit. The frequency sources have low phase noise characteristics to reduce the impact of frequency domain jitter on intermodulation detection accuracy. The first and second frequency sources generate frequencies F1 and F2 respectively, and the interval between the two frequencies can be set according to the test standard.

[0028] Because the two signals use independent frequency source structures, the phase coupling problem present in traditional single-source frequency division structures can be avoided, reducing modulation errors from the source. Furthermore, unified control via an intermodulation controller enables synchronous dual-frequency output and amplitude consistency adjustment, improving test stability.

[0029] In a preferred embodiment, the first frequency source 202 and the second frequency source 203 each have multiple output ports. For example, the first output port out1 is set for a first frequency band, and the second output port out2 is set for a second frequency band. Each output port can correspond to a different RF matching network or filtering network to ensure the output matching characteristics of different frequency bands.

[0030] Specifically, when the first frequency band is selected, the first output port out1 of the first frequency source 202 is connected to the first power amplifier module 301, and the first output port out1 of the second frequency source 203 is connected to the second power amplifier module 302. When the second frequency band is selected, the second output port out2 of the first frequency source 202 is connected to the third power amplifier module 303, and the second output port out2 of the second frequency source 203 is connected to the fourth power amplifier module 304. This matching structure between the frequency band and the power amplifier path ensures power amplification efficiency and output linearity across different frequency bands.

[0031] It should be noted that the number of power amplifier modules can be flexibly adjusted according to actual application requirements. For example, more power amplifier modules can be added in a multi-band system to accommodate more frequency bands; in a simplified version, two broadband power amplifier modules combined with an RF switch structure can also be used to achieve frequency band selection. Therefore, this invention is not limited to a structure of four power amplifier modules.

[0032] In a preferred embodiment, power amplifier modules 301-304 may employ a high-linearity RF power amplifier topology. The power amplifier may use LDMOS power transistors. A high-linearity Class AB structure is preferred to balance efficiency and linearity. To reduce residual intermodulation, the power amplifier modules may employ a multi-stage amplification structure, including a driver stage, a power stage, and an output matching network, and include linear compensation circuitry to reduce distortion.

[0033] Each power amplifier module preferably has a directional coupler at its output to couple a portion of the RF power for power detection. The coupled signal is converted into a voltage signal by a detector and then sent to the intermodulation controller 201 for real-time power monitoring. Through a closed-loop control algorithm, the intermodulation controller can fine-tune the power amplifier gain to ensure constant output power.

[0034] The outputs of multiple power amplifier modules are respectively connected to the transmit ports TX1, TX2, TX3, and TX4 of the multiplexer 306. In one embodiment, the multiplexer 306 may employ a high-isolation RF duplexer or multiplexer structure. Internally, it may include bandpass filters and matching networks. Preferably, the isolation between each path is sufficiently high to avoid coupling between different frequency paths.

[0035] Here, the multiplexer 306 combines two high-power carrier signals and outputs them to the device under test (DUT) through a single RF port. The single-port structure preferably uses a high-power DIN-type RF interface. This single-port design allows for a shared interface between the transmit and receive paths, reducing the number of external connection cables and improving device portability.

[0036] In the reflective receiving path, multiplexer 306 also has a receive port RX. The reflected intermodulation signal enters receiver 305 through a filtering path inside the multiplexer. Receiver 305 may include a low-noise amplifier (LNA), a bandpass filter, and an adjustable gain amplifier to improve the signal-to-noise ratio.

[0037] Subsequently, the intermodulation signal enters the frequency converter and digital receiver 204. This receiver may include a superheterodyne structure signal that has been down-converted and then entered into an analog-to-digital converter (ADC) to convert it into a digital signal. The digital signal processing unit performs Fast Fourier Transform (FFT) analysis on the signal to calculate the amplitude of each order of intermodulation components.

[0038] In a preferred embodiment, the system supports automatic identification and measurement of third-, fifth-, seventh-, and ninth-order intermodulation. The system also supports spectrum display, noise floor measurement, and frequency sweep analysis.

[0039] Preferably, the display and control module 1 includes an LCD touch screen and a control unit. The display screen is a high-brightness LCD screen that supports touch operation. Users can input parameters such as F1 and F2 frequencies, output power, and test modes through the interface. The display and control module communicates with the intermodulation controller via an FPC cable to achieve data interaction.

[0040] The battery and power supply module 4 includes an external adapter, an internal lithium battery, an automatic switching circuit, and an internal power supply module. Here, the internal power supply module is used to regulate the voltage of the internal lithium battery and the voltage of the external adapter to appropriate voltages, and then supply them to the aforementioned modules.

[0041] Through the above structure, the present invention not only achieves dual-frequency high-power output and multi-order intermodulation detection, but also significantly reduces the residual intermodulation of the system itself and improves the test accuracy through the high linearity power amplifier structure, high isolation multiplexer structure and closed-loop power control structure.

[0042] Furthermore, each module adopts a modular design. For example, the intermodulation control module and multiplexer module described in the above embodiments can be replaced or expanded according to different application scenarios, thereby achieving different frequency band coverage and power levels.

[0043] The working process of the dual-frequency single-port intermodulation tester of the present invention is described below.

[0044] The dual-frequency single-port intermodulation tester of the present invention first enters the initialization process after power-on: the display and control module 1 (in one embodiment, it can be a combination of a touch screen and a control unit) completes self-test and establishes a communication link with the intermodulation control module 2; the intermodulation controller 201 in the intermodulation control module 2 loads default operating parameters for the first frequency source 202, the second frequency source 203, and the frequency converter and digital receiver 204, and initializes the multiplexer module 3. At the same time, the battery and power supply module 4 automatically switches according to the power supply status of the external adapter or the built-in lithium battery, providing the power amplifier operating voltage (e.g., +28V) for the power amplifier link of the multiplexer module 3, and providing the digital operating voltage (e.g., +6V) for the intermodulation control module 2 and the display and control module 1, so as to ensure that the whole machine can work stably in portable or external power supply scenarios.

[0045] After the user sets parameters such as the test frequency band, two carrier frequencies, output power, and intermodulation order through the display and control module 1, the display and control module 1 sends the configuration command to the intermodulation controller 201 of the intermodulation control module 2. The intermodulation controller 201 then controls the first frequency source 202 and the second frequency source 203 to generate two carrier signals of different frequencies, and selects the corresponding output port according to the selected frequency band: for example, during testing in the 700 MHz band, the first frequency source 202 outputs a carrier from the first output port out1 and sends it to the power amplifier 301, while the second frequency source 203 outputs a carrier from the first output port out1 and sends it to the power amplifier 302; during testing in the 1800 MHz band, the first frequency source 202 outputs a carrier from the second output port out2 and sends it to the power amplifier 303, while the second frequency source 203 outputs a carrier from the second output port out2 and sends it to the power amplifier 304. To avoid out-of-band coupling and the introduction of residual intermodulation, in any test configuration, only the two power amplifier channels (301 / 302 or 303 / 304) corresponding to the currently selected frequency band are enabled, while the other power amplifier channels are kept off or RF isolated.

[0046] Subsequently, the two carrier waves are amplified by the corresponding power amplifier modules (301-304) within the multiplexer module 3. The amplified RF signals are then input through the transmit ports TX1-TX4 of the multiplexer 306, and combined by the multiplexer 306 to form a dual-frequency test signal, which is then output to the device under test from a single RF output port (e.g., a DIN RF output interface). Simultaneously, the coupled detector signal at the power amplifier output can be fed back to the intermodulation controller 201 of the intermodulation control module 2 for real-time monitoring of the output power status of the two carrier waves, thus providing a basis for transmit power consistency verification, power stability recording, or power correction.

[0047] The intermodulation products and reflected echoes generated by the device under test under dual-frequency excitation return from the same RF port. They first enter the multiplexer 306 in the multiplexer module 3, where the internal transmit / receive separation and filtering path guides the reflected signal to the receiving path RX. The intermodulation signal after transmit / receive separation enters the receiver 305 for filtering, amplification, and gain adjustment, and is then output to the frequency converter and digital receiver 204 in the intermodulation control module 2 to complete down-conversion, sampling, and digitization processing, resulting in a digital signal that can be used for intermodulation spectral analysis.

[0048] Subsequently, the intermodulation controller 201 of the intermodulation control module 2 combines the transmission frequency point information of the first frequency source 202 and the second frequency source 203 with the preset intermodulation order to perform frequency domain analysis and amplitude extraction on the data output by the frequency converter and digital receiver 204, and obtains the power / level results of the intermodulation products of the target order (e.g., third order, fifth order, seventh order, ninth order, etc.), and sends the intermodulation test results and necessary status information back to the display and control module 1 for display, storage and report export.

[0049] In the above embodiments of the present invention, a dual-frequency single-port reflective intermodulation test structure is adopted, which organizes the generation, amplification, combining output, echo reception, and resolution of two carrier waves into a closed signal link. Since the transmitted signal and intermodulation products share the same RF port for injection and reception, only one connection is needed in the field to complete the intermodulation test of the same device under test at different frequency bands. This avoids the time consumption and connection uncertainty caused by repeated plugging and unplugging and replacing external connectors / splitters in different frequency bands or ports, as required by traditional solutions. This improves the consistency and retest stability of field testing.

[0050] Furthermore, this invention highly integrates the power amplifier link, transceiver combining / splitting, and receiver front-end in its structure, resulting in shorter RF links, fewer connection points, and fewer external interconnecting devices. Intermodulation testing is extremely sensitive to any nonlinearity in the link. Traditional discrete structures often require multiple RF jumpers and multiple connecting devices to complete combining and transceiver separation. These external connections and devices themselves can become significant sources of residual intermodulation and introduce additional insertion loss. Through integrated design, reduced link insertion loss makes the dual-frequency signal reaching the device under test more stable, and the transmission loss of echo intermodulation products is lower. At the same time, fewer connection points reduce the probability of the system itself generating intermodulation. The combination of these two factors can improve the effective signal-to-noise ratio and resolvability of the receiver under the same transmit power conditions, thereby improving the sensitivity and repeatability of intermodulation detection results.

[0051] Furthermore, this invention also provides a passive intermodulation testing method, which is implemented based on a dual-frequency single-port intermodulation tester 100. (See reference) Figure 2 The method includes steps such as parameter configuration, dual-frequency signal generation, high-power amplification and combining, reflective intermodulation reception, and digital analysis and display. A detailed description follows: In step S1, test parameters are first set and configuration instructions are generated. Specifically, the user inputs test parameters, including carrier frequency F1, carrier frequency F2, output power level, and intermodulation order, through the LCD touch screen of the display and control module 1.

[0052] In one embodiment, the interval between carrier frequencies F1 and F2 can be set according to industry standards or field testing requirements, such as a fixed frequency difference or a configuration based on a specific bandwidth. The output power can be set to, for example, 2 × 43 dBm or other power levels to meet high-power passive intermodulation testing requirements. The intermodulation order can be set to third, fifth, seventh, ninth, etc., to specify the type of intermodulation components to be analyzed. The control unit within the display and control module 1 generates corresponding configuration commands based on user input and transmits them to the intermodulation control module 2 via an FPC cable.

[0053] In step S2, the intermodulation controller 201 receives the configuration command and controls the first frequency source 202 and the second frequency source 203 to output the first carrier signal and the second carrier signal respectively according to the configuration. Preferably, the first carrier signal corresponds to frequency F1, and the second carrier signal corresponds to frequency F2. Since the two frequency sources adopt independent structures, they can perform frequency synthesis and power adjustment separately, thereby ensuring the frequency stability and amplitude consistency of the dual-frequency excitation signal. Subsequently, the two carrier signals enter the corresponding power amplifier modules in the multiplexer module 3 for power amplification. Preferably, the power amplifier module adopts a high-linearity RF power amplifier topology, such as an LDMOS power transistor structure, to reduce nonlinear distortion during the amplification stage. During the amplification process, the coupling signal can be extracted by a power coupler for power detection, and the detection data is fed back to the intermodulation controller 201 in real time to achieve closed-loop power regulation and ensure the stability of the output power of the two carriers.

[0054] According to a preferred embodiment, the configuration command is further used to select a first frequency band or a second frequency band. When the configuration command selects the first frequency band (e.g., the 700MHz band), the intermodulation controller 201 controls the first frequency source 202 to drive the first power amplifier module 301 via the first output port out1, and the second frequency source 203 to drive the second power amplifier module 302 via the first output port out1; when the configuration command selects the second frequency band (e.g., the 1800MHz band), the first frequency source 202 drives the third power amplifier module 303 via the second output port out2, and the second frequency source 203 drives the fourth power amplifier module 304 via the second output port out2. This frequency band and power amplifier path matching mechanism ensures power amplification efficiency and output matching performance during testing at different frequency bands.

[0055] In step S3, the two carrier signals amplified by the power amplifier module are combined using multiplexer 306. Specifically, the output ports of power amplifier modules 301, 302, 303, and 304 are connected to the transmit ports TX1, TX2, TX3, and TX4 of multiplexer 306, respectively. Multiplexer 306 may include a filter network and a high isolation structure to ensure sufficient isolation between the paths, thereby reducing coupling interference between paths. After the two high-power carrier signals are combined inside multiplexer 306, they are output to the device under test from a single RF output interface. This single-port output structure preferably uses a high-power RF interface, such as a DIN type interface, to ensure good matching characteristics and low insertion loss under high power conditions.

[0056] In step S4, after the dual-frequency high-power signal is injected into the device under test (DUT), the DUT generates intermodulation products under nonlinear effects. These intermodulation products are reflected back into the test instrument via the same RF port. The reflected intermodulation signal first enters the receiving path through the receiving port RX of the multiplexer 306. The filtering path inside the multiplexer effectively isolates the transmitted and received signals to ensure accurate extraction of the intermodulation signal. Subsequently, the intermodulation signal enters the receiver 305. The receiver 305 may include a low-noise amplifier (LNA), a bandpass filter, and an adjustable gain amplifier to filter and amplify the intermodulation products, thereby improving the signal-to-noise ratio and suppressing out-of-band interference.

[0057] In step S5, the intermodulation signal processed by receiver 305 is sent to frequency converter and digital receiver 204. Frequency converter and digital receiver 204 can employ a superheterodyne structure or a direct frequency conversion structure. Preferably, the intermodulation signal is first converted to an intermediate frequency or baseband signal by an RF downconversion circuit, then bandwidth-limited by an analog filtering unit, and subsequently digitally sampled by an analog-to-digital converter. The sampled digital signal is then subjected to spectral analysis by a digital signal processing unit, for example, by using a Fast Fourier Transform (FFT) algorithm to extract spectral components and calculate the intermodulation values ​​of the corresponding orders. In a preferred embodiment, the amplitude values ​​of third-order, fifth-order, seventh-order, and ninth-order intermodulation components can be extracted and expressed in dBc or dBm. It should be noted that this invention does not limit the order of intermodulation; those skilled in the art can select the order to be analyzed according to actual needs.

[0058] After the analysis is completed, the intermodulation test results are transmitted back from the intermodulation control module 2 to the display and control module 1 via an FPC cable. On the display and control module 1, the test results can be displayed in real time as curves, such as a spectrum diagram showing each order of intermodulation components; simultaneously, specific intermodulation values ​​can also be displayed numerically. Preferably, the test results can be refreshed on the screen in real time so that the user can dynamically observe the test changes.

[0059] In an optional embodiment, the intermodulation test results can also be stored as TXT or XLS format files and saved in the device's internal storage unit. Users can generate test reports in PDF or JPEG format from the test data and export them via USB interface for subsequent analysis or archiving management.

[0060] Furthermore, in a preferred embodiment, the coupled detection data at the output of the power amplifier module is transmitted to the intermodulation controller 201 via an FPC cable for real-time monitoring of the carrier power. If a power deviation from the set value is detected, the intermodulation controller can automatically adjust the frequency source output amplitude or the power amplifier gain to maintain a stable output, thereby ensuring the accuracy of the intermodulation test results.

[0061] Through the above steps, the method of this invention realizes a complete test process from parameter setting, dual-frequency excitation generation, high-power amplification and combining, reflective intermodulation reception, digital analysis to result display and data export. This method not only ensures stable dual-frequency high-power output but also enables multiplexing of the transmit and receive paths through a single-port structure, thereby improving system integration and reducing field connection errors. Simultaneously, the extraction of multi-order intermodulation components through digital signal processing algorithms improves test accuracy and reliability.

[0062] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention is not limited to the specific combination of the above-described technical features, but also includes other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions as those in the present invention.

[0063] Although the subject matter has been described using language specific to structural features and / or methodological logic, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are merely illustrative examples of implementing the claims.

Claims

1. A dual-frequency single-port intermodulation tester, characterized in that... include: An intermodulation control module includes an intermodulation controller, a first frequency source, and a second frequency source. The intermodulation controller controls the first frequency source and the second frequency source to generate two carrier signals of different frequencies respectively by receiving configuration instructions. and The multiplexer module includes multiple power amplifier modules and a multiplexer. The multiple power amplifier modules are used to amplify the two carrier signals and combine the two carrier signals through the multiplexer before outputting them to the device under test. At the same time, the multiple power amplifier modules receive and process the intermodulation products reflected back from the device under test.

2. The dual-frequency single-port intermodulation tester according to claim 1, characterized in that: The plurality of power amplifier modules include a first to a fourth power amplifier module; the first frequency source and the second frequency source each have a first output port and a second output port; when the configuration command selects a first frequency band, the first output port of the first frequency source is connected to the first power amplifier module, and the first output port of the second frequency source is connected to the second power amplifier module; when the configuration command selects a second frequency band, the second output port of the first frequency source is connected to the third power amplifier module, and the second output port of the second frequency source is connected to the fourth power amplifier module.

3. The dual-frequency single-port intermodulation tester according to claim 1, characterized in that: The multiple power amplifier modules are respectively connected to the transmit port of the multiplexer, so as to amplify the two carrier signals through the multiple power amplifier modules and then combine them with the multiplexer before outputting them to the device under test from a single radio frequency port.

4. The dual-frequency single-port intermodulation tester according to claim 1, characterized in that: The intermodulation control module further includes a frequency converter and a digital receiver; the multiplexer module further includes a receiver; the multiplexer has a receiving port connected to the receiver to filter and amplify the intermodulation products and output them to the frequency converter and digital receiver; the frequency converter and digital receiver is used to frequency-convert, filter, and amplify the intermodulation products and sample and analyze them to extract the intermodulation values ​​of at least third-order, fifth-order, seventh-order, and ninth-order passive intermodulation products.

5. The dual-frequency single-port intermodulation tester according to claim 1, characterized in that: A signal is coupled to the output of the plurality of power amplifier modules for power detection, and the detected data is transmitted to the intermodulation controller to monitor the carrier power in real time.

6. The dual-frequency single-port intermodulation tester according to claim 1, characterized in that... Further includes: The display and control module is used to display the test configuration parameters and test results when the intermodulation control module is running.

7. The dual-frequency single-port intermodulation tester according to claim 6, characterized in that: The display and control module includes an LCD touch screen and a control unit; the LCD touch screen is used to display parameters, which include at least two carrier frequencies, output power and intermodulation order, and the control unit generates configuration commands by operating the LCD touch screen and sends them to the intermodulation control module.

8. The dual-frequency single-port intermodulation tester according to claim 7, characterized in that: The display and control module is connected to the intermodulation controller via an FPC cable to enable communication of configuration commands and feedback of intermodulation test results.

9. The dual-frequency single-port intermodulation tester according to claim 1, characterized in that... Further includes: The battery and power supply module includes an external adapter, an internal lithium battery, an automatic switching circuit, and an internal power supply module. The internal power supply module is used to regulate the voltage of the internal lithium battery and the voltage of the external adapter and then supply power to each module.

10. The dual-frequency single-port intermodulation tester according to claim 9, characterized in that: The automatic switching circuit is configured to automatically switch between the external adapter and the internal lithium battery, and to manage the charging of the internal lithium battery.

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