A testing method and system for high-power transmitter products

Abstract

The present specification relates to the field of signal measurement, and discloses a test method and system for high-power transmitter products to solve the problem of insufficient accuracy of harmonic and spurious amplitude measurement results of high-power transmitters in the prior art. The present application comprises: sequentially connecting the to-be-tested transmitter, the high-power attenuator and the EMI receiver through a cable; making the to-be-tested transmitter output a preset working signal; adjusting the scanning parameters of the EMI receiver to obtain the maximum indication value of the fundamental power level; replacing the high-power attenuator with a band-stop filter suitable for the frequency band to suppress the fundamental amplitude and obtain the transmission signal; scanning to obtain the antenna port harmonic and spurious conducted emission level; and comparing the preset test standard to obtain the test result. The present application improves the test method, effectively improves the measurement and evaluation of the antenna port harmonic and spurious conducted emission level of the key transmitter product, and improves the accuracy and operability of the laboratory in the antenna port conducted emission test process.

Description

Technical Field

[0001] This document relates to the field of signal measurement, and in particular to a test method and system for high-power transmitter products. Background Technology

[0002] Transmitters generate a rich spectrum, producing a significant amount of interference in addition to useful signals. This interference primarily includes co-channel interference, adjacent-channel interference, harmonic interference, and intermodulation interference, but harmonic interference is the most prevalent form of interference. When a transmitter operates at its maximum transmit power, the RF power amplifier operates in the nonlinear region. This amplifies the input signal to unequal values, resulting in nonlinear distortion. Furthermore, as the amplitude of the transmitter's input signal continues to increase until it exceeds the dynamic range of this nonlinear system, the amplifier's operating curve enters the saturation or cutoff region, leading to a large number of harmonics. High-frequency harmonic components can interfere with other devices along conductors or power lines, making harmonic interference a typical form of interference signal in electronic equipment. Methods for measuring and evaluating harmonic distortion in high-power transmitters or high-frequency products can be applied to the CE106 test item in GJB151B. The CE106 test item is applicable to port measurements of transmitter, receiver and amplifier equipment. It is an important way to evaluate the harmonic and spurious output amplitude of the transmitter in GJB151B-2013, and prevent it from being interfered with during operation, which would cause a reduction in performance.

[0003] Currently, accurate measurement of harmonics and spurious interference faces the following difficulties. High-power transmitters typically have high amplitude and wide bandwidth, making accurate measurement of harmonics and spurious interference challenging. Therefore, during high-power equipment measurement tests, existing suppression networks are used to attenuate the signal in the fundamental frequency band, or high-attenuation, wide-band attenuators are placed at the receiver front end. However, existing electromagnetic compatibility laboratory suppression networks have narrow bandwidths; high-suppression networks have bandwidths below 10kHz, making it difficult to effectively suppress the transmitter's fundamental signal and affecting the accuracy of harmonic and spurious interference amplitude measurements. While attenuating the fundamental signal amplitude, attenuators also attenuate lower-power spurious signals, requiring correction of the attenuation coefficient. The corrected attenuation coefficient curve is then inflated due to the addition of attenuators, causing low-amplitude spurious signals and second and third harmonics to be submerged by noise, making accurate measurement impossible and affecting the performance evaluation of transmitters and radar power amplifiers. Summary of the Invention

[0004] This specification provides a testing method for high-power transmitter products to address the problems in existing technologies where suppression networks have narrow bandwidths (high-suppression networks typically have bandwidths below 10kHz), making it difficult to effectively suppress the transmitter's fundamental signal and affecting the accuracy of harmonic and spurious amplitude measurements. It also addresses the issue that attenuators, while attenuating the fundamental signal amplitude, also attenuate lower-power spurious signals, requiring correction of the attenuation coefficient. Furthermore, the corrected attenuation coefficient curve is then inflated due to the addition of the attenuator, causing low-amplitude spurious signals and second and third harmonics to be submerged by noise, hindering accurate measurement and impacting the performance evaluation of transmitters and radar power amplifiers.

[0005] A testing method for high-power transmitter products according to the present invention includes:

[0006] Each transmitter under test (EUT) is tested through a high-power attenuator, a band-stop filter, and an EMI receiver;

[0007] Connect the transmitter under test, the high-power attenuator, and the EMI receiver sequentially via cables to obtain a test equipment group;

[0008] To bring the transmitter under test into a stable working state and emit a working signal at a preset working frequency f0;

[0009] Adjust the scanning parameters of the EMI receiver to obtain the maximum indicated value of the fundamental power level at the operating frequency f0;

[0010] Replace the high-power attenuator in the test equipment group with a band-stop filter that is adapted to the stopband frequency band of the working signal to suppress the fundamental amplitude and obtain the transmitted signal.

[0011] The transmitted signal is scanned within a preset project frequency range by an EMI receiver, and the harmonic spurious limit is obtained based on the maximum indication value of the fundamental power level. Then, the harmonic and spurious conducted transmission levels at the antenna port are measured. The attenuation coefficient and insertion loss of the path are used for correction to obtain accurate measurement values ​​of harmonics and accurate measurement values ​​of spurious conducted transmission levels.

[0012] Compare the accurate measured values ​​of the harmonics and the accurate measured values ​​of the spurious conducted emission level to see if they meet the preset test standards; if they do, the test result of the transmitter under test is passed; otherwise, the test result of the transmitter under test is failed.

[0013] In some preferred embodiments, the process of bringing the transmitter under test into a stable operating state is achieved by preheating it by energizing it in advance.

[0014] In some preferred embodiments, the scanning parameters include receiver bandwidth, measurement time, fundamental scanning frequency range, scanning step, and input attenuation.

[0015] In some preferred embodiments, the scanning frequency range is specifically the greater of ±5% of the operating signal bandwidth or ±5% of the operating signal base frequency.

[0016] In some preferred embodiments, after obtaining the antenna port harmonics and spurious conducted emission levels, the method further includes a step of confirming that the antenna port harmonics and spurious conducted emission levels originate from the transmitter under test rather than the test equipment group. Specifically, this involves scanning with an EMI receiver while the transmitter is in standby mode. If the EMI receiver does not display a signal, it is determined that the antenna port harmonics and spurious conducted emission levels originate from the transmitter under test.

[0017] In some preferred embodiments, the preset test standard is specifically set according to GJB151B-2013, under the stable operating state of the transmitter under test, the second and third harmonic emissions in the accurate harmonic measurement values ​​are not greater than -20dBm or lower than the fundamental level of the operating frequency f0 by 80dB, whichever is higher, and all other accurate harmonic measurement values ​​and spurious conducted emission level accurate measurement values ​​are less than the peak value of the fundamental level of the operating frequency f0 by 80dB.

[0018] In another aspect, the present invention provides a test system for high-power transmitter products, the system being implemented based on a high-power attenuator, a band-stop filter, and an EMI receiver;

[0019] Connect the transmitter under test, high-power attenuator, and EMI receiver sequentially via cables to obtain the test equipment group;

[0020] The signal transmitting module is configured to enable the transmitter under test to enter a stable working state by transmitting a working signal at a preset working frequency f0.

[0021] The maximum power level indication module is configured to adjust the scanning parameters of the EMI receiver to obtain the maximum power level indication value of the fundamental frequency at the operating frequency f0.

[0022] The band-stop filter replacement module is configured to replace the high-power attenuator in the test equipment group with a band-stop filter adapted to the stopband frequency band of the working signal, thereby suppressing the fundamental amplitude and obtaining the transmitted signal.

[0023] The data receiving module is configured to scan the transmitted signals within a preset project frequency range using an EMI receiver, and obtain the harmonic spurious limit based on the maximum indication value of the fundamental power level, thereby measuring the harmonics and spurious conducted transmission levels at the antenna port. The attenuation coefficient and insertion loss of the path are used for correction to obtain accurate measurement values ​​of the harmonics and spurious conducted transmission levels.

[0024] The data evaluation module is configured to compare whether the accurate measurement value of the harmonics and the accurate measurement value of the spurious conducted emission level meet the preset test standards; if they meet the standards, the test result of the transmitter under test is passed; otherwise, the test result of the transmitter under test is failed.

[0025] In some preferred embodiments, the scanning parameters include receiver bandwidth, measurement time, fundamental scanning frequency range, scanning step, and input attenuation.

[0026] In some preferred embodiments, the fundamental frequency range is specifically the greater of ±5% of the operating signal bandwidth or ±5% of the operating signal fundamental frequency.

[0027] In some preferred embodiments, the method further includes a step of confirming that the antenna port harmonics and spurious conducted emission levels originate from the transmitter under test rather than the test equipment group. Specifically, this involves scanning with an EMI receiver while the transmitter is in standby mode. If the EMI receiver does not display a signal, it is determined that the antenna port harmonics and spurious conducted emission levels originate from the transmitter under test.

[0028] The above-described at least one technical solution adopted in the embodiments of this specification can achieve the following beneficial effects:

[0029] The test method proposed in this invention is applied to the measurement and testing of conducted emissions (CE106) at the antenna port of a radar transmitter. By improving the test method, it effectively enhances the measurement and evaluation of antenna port harmonics and spurious conducted emission levels for key transmitter products. This improves the accuracy and operability of the laboratory's antenna port conducted emission testing process. Attached Figure Description

[0030] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0031] Figure 1 This is a flowchart illustrating a testing method for a high-power transmitter product according to an embodiment of this application.

[0032] Figure 2 This is a schematic diagram of the connection of the test equipment group in one embodiment of this application;

[0033] Figure 3 This is a schematic diagram showing the measurement results of the fundamental peak value of the transmitter product in the range of 1.5 GHz to 2.0 GHz in one embodiment of this application;

[0034] Figure 4 This is a schematic diagram showing the measurement results of the fundamental peak value of the transmitter product in the range of 2.0 GHz to 2.5 GHz in one embodiment of this application. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] To address the harmonic and spurious output characteristics of radar transmitters, a measurement technique for small-signal harmonics and spurious emissions under high-power fundamental frequency backgrounds has been developed using band-stop filters and high-power attenuators. This technique can solve the electromagnetic compatibility (EMC) evaluation problem of high-power system transmitters. During the measurement process, stopband suppression is added within the fundamental frequency band to prevent the high-power attenuator from raising the noise floor and drowning out the target's small signal. Furthermore, the passband insertion loss of the band-stop filter is corrected, making the measurement results within the passband more accurate. This measurement method can be applied to the conducted emission (CE106) measurement test at the antenna port of the GJB151B radar transmitter. By refining the test method, it effectively improves the measurement and evaluation of harmonic and spurious emissions from critical transmitters.

[0037] The high-power microwave signals generated by high-power microwave transmitters in radar equipment are always accompanied by harmonic components, which degrade the performance of microwave systems. Over the years, much discussion on the harmonic handling of high-power microwave signals has focused on: (1) the harmonic components accompanying high-power microwave transmitters seriously affect the technical performance of microwave systems; (2) it is difficult to accurately measure and evaluate harmonic levels, causing contradictions in evaluation between the supply and demand sides; (3) the fundamental frequency loss is too large during harmonic suppression. Furthermore, GJB151A and GJB151B stipulate that the emission state limits of transmitters and amplifiers, except for the second and third harmonics, all harmonic emissions and spurious emissions should be at least 80dB lower than the fundamental frequency level, and the second and third harmonics should be suppressed to -20dBm or 80dB lower than the fundamental frequency level, taking the higher limit. The national military standard has very strict requirements for the harmonic emissions and spurious emissions of transmitters, so it is necessary to accurately measure the harmonics and spurious emissions of high-power transmitters.

[0038] The technical solutions provided by the various embodiments of this application are described in detail below with reference to the accompanying drawings.

[0039] Figure 1 This document provides a flowchart illustrating a testing method for high-power transmitter products, as part of one embodiment. This method effectively improves the measurement and evaluation of antenna port harmonics and spurious conducted emission levels for critical transmitter products. It enhances the accuracy and operability of laboratory tests for conducted emissions at antenna ports. (See also...) Figure 1The method may specifically include the following steps:

[0040] Each transmitter under test was tested using a high-power attenuator, a band-stop filter, and an EMI receiver.

[0041] Step S100: Connect the transmitter under test, high-power attenuator, and EMI receiver sequentially via cables to obtain a test equipment group. For example... Figure 2 As shown, an RF cable can be used.

[0042] Step S200: The transmitter under test is brought into a stable working state and emits a working signal at a preset working frequency f0. In this embodiment, the process of bringing the transmitter under test into a stable working state is achieved by preheating it by powering it on in advance.

[0043] Step S300: Adjust the scanning parameters of the EMI receiver to obtain the maximum indication value of the fundamental power level at the operating frequency f0; in this embodiment, the scanning parameters include receiver bandwidth, measurement time, fundamental scanning frequency range, scanning step, and input attenuation.

[0044] The scanning frequency range is specifically the greater of ±5% of the operating signal bandwidth or ±5% of the operating signal base frequency.

[0045] Step S400: Replace the high-power attenuator in the test equipment group with a band-stop filter adapted to the stopband frequency band of the working signal to suppress the fundamental amplitude and obtain the transmitted signal. By adding stopband suppression within the fundamental frequency band, the high-power attenuator is prevented from raising the noise floor and drowning out the target small signal, and the passband insertion loss of the band-stop filter is corrected, making the measurement results in the passband more accurate. Filters that suppress signal spurious radiation are usually band-pass or band-stop filters. Band-pass filters allow the working signal of a specific frequency to pass through without attenuation, while band-stop filters prevent interference signals of a certain frequency from passing through smoothly. Because band-pass filters are not as good as band-stop filters in ensuring that the working signal has low insertion loss and return loss, and band-stop filters can often withstand greater power than band-pass filters, band-stop filters have good application prospects in applications that separate narrowband strong interference signals from the working signal.

[0046] To accurately measure harmonics and spurious small signals from high-power transmitters, a band-stop filter is used to remove the fundamental high-power signal before the RF input signal enters the receiver. This ensures the power level at the input port meets requirements, avoids saturation nonlinearity in the mixer caused by the fundamental high-power signal, and increases the measurement dynamic range, ensuring lossless measurement of the spurious small signals. Therefore, a shortwave band-stop filter capable of handling high-power signals is used. This filter effectively removes the fundamental signal, has a flat out-of-band performance, and provides almost no loss to the spurious signals to be measured, thus meeting the measurement requirements.

[0047] Step S500: Scan the transmitted signal within the preset project frequency range using an EMI receiver, and obtain the harmonic spurious limit based on the maximum indication value of the fundamental power level. Then, measure the harmonics and spurious conducted transmission level at the antenna port. Correct the values ​​by using the path attenuation coefficient and insertion loss to obtain accurate measurements of the harmonics and spurious conducted transmission level.

[0048] In this embodiment, after obtaining the antenna port harmonics and spurious conducted emission levels, the method further includes a step of confirming that the antenna port harmonics and spurious conducted emission levels originate from the transmitter under test rather than the test equipment group. Specifically, when the transmitter is in standby mode, a scan is performed using an EMI receiver. If the EMI receiver does not display a signal, it is determined that the antenna port harmonics and spurious conducted emission levels originate from the transmitter under test.

[0049] Step S600: Compare whether the accurate measured value of the harmonics and the accurate measured value of the spurious conducted emission level meet the preset test standards; if they meet the standards, the test result of the transmitter under test is passed; otherwise, the test result of the transmitter under test is failed.

[0050] In this embodiment, the preset test standard is specifically set according to GJB151B-2013, under the stable operating state of the transmitter under test, the second and third harmonic emissions in the accurate harmonic measurement values ​​are not greater than -20dBm or lower than the fundamental level of the operating frequency f0 by 80dB, whichever is higher, and all other accurate harmonic measurement values ​​and spurious conducted emission level accurate measurement values ​​are less than the peak value of the fundamental level of the operating frequency f0 by 80dB.

[0051] The results of CE106 tests conducted using the method of this invention with different models of high-power radar equipment, such as... Figure 3 and Figure 4 As shown, Figure 3 For the transmitter's fundamental peak frequency to be in the range of 1.5 GHz to 2.0 GHz, a band-stop filter with the corresponding stopband suppression frequency band was selected, and the harmonics and spurious emissions in the range of 1 MHz to 40 GHz were measured. The measurement results showed that the harmonics and spurious emissions were within the standard limits, and the project passed. Figure 4 With the fundamental peak frequency of the transmitter in the range of 2.0 GHz to 2.5 GHz, a band-stop filter with a corresponding stopband suppression frequency band was selected. Harmonics and spurious emissions in the range of 1 MHz to 40 GHz were measured. The measurement results showed that the fundamental peak frequency was 142.39 dBμV, and the second and third harmonic emissions were no greater than 87 dBμV. The project passed.

[0052] In this embodiment, a band-stop filter is used to suppress the fundamental power during measurement, thereby preventing harmonics and spurious signals from being overwhelmed by bottom noise through attenuators, and accurately obtaining the measurement results of harmonics and spurious signals emitted by the transmitter. Ideally, the filter should have no loss in the passband, but in actual design, it is impossible to have no loss at all. Insertion loss describes the power loss in the passband caused by the insertion of the filter. Therefore, the insertion loss in the passband of the band-stop filter is corrected before testing, and the compensation coefficient in the passband frequency band is obtained and the amplitude is corrected to ensure accurate measurement of harmonics and spurious signals while suppressing the fundamental power.

[0053] A second embodiment of the present invention proposes a test system for high-power transmitter products, the system being implemented based on a high-power attenuator, a band-stop filter, and an EMI receiver;

[0054] Connect the transmitter under test, high-power attenuator, and EMI receiver sequentially via cables to obtain the test equipment group;

[0055] The signal transmitting module is configured to enable the transmitter under test to enter a stable working state by transmitting a working signal at a preset working frequency f0.

[0056] The maximum power level indication module is configured to adjust the scanning parameters of the EMI receiver to obtain the maximum power level indication value of the fundamental frequency at the operating frequency f0. In this embodiment, the scanning parameters include receiver bandwidth, measurement time, fundamental frequency scanning range, scanning step, and input attenuation. The fundamental frequency scanning range is specifically the greater of ±5% of the operating signal bandwidth or ±5% of the operating signal fundamental frequency.

[0057] The band-stop filter replacement module is configured to replace the high-power attenuator in the test equipment group with a band-stop filter adapted to the stopband frequency band of the working signal, thereby suppressing the fundamental amplitude and obtaining the transmitted signal.

[0058] The data receiving module is configured to scan the transmitted signals within a preset project frequency range using an EMI receiver, and obtain the harmonic spurious limit based on the maximum indication value of the fundamental power level. This allows for the measurement of antenna port harmonics and spurious conducted emission levels. Corrections are made using the path attenuation coefficient and insertion loss to obtain accurate harmonic and spurious conducted emission level measurements. In this embodiment, the module also includes a step to confirm that the antenna port harmonics and spurious conducted emission levels originate from the transmitter under test rather than the test equipment group. Specifically, this involves scanning with an EMI receiver while the transmitter is in standby mode. If the EMI receiver does not display a signal, it is determined that the antenna port harmonics and spurious conducted emission levels originate from the transmitter under test.

[0059] The data evaluation module is configured to compare whether the accurate measurement values ​​of harmonics and spurious signals meet the preset test standards; if they do, the test result of the transmitter under test is passed; otherwise, the test result of the transmitter under test is failed.

[0060] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A test method for high-power transmitter products, characterized in that, The method includes: Each transmitter under test was tested using a high-power attenuator, a band-stop filter, and an EMI receiver. Connect the transmitter under test, the high-power attenuator, and the EMI receiver sequentially via cables to obtain a test equipment group; To bring the transmitter under test into a stable operating state and transmit at the preset operating frequency. f 0 is the working signal; Adjust the scanning parameters of the EMI receiver to obtain the operating frequency. f Maximum indicated value of fundamental power level at 0; Replace the high-power attenuator in the test equipment group with a band-stop filter that is adapted to the stopband frequency band of the working signal to suppress the fundamental amplitude and obtain the transmitted signal. The transmitted signal is scanned within a preset project frequency range by an EMI receiver, and the harmonic spurious limit is obtained based on the maximum indication value of the fundamental power level. Then, the harmonic and spurious conducted transmission levels at the antenna port are measured. The attenuation coefficient and insertion loss of the path are used for correction to obtain accurate measurement values ​​of harmonics and accurate measurement values ​​of spurious conducted transmission levels. Compare the accurate measured values ​​of the harmonics and the accurate measured values ​​of the spurious conducted emission level to see if they meet the preset test standards; if they do, the test result of the transmitter under test is passed; otherwise, the test result of the transmitter under test is failed. It also includes the step of confirming that the antenna port harmonics and spurious conducted emission levels come from the transmitter under test rather than the test equipment group. Specifically, when the transmitter is in standby mode, it is scanned by an EMI receiver. If the EMI receiver does not display a signal, it is determined that the accurate measurement values ​​of the harmonics and spurious conducted emission levels come from the transmitter under test.

2. The test method for high-power transmitter products according to claim 1, characterized in that, The process of bringing the transmitter under test into a stable working state is achieved by preheating it by powering it on in advance.

3. The test method for high-power transmitter products according to claim 1, characterized in that, The scanning parameters include receiver bandwidth, measurement time, fundamental frequency range, scanning step, and input attenuation.

4. The test method for high-power transmitter products according to claim 3, characterized in that, The fundamental frequency range is specifically the greater of ±5% of the operating signal bandwidth or ±5% of the operating signal fundamental frequency.

5. The test method for high-power transmitter products according to claim 1, characterized in that, The preset test standard is specifically set according to GJB151B-2013, under the stable operating condition of the transmitter under test, the second and third harmonic emissions in the accurate harmonic measurement value are not greater than -20dBm or lower than the operating frequency. f The higher of the 0 fundamental level and 80dB is selected, and the accurate measurements of all other harmonics and the accurate measurements of the spurious conducted emission level are all less than the operating frequency. f The peak value of the fundamental frequency is 80dB.

6. A test system for high-power transmitter products, characterized in that, The system is implemented based on a high-power attenuator, a band-stop filter, and an EMI receiver. Connect the transmitter under test, high-power attenuator, and EMI receiver sequentially via cables to obtain the test equipment group; The signal transmitting module is configured to transmit a preset operating frequency to bring the transmitter under test into a stable operating state. f 0 is the working signal; The maximum level indication value acquisition module is configured to adjust the scanning parameters of the EMI receiver to obtain the operating frequency. f Maximum indicated value of fundamental power level at 0; The band-stop filter replacement module is configured to replace the high-power attenuator in the test equipment group with a band-stop filter adapted to the stopband frequency band of the working signal, thereby suppressing the fundamental amplitude and obtaining the transmitted signal. The data receiving module is configured to scan the transmitted signals within a preset project frequency range using an EMI receiver, and obtain the harmonic spurious limit based on the maximum indication value of the fundamental power level, thereby measuring the harmonics and spurious conducted transmission levels at the antenna port. The attenuation coefficient and insertion loss of the path are used for correction to obtain accurate measurements of the harmonics and spurious conducted transmission levels. The data evaluation module is configured to compare whether the accurate measurement value of the harmonics and the accurate measurement value of the spurious conducted emission level meet the preset test standards; if they meet the standards, the test result of the transmitter under test is passed; otherwise, the test result of the transmitter under test is failed. It also includes a module to confirm that the antenna port harmonics and spurious conducted emission levels come from the transmitter under test rather than the test equipment group. It is configured to scan through the EMI receiver when the transmitter is in standby mode. If the EMI receiver does not display a signal, it is determined that the antenna port harmonics and spurious conducted emission levels come from the transmitter under test.

7. The test system for high-power transmitter products according to claim 6, characterized in that, The scanning parameters include receiver bandwidth, measurement time, fundamental frequency range, scanning step, and input attenuation.

8. The test system for high-power transmitter products according to claim 7, characterized in that, The fundamental frequency range is specifically the greater of ±5% of the operating signal bandwidth or ±5% of the operating signal fundamental frequency.

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