Device forward non-linear testing device and testing method

Abstract

The invention relates to the technical field of testing, in particular to a device forward non-linear testing device and a testing method.The device forward non-linear testing device comprises a signal source, a frequency spectrograph, a duplexer and a load, the duplexer is electrically connected with the frequency spectrograph, the load and a to-be-tested piece, the signal source is electrically connected with the to-be-tested piece, and the frequency spectrograph is used for monitoring the forward non-linear degree of the to-be-tested piece; in this way, in the testing process, the signal source transmits a signal to the to-be-tested piece, due to the nonlinear factor of the to-be-tested piece, nonlinear energy such as harmonic stray is generated, one part of the nonlinear energy is reflected, and the other part of the nonlinear energy continues to be transmitted after passing through the to-be-tested piece; the nonlinear energy continuously transmitted by the to-be-tested piece is transmitted to the load and the frequency spectrograph through the duplexer, and the forward nonlinearity degree of the to-be-tested piece can be monitored on the frequency spectrograph, so that the forward nonlinearity degree of the to-be-tested piece is tested.

Description

Technical Field

[0001] The invention relates to the field of testing technology, and in particular to a device forward nonlinear testing apparatus and a testing method. Background Art

[0002] When two or more signals pass through a nonlinear device, the synthesized signal will generate an intermodulation product (IMP). When the IMP falls into the passband of an adjacent receiver, parasitic interference is formed. The multi-band wireless communication system in which the RF multi-coupler is located is a typical application of multi-band wireless communication, in which the nonlinearity of passive devices and their related structures is a potential source of passive intermodulation (PIM), and the passive intermodulation product (PIMP) can cause relatively serious electromagnetic interference.

[0003] Passive intermodulation measurement systems can be divided into:

[0004] 1) Radiating type, suitable for the study of radiators (such as antennas, feeders, structural components), placed in an anechoic room or open measurement site, and greatly affected by the local signal environment;

[0005] 2) Non-radiative type, suitable for the study of nonlinear materials, connectors, coaxial cables, filters and waveguide devices. It is placed in a shielded room with a matching load at the terminal.

[0006] Among them, the non-radiative type is divided into two categories: reflection (reverse) intermodulation test and propagation (forward) intermodulation test; and the existing non-radiative measurement device can only test the intermodulation products of the reflection (reverse) path, and cannot evaluate the intermodulation products in the forward transmission. The propagation (forward) intermodulation products are coupled and received by other local antennas and enter other local receivers to cause intermodulation interference. In order to comprehensively improve the complex electromagnetic environment and enhance the overall electromagnetic compatibility of the communication system, the size of the propagation (forward) intermodulation products also needs to be quantitatively evaluated, and the root cause needs to be located for improvement and optimization. Therefore, there is a special need for a device and method for measuring the forward nonlinear products of a device. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a device and method for testing forward nonlinearity of a device, so as to realize the testing of the forward nonlinearity degree of the device to be tested.

[0008] In order to solve the above technical problems, the first technical solution adopted by the present invention is:

[0009] A device forward nonlinear test apparatus comprises a signal source, a spectrum analyzer, a duplexer and a load, wherein the duplexer is electrically connected to the spectrum analyzer, the load and the device under test respectively, the signal source is electrically connected to the device under test, and the spectrum analyzer is used to monitor the forward nonlinearity degree of the device under test.

[0010] The second technical solution adopted by the present invention is:

[0011] A device forward nonlinearity testing method is applied to the device forward nonlinearity testing device, comprising the following steps:

[0012] The signal source transmits a signal to the device under test;

[0013] The DUT generates nonlinear energy, part of which is reflected, and the other part continues to be transmitted after passing through the DUT;

[0014] The nonlinear energy that continues to be transmitted through the device under test is delivered to the load and the spectrum analyzer through the duplexer, and the forward nonlinearity of the device under test is monitored by the spectrum analyzer.

[0015] The beneficial effects of the present invention are:

[0016] This scheme is provided with a signal source, a spectrum analyzer, a duplexer and a load. The duplexer is electrically connected to the spectrum analyzer, the load and the device under test respectively, and the signal source is electrically connected to the device under test. Thus, during the test process, the signal source transmits a signal to the device under test. Due to the nonlinear factors of the device under test, nonlinear energy such as harmonic spurious waves is generated, part of which is reflected, and the other part of the nonlinear energy continues to be transmitted after passing through the device under test. The nonlinear energy that continues to be transmitted through the device under test is transmitted to the load and the spectrum analyzer through the duplexer. At this time, the forward nonlinear degree of the device under test can be monitored on the spectrum analyzer, thereby realizing the test of the forward nonlinear degree of the device under test. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a connection block diagram of the device forward nonlinear test device of the present invention;

[0018] Figure 2 It is a flow chart of the steps of the device forward nonlinear testing method of the present invention;

[0019] Description of labels:

[0020] 1. Signal source; 2. Spectrum analyzer; 3. Duplexer; 301. First bandpass filter; 302. Second bandpass filter; 4. Load; 5. T-connector branch assembly; 501. First transmission line; 502. Second transmission line; 503. Third transmission line; 6. Power amplifier; 7. DUT. DETAILED DESCRIPTION

[0021] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

[0022] Please refer to Figure 1 , the first technical solution adopted by the present invention is:

[0023] A device forward nonlinear test apparatus comprises a signal source, a spectrum analyzer, a duplexer and a load, wherein the duplexer is electrically connected to the spectrum analyzer, the load and the device under test respectively, the signal source is electrically connected to the device under test, and the spectrum analyzer is used to monitor the forward nonlinearity degree of the device under test.

[0024] From the above description, it can be seen that the beneficial effects of the present invention are:

[0025] This scheme is provided with a signal source, a spectrum analyzer, a duplexer and a load. The duplexer is electrically connected to the spectrum analyzer, the load and the device under test respectively, and the signal source is electrically connected to the device under test. Thus, during the test process, the signal source transmits a signal to the device under test. Due to the nonlinear factors of the device under test, nonlinear energy such as harmonic spurious waves is generated, part of which is reflected, and the other part of the nonlinear energy continues to be transmitted after passing through the device under test. The nonlinear energy that continues to be transmitted through the device under test is transmitted to the load and the spectrum analyzer through the duplexer. At this time, the forward nonlinear degree of the device under test can be monitored on the spectrum analyzer, thereby realizing the test of the forward nonlinear degree of the device under test.

[0026] Furthermore, the duplexer includes a first bandpass filter and a second bandpass filter, the first bandpass filter is electrically connected to the load and the device under test, respectively, and the second bandpass filter is electrically connected to the spectrum analyzer and the device under test, respectively.

[0027] Furthermore, it also includes a T-joint branch component, which is a three-port microwave network, and the three ports of the T-joint branch component are respectively connected to the first bandpass filter, the second bandpass filter and the device to be tested.

[0028] From the above description, it can be seen that the T-connector branch assembly is a three-port microwave network. The T-connector branch assembly has lower insertion loss than the method of coupling with other devices, and the T-connector branch assembly can further reduce the insertion loss by adjusting the length of the transmission line. At the same time, the T-connector branch assembly can adjust the corresponding branch length according to the wavelength of the test microwave frequency, and can adapt to the nonlinear measurement of test signals of different frequencies.

[0029] Further, the T-joint branch assembly includes a first transmission line, a second transmission line and a third transmission line, one end of the first transmission line is electrically connected to one end of the second transmission line and one end of the third transmission line respectively, the other end of the first transmission line is electrically connected to a first band-pass filter, the other end of the second transmission line is electrically connected to a second band-pass filter, and the other end of the third transmission line is electrically connected to a device under test;

[0030] The lengths of the first transmission line, the second transmission line and the third transmission line are set according to the frequency of the first bandpass filter, the frequency of the second bandpass filter, the impedance of the three ports of the T-connector branch assembly, the dielectric constant of the first transmission line, the dielectric constant of the second transmission line and the dielectric constant of the third transmission line to minimize the insertion loss of the T-connector branch assembly.

[0031] From the above description, it can be seen that the T-connector branch assembly includes a first transmission line, a second transmission line and a third transmission line. In this way, the T-connector branch assembly can minimize the insertion loss by adjusting the length of the transmission line, thereby being able to transmit a stronger excitation signal and capture weaker harmonics, and can also achieve good measurement effects for devices with lower nonlinearity.

[0032] Furthermore, the first transmission line, the second transmission line and the third transmission line are all semi-rigid lines.

[0033] Furthermore, the load is a low intermodulation load.

[0034] It can be seen from the above description that a load with a low intermodulation level avoids the parasitic intermodulation generated by the load from affecting the measurement of passive components.

[0035] Furthermore, it also includes a power amplifier, wherein the input end of the power amplifier is electrically connected to the signal source, and the output end of the power amplifier is electrically connected to the device under test.

[0036] From the above description, it can be seen that by setting the power amplifier to strengthen the signal generated by the signal source, it is ensured that a stronger excitation signal is input to the device under test, and the detection capability of low nonlinear passive devices is further enhanced.

[0037] Please refer to Figure 2 , the second technical solution adopted by the present invention is:

[0038] A device forward nonlinearity testing method is applied to the device forward nonlinearity testing device, comprising the following steps:

[0039] The signal source transmits a signal to the device under test;

[0040] The DUT generates nonlinear energy, part of which is reflected, and the other part continues to be transmitted after passing through the DUT;

[0041] The nonlinear energy that continues to be transmitted through the device under test is delivered to the load and the spectrum analyzer through the duplexer, and the forward nonlinearity of the device under test is monitored by the spectrum analyzer.

[0042] Please refer to Figure 1 , Embodiment 1 of the present invention is:

[0043] A device forward nonlinear test apparatus comprises a signal source 1 (whose center frequency is 120 MHz and model is IFR2025), a spectrum analyzer 2 (whose center frequency is 360 MHz and model is E4402B), a duplexer 3 and a load 4 (model is TF200-LIM-DIN), wherein the duplexer 3 is electrically connected to the spectrum analyzer 2, the load 4 and a device under test 7 respectively, the signal source 1 is electrically connected to the device under test 7, and the spectrum analyzer 2 is used to monitor the degree of forward nonlinearity of the device under test 7.

[0044] The duplexer 3 includes a first bandpass filter 301 (whose center frequency is 120 MHz, and a filter of model XH / BPF-12085 can be used) and a second bandpass filter 302 (whose center frequency is 360 MHz, and a filter of model XH / BPF-36085 can be used). The first bandpass filter 301 is electrically connected to the load 4 and the device under test 7, respectively, and the second bandpass filter 302 is electrically connected to the spectrum analyzer 2 and the device under test 7, respectively.

[0045] It also includes a T-joint branch component 5 , which is a three-port microwave network. The three ports of the T-joint branch component 5 are respectively connected to the first bandpass filter 301 , the second bandpass filter 302 and the device under test 7 .

[0046] The T-joint branch assembly 5 includes a first transmission line 501, a second transmission line 502 and a third transmission line 503, one end of the first transmission line 501 is electrically connected to one end of the second transmission line 502 and one end of the third transmission line 503 respectively, the other end of the first transmission line 501 is electrically connected to the first band-pass filter 301, the other end of the second transmission line 502 is electrically connected to the second band-pass filter 302, and the other end of the third transmission line 503 is electrically connected to the device under test 7;

[0047] The lengths of the first transmission line 501, the second transmission line 502 and the third transmission line 503 are set according to the frequency of the first bandpass filter 301, the frequency of the second bandpass filter 302, the impedance of the three ports of the T-connector branch component 5, the dielectric constant of the first transmission line 501, the dielectric constant of the second transmission line 502 and the dielectric constant of the third transmission line 503, so as to minimize the insertion loss of the T-connector branch component 5.

[0048] The first transmission line 501, the second transmission line 502 and the third transmission line 503 are all semi-rigid lines (or other low intermodulation cables), and the first transmission line 501 and the second transmission line 502 are two semi-rigid lines of specific lengths (the length of the first transmission line 501 is 286.6 mm, and the length of the second transmission line 502 is 347 mm), and the third transmission line 503 is a semi-rigid line of unlimited length.

[0049] The load 4 is a low intermodulation load 4 .

[0050] It also includes a power amplifier 6 , an input end of the power amplifier 6 is electrically connected to the signal source 1 , and an output end of the power amplifier 6 is electrically connected to the device under test 7 .

[0051] According to the PIMP frequency component f in the communication system PIM Expression, f PIM =mf 1 ±nf 2 , harmonics can be broadly understood as a nonlinear energy when m=0 and n=2 or when n=0 and m=2. This energy and the third-order intermodulation nonlinear energy when m=2 and n=1 or n=2 and m=1 can quantitatively characterize the nonlinearity of the DUT 7, and the two methods are consistent in qualitative trends. For example, if the linearity of DUT A is inferior to that of DUT B, then its third-order intermodulation and harmonics show that DUT A is inferior to DUT B. In this way, the relative quality of A and B can be distinguished, which is particularly important for scheme demonstration and component selection in the research, development and design of communication systems / equipment.

[0052] The test process is that the signal source 1 transmits a 120MHz signal, which enters the device under test 7 through the linear power amplifier 6. Due to the nonlinear factors of the device under test 7, part of the nonlinear energy such as the generated harmonic spurious (including the second harmonic 240MHz and the third harmonic 360MHz) is reflected, and the other part continues to be transmitted after passing through the device under test 7. The remaining excitation that continues to be transmitted through the device under test 7 is connected to the low intermodulation load 4 through the first bandpass filter 301 of 120MHz, and the third harmonic is sent to the spectrum analyzer 2 with a smaller insertion loss through the second bandpass filter 302 of 360MHz. At this time, the forward nonlinearity of the device under test 7 can be monitored on the spectrum analyzer 2.

[0053] The device under test 7 can be an active device or a passive device. The operating frequency of the T-junction branch component 5 is determined by the operating frequency of the device under test 7 . Meanwhile, the excitation power output by the power amplifier 6 is also determined by the input power range of the device under test 7 .

[0054] Please refer to Figure 2 , Embodiment 2 of the present invention is:

[0055] A device forward nonlinear product testing method is applied to the device forward nonlinear testing device in the first embodiment, and is characterized by comprising the following steps:

[0056] The signal source 1 transmits a signal to the device under test 7;

[0057] The device under test 7 generates nonlinear energy, a part of which is reflected, and another part of which continues to be transmitted after passing through the device under test 7;

[0058] The nonlinear energy that continues to be transmitted through the device under test 7 is delivered to the load 4 and the spectrum analyzer 2 through the duplexer 3 , and the forward nonlinear degree of the device under test 7 is monitored by the spectrum analyzer 2 .

[0059] In summary, the present invention provides a device and method for testing forward nonlinearity of a device. By setting a signal source, a spectrum analyzer, a duplexer and a load, the duplexer is electrically connected to the spectrum analyzer, the load and the device under test respectively, and the signal source is electrically connected to the device under test. In this way, during the test process, the signal source transmits a signal to the device under test. Due to the nonlinear factors of the device under test, nonlinear energy such as harmonic spurious energy is generated, part of which is reflected, and the other part of the nonlinear energy continues to be transmitted after passing through the device under test. The nonlinear energy that continues to be transmitted through the device under test is transmitted to the load and the spectrum analyzer through the duplexer. At this time, the forward nonlinear degree of the device under test can be monitored on the spectrum analyzer, thereby realizing the test of the forward nonlinear degree of the device under test.

[0060] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A device forward nonlinear test device, It is characterized in that It includes a signal source, a spectrum analyzer, a duplexer and a load. The duplexer is electrically connected to the spectrum analyzer, the load and the device under test respectively. The signal source is electrically connected to the device under test. The spectrum analyzer is used to monitor the forward nonlinearity of the device under test.

2. The device forward nonlinear test device according to claim 1, It is characterized in that The duplexer includes a first bandpass filter and a second bandpass filter. The first bandpass filter is electrically connected to the load and the device under test, respectively. The second bandpass filter is electrically connected to the spectrum analyzer and the device under test, respectively.

3. The device forward nonlinear test device according to claim 2, It is characterized in that It also includes a T-joint branch component, which is a three-port microwave network, and the three ports of the T-joint branch component are respectively connected to the first bandpass filter, the second bandpass filter and the device to be tested.

4. The device forward nonlinear test device according to claim 3, It is characterized in that The T-joint branch assembly comprises a first transmission line, a second transmission line and a third transmission line, one end of the first transmission line is electrically connected to one end of the second transmission line and one end of the third transmission line respectively, the other end of the first transmission line is electrically connected to a first band-pass filter, the other end of the second transmission line is electrically connected to a second band-pass filter, and the other end of the third transmission line is electrically connected to a device under test; The lengths of the first transmission line, the second transmission line and the third transmission line are set according to the frequency of the first bandpass filter, the frequency of the second bandpass filter, the impedance of the three ports of the T-connector branch assembly, the dielectric constant of the first transmission line, the dielectric constant of the second transmission line and the dielectric constant of the third transmission line to minimize the insertion loss of the T-connector branch assembly.

5. The device forward nonlinear test device according to claim 4, It is characterized in that The first transmission line, the second transmission line and the third transmission line are all semi-rigid lines.

6. The device forward nonlinear test device according to claim 1, It is characterized in that The load is a low intermodulation load.

7. The device forward nonlinear test device according to claim 1, It is characterized in that It also includes a power amplifier, wherein the input end of the power amplifier is electrically connected to the signal source, and the output end of the power amplifier is electrically connected to the device under test.

8. A device forward nonlinearity testing method, applied to the device forward nonlinearity testing device according to any one of claims 1 to 7, It is characterized in that The following steps are involved: The signal source transmits a signal to the device under test; The DUT generates nonlinear energy, part of which is reflected, and the other part continues to be transmitted after passing through the DUT; The nonlinear energy that continues to be transmitted through the device under test is delivered to the load and the spectrum analyzer through the duplexer, and the forward nonlinearity of the device under test is monitored by the spectrum analyzer.

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