System and method for testing output linearity of broadband radio frequency radiation unit

Abstract

The invention provides a broadband radio frequency radiation unit output linearity test system and method, relates to the technical field of radio frequency microwave measurement, and solves the limitation problems of low system debugging efficiency, difficult spectrum quality regulation and control and the like in the prior art. The system comprises a signal generation device, a spectrum analysis device, a power attenuation device, a control device and a connection device, and the control device is configured to control output parameters of the signal generation device, attenuation parameters of the power attenuation device and working parameters of the spectrum analysis device and send a control instruction to a tested broadband radio frequency radiation unit. The attenuation state of an internal power regulation unit and the conduction path of an internal signal selection unit are regulated; and the connecting device constructs a radio frequency link between a preset monitoring point in the tested broadband radio frequency radiation unit and the input end of the spectrum analysis device through the radio frequency transmission line. The method effectively improves the final output frequency spectrum quality of the system, shortens the debugging period of the system, and is beneficial to batch production and maintenance.

Description

Technical Field

[0001] This invention relates to the field of radio frequency microwave measurement technology, and specifically to a system and method for testing the output linearity of a broadband radio frequency radiation unit. Background Technology

[0002] As a key component of modern wireless communication systems, the performance of the broadband radio frequency radiating unit directly affects signal transmission quality and system reliability. This unit typically comprises multiple functional modules, covering small-signal amplification, frequency conversion, intermediate-power amplification, and final-stage power amplification. Under ideal operating conditions, each amplifier stage must strictly maintain its linear region to ensure stable gain for the main signal while effectively suppressing harmonics and spurious components. At this point, the system output spectrum exhibits high purity, and harmonic suppression capability reaches its optimal level, providing a high-quality signal foundation for subsequent radiating stages.

[0003] In engineering design, gain allocation often includes adjustment margins to address the variability of device parameters and environmental fluctuations. However, in actual operation, if an amplifier stage enters the nonlinear saturation region due to factors such as abnormal input levels, temperature drift, or device aging, it will cause compression of the main signal gain, while harmonics and spurious components are significantly amplified due to nonlinear effects. This distortion, after subsequent cascaded amplification, severely degrades the overall output spectrum characteristics, reduces the harmonic rejection ratio, and makes it difficult to meet specification requirements for radiated signal purity, thereby affecting the stability and anti-interference capability of the communication link.

[0004] Current testing methods for RF link linearity have significant limitations. For the front-end small-signal amplification stage, scattering parameters and linearity can be evaluated under low-power conditions using a vector network analyzer. However, when the signal flows through the frequency conversion module, the frequency conversion characteristics make it difficult to directly trace the source using traditional frequency domain measurement methods. Furthermore, when the mid-to-high power stages involve medium-to-high power signals, the test equipment faces constraints such as insufficient dynamic range and limited power tolerance; forcibly connecting such equipment can easily lead to instrument damage or introduce measurement errors. In addition, in the cascaded operation of the system, the nonlinear effects at each stage are coupled with each other, further increasing the complexity of distortion source location and quantification evaluation.

[0005] The aforementioned testing bottlenecks make it difficult to quickly and accurately quantify the linearity of the entire output of the radiating unit during the overall debugging and production stages. Technicians often rely on experience for repeated trial-and-error adjustments, a time-consuming process with highly subjective results, making it difficult to guarantee consistency across different batches of products. This problem is particularly prominent in mass production scenarios, not only extending the debugging cycle and increasing labor costs, but also leading to ambiguous quality control standards, affecting product yield and delivery efficiency, and hindering the large-scale manufacturing and reliable application of high-performance RF equipment.

[0006] Existing technologies have significant shortcomings in the online monitoring and quantitative evaluation of the output linearity of broadband RF radiating units, especially lacking efficient and safe testing methods under frequency conversion and high-power conditions. Overcoming the limitations of traditional measurement methods and achieving convenient diagnosis and precise control of the spectrum quality under actual system operating conditions has become an urgent need to improve RF front-end design capabilities and industrialization. Summary of the Invention

[0007] The purpose of this invention is to address the difficulty in testing and evaluating the output linearity of broadband RF radiating units, which leads to low system debugging efficiency, difficulties in spectrum quality control, and challenges in ensuring consistency in mass production. Therefore, a broadband RF radiating unit output linearity testing system and method are proposed. This invention enables rapid detection of the linearity of the radiating unit link and provides effective reference values ​​for system link debugging. Practical application has effectively improved the final output spectrum quality of the system, shortened the system debugging cycle, and facilitated mass production and maintenance.

[0008] The present invention employs the following technical solutions to achieve its objective: A broadband radio frequency radiation unit output linearity testing system includes: A signal generating device is configured to generate a test radio frequency signal and provide the test radio frequency signal to the input terminal of the broadband radio frequency radiation unit under test through a radio frequency connection path; A spectrum analysis device configured to receive and analyze the spectral characteristics of radio frequency signals; A power attenuation device is connected in series in the radio frequency connection path between the output end of the broadband radio frequency radiation unit under test and the input end of the spectrum analysis device, and is used to attenuate the power of the radio frequency signal output from the output end of the broadband radio frequency radiation unit under test. The control device establishes communication connections with the control interfaces of the signal generating device, the spectrum analysis device, the power attenuation device, and the broadband radio frequency radiation unit under test, respectively. The control device is configured to control the output parameters of the signal generating device, the attenuation parameters of the power attenuation device, and the operating parameters of the spectrum analysis device, and send control commands to the broadband radio frequency radiation unit under test through the control interface to adjust the attenuation state of its internal power adjustment unit and the conduction path of its internal signal selection unit. The connection device includes a radio frequency (RF) transmission line and a control signal line. The RF transmission line is used to establish a first RF link between the signal generating device and the input terminal of the broadband RF radiation unit under test, a second RF link between a preset monitoring point inside the broadband RF radiation unit under test and the input terminal of the spectrum analysis device, and a third RF link between the output terminal of the broadband RF radiation unit under test connected through the power attenuation device and the input terminal of the spectrum analysis device. The control signal line is used to establish a control link between the control device and the control interface of the broadband RF radiation unit under test.

[0009] Specifically, the broadband RF radiation unit under test includes a front-end frequency converter module, a local oscillator module, an intermediate stage power amplifier module, a final stage power amplifier module, and at least one power control module. The power control module is located between the front-end frequency converter module and the intermediate stage power amplifier module, or between the intermediate stage power amplifier module and the final stage power amplifier module. Each power control module includes a digitally controlled attenuator, a power divider, and an RF switch. The input terminal of the digitally controlled attenuator is connected to the output terminal of the front-end module, the output terminal of the digitally controlled attenuator is connected to the input terminal of the power divider, the first output terminal of the power divider is connected to the input terminal of the rear-end module, and the second output terminal of the power divider is connected to the second RF link after passing through the RF switch.

[0010] Preferably, the control device is configured to send instructions to the broadband radio frequency radiation unit under test, control the digitally controlled attenuator in the power control module to adjust the attenuation value in a fixed step according to a preset time sequence, and synchronously control the radio frequency switch to switch the conduction state at a specified time point; the control device is also configured to control the signal generating device to output radio frequency signals of multiple test frequency points in sequence, and trigger the spectrum analysis device to perform spectrum data acquisition operation at each test frequency point.

[0011] Specifically, the connection device further includes a combiner, the multiple input terminals of which are respectively connected to the RF switch output terminals of each power control module in the broadband RF radiation unit under test, and the output terminal of the combiner is connected to the input terminal of the spectrum analysis device via an RF transmission line; the second RF link transmits the RF signals of multiple preset monitoring points inside the broadband RF radiation unit under test to the spectrum analysis device via the combiner.

[0012] Preferably, the power attenuation device is at least one of a high-power fixed attenuator, a high-power adjustable attenuator, or a directional coupler. The power capacity of the RF port of the power attenuation device is greater than or equal to the maximum continuous wave output power of the output terminal of the broadband RF radiation unit under test. The input terminal of the power attenuation device is fixedly connected to the output terminal of the broadband RF radiation unit under test through an RF connector, and the output terminal of the power attenuation device is connected to the RF input port of the spectrum analysis device via an RF cable.

[0013] This invention also provides a method for testing the output linearity of a broadband radio frequency radiation unit based on the aforementioned system, comprising the following steps: S1. The control device performs initialization operations on the signal generating device, the spectrum analysis device, and the broadband radio frequency radiation unit under test, and establishes a communication connection between the control device and the control interface of the broadband radio frequency radiation unit under test. S2. Configure the test parameter set, which includes the output frequency sequence and output power value of the signal generator, the center frequency, analysis bandwidth and scan duration of the spectrum analysis device, and the attenuation adjustment sequence of the internal power adjustment unit and the path switching instruction sequence of the internal signal selection unit in the broadband radio frequency radiation unit under test. S3. Control the signal generating device to output test radio frequency signals sequentially according to the output frequency sequence, and simultaneously control the internal power adjustment unit to adjust the attenuation value in stages within a preset time interval according to the attenuation adjustment sequence. During each stable attenuation period, control the internal signal selection unit to conduct to the specified monitoring path according to the path switching instruction sequence, so that the spectrum analysis device can obtain the spectrum data of the preset monitoring point inside the tested broadband radio frequency radiation unit through the second radio frequency link, and at the same time obtain the output spectrum data after attenuation processing by the power attenuation device through the third radio frequency link. S4. The acquired spectrum data of the internal preset monitoring points at each frequency point and the corresponding output spectrum data are associated and stored according to the test time sequence, and a test data file containing the original spectrum data and test configuration parameters is generated to complete the test.

[0014] Preferably, in step S2, the attenuation adjustment sequence includes multiple attenuation values ​​arranged in chronological order and corresponding duration periods. The attenuation values ​​increase or decrease with a preset step size, and the duration of the duration period is greater than or equal to the minimum time required for a single scan by the spectrum analysis device. The path switching instruction sequence includes sending an instruction to the broadband radio frequency radiation unit under test at the start of the duration period corresponding to each attenuation value, controlling its internal radio frequency switch to switch to the port connection state matching the current test stage.

[0015] Specifically, in step S3, for each test frequency point, the following operations are performed: the spectrum analysis device is controlled to set the center frequency to the peak frequency position of the current input signal, the analysis bandwidth is set to 0Hz, and the scan time is set to a fixed duration that matches the duration of a single attenuation value in the attenuation adjustment sequence; during the execution of the attenuation adjustment sequence, the spectrum analysis device continuously collects spectrum amplitude data according to the set parameters.

[0016] Specifically, in step S3, when collecting spectrum data of the internal preset monitoring point, the RF switch inside the broadband RF radiation unit under test is controlled to be turned on to the port connected to the second output terminal of the power divider, so that the monitoring signal is transmitted to the spectrum analysis device via the second RF link; when collecting spectrum data of the output terminal of the broadband RF radiation unit under test, the RF switch is controlled to switch to the path connected to the output terminal of the final stage power amplifier, and the attenuation value of the power attenuation device is set to a preset fixed value, so that the attenuated output signal is transmitted to the spectrum analysis device via the third RF link.

[0017] Preferably, in step S4, after storing the data according to the test time sequence, the method further includes: arranging the spectrum data of the internal preset monitoring points according to the attenuation value time sequence to generate a first spectrum amplitude sequence curve; arranging the spectrum data of the output end of the broadband radio frequency radiation unit under test according to the same attenuation value time sequence to generate a second spectrum amplitude sequence curve; aligning the first spectrum amplitude sequence curve and the second spectrum amplitude sequence curve in time sequence, and generating a spectrum data chart containing a hyperbola comparison relationship in a superimposed or parallel manner; and incorporating the spectrum data chart into the test data file.

[0018] In summary, due to the adoption of this technical solution, the beneficial effects of this invention are as follows: This invention effectively overcomes the technical bottleneck of directly evaluating the linearity of the RF link under frequency conversion and high-power conditions, realizing full-process linearity testing of broadband RF radiation units in real-world operating conditions. The testing procedure is simple and standardized, requiring no equipment disassembly or interruption of the normal signal link, significantly reducing the testing threshold and the risk of human intervention. The spectrum analysis results are presented intuitively as time-series correlated step curves, clearly reflecting the dynamic relationship between input power changes and responses at each stage, clearly revealing the nonlinear operating point and distortion characteristics.

[0019] This invention, by synchronously acquiring spectral data from key internal nodes and the final output, and performing timing alignment and comparative analysis, can accurately pinpoint the specific modules in the link that cause linearity degradation, providing clear quantitative basis and adjustment direction for system debugging. The automated testing process supports multi-frequency scanning and dynamic adjustment of attenuation sequences, significantly improving testing efficiency and data consistency. In mass production, this invention establishes a standardized linearity verification process, effectively ensuring batch stability of product performance and factory quality reliability. Simultaneously, this invention is also applicable to field maintenance and fault diagnosis scenarios, providing practical technical support for the full lifecycle quality control of RF equipment, significantly enhancing the maintainability and engineering application adaptability of related systems. Attached Figure Description

[0020] The present invention is described in detail with reference to the following figures, which include five figures as follows: Figure 1 This is a schematic diagram showing the specific composition and connection relationship of the broadband radio frequency radiation unit output linearity test system of the present invention. Figure 2 This is a schematic diagram illustrating the specific process of the broadband radio frequency radiation unit output linearity test method of the present invention. Figure 3 This is a schematic diagram illustrating the working timing and attenuation control of an example of the present invention; Figure 4 This is a schematic diagram of the output spectrum of an example of the present invention; Figure 5 This is a schematic diagram illustrating the saturation region in the output spectrum of an example of the present invention. Detailed Implementation

[0021] 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, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] Example 1 A broadband radio frequency radiation unit output linearity testing system includes: The signal generating device is configured to generate a test radio frequency signal and provide the test radio frequency signal to the input terminal of the broadband radio frequency radiation unit under test through a radio frequency connection path; A spectrum analysis device configured to receive and analyze the spectral characteristics of radio frequency signals; A power attenuation device is connected in series on the radio frequency connection path between the output end of the broadband radio frequency radiation unit under test and the input end of the spectrum analysis device, and is used to attenuate the power of the radio frequency signal output from the output end of the broadband radio frequency radiation unit under test. The control device establishes communication connections with the control interfaces of the signal generator, the spectrum analysis device, the power attenuation device, and the broadband radio frequency radiation unit under test, respectively. The control device is configured to control the output parameters of the signal generator, the attenuation parameters of the power attenuation device, and the operating parameters of the spectrum analysis device, and send control commands to the broadband radio frequency radiation unit under test through the control interface to adjust the attenuation state of its internal power adjustment unit and the conduction path of its internal signal selection unit. The connection device includes a radio frequency transmission line and a control signal line; the radio frequency transmission line is used to establish a first radio frequency link between the signal generating device and the input terminal of the broadband radio frequency radiation unit under test, a second radio frequency link between the preset monitoring point inside the broadband radio frequency radiation unit under test and the input terminal of the spectrum analysis device, and a third radio frequency link between the output terminal of the broadband radio frequency radiation unit under test and the input terminal of the spectrum analysis device, which is connected through a power attenuation device; the control signal line is used to establish a control link between the control device and the control interface of the broadband radio frequency radiation unit under test.

[0024] Figure 1 The specific components and connections of the above system are shown and can be viewed concurrently. In this embodiment, the signal generator is a microwave signal source, which can output test RF signal parameters and power values ​​according to system control. The spectrum analysis device is a spectrum analyzer, which performs detection spectrum analysis. The control device is a computer, which has built-in corresponding test control software to control the test instruments and the broadband RF receiving system. The key components of the system will be further described below.

[0025] In this embodiment, as Figure 1 As shown, the broadband RF radiation unit under test includes a front-end frequency converter module, a local oscillator module, an intermediate stage power amplifier module, a final stage power amplifier module, and at least one power control module. The power control module is located between the front-end frequency converter module and the intermediate stage power amplifier module, or between the intermediate stage power amplifier module and the final stage power amplifier module. Each power control module includes a digitally controlled attenuator, a power divider, and an RF switch. The input terminal of the digitally controlled attenuator is connected to the output terminal of the front-end module, the output terminal of the digitally controlled attenuator is connected to the input terminal of the power divider, the first output terminal of the power divider is connected to the input terminal of the rear-end module, and the second output terminal of the power divider is connected to the second RF link after passing through the RF switch.

[0026] This embodiment uses two power control modules, denoted as A and B, which are respectively located between the front-end frequency converter module and the intermediate stage power amplifier module, and between the intermediate stage power amplifier module and the final stage power amplifier module.

[0027] In this embodiment, the broadband RF radiation unit under test will be controlled by the test control software in the computer. The main function of the front-end frequency conversion module is to amplify the test signal by frequency conversion; the local oscillator module provides the corresponding local oscillator signal to the front-end frequency conversion module to realize frequency conversion to the required frequency; the power control module performs amplitude control through its digitally controlled attenuator; the intermediate stage power amplifier module mainly amplifies the intermediate stage signal; and the final stage power amplifier module mainly amplifies and outputs the link signal.

[0028] In a preferred embodiment, the control device is configured to send instructions to the broadband radio frequency radiation unit under test, control the digitally controlled attenuator in the power control module to adjust the attenuation value in a fixed step according to a preset time sequence, and synchronously control the radio frequency switch to switch the conduction state at a specified time point; the control device is also configured to control the signal generator to output radio frequency signals of multiple test frequencies in sequence, and trigger the spectrum analysis device to perform spectrum data acquisition operation at each test frequency.

[0029] In this embodiment, the connecting device further includes a combiner, i.e. Figure 1 The single-pole multi-throw RF switch A is used. The multiple input terminals of the combiner are respectively connected to the RF switch output terminals of each power control module in the broadband RF radiation unit under test. The output terminal of the combiner is connected to the input terminal of the spectrum analysis device via an RF transmission line. The second RF link, via the combiner, combines the RF signals of multiple preset monitoring points inside the broadband RF radiation unit under test and transmits them to the spectrum analysis device.

[0030] In a preferred embodiment, the power attenuation device is at least one of a high-power fixed attenuator, a high-power adjustable attenuator, or a directional coupler. The power capacity of the RF port of the power attenuation device is greater than or equal to the maximum continuous wave output power of the output terminal of the broadband RF radiation unit under test. The input terminal of the power attenuation device is fixedly connected to the output terminal of the broadband RF radiation unit under test via an RF connector, and the output terminal of the power attenuation device is connected to the RF input port of the spectrum analyzer via an RF cable. The main function of the power attenuation device is to attenuate the high-power signal finally output by the radiation unit, so that its signal power value is suitable for the detection power range of the spectrum analyzer. Therefore, when selecting a high-power attenuator / coupler, attention should be paid to its power handling range to avoid damage to itself or the detection instrument.

[0031] Example 2 Based on Example 1, this example provides a method for testing the output linearity of a broadband radio frequency radiation unit according to the system of Example 1, including the following steps: S1. Initialize the signal generator, spectrum analyzer and the broadband radio frequency radiation unit under test by the control device, and establish a communication connection between the control device and the control interface of the broadband radio frequency radiation unit under test. S2. Configure the test parameter set, which includes the output frequency sequence and output power value of the signal generator, the center frequency, analysis bandwidth and scan duration of the spectrum analysis device, and the attenuation adjustment sequence of the internal power adjustment unit and the path switching command sequence of the internal signal selection unit in the broadband RF radiation unit under test. S3. The control signal generating device outputs test radio frequency signals sequentially according to the output frequency point sequence. Simultaneously, it controls the internal power adjustment unit to adjust the attenuation value in stages within a preset time interval according to the attenuation adjustment sequence. During each stable attenuation period, it controls the internal signal selection unit to conduct to the designated monitoring path according to the path switching instruction sequence. This enables the spectrum analysis device to obtain the spectrum data of the preset monitoring point inside the tested broadband radio frequency radiation unit through the second radio frequency link, and at the same time obtain the output spectrum data after attenuation processing by the power attenuation device through the third radio frequency link. S4. The acquired spectrum data of the internal preset monitoring points at each frequency point and the corresponding output spectrum data are associated and stored according to the test time sequence, and a test data file containing the original spectrum data and test configuration parameters is generated to complete the test.

[0032] Figure 2 The specific execution flow of the above method is shown and can be viewed simultaneously for understanding. This embodiment further describes and explains the key steps in the method.

[0033] In step S2 of this embodiment, the attenuation adjustment sequence includes multiple attenuation values ​​arranged in chronological order and corresponding duration periods. The attenuation values ​​increase or decrease with a preset step size, and the duration of the duration period is greater than or equal to the minimum time required for a single scan by the spectrum analysis device. The path switching instruction sequence includes sending an instruction to the broadband radio frequency radiation unit under test at the start of the duration period corresponding to each attenuation value, controlling its internal radio frequency switch to switch to the port connection state matching the current test stage.

[0034] In step S3 of this embodiment, for each test frequency point, the following operations are performed: the control spectrum analysis device sets the center frequency to the peak frequency position of the current input signal, sets the analysis bandwidth to 0Hz, and sets the scan time to a fixed duration that matches the duration of a single attenuation value in the attenuation adjustment sequence; during the execution of the attenuation adjustment sequence, the spectrum analysis device continuously collects spectrum amplitude data according to the set parameters.

[0035] In step S3 of this embodiment, when collecting spectrum data of the internal preset monitoring point, the radio frequency switch inside the broadband radio frequency radiation unit under test is controlled to be turned on to the port connected to the second output terminal of the power divider, so that the monitoring signal is transmitted to the spectrum analysis device via the second radio frequency link; when collecting spectrum data of the output terminal of the broadband radio frequency radiation unit under test, the radio frequency switch is controlled to switch to the path connected to the output terminal of the final stage power amplifier, and the attenuation value of the power attenuation device is set to a preset fixed value, so that the attenuated output signal is transmitted to the spectrum analysis device via the third radio frequency link.

[0036] In a preferred embodiment, after storing the data according to the test timing sequence in step S4, the method further includes: arranging the spectrum data of the internal preset monitoring points according to the attenuation value timing sequence to generate a first spectrum amplitude sequence curve; arranging the spectrum data of the output terminal of the broadband radio frequency radiation unit under test according to the same attenuation value timing sequence to generate a second spectrum amplitude sequence curve; aligning the first spectrum amplitude sequence curve and the second spectrum amplitude sequence curve in timing; generating a spectrum data chart containing a hyperbola comparison relationship in a superimposed or parallel manner; and incorporating the spectrum data chart into the test data file.

[0037] Example 3 Based on the above embodiments, this embodiment describes the linearity testing process of the intermediate stage power amplifier module of the broadband RF receiver / radiator unit in the system link. The connection of the hardware devices adopts... Figure 1 The testing process follows this approach. Figure 2 The diagram illustrates the testing process under the condition that each module is functioning normally.

[0038] In this embodiment, after confirming the system hardware connection is correct, the microwave signal source, spectrum analyzer, and broadband RF radiation unit are initialized and powered on, allowing them to enter normal amplification operation. The RF switch is set to enable the monitoring path of power control module A, so that the intermediate stage input monitoring signal split by the power divider is connected to the spectrum analyzer. The microwave signal source outputs test signals according to a preset frequency sequence, synchronously controlling the digitally controlled attenuator of power control module A to perform attenuation adjustment according to the time sequence. The attenuation value starts from 0dB and increases in fixed steps, with each attenuation value maintained for a set duration. The spectrum analyzer locks the center frequency to the real-time peak frequency, sets the analysis bandwidth to 0Hz, matches the scan time with the attenuation step duration, and displays a stepped spectrum amplitude curve that changes over time. Subsequently, the RF switch is switched to the output monitoring path, power control module B is enabled, and the attenuation is set to a fixed value. The final stage output spectrum data after processing by the high-power attenuator is collected. The intermediate stage monitoring spectrum and the output spectrum are superimposed and compared according to the same time base, and the amplitude change trajectory and morphological characteristics of the two sets of stepped curves are recorded.

[0039] The specific testing steps are as follows: 1) Confirm the connection is in place; 2) Initialize the signal source, spectrum analyzer, and other test instruments; 3) The broadband radio frequency radiation unit is powered on and in amplification mode; 4) Detection channel settings: The switch of single-pole multi-throw RF switch A is set to the ON state from port 1 to port 4; 5) Turn on the signal source and output according to the parameter requirements of the test frequency points F0 to Fn; 6) Configure the attenuation control of power control module A. Assume the operating timing is from T0 to T6, with a 1ms step, and the attenuation control starts from 0dB with a 3dB step. For specific operating timing and attenuation control details, please refer to [link to documentation]. Figure 3 The step value can be adjusted according to actual needs. 7) Confirm the input test signal power control of the intermediate stage power amplifier module. Find the maximum peak frequency on the spectrum analyzer and set it as the center frequency. Set the bandwidth to 0Hz and the scan time to 20ms. At this time, the spectrum will show something like... Figure 4 The “stepped spectrum” diagram shown; 8) Detection channel settings: Turn off the detection signal channel of power control module A, that is, turn off its internal RF switch, and set the switch of single-pole multi-throw RF switch A to the state of conduction from port 1 to port 2; set the attenuation control of power control module B to 0dB and turn on its internal RF switch to enable detection output. 9) Locate the maximum peak frequency on the spectrum analyzer and set it as the center frequency. Set the bandwidth to 0Hz and the scan time to 20ms. Observe the output spectrum and compare it with the input and output "stepped spectrum". If the spectrum at this time shows the following... Figure 4 The spectrum pattern shown indicates that the system is operating in the linear region; if the spectrum shows a pattern like this... Figure 5 The spectrum diagram shown indicates that when the operating timing is T1 and T2 for large signals, it is still operating in the saturation region. Its attenuation control starts from 0dB and increments in 3dB steps. The saturation depth can be clearly seen from the spectrum as 4.5dB. Therefore, it can be concluded that an attenuation of 4.5dB needs to be added to the input of the intermediate stage power amplifier module in order to make it operate in the linear output region. 10) Determine if this is the last test frequency point. If it is not the last test frequency point, return to step 5) to perform the test. If it is the last point, save the suggested value for the test point to exit the saturation region. 11) Statistically analyze the recommended values ​​for exiting the saturation zone of frequency points, and determine the recommended values ​​for exiting the saturation zone based on the actual frequency bands used; 12) Save the test report; 13) Turn off the broadband radio frequency receiving system; 14) End the test.

[0040] Example 4 Based on the above embodiments, this embodiment describes the linearity test process of the final stage power amplifier module of the broadband RF receiver-radiator unit in the system link. The connection of the hardware device adopts... Figure 1 The testing process follows this approach. Figure 2 The diagram illustrates the testing process under the condition that each module is functioning normally.

[0041] In this embodiment, after system initialization, the RF switch is configured to enable the monitoring path of the power control module B, allowing the monitoring signal at the input of the final stage power amplifier module to be connected to the spectrum analyzer. The attenuation of the preceding power control module A is kept constant to provide a stable excitation signal, and the digitally controlled attenuator of the power control module B executes the same timing attenuation sequence as described above. The spectrum analyzer synchronously acquires the stepped spectrum data of the final stage input monitoring points; after acquisition, the RF switch is switched to the final output monitoring path to acquire the output spectrum of the radiating unit after attenuation by the high-power attenuator. The final stage input monitoring spectrum and output spectrum are time-aligned to generate a hyperbola comparison chart, detailing the amplitude correspondence and spectral shape changes of the input and output signals at each attenuation stage, providing complete data for module-level linearity evaluation.

[0042] The specific testing steps are as follows: 1) Confirm the connection is in place; 2) Initialize the signal source, spectrum analyzer, and other test instruments; 3) The broadband radio frequency radiation unit is powered on and in amplification mode; 4) Detection channel settings: The switch of single-pole multi-throw RF switch A is set to the state where port 1 to port 2 is open; 5) Turn on the signal source and output according to the parameter requirements of the test frequency points F0 to Fn; 6) Configure the attenuation control of power control module B. Assume the operating timing is from T0 to T6, with a 1ms step, and the attenuation control starts from 0dB with a 3dB step. For detailed operating timing and attenuation control, please refer to [link to documentation]. Figure 3 The step value can be adjusted according to actual needs. 7) Confirm and identify the control accuracy of the input test signal power control for the final stage power amplifier module. Find the maximum peak frequency on the spectrum analyzer and set it as the center frequency. Set the bandwidth to 0Hz and the scan time to 20ms. At this time, the spectrum will show something like... Figure 4 The “stepped spectrum” diagram shown; 8) Detection channel settings: Turn off the detection signal channel of power control module B, that is, turn off its internal RF switch, and set the switch of single-pole multi-throw RF switch A to the state of conduction from port 1 to port 3. 9) Locate the maximum peak frequency on the spectrum analyzer and set it as the center frequency. Set the bandwidth to 0Hz and the scan time to 20ms. Observe the output spectrum and compare it with the input and output "stepped spectrum". If the spectrum at this time shows the following... Figure 4 The spectrum pattern shown indicates that the system is operating in the linear region; if the spectrum shows a pattern like this... Figure 5The spectrum diagram shown indicates that when the operating timing is T1 and T2 for large signals, it is still operating in the saturation region; its attenuation step is 3dB, and the saturation depth can be intuitively seen from the spectrum as 4.5dB; therefore, it can be seen that an attenuation of 4.5dB needs to be added at the input of the final stage power amplifier module in order to make it operate in the linear output region. 10) Determine if this is the last test frequency point. If it is not the last test frequency point, return to step 5) to perform the test. If it is the last point, save the suggested value for the test point to exit the saturation region. 11) Statistically analyze the recommended values ​​for exiting the saturation zone of the frequency points, and determine the recommended values ​​for exiting the saturation zone based on the actual frequency band used; as shown in Table 1 below, if the actual frequency band used is in the F1 to F3 frequency band, then look up the table and select the value with the highest saturation for reference, and recommend an attenuation configuration of 7.5dB; Table 1. Statistical Table of Saturation at Test Frequency Points

[0043] 12) Save the test report; 13) Power off the broadband radio frequency radiation unit; 14) End the test.

Claims

1. A broadband radio frequency radiation unit output linearity testing system, characterized in that, include: A signal generating device is configured to generate a test radio frequency signal and provide the test radio frequency signal to the input terminal of the broadband radio frequency radiation unit under test through a radio frequency connection path; A spectrum analysis device configured to receive and analyze the spectral characteristics of radio frequency signals; A power attenuation device is connected in series in the radio frequency connection path between the output end of the broadband radio frequency radiation unit under test and the input end of the spectrum analysis device, and is used to attenuate the power of the radio frequency signal output from the output end of the broadband radio frequency radiation unit under test. The control device establishes communication connections with the control interfaces of the signal generating device, the spectrum analysis device, the power attenuation device, and the broadband radio frequency radiation unit under test, respectively. The control device is configured to control the output parameters of the signal generating device, the attenuation parameters of the power attenuation device, and the operating parameters of the spectrum analysis device, and send control commands to the broadband radio frequency radiation unit under test through the control interface to adjust the attenuation state of its internal power adjustment unit and the conduction path of its internal signal selection unit. The connection device includes a radio frequency (RF) transmission line and a control signal line. The RF transmission line is used to establish a first RF link between the signal generating device and the input terminal of the broadband RF radiation unit under test, a second RF link between a preset monitoring point inside the broadband RF radiation unit under test and the input terminal of the spectrum analysis device, and a third RF link between the output terminal of the broadband RF radiation unit under test connected through the power attenuation device and the input terminal of the spectrum analysis device. The control signal line is used to establish a control link between the control device and the control interface of the broadband RF radiation unit under test.

2. The broadband radio frequency radiation unit output linearity testing system according to claim 1, characterized in that: The broadband RF radiation unit under test includes a front-end frequency converter module, a local oscillator module, an intermediate stage power amplifier module, a final stage power amplifier module, and at least one power control module. The power control module is located between the front-end frequency converter module and the intermediate stage power amplifier module, or between the intermediate stage power amplifier module and the final stage power amplifier module. Each power control module includes a digitally controlled attenuator, a power divider, and an RF switch. The input terminal of the digitally controlled attenuator is connected to the output terminal of the front-end module, the output terminal of the digitally controlled attenuator is connected to the input terminal of the power divider, the first output terminal of the power divider is connected to the input terminal of the rear-end module, and the second output terminal of the power divider is connected to the second RF link after passing through the RF switch.

3. The broadband radio frequency radiation unit output linearity testing system according to claim 2, characterized in that: The control device is configured to send instructions to the broadband radio frequency radiation unit under test, control the digitally controlled attenuator in the power control module to adjust the attenuation value in a fixed step according to a preset time sequence, and synchronously control the radio frequency switch to switch the conduction state at a specified time point; the control device is also configured to control the signal generating device to output radio frequency signals of multiple test frequency points in sequence, and trigger the spectrum analysis device to perform spectrum data acquisition operation at each test frequency point.

4. The broadband radio frequency radiation unit output linearity testing system according to claim 1, characterized in that: The connection device further includes a combiner, the multiple input terminals of which are respectively connected to the RF switch output terminals of each power control module in the broadband RF radiation unit under test, and the output terminal of the combiner is connected to the input terminal of the spectrum analysis device via an RF transmission line; the second RF link transmits the RF signals of multiple preset monitoring points inside the broadband RF radiation unit under test to the spectrum analysis device via the combiner.

5. The broadband radio frequency radiation unit output linearity testing system according to claim 1, characterized in that: The power attenuation device is at least one of a high-power fixed attenuator, a high-power adjustable attenuator, or a directional coupler. The power capacity of the RF port of the power attenuation device is greater than or equal to the maximum continuous wave output power of the output terminal of the broadband RF radiation unit under test. The input terminal of the power attenuation device is fixedly connected to the output terminal of the broadband RF radiation unit under test through an RF connector, and the output terminal of the power attenuation device is connected to the RF input port of the spectrum analysis device via an RF cable.

6. A method for testing the output linearity of a broadband radio frequency radiation unit in the system according to claim 1, characterized in that, Includes the following steps: S1. The control device performs initialization operations on the signal generating device, the spectrum analysis device, and the broadband radio frequency radiation unit under test, and establishes a communication connection between the control device and the control interface of the broadband radio frequency radiation unit under test. S2. Configure the test parameter set, which includes the output frequency sequence and output power value of the signal generator, the center frequency, analysis bandwidth and scan duration of the spectrum analysis device, and the attenuation adjustment sequence of the internal power adjustment unit and the path switching instruction sequence of the internal signal selection unit in the broadband radio frequency radiation unit under test. S3. Control the signal generating device to output test radio frequency signals sequentially according to the output frequency sequence, and simultaneously control the internal power adjustment unit to adjust the attenuation value in stages within a preset time interval according to the attenuation adjustment sequence. During each stable attenuation period, control the internal signal selection unit to conduct to the specified monitoring path according to the path switching instruction sequence, so that the spectrum analysis device can obtain the spectrum data of the preset monitoring point inside the tested broadband radio frequency radiation unit through the second radio frequency link, and at the same time obtain the output spectrum data after attenuation processing by the power attenuation device through the third radio frequency link. S4. The acquired spectrum data of the internal preset monitoring points at each frequency point and the corresponding output spectrum data are associated and stored according to the test time sequence, and a test data file containing the original spectrum data and test configuration parameters is generated to complete the test.

7. The method for testing the output linearity of a broadband radio frequency radiation unit according to claim 6, characterized in that: In step S2, the attenuation adjustment sequence includes multiple attenuation values ​​arranged in chronological order and corresponding duration periods. The attenuation values ​​increase or decrease with a preset step size, and the duration of the duration period is greater than or equal to the minimum time required for a single scan by the spectrum analysis device. The path switching instruction sequence includes sending an instruction to the broadband RF radiation unit under test at the start of the duration period corresponding to each attenuation value, controlling its internal RF switch to switch to the port connection state matching the current test stage.

8. The method for testing the output linearity of a broadband radio frequency radiation unit according to claim 6, characterized in that, In step S3, for each test frequency point, the following operations are performed: the spectrum analysis device is controlled to set the center frequency to the peak frequency position of the current input signal, set the analysis bandwidth to 0Hz, and set the scan time to a fixed duration that matches the duration of a single attenuation value in the attenuation adjustment sequence; during the execution of the attenuation adjustment sequence, the spectrum analysis device continuously collects spectrum amplitude data according to the set parameters.

9. The method for testing the output linearity of a broadband radio frequency radiation unit according to claim 6, characterized in that: In step S3, when collecting spectrum data of internal preset monitoring points, the radio frequency switch inside the measured broadband radio frequency radiation unit is controlled to be turned on to the port connected to the second output terminal of the power divider, so that the monitoring signal is transmitted to the spectrum analysis device via the second radio frequency link. When acquiring spectrum data from the output of the broadband radio frequency radiation unit under test, the radio frequency switch is controlled to switch to the path connecting to the output of the final stage power amplifier, and the attenuation value of the power attenuation device is set to a preset fixed value, so that the attenuated output signal is transmitted to the spectrum analysis device via the third radio frequency link.

10. The method for testing the output linearity of a broadband radio frequency radiation unit according to claim 6, characterized in that, In step S4, after storing the data according to the test timing sequence, the method further includes: arranging the spectrum data of the internal preset monitoring points according to the attenuation value timing sequence to generate a first spectrum amplitude sequence curve; arranging the spectrum data of the output end of the broadband radio frequency radiation unit under test according to the same attenuation value timing sequence to generate a second spectrum amplitude sequence curve; aligning the first spectrum amplitude sequence curve and the second spectrum amplitude sequence curve in timing, and generating a spectrum data chart containing a hyperbola comparison relationship in a superimposed or parallel manner; and incorporating the spectrum data chart into the test data file.

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