Power calibration system of solid-state high-power AM short-wave transmitter

Abstract

The utility model provides a power calibration system of a solid-state high-power AM short-wave transmitter, relates to the technical field of radio and television, and adopts the technical scheme that the system can quickly respond to power deviation and continuously adjust parameters of excitation signals through a control mechanism based on real-time feedback, so that the output power is accurately controlled. After the exciter unit receives the control signal sent by the computer, the optimized excitation signal can be generated, it is ensured that the input signal received by the power amplifier unit is adjusted in advance, and the power amplifier efficiency and the output signal quality can be improved. And the power amplifier unit amplifies the optimized excitation signal into a high-power radio-frequency signal and outputs the high-power radio-frequency signal to complete the whole power amplification process. Through cooperative work of the computer, the exciter unit, the power amplifier unit, the frequency spectrograph and the power meter, a closed-loop control system is formed, and high-precision and high-efficiency power calibration can be realized.

Description

Technical Field

[0001] This application relates to the field of radio and television technology, and particularly to a power calibration system for a solid-state high-power AM short-wave transmitter. Background Art

[0002] Solid-state high-power AM short-wave transmitters are important components in wireless communication systems and are widely used in fields such as broadcasting, communication, and electronic countermeasures. These transmitters adopt solid-state power amplifier technology and have advantages such as high efficiency, high reliability, and good linearity. A typical solid-state high-power AM short-wave transmitter includes main parts such as a signal source, a modulator, a power amplifier, and an output matching network. They can operate in the short-wave frequency band from 2 MHz to 30 MHz.

[0003] In related technologies, the power calibration methods for solid-state high-power AM short-wave transmitters mostly use manual or semi-automatic methods. The specific approach is to adjust the input power one by one at different frequency points, then measure the output power, and achieve the target power level through repeated adjustments. In actual applications, due to the large span of the short-wave frequency band, there are a large number of frequency points that need to be calibrated, and the gain characteristics of the power amplifier may vary at different frequency points and power levels, resulting in poor power calibration accuracy and low efficiency. Summary of the Utility Model

[0004] In view of the deficiencies of the existing technology, the power calibration system for a solid-state high-power AM short-wave transmitter provided by this application can improve the power calibration accuracy and calibration efficiency of the solid-state high-power AM short-wave transmitter.

[0005] The above-mentioned inventive purpose of this application is achieved through the following technical solutions:

[0006] This application provides a power calibration system for a solid-state high-power AM short-wave transmitter. The system includes a computer, an exciter unit, a power amplifier unit, a spectrum analyzer, and a power meter. The computer is respectively connected to the exciter unit, the spectrum analyzer, and the power meter. The power amplifier unit is respectively connected to the exciter unit, the spectrum analyzer, and the power meter, where:

[0007] The power meter is used to collect the output power of the radio frequency signal of the power amplifier unit and send the output power to the computer;

[0008] The computer is used to generate a control signal and update the control signal according to the output power;

[0009] The exciter unit is used to generate an excitation signal according to the control signal of the computer and transmit the excitation signal to the power amplifier unit;

[0010] The power amplifier unit is used to amplify the excitation signal into the radio frequency signal and output the radio frequency signal.

[0011] By adopting the above technical solution, the power meter in the system collects the power of the radio frequency signal output by the power amplifier unit in real time and feeds this information back to the computer. The computer compares the actual output power data received with the preset target power and dynamically generates and updates the control signal. This control mechanism based on real-time feedback enables the system to quickly respond to power deviations, continuously adjust the parameters of the excitation signal, and thus precisely control the output power. After receiving the control signal sent by the computer, the exciter unit can generate an optimized excitation signal to ensure that the input signal received by the power amplifier unit has been pre-adjusted, which is beneficial to improving the power amplifier efficiency and the quality of the output signal. The power amplifier unit amplifies the optimized excitation signal into a high-power radio frequency signal and outputs it, completing the entire power amplification process. Through the collaborative work of the computer, the exciter unit, the power amplifier unit, the spectrum analyzer, and the power meter, a closed-loop control system is formed, which can achieve high-precision and high-efficiency power calibration.

[0012] In a preferred example of the present application, it can be further configured that: the power amplifier unit includes a power divider, a power amplifier module, a filter, and a coupler. The power divider is respectively connected to the exciter unit and the power amplifier module. The power amplifier module is connected to the filter. The coupler is respectively connected to the filter, the exciter unit, and the power meter, where:

[0013] The power divider is used to divide the excitation signal into multiple power amplifier signals;

[0014] The power amplifier module is used to amplify and combine multiple power amplifier signals into an initial radio frequency signal;

[0015] The filter is used to filter the initial radio frequency signal to obtain a radio frequency signal;

[0016] The coupler is used to couple out a sampling signal and an AM modulation signal from the radio frequency signal, transmit the sampling signal to the spectrum analyzer, and transmit the AM modulation signal to the exciter unit.

[0017] By adopting the above technical solution, the power divider divides the excitation signal from the exciter unit into multiple power amplifier signals. This distribution strategy not only improves the power handling capacity but also enhances the reliability of the system. The power amplifier module receives these divided signals and generates an initial radio frequency signal through parallel amplification and synthesis processing, effectively improving the power output capacity of the system. The filter filters the initial radio frequency signal to remove harmonic and spurious signals, ensuring the purity of the output radio frequency signal and improving the spectral utilization efficiency. The coupler plays a key role in the final stage, coupling out the sampling signal and the AM modulation signal from the radio frequency signal. The sampling signal is transmitted to the spectrum analyzer, enabling the system to monitor the spectral characteristics of the output signal in real time and providing accurate feedback information for power calibration. The AM modulation signal is sent back to the exciter unit, forming a closed-loop control system that allows the system to dynamically adjust the excitation signal according to the actual output, further improving the accuracy of power control.

[0018] In a preferred example, the present application can be further configured as follows: The power amplifier module includes a first power amplifier, a second power amplifier, a third power amplifier, a fourth power amplifier, a first synthesizer, a second synthesizer, and a third synthesizer, where:

[0019] The four output terminals of the power divider are respectively connected to the input terminals of the first power amplifier, the second power amplifier, the third power amplifier, and the fourth power amplifier;

[0020] The two input terminals of the first synthesizer are respectively connected to the output terminal of the first power amplifier and the output terminal of the second power amplifier, and the two input terminals of the second synthesizer are respectively connected to the output terminal of the third power amplifier and the output terminal of the fourth power amplifier;

[0021] The two input terminals of the third synthesizer are respectively connected to the output terminal of the first synthesizer and the output terminal of the second synthesizer, and the output terminal of the third synthesizer is connected to the filter.

[0022] By adopting the above technical solution, the power divider evenly distributes the input signal to four power amplifier units, and each power amplifier only needs to process signals with lower power. This parallel processing method significantly reduces the load on a single power amplifier. This multi-stage synthesis structure not only improves the overall power output capacity of the system but also enhances the flexibility and reliability of the system. By adjusting the working states of different power amplifiers, the system can achieve more refined power regulation to adapt to different working requirements.

[0023] In a preferred example, the present application can be further configured as follows: The filter is a harmonic filter, and the working band of the filter is any one of six bands in the short-wave range of 2 - 30 MHz.

[0024] By adopting the above technical solution, the harmonic filter can effectively suppress the harmonic components generated during the power amplification process, ensure the purity of the output signal, and thus improve the communication quality and spectrum utilization efficiency. The design strategy of dividing the short-wave range of 2 - 30 MHz into six bands enables the system to be optimized according to the propagation characteristics and application requirements of different frequency bands, improving the filtering effect.

[0025] In a preferred example of the present application, it can be further configured that: the exciter unit includes a digital signal processing module, a feedback path, and a transmission path. The digital signal processing module is respectively connected to the computer, the transmission path, and the feedback path. The transmission path and the feedback path are respectively connected to the power amplifier unit, where;

[0026] The digital signal processing module is used to receive and process the control signal sent by the computer and the feedback signal sent by the feedback path, generate an excitation signal according to the control signal and the feedback signal, and transmit the excitation signal to the transmission path;

[0027] The transmission path is used to process the excitation signal and then send it to the power amplifier unit;

[0028] The feedback path is used to collect the feedback signal at the output end of the power amplifier unit and transmit the feedback signal to the digital signal processing module.

[0029] By adopting the above technical solution, the digital signal processing module simultaneously receives the control signal from the computer and the feedback signal from the feedback path. This dual-input mechanism enables the system to achieve a balance between preset control and real-time feedback, being able to operate according to a predetermined plan and make dynamic adjustments according to the actual situation. By comprehensively processing these two signals, the digital signal processing module can generate the optimal excitation signal, effectively improving the adaptability and control precision of the system.

[0030] In a preferred example of the present application, it can be further configured that: the digital signal processing module includes a baseband signal processing sub-module and a DPD pre-distortion processing sub-module.

[0031] In a preferred example of the present application, it can be further configured that: the transmission path includes a digital-to-analog converter, a low-pass filter, a first variable gain amplifier, a first digital control attenuator, and a driver amplifier;

[0032] The feedback path includes an analog-to-digital converter, a first variable gain amplifier, a second digital control attenuator, and a demodulation chip.

[0033] In a preferred embodiment, the present application can be further configured as follows: the system further includes a network analyzer, which is respectively connected to the spectrum analyzer, the power amplifier unit, and the computer, where:

[0034] The network analyzer is used to test the attenuation of the RF cable in the entire frequency band of the system and transmit the test results to the computer, so that the computer compensates the output power according to the test results.

[0035] By adopting the above technical solution, through scanning and testing in the entire working frequency band of the system, the network analyzer can capture the insertion loss of the RF cable at each frequency point, and these data directly reflect the power loss of the signal during transmission. After the test results are transmitted to the computer, the computer can compensate the output power according to these accurate attenuation data, and this compensation mechanism ensures that the system can output accurate power at different frequencies. Brief Description of the Drawings

[0036] Figure 1 It is a schematic structural diagram of a power calibration system for a solid-state high-power AM short-wave transmitter provided by an embodiment of the present application. Detailed Description of the Embodiment

[0037] The following further describes the present application in detail with reference to the accompanying drawings.

[0038] Refer to Figure 1 , which is a schematic structural diagram of a power calibration system for a solid-state high-power AM short-wave transmitter provided by an embodiment of the present application. The system includes a computer, an exciter unit, a power amplifier unit, a spectrum analyzer, and a power meter. The computer is respectively connected to the exciter unit, the spectrum analyzer, and the power meter, and the power amplifier unit is respectively connected to the exciter unit, the spectrum analyzer, and the power meter, where:

[0039] The power meter is used to collect the output power of the RF signal of the power amplifier unit and send the output power to the computer;

[0040] The computer is used to generate a control signal and update the control signal according to the output power;

[0041] The exciter unit is used to generate an excitation signal according to the control signal of the computer and transmit the excitation signal to the power amplifier unit;

[0042] The power amplifier unit is used to amplify the excitation signal into an RF signal and output the RF signal.

[0043] In this embodiment, a power calibration system for a solid-state high-power AM shortwave transmitter is proposed. The power calibration system for a solid-state high-power AM shortwave transmitter is intended to achieve accurate power calibration to ensure that the actual output power of the transmitter matches the preset target power. The system includes a computer, an exciter unit, a power amplifier unit, a spectrum analyzer, and a power meter, and these components form a closed-loop control system through a specific connection method.

[0044] The computer, as the control center of the system, generates an initial control signal and sends it to the exciter unit. This initial control signal contains information such as frequency and initial power setting, which is carefully calculated to ensure safety and calibration effectiveness.

[0045] After receiving the control signal, the exciter unit generates a corresponding excitation signal and transmits it to the power amplifier unit. The power amplifier unit amplifies the excitation signal into a high-power RF signal output. The power meter measures the power of the output RF signal in real time and sends the measurement results back to the computer.

[0046] After receiving the actual output power data, the computer compares it with the preset target power. Based on the comparison results, the computer generates a new control signal. If the actual output power is lower than the target value, the control signal will indicate an increase in output; if it is higher than the target value, it will indicate a decrease in output. This process will be repeated multiple times, and each time the control signal will be adjusted according to the difference between the current power and the target power until the predetermined accuracy requirement is achieved.

[0047] The design of the system takes into account the characteristics of the power amplifier unit at different frequencies and powers. In order to deal with the unevenness of the gain of the power amplifier in the full frequency band, the system adopts a segmented calibration strategy. A representative frequency point is selected for calibration in each frequency band, and other frequency points in the band are adjusted according to this calibration result.

[0048] In order to ensure the safety and accuracy of the calibration process, the system adopts a progressive calibration method. The calibration process is divided into multiple stages, each with its own specific target power. This method can effectively avoid the risk of the amplifier output power suddenly being too high due to excessive excitation signals, while also improving the accuracy of calibration.

[0049] The structure of the power calibration system of the solid-state high-power AM shortwave transmitter in this application is described in detail below.

[0050] Specifically, the power amplifier unit includes a power distributor, a power amplifier module, a filter and a coupler, the power distributor is connected to the exciter unit and the power amplifier module respectively, the power amplifier module is connected to the filter, and the coupler is connected to the filter, the exciter unit and the power meter respectively, wherein:

[0051] A power divider for splitting an excitation signal into multiple power amplifier signals;

[0052] A power amplifier module for amplifying and combining multiple power amplifier signals into an initial radio frequency signal;

[0053] A filter for filtering the initial radio frequency signal to obtain a radio frequency signal;

[0054] A coupler for coupling out a sampling signal and an AM modulation signal from the radio frequency signal, transmitting the sampling signal to a spectrum analyzer, and transmitting the AM modulation signal to an exciter unit.

[0055] The power divider is connected to the exciter unit and the power amplifier module. Its main function is to split the excitation signal from the exciter unit into multiple power amplifier signals. The purpose of this distribution design is to make full use of the parallel processing ability of the power amplifier module and improve the overall power amplification efficiency. By splitting a single excitation signal into multiple paths, the power burden of each path can be reduced, thereby reducing the pressure on individual power amplifier components, extending their service life, and also facilitating heat dissipation and heat management.

[0056] The power amplifier module receives these split power amplifier signals and amplifies them. The amplified multiple signals are then combined into an initial radio frequency signal. This method of parallel amplification and then combination not only improves the power processing ability of the system but also enhances the reliability of the system.

[0057] The initial radio frequency signal is processed by a filter to obtain the final radio frequency signal. The function of the filter is to remove harmonics and spurious signals generated during the amplification process and ensure the purity of the output signal. This step is crucial for ensuring communication quality because it can reduce interference with other frequency bands and improve spectrum utilization efficiency.

[0058] Finally, the coupler couples out two important signals from the radio frequency signal: the sampling signal and the AM modulation signal. The sampling signal is transmitted to the spectrum analyzer for real-time monitoring of the spectral characteristics of the output signal. This provides key feedback information for the system, helping to detect and correct possible signal anomalies in a timely manner. The AM modulation signal is transmitted back to the exciter unit for closed-loop control and signal modulation. This feedback mechanism enables the system to dynamically adjust the excitation signal according to the actual output situation, thereby achieving more precise power control and modulation effects.

[0059] The design of this power amplifier unit fully considers the special requirements of high-power AM shortwave transmitters. Through power distribution and parallel amplification, the system can handle higher power levels; through filtering and signal coupling, it can ensure the quality of the output signal and the controllability of the system. This structure not only improves the power processing ability and efficiency of the system but also enhances the reliability and stability of the system.

[0060] Based on the above embodiments, as an alternative implementation, the power amplifier module includes a first power amplifier, a second power amplifier, a third power amplifier, a fourth power amplifier, a first synthesizer, a second synthesizer, and a third synthesizer, where:

[0061] The four output terminals of the power splitter are respectively connected to the input terminals of the first power amplifier, the second power amplifier, the third power amplifier, and the fourth power amplifier;

[0062] The two input terminals of the first synthesizer are respectively connected to the output terminal of the first power amplifier and the output terminal of the second power amplifier, and the two input terminals of the second synthesizer are respectively connected to the output terminal of the third power amplifier and the output terminal of the fourth power amplifier;

[0063] The two input terminals of the third synthesizer are respectively connected to the output terminal of the first synthesizer and the output terminal of the second synthesizer, and the output terminal of the third synthesizer is connected to the filter.

[0064] The power splitter divides the input excitation signal into four paths and is respectively connected to the input terminals of four power amplifiers (the first power amplifier, the second power amplifier, the third power amplifier, and the fourth power amplifier). The main purpose of this distribution method is to disperse the amplification task of high-power signals to multiple power amplifier units. Each power amplifier only needs to process signals with lower power. This can significantly reduce the load of a single power amplifier, reduce the problem of heat concentration, extend the service life of power amplifier components, and improve the reliability of the overall system at the same time.

[0065] The amplified signals are power-combined through a two-stage synthesis process. First, the output signals of the first power amplifier and the second power amplifier are combined by the first synthesizer, and the output signals of the third power amplifier and the fourth power amplifier are combined by the second synthesizer. This pairwise combination method can achieve partial power combination in the intermediate stage, which is beneficial to the step-by-step processing and control of signals. Subsequently, the output signals of the first synthesizer and the second synthesizer are finally power-combined by the third synthesizer to obtain a complete high-power RF signal.

[0066] This structure provides more flexible power control capabilities. By adjusting the working states of different power amplifiers, the system can achieve more refined power adjustment to adapt to different working requirements. Moreover, multi-stage synthesis helps to optimize the phase and amplitude consistency of signals, which is beneficial to improving the quality of the finally combined signal.

[0067] Based on the above embodiments, as an alternative implementation, the filter is a harmonic filter, and the working band of the filter is any one of six bands in the short-wave 2 - 30 MHz range.

[0068] During the power amplification process, the signals output by the power amplifier module will generate harmonic and spurious signals. These unwanted signals will not only reduce the communication quality but may also cause interference to other frequency bands. The harmonic filter can effectively suppress these harmonic components, ensure the purity of the output signal, and thus improve the communication quality and spectrum utilization efficiency.

[0069] The design of dividing the shortwave range of 2 - 30 MHz into six bands takes into account the frequency characteristics of shortwave communication and the actual application requirements. Each band has its specific propagation characteristics and application scenarios. Through segmented design, optimization can be carried out according to the characteristics of different bands, improving the filtering effect. At the same time, this segmented design also increases the flexibility of the system, enabling the transmitter to quickly switch the operating frequency band according to different communication requirements.

[0070] The specific structure of the exciter unit will be described below.

[0071] The exciter unit includes a digital signal processing module, a feedback path, and a transmission path. The digital signal processing module is respectively connected to a computer, the transmission path, and the feedback path. The transmission path and the feedback path are respectively connected to the power amplifier unit, where;

[0072] The digital signal processing module is used to receive and process the control signals sent by the computer and the feedback signals sent by the feedback path, generate excitation signals according to the control signals and the feedback signals, and transmit the excitation signals to the transmission path;

[0073] The transmission path is used to process the excitation signals and then send them to the power amplifier unit;

[0074] The feedback path is used to collect the feedback signals at the output end of the power amplifier unit and transmit the feedback signals to the digital signal processing module.

[0075] The digital signal processing module receives control signals from the computer, which contain key parameters such as frequency, power, modulation mode, etc. At the same time, it also receives feedback signals from the feedback path, which reflect the actual state of the output of the power amplifier unit. By comprehensively processing these two types of signals, the digital signal processing module can generate the optimal excitation signals. This dual-input processing mechanism enables the system to achieve a balance between preset control and real-time feedback, being able to operate according to the predetermined plan and make dynamic adjustments according to the actual situation.

[0076] The generated excitation signals are then transmitted to the transmission path. The transmission path is responsible for performing necessary processing on the excitation signals, such as digital-to-analog conversion, filtering, amplification, etc., to ensure that the signal quality and power level meet the input requirements of the power amplifier unit. The importance of this step lies in that it directly affects the working efficiency of the power amplifier unit and the quality of the output signals. Through a carefully designed transmission path, the purity and stability of the excitation signals can be maximally guaranteed.

[0077] The design of the feedback path embodies the closed-loop control concept of the system. It is responsible for collecting feedback signals at the output end of the power amplifier unit, and these signals may contain key information such as power level, frequency deviation, modulation depth, etc. The collected feedback signals are sent back to the digital signal processing module for real-time evaluation and adjustment of the system's working state. This feedback mechanism enables the system to quickly respond to changes at the output end, such as load changes, temperature fluctuations, etc., thus maintaining stable output characteristics.

[0078] Specifically, the digital signal processing module includes a baseband signal processing sub-module and a DPD predistortion processing sub-module.

[0079] The working principle of the baseband signal processing sub-module revolves around the generation and optimization of the original signal. It first receives control signals from the computer and generates baseband signals according to the specified communication protocol and modulation scheme. In AM modulation, this usually manifests as precise adjustment of the carrier amplitude. The ultimate goal of these processing steps is to generate a high-quality, stable baseband signal that meets specific communication requirements. The role of the baseband signal processing sub-module is reflected in multiple aspects: it not only ensures the basic quality of the signal, but also improves the frequency band utilization rate by optimizing the spectrum characteristics. At the same time, its flexible design enables the system to adapt to various modulation methods and communication protocols, enhancing the adaptability and anti-interference ability of the entire system.

[0080] The DPD predistortion processing sub-module is dedicated to solving the problem of nonlinear distortion in the power amplification process, and its working principle is based on the precise modeling and compensation of the nonlinear characteristics of the power amplifier. This sub-module first calculates a predistortion function that can compensate for the nonlinearity of the power amplifier by analyzing the feedback signals output by the power amplifier. Before the signal enters the power amplifier, the predistortion function is applied to the signal to pre-compensate for the distortion that the power amplifier may introduce. This process is dynamic, and the system continuously updates the predistortion function according to the continuously collected feedback signals to adapt to the dynamic changes of the power amplifier characteristics. The calculated DPD coefficients are stored in the flash memory, enabling the system to quickly call appropriate predistortion parameters when needed. The role of the DPD predistortion processing sub-module is mainly reflected in significantly improving signal quality, increasing power amplifier efficiency, enhancing spectral purity, and optimizing key indicators of AM modulation signals. By effectively compensating for nonlinear distortion, it not only improves signal quality but also allows the power amplifier to operate in a region closer to the saturation point, thus improving power calibration efficiency.

[0081] Based on the above embodiments, as an alternative implementation, the transmission path includes a digital-to-analog converter, a low-pass filter, a first variable gain amplifier, a first digital control attenuator, and a driver amplifier;

[0082] The feedback path includes an analog-to-digital converter, a first variable gain amplifier, a second digitally controlled attenuator, and a demodulation chip.

[0083] The design of the transmit path starts with the conversion from the digital domain to the analog domain. First, the baseband signal processed by digital signal processing is converted into an analog form through a digital-to-analog converter. This step is necessary because although digital processing provides extremely high precision and flexibility, the final RF transmission still requires an analog signal. After digital-to-analog conversion, the signal passes through a low-pass filter. The purpose of this link is to filter out the high-frequency noise and image frequencies that may be introduced during the conversion process to ensure the purity of the signal. Subsequently, the signal enters the first variable gain amplifier, which allows the system to dynamically adjust the signal strength to adapt to different transmission requirements and environmental conditions. The immediately following first digitally controlled attenuator provides a more refined amplitude control ability, and it can precisely adjust the signal strength according to the system requirements or the requirements of the DPD algorithm. Finally, the driver amplifier boosts the signal power to a level sufficient to drive the subsequent power amplification stage.

[0084] The design of the feedback path is to capture the actual signal characteristics of the power amplifier output and provide the necessary information for the DPD algorithm. This path starts with an analog-to-digital converter, which converts the analog signal output by the power amplifier back to the digital domain, providing a basis for subsequent digital signal processing and analysis. The role of the second variable gain amplifier here is to adjust the strength of the feedback signal to ensure that it is within the optimal operating range of the analog-to-digital converter. The second digitally controlled attenuator further provides a refined amplitude control, enabling the system to adapt to output signals of different power levels. Finally, the introduction of the demodulation chip enables the system to directly analyze the characteristics of the modulated signal, thereby realizing the quality assessment of the AM modulated signal and the precise quantification of nonlinear distortion.

[0085] Based on the above embodiments, as an optional implementation manner, the system further includes a network analyzer, which is respectively connected to a spectrum analyzer, a power amplifier unit, and a computer, wherein:

[0086] The network analyzer is used to test the attenuation amount of the RF line in the system within the full frequency band and transmit the test results to the computer, so that the computer compensates the output power according to the test results.

[0087] The main task of the network analyzer in this system is to test the attenuation of the RF cable within the full frequency band. The necessity of this test stems from the fact that the RF cable exhibits different attenuation characteristics at different frequencies, and this attenuation directly affects the signal transmission quality and power. By connecting the network analyzer to the spectrum analyzer, the power amplifier unit, and the computer respectively, the system can comprehensively evaluate the performance of the entire transmission link from signal generation to final output. The network analyzer will scan the entire frequency band with a certain frequency step within the working frequency band of the system. At each frequency point, the network analyzer will measure the insertion loss of the RF cable, and this value directly reflects the power loss of the signal during transmission. During the test, the network analyzer will consider the attenuation under different power levels because the attenuation characteristics of the RF cable may change with the change of the transmission power. After the test is completed, the network analyzer will transmit the collected full-frequency band attenuation data to the computer.

[0088] In this embodiment, the power meter in the system real-time collects the power of the RF signal output by the power amplifier unit and feeds this information back to the computer. The computer compares the received actual output power data with the preset target power and dynamically generates and updates the control signal. This control mechanism based on real-time feedback enables the system to quickly respond to power deviations and continuously adjust the parameters of the excitation signal, thereby precisely controlling the output power. After receiving the control signal sent by the computer, the exciter unit can generate an optimized excitation signal to ensure that the input signal received by the power amplifier unit has been pre-adjusted, which is beneficial to improving the power amplifier efficiency and the output signal quality. The power amplifier unit amplifies the optimized excitation signal into a high-power RF signal for output, completing the entire power amplification process. Through the collaborative work of the computer, the exciter unit, the power amplifier unit, the spectrum analyzer, and the power meter, a closed-loop control system is formed, which can achieve high-precision and high-efficiency power calibration.

[0089] The embodiments of this specific implementation manner are all preferred embodiments of the present invention, and do not limit the protection scope of the present invention accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A power calibration system for a solid-state high-power AM short-wave transmitter, characterized in that, The system includes a computer, an exciter unit, a power amplifier unit, a spectrum analyzer, and a power meter. The computer is respectively connected to the exciter unit, the spectrum analyzer, and the power meter. The power amplifier unit is respectively connected to the exciter unit, the spectrum analyzer, and the power meter, where: The power meter is configured to collect the output power of the radio frequency signal of the power amplifier unit and send the output power to the computer; The computer is configured to generate a control signal and update the control signal according to the output power; The exciter unit is configured to generate an excitation signal according to the control signal of the computer and transmit the excitation signal to the power amplifier unit; The power amplifier unit is configured to amplify the excitation signal into the radio frequency signal and output the radio frequency signal.

2. The power calibration system of the solid-state high-power AM short-wave transmitter according to claim 1, wherein The power amplifier unit includes a power divider, a power amplifier module, a filter, and a coupler. The power divider is respectively connected to the exciter unit and the power amplifier module. The power amplifier module is connected to the filter. The coupler is respectively connected to the filter, the exciter unit, and the power meter, where: The power divider is configured to divide the excitation signal into multiple power amplifier signals; The power amplifier module is configured to amplify and synthesize multiple power amplifier signals into an initial radio frequency signal; The filter is configured to perform filtering processing on the initial radio frequency signal to obtain a radio frequency signal; The coupler is configured to couple out a sampling signal and an AM modulation signal from the radio frequency signal, transmit the sampling signal to the spectrum analyzer, and transmit the AM modulation signal to the exciter unit.

3. The power calibration system of the solid-state high-power AM short-wave transmitter according to claim 2, characterized in that, The power amplifier module includes a first power amplifier, a second power amplifier, a third power amplifier, a fourth power amplifier, a first synthesizer, a second synthesizer, and a third synthesizer, where: Four output terminals of the power divider are respectively connected to input terminals of the first power amplifier, the second power amplifier, the third power amplifier, and the fourth power amplifier; Two input terminals of the first synthesizer are respectively connected to an output terminal of the first power amplifier and an output terminal of the second power amplifier. Two input terminals of the second synthesizer are respectively connected to an output terminal of the third power amplifier and an output terminal of the fourth power amplifier; Two input terminals of the third synthesizer are respectively connected to an output terminal of the first synthesizer and an output terminal of the second synthesizer. An output terminal of the third synthesizer is connected to the filter.

4. The power calibration system of the solid-state high-power AM short-wave transmitter according to claim 2, characterized in that, The filter is a harmonic filter, and the operating band of the filter is any one of six bands in the short-wave 2 - 30 MHz range.

5. The power calibration system of the solid-state high-power AM short-wave transmitter according to claim 1, characterized in that, The exciter unit includes a digital signal processing module, a feedback path, and a transmission path. The digital signal processing module is respectively connected to the computer, the transmission path, and the feedback path. The transmission path and the feedback path are respectively connected to the power amplifier unit, where; The digital signal processing module is configured to receive and process the control signal sent by the computer and the feedback signal sent by the feedback path, generate an excitation signal according to the control signal and the feedback signal, and transmit the excitation signal to the transmission path; The transmission path is used to process the excitation signal and then send it to the power amplifier unit; The feedback path is used to collect the feedback signal at the output end of the power amplifier unit and transmit the feedback signal to the digital signal processing module.

6. The power calibration system of the solid-state high-power AM short-wave transmitter according to claim 5, characterized in that, The digital signal processing module includes a baseband signal processing sub-module and a DPD predistortion processing sub-module.

7. The power calibration system of the solid-state high-power AM shortwave transmitter according to claim 5, characterized in that, The transmission path includes a digital-to-analog converter, a low-pass filter, a first variable gain amplifier, a first digital controlled attenuator, and a driver amplifier; The feedback path includes an analog-to-digital converter, a first variable gain amplifier, a second digital controlled attenuator, and a demodulation chip.

8. The power calibration system of the solid-state high-power AM short-wave transmitter according to claim 1, characterized in that The system further includes a network analyzer, which is respectively connected to the spectrum analyzer, the power amplifier unit, and the computer, wherein: The network analyzer is used to test the attenuation amount of the RF line in the system within the full frequency band and transmit the test result to the computer, so that the computer compensates the output power according to the test result.

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