Radio frequency harmonic distortion test system

Abstract

The utility model provides a radio frequency harmonic distortion test system, which is used for carrying out harmonic test on a to-be-tested object and comprises a signal generator; the first power divider is used for dividing the fundamental wave signal into a first path of signal and a second path of signal; a first branch circuit, wherein the first path of signal enters the first branch circuit; a second branch circuit, wherein the second path of signal enters the second branch circuit; and the second power divider is connected with the output end of the first branch and the output end of the second branch and is used for combining the first branch signal and the second branch signal, and the combined signal is output to harmonic test equipment. Phase shifting is carried out on interference signals through the first branch and the second branch, so that the interference signals are offset after combination, and only third harmonic signals needing to be tested are reserved.

Description

Technical Field

[0001] This application relates to the field of radio frequency, and in particular to a radio frequency harmonic distortion testing system. Background Technology

[0002] Radio frequency (RF) harmonic distortion (HDC) testing is a method used to evaluate the harmonic components in the output signal of an RF system or device. RF HDC refers to harmonic components with frequencies that are integer multiples of the fundamental frequency, generated during the transmission, processing, or amplification of an RF signal due to the nonlinear characteristics of the system. For example, in single-tone IIP3 (Input Third-order Intercept Point) testing, it is necessary to measure the fundamental power entering the device under test (DUT) and the third harmonic power generated by the fundamental power exciting the DUT's RF substrate. The DUT can be a device under test, a chip under test (DUT), or an RF substrate under test, etc.

[0003] However, since the fundamental wave of the test object is excited by a high-power signal, it remains a high-power signal after passing through the test object. If passive devices such as attenuators and high-pass filters are connected after the test object, the high-power signal will excite the third harmonic of the subsequent passive devices such as attenuators and high-pass filters, thereby affecting the measurement accuracy of the third harmonic power generated by the RF substrate under test itself. Utility Model Content

[0004] This application proposes a radio frequency harmonic distortion testing system that can eliminate the influence of third harmonics generated by passive devices in existing testing systems on the test results.

[0005] This radio frequency harmonic distortion testing system is used to perform harmonic testing on the object under test. It includes: a signal generator for generating a fundamental frequency signal; a first power divider for dividing the fundamental frequency signal into a first signal and a second signal; a first branch into which the first signal enters; and a second branch into which the second signal enters. The first branch or the main branch before the first power divider has a connection point for the object under test. The devices installed in the first and second branches satisfy the following conditions: the first signal, after passing through the devices installed in the first branch, outputs a first branch signal; the second signal, after passing through the devices installed in the second branch, outputs a second branch signal; the first signal in the first branch signal is filtered out. The second signal in the second branch signal is filtered out. The first branch signal contains the harmonic signal of the object under test. The harmonic signal generated by the device on the first branch is out of phase with the harmonic signal generated by the device on the second branch. Alternatively, the first branch signal contains the fundamental signal and harmonic signal of the object under test, and the second branch signal contains the fundamental signal and harmonic signal of the object under test. The fundamental signal in the first branch signal and the second branch signal are out of phase, and the harmonic signals are in phase. A second power divider is connected to the output terminal of the first branch and the output terminal of the second branch. It is used to combine the first branch signal and the second branch signal. The combined signal is output to the harmonic testing equipment.

[0006] Optionally, the first branch includes: the connection position of the object under test and a first high-pass filter, wherein the object under test receives the first signal and outputs the first signal and the harmonic signal of the object under test; the first high-pass filter is used to filter out the first signal output by the object under test and output the harmonic signal of the object under test and the harmonic signal filtered by the first high-pass filter.

[0007] The second branch includes: a second high-pass filter, which is used for the second signal and outputs the harmonic signal of the second high-pass filter; wherein the harmonic signals of the first high-pass filter and the second high-pass filter are in phase.

[0008] The first branch and / or the second branch further includes a first phase shifter for shifting the phase of the harmonic signal of the first high-pass filter or the second high-pass filter, such that the phase difference between the harmonic signals of the first high-pass filter and the second high-pass filter is 180 degrees.

[0009] Optionally, the second branch further includes a second phase shifter connected between the first power divider and the second high-pass filter; wherein,

[0010] The phase shift angle of the second phase shifter on the first signal is the same as the phase shift angle of the object under test on the second signal.

[0011] Optionally, the first phase shifter and / or the second phase shifter may include a transmission line phase shifter.

[0012] Optionally, the first branch further includes a first attenuator connected between the object under test and the first high-pass filter for attenuating the signal output by the object under test, wherein the first attenuator generates the harmonic signal of the first attenuator;

[0013] The second branch also includes a second attenuator connected between the second phase shifter and the second high-pass filter, used to attenuate the signal output by the second phase shifter, and the second attenuator generates the harmonic signal of the second attenuator;

[0014] The first phase shifter is further configured to shift the phase of the harmonic signal of the first attenuator or the second attenuator, such that the phase difference between the harmonic signals of the first attenuator and the second attenuator is 180 degrees.

[0015] Optionally, the first high-pass filter and the second high-pass filter have the same structure.

[0016] Optionally, the object under test is located between the signal generator and the first power divider;

[0017] The first power divider receives the fundamental signal and the harmonic signal of the object under test. The first power divider also divides the harmonic signal of the object under test into a first sub-harmonic signal and a second sub-harmonic signal, and outputs them to the first branch and the second branch respectively.

[0018] The first branch and / or the second branch further includes a phase shifting module for shifting the phase of the signals of the first branch and / or the second branch, such that the phase difference between the first signal and the second signal is 180°, and the phases of the first sub-harmonic signal and the second sub-harmonic signal are the same.

[0019] Optionally, the phase shifting module includes a first phase shifter and a second phase shifter, both of which are located in the second branch;

[0020] The first phase shifter is used to shift the second signal by 90 degrees and shift the second sub-harmonic signal by 270 degrees;

[0021] The second phase shifter is used to shift the second signal and the second sub-harmonic signal by 90 degrees respectively.

[0022] Optionally, the phase shifting module includes a first phase shifter and a second phase shifter, wherein the first phase shifter is located in the first branch and the second phase shifter is located in the second branch;

[0023] The first phase shifter is used to shift the second signal by 90 degrees and shift the second sub-harmonic signal by 270 degrees;

[0024] The second phase shifter is used to shift the first signal and the first sub-harmonic signal by 90 degrees respectively.

[0025] Optionally, the first phase shifter is a transmission line phase shifter, and the second phase shifter is a broadband phase shifter.

[0026] Optionally, it also includes:

[0027] A power amplifier, connected between the signal generator and the first power divider, is used to amplify the fundamental signal generated by the signal generator;

[0028] A filtering device is connected between the power amplifier and the first power divider to filter out harmonic signals from the power amplifier.

[0029] Optionally, the filtering device is a low-pass filter; or,

[0030] The filtering device includes:

[0031] The third power divider is used to divide the harmonic signal of the power amplifier into a first interference signal and a second interference signal.

[0032] The third branch is used to transmit the first interference signal;

[0033] The fourth branch is used to transmit the second interference signal, and the fourth branch includes a third phase shifter for shifting the second interference signal by 180 degrees.

[0034] The fourth power divider connects the third branch and the fourth branch, and combines the output signals of the third branch and the fourth branch.

[0035] Optionally, the third phase shifter is a transmission line phase shifter.

[0036] Optionally, the first power divider and / or the second power divider may include any one of a resistive power divider, a waveguide power divider, a coaxial power divider, or a microstrip power divider.

[0037] Optionally, the first signal and the second signal have the same power.

[0038] Optionally, the harmonic testing equipment includes a spectrum analyzer.

[0039] The radio frequency harmonic distortion testing system proposed in this application can be used to perform harmonic testing on the object under test. The fundamental frequency signal will cause harmonic signals to be generated in the object under test. The first power divider splits the fundamental frequency signal generated by the signal generator into two signals and inputs them into two branches. Through the devices set in the two branches, the fundamental frequency signals on the two signal branches are made to have a phase difference of 180 degrees (opposite phase). Thus, after being combined by the second power divider, the fundamental frequency signal is eliminated, thereby eliminating unwanted signals (including the fundamental frequency signal) in the harmonic distortion test.

[0040] The radio frequency harmonic distortion test system used in this application splits the signal into two paths to eliminate the fundamental signal before the signal enters the spectrum analyzer, which greatly improves the accuracy of radio frequency harmonic distortion test; at the same time, the power divider and other components used are low-cost, which can effectively reduce costs. Attached Figure Description

[0041] Figure 1 It is a third harmonic measurement system.

[0042] Figure 2 This is a radio frequency harmonic distortion testing system according to an embodiment of this application.

[0043] Figure 3 This is a schematic diagram of the structure of a radio frequency harmonic distortion testing system according to an embodiment of this application.

[0044] Figure 4 This is a schematic diagram of the structure of a radio frequency harmonic distortion testing system according to an embodiment of this application. Detailed Implementation

[0045] like Figure 1 As shown, a third harmonic measurement system typically includes the following components:

[0046] Signal generator: generates a fundamental frequency signal (frequency f1, corresponding wavelength λ1);

[0047] Power amplifier: Amplifies the fundamental signal generated by the signal generator. The power amplifier will generate the third harmonic signal (frequency f3, corresponding wavelength λ3, where f3 = f1 * 3, λ3 = λ1 / 3).

[0048] Low-pass filter: filters out the third harmonic signal generated by the signal generator and power amplifier to ensure that the fundamental signal entering the device under test is relatively pure;

[0049] Device under test: Receives the fundamental frequency signal and generates the third harmonic signal of the device under test;

[0050] Attenuator: Attenuates the power of the fundamental and third harmonic signals output by the device under test, reduces the impact of the high-power fundamental signal on subsequent devices, and reduces the signal power of the fundamental signal reflected back to the device under test at the high-pass filter.

[0051] High-pass filter: Filters out the fundamental signal and retains the third harmonic signal of the device under test, ensuring that the fundamental signal will not excite the spectrum analyzer's own harmonic signal, thereby reducing the impact of the spectrum analyzer's own harmonic signal on the test results.

[0052] Ideally, after the fundamental signal generated by the signal generator passes through the aforementioned devices, only the third harmonic signal generated by the object under test (including the device under test or component under test) will enter the spectrum analyzer for testing. However, since the fundamental signal also excites passive devices such as attenuators and high-pass filters to generate harmonic signals (also third harmonic signals, with frequencies similar to the third harmonic signal of the device under test), this affects the detection results of the third harmonic signal of the device under test.

[0053] Therefore, this application proposes a novel radio frequency harmonic distortion testing system to avoid interference signals (such as harmonic signals generated by passive devices such as attenuators and high-pass filters) affecting the third harmonic signal to be tested when performing harmonic testing on the object under test.

[0054] Figure 2 This is a schematic diagram of the radio frequency harmonic distortion testing system of this application, which mainly includes: a signal generator 201, a first power divider 202, a first branch 203, a second branch 204, and a second power divider 205. The signal generator 201 generates a fundamental frequency signal to excite the object under test (DUT) to generate the required third harmonic signal. The first power divider 202 is connected to the output of the signal generator 201 and is used to divide the fundamental frequency signal into a first signal and a second signal. The first signal enters the first branch 203, and the second signal enters the second branch 204. The DUT 206 can be connected to the first branch 203, or connected to the main circuit before the fundamental frequency signal is divided by the first power divider 201, for example... Figure 2 The dashed box in the diagram indicates the optional connection position for the object under test 206. The second power divider 205 connects to the output terminals of the first branch 203 and the second branch 204, and is used to combine the first branch signal output from the first branch 203 with the second branch signal output from the second branch 204, and output the combined signal to the harmonic testing equipment 207, such as a spectrum analyzer. Furthermore, the first power divider and / or the second power divider can include any one of a resistive power divider, a waveguide power divider, a coaxial power divider, or a microstrip power divider.

[0055] In one embodiment, the first branch 203 and / or the second branch 204 may also be provided with some devices, such that the first signal is filtered out after passing through the devices provided on the first branch 203, and the second signal is filtered out after passing through the devices provided on the second branch 203. That is, the first branch signal output by the first branch 203 does not include the first signal, and retains the harmonic signals of the object under test 206 (e.g., the third harmonic signal, or the second harmonic signal, the fourth harmonic signal, etc.), and the second branch signal output by the second branch 204 does not include the second signal. The harmonic signals generated by the devices provided on the first branch 203 are out of phase with the harmonic signals generated by the devices provided on the second branch 204. Therefore, the combining function of the second power divider 205 can be used. When the first branch 203 and the second branch 204 are combined, the harmonic signals generated by the devices provided on the first branch 203 cancel out the harmonic signals generated by the devices provided on the second branch 204, thereby retaining only the required harmonic signals of the object under test.

[0056] Alternatively, in another embodiment, both the first branch signal and the second branch signal include the fundamental and harmonic signals of the object under test. The difference from one embodiment is that the fundamental signals in the first and second branch signals are out of phase, while the harmonic signals of the object under test (e.g., the third harmonic signal, or the second, fourth, etc.) are in phase. Therefore, the combining function of the second power divider 205 can be used to cancel out the fundamental signals in the first and second branch signals, thus retaining only the desired harmonic signals of the object under test.

[0057] It is understood that in the two implementations described above, the power of the first signal and the second signal is the same, so that the interference signals generated based on the first signal and the second signal can cancel each other out after being combined. The aforementioned interference signals are the fundamental signal and / or the interference harmonic signals generated by the devices in the first branch.

[0058] Next reference Figures 3-4 The two implementation methods described above will be explained in detail based on an example circuit structure.

[0059] like Figure 3 As shown, the object under test 206 is set on the first branch 203, which also includes a first high-pass filter 301. The input terminal of the first power divider 202 is used to connect to the output terminal of the signal generator 201. The fundamental signal generated by the signal generator 201 is divided into two paths by the first power divider. Both the first and second paths include the divided fundamental signal.

[0060] For the first branch 203, the device under test (DUT) 206 is connected to an output terminal of the first power divider 202, and the input terminal of the first high-pass filter 301 is connected to the output terminal of the DUT 206. After receiving the first signal, the DUT 206 generates a third harmonic signal and outputs both the first signal and the third harmonic signal. Since the frequency of the third harmonic signal is three times the frequency of the fundamental signal, the first signal is filtered out after the first signal and the third harmonic signal output by the DUT 206 pass through the first high-pass filter 301. However, the first signal also generates a first interference harmonic signal in the first high-pass filter 301. This first interference harmonic signal is a harmonic signal generated by the first high-pass filter 301 and will interfere with the third harmonic signal of the DUT 206. Therefore, the output signal of the first high-pass filter 301 (i.e., the first branch signal) includes both the third harmonic signal of the DUT 206 and the first interference harmonic signal.

[0061] A second high-pass filter 302 and a first phase shifter 303 are provided on the second branch 204. The second high-pass filter 302 is connected to the other output terminal of the first power divider 202, and the input terminal of the first phase shifter 303 is connected to the output terminal of the second high-pass filter 302. The second high-pass filter 302 is used to simulate the first high-pass filter 301. Since the power divider divides power into the same first signal and second signal, the second high-pass filter 302 will be excited by the second signal to generate a second interference harmonic signal that is the same as the first interference harmonic signal. Therefore, a first phase shifter 303 can be set after the second high-pass filter 302 to shift the phase of the second interference harmonic signal, so that the phase difference between the first interference harmonic signal and the second interference harmonic signal is 180 degrees. For example, when the phase of the fundamental signal is 0 degrees, the first phase shifter can shift the phase by 180 degrees. In addition, a 90-degree phase shifter can be installed in the first branch 203 and the second branch 204 respectively. One 90-degree phase shifter shifts the phase by 90 degrees in the positive direction, and the other 90-degree phase shifter shifts the phase by 90 degrees in the negative direction, so that the phase difference between the first interference harmonic signal and the second interference harmonic signal is still 180 degrees.

[0062] Therefore, in this circuit structure, the fundamental signal in the first branch has been filtered out by the first high-pass filter, and the fundamental signal in the second branch has been filtered out by the second high-pass filter. The interference harmonic signals generated by the first and second high-pass filters cancel each other out after being combined by the second power divider. In addition, the first branch signal output from the first branch includes the third harmonic signal of the object under test 206, and the second branch signal output from the second branch does not include the third harmonic signal of the object under test 206. When the combined signal can retain the third harmonic signal of the object under test 206, the signal input to the harmonic testing equipment only retains the third harmonic signal generated by the object under test 206.

[0063] In some embodiments, the first high-pass filter 301 and the second high-pass filter 302 must have identical structural performance and connection relationship in order to ensure that the generated first interference harmonic signal and the second interference harmonic signal are identical.

[0064] It is understandable that since the function of the first phase shifter 303 is to make the phase difference between the first interference harmonic signal and the second interference harmonic signal 180 degrees, the first phase shifter 303 can also be set in the first branch 203 to shift the phase of the first interference harmonic signal to achieve the same function.

[0065] In some embodiments, since the object under test may cause a slight phase shift in the first signal, to ensure the accuracy of the test results, a second phase shifter 304 can be set at the front end of the second branch 204 (in this embodiment, between the first power divider and the second high-pass filter). The phase shift angle of the second signal is the same as that of the object under test 206, ensuring that the phase difference between the subsequent first and second interference harmonic signals is as close to 180 degrees as possible. The first phase shifter 303 and the second phase shifter 304 are preferably transmission line phase shifters. A transmission line phase shifter is a device that adjusts the signal phase using the characteristics of a transmission line. It changes the phase of the signal as it passes through the transmission line by changing the electrical or physical length of the transmission line and by utilizing specific material properties of the transmission line (such as dielectric constant), without changing the signal amplitude. The energy of the harmonic signal generated by this transmission line phase shifter is much smaller than the energy of the harmonic signals generated by other devices and the object under test, thus avoiding any impact on the test results.

[0066] In addition, to prevent excessive signal power from entering the harmonic testing equipment, attenuators are usually included in the circuit structure. For example... Figure 3As shown, in the first branch 203, a first attenuator 305 is provided between the object under test 206 and the first high-pass filter 301 to attenuate the signal output by the object under test 206. However, while the first attenuator 305 is introduced, it will also be excited by the first signal to generate an interfering harmonic signal, denoted as the third interference harmonic signal. The third interference harmonic signal is a harmonic signal generated by the first attenuator 305, which will interfere with the third harmonic signal of the object under test 206. In order to cancel the third interference harmonic signal generated by the first attenuator 305, a second attenuator 306 with the same performance as the first attenuator 305 is provided in the second branch 204 to generate a fourth interference harmonic signal with the same performance as the third interference harmonic signal. Therefore, the harmonic signal of the first attenuator (i.e., the third interference harmonic signal) or the harmonic signal of the second attenuator (i.e., the fourth interference harmonic signal) can be phase-shifted by the first phase shifter 303 set in the first branch 203 or the second branch 204, so that the phase difference between the third interference harmonic signal and the fourth interference harmonic signal is 180 degrees, thereby canceling each other out when the circuit is combined.

[0067] exist Figure 3 The radio frequency harmonic distortion testing system shown may further include a power amplifier 51 and a filter 52. The power amplifier 51 is connected between the signal generator 201 and the first power divider 203 to amplify the fundamental signal generated by the signal generator 201. The filter 52 is connected between the power amplifier 51 and the first power divider 202 to filter out the harmonic signals generated by the power amplifier 51. The filter 52 may be a low-pass filter.

[0068] To simplify the circuit structure, this application also proposes another circuit structure that does not require devices such as high-pass filters that generate interfering harmonic signals, such as... Figure 4 As shown.

[0069] exist Figure 4 In the circuit structure shown, the device under test (DUT) 206 is positioned between the signal generator 201 and the first power divider 202; that is, the DUT 206 is located on the main circuit before the first power divider 202. The DUT 206 receives the fundamental signal generated by the signal generator 201 to generate the required third harmonic signal for testing, and transmits both the fundamental and third harmonic signals to the first power divider 202. The first power divider 202 divides the received fundamental and third harmonic signals and transmits the divided signals to the first branch 203 and the second branch 204. The third harmonic signal is divided into a first sub-harmonic signal output to the first branch 203 and a second sub-harmonic signal output to the second branch 204. Since a high-pass filter is not used in this embodiment, other devices are required to eliminate the fundamental signal.

[0070] like Figure 4As shown, the first branch 203 may have no other components and can be a transmission line. The second branch 204 is equipped with a phase-shifting module 401, used to phase-shift the signal in the second branch 204, so that the phase difference between the first signal and the second signal (i.e., the fundamental signals in the first branch 203 and the second branch 204) is 180 degrees, and the first sub-harmonic signal and the second sub-harmonic signal are in phase. It can be understood that the phase-shifting module 401 can also be located in the first branch 203.

[0071] Specifically, in one embodiment, the phase shifting module 401 may include a first phase shifter 402 and a second phase shifter 403 disposed in the second branch 204, wherein the first phase shifter 402 and the second phase shifter 403 are connected in series between the first power divider 202 and the second power divider 205, such as... Figure 4 As shown in the diagram. The first phase shifter 402 is a transmission line phase shifter, used to shift the second signal by 90 degrees and simultaneously shift the second sub-harmonic signal by 270 degrees. The second phase shifter 403 is a broadband phase shifter, capable of simultaneously shifting the second signal and the second sub-harmonic signal by 90 degrees. Therefore, after passing through the phase shifting module 401, the second signal is shifted by a total of 180 degrees, and the second sub-harmonic signal is shifted by a total of 360 degrees. Consequently, in the signal after being combined by the second power divider 205, the first and second signals cancel each other out, and the first and second sub-harmonic signals are combined to form the third harmonic signal to be tested.

[0072] It is understandable that the positional order of the first phase shifter 402 and the second phase shifter 403 can be interchanged. For example, the first phase shifter 402 can be located before the second phase shifter 403, or the second phase shifter 403 can be located before the first phase shifter 402.

[0073] In this implementation, a large number of passive components are eliminated, and the testing capability of the RF nonlinear harmonic distortion system is improved with only two phase shifters, which not only reduces monetary costs but also saves space costs.

[0074] also, Figure 4 The radio frequency harmonic distortion testing system shown typically also includes a power amplifier 51 and a filter 52. The power amplifier 51 is connected between the signal generator 201 and the first power divider 203 to amplify the fundamental signal generated by the signal generator 201. The filter 52 is connected between the power amplifier 51 and the first power divider 203 to filter out the harmonic signals generated by the power amplifier 51. The filter 52 can be a low-pass filter or can also be composed of a power divider, such as... Figure 4 The medium filter device 52 is shown. Figure 4The filtering device 52 shown includes a third power divider 521, a third branch 522, a fourth branch 523, and a fourth power divider 524. The third power divider 521 divides the harmonic signal of the power amplifier 51 into a first interference signal and a second interference signal. The third branch 522 transmits the first interference signal. The fourth branch 523 transmits the second interference signal, and a third phase shifter 206 is provided on the fourth branch 523 to shift the phase of the second interference signal by 180 degrees. The fourth power divider 524 connects the third branch 522 and the fourth branch 523, combining the output signals of the third branch 522 and the fourth branch 523. This allows the first and second interference signals, which have the same power but are 180 degrees out of phase, to cancel each other out, resulting in only the fundamental signal being input to the object under test 206. In some embodiments, the harmonic signal of the power amplifier 51 is a third harmonic, and the third phase shifter 525 shifts the phase of the second interference signal by 180 degrees while also shifting the phase of the fundamental signal by 60 degrees. When the fourth power divider 524 combines the fundamental signals, the power of the combined fundamental signal changes relative to the fundamental signal output by the signal generator 201 because the fundamental signals of the third branch 522 and the fourth branch 523 have a phase deviation. The power of the combined fundamental signal can be detected and calibrated; therefore, the calibrated power can be used as the input power of the object under test 206 to test the third harmonic signal of the object under test 206.

[0075] The above description illustrates the implementation of this application through specific embodiments. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Although the description of this application is presented in conjunction with preferred embodiments, this does not mean that the features of this utility model are limited to this embodiment. Furthermore, to avoid confusion or obscuring the focus of this application, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0076] Furthermore, the various operations will be described as multiple discrete operations in a manner most conducive to understanding the illustrative embodiments; however, the order of description should not be construed as implying that these operations must depend on the order. In particular, these operations do not need to be performed in the order presented.

[0077] Unless the context otherwise specifies, the terms “contains,” “has,” and “includes” are synonyms. The phrase “A / B” means “A or B.” The phrase “A and / or B” means “(A and B) or (A or B).”

[0078] As used herein, the terms “module” or “unit” may refer to, be, or include: application-specific integrated circuits (ASICs), electronic circuits, (shared, dedicated, or group) processors and / or memories that execute one or more software or firmware programs, combinational logic circuits, and / or other suitable components that provide the described functionality.

[0079] In the accompanying drawings, certain structural or methodological features are shown in a specific arrangement and / or order. However, it should be understood that such a specific arrangement and / or order may not be necessary. In some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative drawings. Furthermore, the inclusion of structural or methodological features in a particular figure does not imply that such features are required in all embodiments, and in some embodiments, these features may be omitted or may be combined with other features.

[0080] It should be understood that although terms such as "first," "second," etc., may be used herein to describe various units or data, these units or data should not be limited by these terms. These terms are used merely to distinguish one feature from another. For example, without departing from the scope of the exemplary embodiments, a first feature may be referred to as a second feature, and similarly, a second feature may be referred to as a first feature.

[0081] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0082] Although the present invention has been illustrated and described with reference to certain preferred embodiments thereof, those skilled in the art should understand that various changes in form and detail may be made thereto without departing from the spirit and scope of the present invention.

Claims

1. A radio frequency harmonic distortion testing system, characterized in that, Used for harmonic testing of the object under test, including: A signal generator is used to generate a fundamental frequency signal. The first power divider divides the fundamental signal into the first signal and the second signal. The first branch, the first signal enters the first branch; The second branch, the second signal enters the second branch; wherein... The first branch or the main road before the first power divider has the connection position of the object under test; The devices configured in the first branch and the second branch satisfy the following: The first signal is output as a first branch signal after passing through the device set on the first branch; the second signal is output as a second branch signal after passing through the device set on the second branch. The first signal in the first branch signal is filtered out, the second signal in the second branch signal is filtered out, the first branch signal contains the harmonic signal of the object under test, and the harmonic signal generated by the device in the first branch is out of phase with the harmonic signal generated by the device in the second branch. Alternatively, the first branch signal may contain the fundamental and harmonic signals of the object under test. The second branch signal includes the fundamental wave signal and harmonic signal of the object under test. The fundamental wave signal in the first branch signal and the second branch signal are out of phase, and the harmonic signals are in phase. The second power divider is connected to the output terminals of the first branch and the second branch, and is used to combine the signals of the first branch and the second branch. The combined signal is then output to the harmonic testing equipment.

2. The system according to claim 1, characterized in that, The first branch includes: the connection position of the object under test and a first high-pass filter. The object under test is connected to an output terminal of the first power divider, receives the first signal, and outputs the first signal and the harmonic signal of the object under test. The first high-pass filter is connected to the output terminal of the object under test and is used to filter out the first signal output by the object under test, and output the harmonic signal of the object under test and the harmonic signal of the first high-pass filter. The second branch includes: a second high-pass filter, which is connected to the other output terminal of the first power divider and is used for the second signal to output the harmonic signal of the second high-pass filter; wherein the harmonic signals of the first high-pass filter and the second high-pass filter are in phase. The first branch and / or the second branch further includes a first phase shifter for shifting the phase of the harmonic signal of the first high-pass filter or the second high-pass filter, such that the phase difference between the harmonic signals of the first high-pass filter and the second high-pass filter is 180 degrees.

3. The system according to claim 2, characterized in that, The second branch further includes a second phase shifter connected between the first power divider and the second high-pass filter; wherein, The phase shift angle of the second phase shifter for the second signal is the same as the phase shift angle of the object under test for the first signal.

4. The system according to claim 3, characterized in that, The first phase shifter and / or the second phase shifter include transmission line phase shifters.

5. The system according to claim 3, characterized in that, The first branch also includes a first attenuator connected between the object under test and the first high-pass filter, used to attenuate the signal output by the object under test, and the first attenuator generates the harmonic signal of the first attenuator; The second branch also includes a second attenuator connected between the second phase shifter and the second high-pass filter, used to attenuate the signal output by the second phase shifter, and the second attenuator generates the harmonic signal of the second attenuator; The first phase shifter is further configured to shift the phase of the harmonic signal of the first attenuator or the second attenuator, such that the phase difference between the harmonic signals of the first attenuator and the second attenuator is 180 degrees.

6. The system according to claim 2, characterized in that, The first high-pass filter and the second high-pass filter have the same structure.

7. The system according to claim 1, characterized in that, The object under test is located between the signal generator and the first power divider; The first power divider receives the fundamental signal and the harmonic signal of the object under test. The first power divider also divides the harmonic signal of the object under test into a first sub-harmonic signal and a second sub-harmonic signal, and outputs them to the first branch and the second branch respectively. The first branch and / or the second branch further includes a phase shifting module for shifting the phase of the signals of the first branch and / or the second branch, such that the phase difference between the first signal and the second signal is 180°, and the phases of the first sub-harmonic signal and the second sub-harmonic signal are the same.

8. The system according to claim 7, characterized in that, The phase shifting module includes a first phase shifter and a second phase shifter connected in series, both of which are located in the second branch; The first phase shifter is used to shift the second signal by 90 degrees and shift the second sub-harmonic signal by 270 degrees; The second phase shifter is used to shift the second signal and the second sub-harmonic signal by 90 degrees respectively.

9. The system according to claim 8, characterized in that, The first phase shifter is a transmission line phase shifter, and the second phase shifter is a broadband phase shifter.

10. The system according to claim 2 or 7, characterized in that, Also includes: A power amplifier, connected between the signal generator and the first power divider, is used to amplify the fundamental signal generated by the signal generator; A filtering device is connected between the power amplifier and the first power divider to filter out harmonic signals from the power amplifier.

11. The system according to claim 10, characterized in that, The filtering device is a low-pass filter; or, The filtering device includes: The third power divider is used to divide the harmonic signal of the power amplifier into a first interference signal and a second interference signal. The third branch is used to transmit the first interference signal; The fourth branch is used to transmit the second interference signal, and the fourth branch includes a third phase shifter for shifting the second interference signal by 180 degrees. The fourth power divider connects the third branch and the fourth branch, and combines the output signals of the third branch and the fourth branch.

12. The system according to claim 11, characterized in that, The third phase shifter is a transmission line phase shifter.

13. The system according to claim 1, characterized in that, The first power divider and / or the second power divider includes any one of a resistor power divider, a waveguide power divider, a coaxial power divider, or a microstrip power divider.

14. The system according to claim 1, characterized in that, The first signal and the second signal have the same power.

15. The system according to claim 1, characterized in that, The harmonic testing equipment includes a spectrum analyzer.

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