A multi-band filter s-parameter test method and system based on segmented scanning

Abstract

The application discloses a kind of multi-band filter S parameter test method and system based on segmented scanning, it is related to radio frequency microwave test technical field.The method steps are as follows: through host computer control digital channel board card drive radio frequency switch, expand the radio frequency port of vector network analyzer, so that its quantity matches with the port of filter to be measured;According to the number of filter port and test demand, divide test channel, configure segmented parameter table and calibration parameter for each channel, wherein segmented parameter table contains each sub-section scanning parameter, and the number of sub-section scanning points is adjusted according to passband and stopband characteristics;Vector network analyzer is segmented scanned to each channel based on the above parameters;Host computer obtains S parameter curve from vector network analyzer, completes test.The method can improve the efficiency and accuracy of multi-band filter S parameter test, and is suitable for production test.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of radio frequency microwave test technology, and particularly relates to a multi-band filter S parameter test method and system based on segmented scanning. BACKGROUND

[0002] In the field of wireless communication, as a key device for suppressing out-of-band interference, the performance of a filter directly affects the stability and reliability of a communication system. S parameters are used to comprehensively reflect the reflection and transmission characteristics of a filter, and are the core indicators for evaluating the performance of a filter. With the continuous improvement of the integration of radio frequency chips, multi-band integrated filters have become mainstream. Such filters can simultaneously cover multiple communication frequency bands and meet the needs of complex communication scenarios. However, the multi-band integration feature also significantly increases the amount of S parameter testing. How to improve the efficiency of production testing and reduce testing costs while ensuring testing accuracy has become an important challenge facing the industry.

[0003] Currently, for S parameter testing of multi-port filters, the mainstream method is to use a vector network analyzer (referred to as "net division") to scan the frequency band to be tested in a linear or step-by-step manner. For cases where the number of ports exceeds the inherent radio frequency ports of the net division, the ports of the net division are expanded through a radio frequency switch, and testing is completed by traversing each port. However, this traditional testing method has obvious defects, resulting in low testing efficiency and difficulty in meeting production requirements.

[0004] From the perspective of the scanning process, the scanning time of the net division is mainly determined by the number of scanning points and the intermediate frequency bandwidth (IFBW). When the IFBW is fixed, the more the number of scanning points, the longer the scanning time. However, in actual applications, users only need to focus on the performance of specific frequency bands of the filter, such as the insertion loss within the passband and the out-of-band attenuation within the stopband, and do not need to perform full-point scanning on the entire frequency band. Taking a B42 frequency band filter as an example, a large number of scanning points are needed within the passband to accurately capture performance details, while only specific frequency bands need to be measured for out-of-band attenuation. The traditional uniform scanning method for the entire frequency band will waste a large number of scanning points in frequency bands that do not need to be finely tested, significantly increasing the testing time.

[0005] Meanwhile, with the increase of the number of filter ports, different ports often need different calibration configurations, and each port needs to be calibrated separately in traditional testing, which is complex and time-consuming, especially when the number of filter ports is large, which will greatly increase the preparation time of testing and reduce the testing efficiency; and in the traditional single-channel testing method, the calibration configuration needs to be frequently switched for different ports, and when the frequency band is switched in the scanning process, the calibration often needs to be reconfigured, which not only further prolongs the testing time, but also may introduce errors, affecting the testing accuracy, and it is difficult to meet the dual requirements of efficiency and accuracy in mass production testing of multi-band filters, which seriously restricts the development of S parameter testing of multi-band filters, and a new testing method is urgently needed to solve the problem. SUMMARY

[0006] The purpose of the present application is to provide a multi-band filter S parameter testing method and system based on segmented scanning to solve the above problems.

[0007] To achieve the above purpose, in one aspect of the present application, a multi-band filter S parameter testing method based on segmented scanning is provided, comprising the following steps:

[0008] The host computer controls the digital channel board card to drive the radio frequency switch to expand the radio frequency port of the vector network analyzer, so that the number of radio frequency ports matches the number of ports of the filter to be tested;

[0009] According to the number of ports of the filter to be tested and the testing requirements, the corresponding number of test channels is divided, and the corresponding segmented parameter table and calibration parameters are configured for each test channel of the vector network analyzer, wherein the segmented parameter table includes the scanning parameter configuration of each sub-section, and the number of scanning points of each sub-section is adjusted according to its characteristics of passband and stopband;

[0010] The vector network analyzer performs segmented scanning on each test channel based on the segmented parameter table and calibration parameters of each test channel;

[0011] The host computer obtains the S parameter curve obtained by segmented scanning from the vector network analyzer to complete the multi-band filter S parameter testing.

[0012] Further, in the multi-band filter S parameter testing method, the scanning parameter configuration of each sub-section in the segmented parameter table includes the number of scanning points, IF bandwidth, power level, scanning mode, scanning delay and scanning time.

[0013] Further, in the multi-band filter S parameter testing method, the number of sub-sections in the passband is greater than the number of sub-sections in the stopband.

[0014] Further, in the multi-band filter S parameter testing method, the uniform scanning is used in each sub-band.

[0015] Further, in the multi-band filter S parameter testing method, the step of segment scanning comprises:

[0016] The vector network analyzer sequentially scans each sub-band according to the segment table order of each testing channel;

[0017] After the scanning of each sub-band is completed, the next sub-band is automatically switched to, and no calibration parameter needs to be reconfigured in the switching process, until the scanning of all sub-bands of the testing channel is completed.

[0018] Further, in the multi-band filter S parameter testing method, the calibration parameter is uniformly calibrated for each testing channel.

[0019] In the second aspect of the present application, a multi-band filter S parameter testing system based on segment scanning is further provided, comprising:

[0020] The host computer is configured with a testing control program, and is used to generate testing instructions and process testing data;

[0021] The digital channel board card is connected to the host computer, and is used to receive the testing instructions and drive the radio frequency switch;

[0022] The radio frequency switch is connected to the digital channel board card and the vector network analyzer, and is used to expand the radio frequency port of the vector network analyzer, so that the number of the radio frequency port matches the number of the ports of the filter to be tested;

[0023] The vector network analyzer is connected to the radio frequency switch, and is used to perform S parameter measurement;

[0024] and a testing fixture is used to connect the filter to be tested and the radio frequency port expanded by the radio frequency switch;

[0025] The host computer is configured to:

[0026] According to the number of ports of the filter to be tested and testing requirements, the number of corresponding testing channels is divided;

[0027] The segment parameter table of each testing channel is configured with corresponding calibration parameters, the segment parameter table comprises scanning parameter configuration of each sub-band, and the number of scanning points of each sub-band is adjusted according to the characteristics of passband or stopband;

[0028] The vector network analyzer is controlled to perform segment scanning on each testing channel based on the segment parameter table and the calibration parameter of each testing channel;

[0029] Obtain the S parameter curve obtained by the segmented scanning from the vector network analyzer, and complete the S parameter test of the multi-band filter.

[0030] Further, in the multi-band filter S parameter test system, the scanning parameter configuration of each sub-section in the segmented parameter table includes the number of scanning points, the IF bandwidth, the power level, the scanning mode, the scanning delay and the scanning time.

[0031] The host computer is configured to:

[0032] The number of scanning points of the sub-section in the passband is set to a larger number, and the number of scanning points of the sub-section in the stopband is set to a smaller number; and the uniform scanning mode is adopted within each sub-section.

[0033] Further, in the multi-band filter S parameter test system, the host computer is configured to: uniformly calibrate the port corresponding to each test channel, generate calibration parameters and store them as a calibration file.

[0034] The vector network analyzer is configured to: in the segmented scanning process, sequentially scan the sub-sections according to the order of the segmented parameter table of each test channel, and keep the calibration parameters of the current test channel unchanged during the sub-section switching process.

[0035] Compared with the prior art, the present application has at least the following technical effects:

[0036] The present application expands the radio frequency port of the vector network analyzer by controlling the digital channel board card to drive the radio frequency switch through the host computer, solves the problem of mismatching of the number of ports, and does not need to be frequently switched manually; at the same time, the test channel is divided according to the number of ports of the filter to be tested and the test requirement, and the corresponding segmented parameter table and calibration parameters are configured for each test channel, wherein the segmented parameter table can adjust the scanning point number and other parameters of each sub-section according to the passband and stopband characteristics, and the number of scanning points in the passband is set to be more, and the number of scanning points in the stopband is set to be less, and the IF bandwidth and other parameters can also be configured specifically, so that the vector network analyzer can perform segmented scanning based on these parameters, and the calibration parameters do not need to be reconfigured when switching the sub-sections, and finally the host computer obtains the S parameter curve, which not only ensures the fineness of the passband test and the efficiency of the stopband test, reduces the scanning time, avoids the error and time consumption caused by frequent switching of the calibration parameters, greatly improves the efficiency and precision of the S parameter test of the multi-band filter, and better meets the production test requirement. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The flowchart of the multi-band filter S parameter test method based on segmented scanning in an embodiment of the present application;

[0038] Figure 2 The hardware connection schematic diagram of the multi-band filter S parameter test system in an embodiment of the present application;

[0039] Figure 3 S21 parameter curve schematic diagram of traditional linear scanning mode in an embodiment of the present application;

[0040] Figure 4 S21 parameter curve schematic diagram of adopting segmented scanning mode in an embodiment of the present application. DETAILED DESCRIPTION

[0041] A kind of based on segmented scanning's multi-band filter S parameter test method and system of the present application will be described in more detail below with schematic diagram, wherein the preferred embodiment of the present application is indicated, it should be understood that the present application described herein can be modified by those skilled in the art, and still achieve the advantageous effects of the present application. Therefore, the following description should be understood as extensive knowledge for those skilled in the art, and not as a limitation on the present application.

[0042] For clarity, not all features of actual embodiments are described. In the following description, well-known functions or constructions are not described in detail because they can obscure the present application due to unnecessary details. It should be considered that in the development of any actual embodiment, numerous implementation-specific details must be made to achieve the developer's specific goals, such as from one embodiment to another, according to the relevant system or relevant business restrictions. In addition, it should be considered that such development work can be complex and time-consuming, but only a routine work for those skilled in the art.

[0043] The present application is described in more detail in the following paragraphs with reference to the accompanying drawings. The advantages and features of the present application will be more apparent from the following description. It should be noted that the drawings are very simplified and all use non-precise proportions, only to facilitate, clear and assist the purpose of illustrating the embodiments of the present application.

[0044] Based on the inspiration of the present application, those skilled in the art can form new technical solutions by cross combination of different embodiments without causing technical contradictions, and such variations should be considered to fall within the protection scope of the present application.

[0045] Embodiment one

[0046] The present embodiment proposes a kind of based on segmented scanning's multi-band filter S parameter test method, to take the S parameter test of multi-band integrated filter (such as containing B42, n78 frequency band) as an example, detailed description the specific implementation process of the test method based on segmented scanning, such as Figure 1 , the specific steps of the method are as follows:

[0047] Step one: control the digital channel board card to drive the radio frequency switch through the upper computer to expand the radio frequency port of the vector network analyzer, so that the number of the radio frequency port matches the number of the port of the filter to be tested;

[0048] Step two: according to the number of the port of the filter to be tested and the test requirement, divide the corresponding test channel number, configure the corresponding segmented parameter table and calibration parameter for each test channel of the vector network analyzer, wherein the segmented parameter table includes the scanning parameter configuration of each subsegment, and the number of scanning points of each subsegment is adjusted according to its characteristics of passband and stopband;

[0049] Step three: the vector network analyzer performs segmented scanning on each test channel based on the segmented parameter table and the calibration parameter of each test channel;

[0050] Step four: the upper computer obtains the S parameter curve obtained by the segmented scanning from the vector network analyzer, and completes the S parameter test of the multi-frequency band filter.

[0051] For step one, before performing the S parameter test of the multi-frequency band integrated filter, a complete hardware test system needs to be built, and the hardware composition and connection logic are as follows:

[0052] In terms of hardware composition, a test system as shown in Figure 2 is built, and the system includes multiple key components. The upper computer (ATE PC is adopted in the embodiment) serves as the control core and undertakes the regulation and control task of the whole test process, and can send various operation instructions to the vector network analyzer (VNA) and the ATE digital channel board. The vector network analyzer (VNA) is the core test instrument for realizing the S parameter scanning and measurement, and directly relates to the accuracy of the test data. The main function of the ATE digital channel board is to receive the instructions from the ATE PC and control the switching action of the radio frequency switch according to the instructions. The radio frequency switch is used to expand the radio frequency port of the VNA, and the number of the expanded radio frequency port (i.e. the “Port” marked in Figure 2 , which refers to the radio frequency port expanded by the VNA) needs to be consistent with the number of the port of the filter to be tested. For example, when the filter to be tested is a 4-port filter, 4 radio frequency ports need to be expanded, and for the PortN shown in the figure, N is 4, that is, the 4 radio frequency ports are Port1, Port2, Port3 and Port4. The Lord board is used to place the filter to be tested, and the Prober Card serves to connect the radio frequency port and the filter port, so as to ensure the stable transmission of the signal. The Port refers to the radio frequency port expanded by the VNA.

[0053] The connection logic of each component between the systems is as follows: the upper computer establishes a connection with the network splitter and the digital channel board card through a dedicated control cable to realize the transmission of instructions; the digital channel board card is connected with the radio frequency switch through a control line, so that the switching of the radio frequency switch can be accurately controlled; the output end of the radio frequency switch is connected with each port of the filter to be tested through a pin card, and finally a complete and stable signal path is formed, laying a foundation for subsequent test work.

[0054] For step two, after the hardware configuration is built, the test channel division and parameter configuration phase is entered. This phase is based on the port characteristics of the filter to be tested and the test requirements, and through reasonable division of the test channel, configuration of the segmented parameter table and calibration parameters, it lays a foundation for subsequent efficient scanning.

[0055] In this embodiment, the test channel division needs to be determined in combination with the port number of the filter to be tested and the actual test scene (such as different ports corresponding to different working frequency bands). For example, if the filter to be tested is a 4-port device, port 1 and port 2 jointly correspond to the signal transmission and reception of the B42 frequency band, and port 3 and port 4 jointly correspond to the n78 frequency band, then the test channel can be divided into two (channel1, channel2), wherein channel1 corresponds to port 1 and port 2, and channel2 corresponds to port 3 and port 4.

[0056] Further, in order to improve the test efficiency, segmented parameter table configuration is needed. This configuration needs to be based on the frequency band characteristics of each test channel, to split the test frequency band into multiple sub-segments, and to configure detailed scanning parameters for each sub-segment. The scanning parameter configuration of each sub-segment in the segmented parameter table includes the number of scanning points, IF bandwidth, power level, scanning method, scanning delay and scanning time.

[0057] It should be noted that the parameter configuration needs to follow the "on-demand allocation" principle. In terms of the number of scanning points, the passband (i.e. the frequency band that users focus on, such as 3.4-3.6GHz of the B42 frequency band) needs to increase the number of scanning points to ensure the fineness of the insertion loss measurement, and uniform scanning is used within each sub-segment; as for the stopband, although it does not need to be scanned as densely as the passband, when the stopband involves other communication frequency bands (such as the out-of-band attenuation of the B42 frequency band needs to focus on 900M, 1800M, 2.3G, 2.6G, 5.15G, etc. mobile communication frequency bands), the IFBW (intermediate frequency resolution bandwidth) cannot be set too large, otherwise it will affect the accuracy of the measurement results, therefore the IFBW of the passband and the stopband needs to be uniformly configured as 70kHz or 100kHz in this kind of scene, in order to balance the accurate evaluation of the out-of-band interference suppression effect.

[0058] Further, when configuring the power level, the normal working range of the filter to be tested needs to be adapted to ensure that the signal power input to the filter is within the range in which it can stably work. When configuring the scanning mode, the embodiment adopts a linear scanning mode, which functions to enable the vector network analyzer to scan at a uniform frequency interval in each sub-section. The scanning time is automatically calculated from the number of scanning points and the IF bandwidth of the sub-section, which functions to rationally allocate the test duration of each sub-section. In the case of a certain IF bandwidth, the more the number of scanning points, the longer the required scanning time, so as to ensure that each scanning point can be fully measured; and by reducing the number of scanning points in the frequency band that is not concerned, such as the stopband, the scanning time of the corresponding sub-section can be shortened, so as to optimize the test throughput and improve the test efficiency as a whole. For example, reducing the number of scanning points in the stopband sub-section can shorten the corresponding scanning time, thereby saving the total test time on the premise of meeting the test requirements.

[0059] Further, the calibration parameter configuration needs to be uniformly calibrated for each test channel to avoid the problem of frequent switching of calibration configurations in traditional single-channel testing. Specifically, for channel 1 (corresponding to port 1 and port 2), the two ports are jointly calibrated by the calibration function of the vector network analyzer to generate calibration parameters applicable to channel 1 and store them; similarly, channel 2 (corresponding to port 3 and port 4) is calibrated to generate respective calibration parameters. For step three, after completing the test channel division and parameter configuration of step two, the vector network analyzer (network division) will perform a scanning operation according to the segmentation parameter table of each test channel. Taking the single-channel scanning process as an example, for channel 1 (corresponding to the filter port of the B42 frequency band), as shown in Figure 3 , the traditional method adopts equal-interval uniform scanning (all frequency points are consistent). The embodiment divides the entire test frequency band into five sub-sections (S1-S5) according to the frequency band characteristics, and the specific parameter configurations of the sub-sections are as follows: Figure 4

[0060] The S1 sub-section covers the stopband region of 3.40-3.44 GHz, and is configured with 50 scanning points and an IF bandwidth of 1 MHz;

[0061] The S2 sub-section covers the stopband region of 3.44-3.50 GHz, and is configured with 100 scanning points and an IF bandwidth of 500 kHz;

[0062] The S3 sub-section covers the passband region of 3.50-3.54 GHz (the frequency band of interest of the user core), and is configured with 300 scanning points and an IF bandwidth of 100 kHz;

[0063] The S4 sub-section covers the stopband region of 3.54-3.58 GHz, and is configured with 100 scanning points and an IF bandwidth of 500 kHz;​

[0064] S5 covers the stopband region of 3.58-3.60GHz, and the number of scanning points is 50, and the IF bandwidth is 1MHz.

[0065] When the network analyzer performs the scanning of channel1, it will strictly follow the order of S1-S5 to perform the scanning. Specifically, the network analyzer first starts the scanning of S1, and completes the measurement according to the parameters such as the number of scanning points, the IF bandwidth, the power level (such as -10dBm), the scanning mode (linear scanning) of the subsegment, and generates the S parameter data of the subsegment; after the scanning of S1 is completed, the network analyzer automatically switches to S2, without manual intervention or reconfiguration of the calibration parameters - since the calibration parameters of channel1 have been uniformly configured and stored in the early stage, the pre-stored calibration parameters can be called to ensure the measurement accuracy during the switching process; and the process is repeated until the scanning of S5 is completed, and the segmented scanning process of channel1 is completed.

[0066] For the multi-channel scenario (such as testing the filter integrated with B42 and n78 multi-frequency bands at the same time), the network analyzer supports the multi-channel parallel processing mechanism. While channel1 performs the scanning of B42 frequency band, the segmented scanning process of channel2 (corresponding to the n78 frequency band port) can be started at the same time. Each channel independently calls the segmented parameter table and the calibration parameters of itself, and does not interfere with each other: channel2 performs the scanning of the corresponding subsegment of n78 frequency band. Through the multi-channel parallel scanning, the waiting time of the traditional single-channel sequential testing is avoided, the overall test period is further shortened, and the throughput of the mass production testing is significantly improved.

[0067] For step four, during the segmented scanning process of each test channel, the vector network analyzer (network analyzer) will record the measurement data of each subsegment in real time.

[0068] Specifically, the network is divided according to the preset segmentation parameter table, and after completing the scanning of each sub-band, the S parameters (including S11, S21, S22, wherein S11 represents the port reflection characteristic, and S21 represents the inter-port transmission characteristic) in the sub-band are automatically stored in the internal cache in the form of data points. These data points contain frequency values and corresponding S parameter amplitude (in dB) or phase information (in degrees). For example, in the B42 frequency band pass sub-band (3.50-3.54GHz), 300 scanning points will correspond to 300 groups of "frequency-S21 amplitude" data, and the frequency interval is uniform to ensure fine characterization of the insertion loss characteristic; while in the stop band sub-band (such as 3.40-3.44GHz), the frequency interval of 50 scanning points is larger, and the core indicator of the stop band is the attenuation value, which is usually much larger than the insertion loss of the pass band, so the influence of the fluctuation in the network test process on the attenuation value is relatively small, and therefore it is not necessary to characterize the details through dense scanning points, and only a few points can meet the evaluation needs of the attenuation performance.

[0069] After the scanning is completed, the host computer (ATE PC) establishes data communication with the network through the GPIB (general purpose interface bus) or LAN (local area network) interface, and reads the data in the cache according to the test channel sequence. For example, for a system containing 2 test channels, the host computer first reads all the sub-band data of channel 1 (such as 50+100+300+100+50=600 points of S1 to S5 sub-bands), and then reads the data of channel 2. During the reading process, the host computer automatically identifies the frequency range of each sub-band and the corresponding data points by analyzing the data packets returned by the network, and integrates the complete S parameter curve according to the frequency band sequence.

[0070] After the data is integrated, the host computer further processes the S parameter curve to extract the core indicators of interest to the user: for the pass band (such as 3.4-3.6GHz of B42), the insertion loss curve is generated based on 300-point S21 data, the average value of the insertion loss in the pass band, the fluctuation range (such as ±0.3dB) and the center frequency insertion loss value (such as 1.2dB) are calculated, and compared with the preset threshold (such as insertion loss ≤2dB) to determine whether it is qualified; for the stop band (such as 3.40-3.50GHz, 3.54-3.60GHz), the attenuation curve is generated based on 100-point S21 data, and it is verified whether the attenuation value at a specific frequency point (such as 3.0GHz, 4.0GHz) is ≥40dB, and at the same time, it is checked whether there is an abnormal protrusion (sudden decrease in attenuation) to exclude out-of-band interference. Finally, the host computer displays the processing results in the form of charts (such as pass band insertion loss curve, stop band attenuation curve), and generates a test report containing the qualified / failed judgment and key parameter values, completing the entire S parameter test process.

[0071] Embodiment Two

[0072] As Figure 2The embodiment provides a multi-band filter S parameter test system based on segmented scanning, which comprises an upper computer, a digital channel board card, a radio frequency switch, a vector network analyzer and a test fixture.

[0073] In the embodiment, the upper computer is configured with a test control program for generating test instructions and processing test data. For example, for a 4-port filter containing two frequency bands of B42 and n78, the upper computer can divide 3 test channels according to the port quantity and test requirements of the filter, wherein Channel1 corresponds to ports 1-2 (B42 frequency band) and Channel2 corresponds to ports 3-4 (n78 frequency band). The digital channel board card is connected to the upper computer and used for receiving the test instructions and driving the radio frequency switch. The radio frequency switch is connected to the digital channel board card and the vector network analyzer and used for expanding the radio frequency ports of the vector network analyzer, so that the number of the radio frequency ports matches the four ports of the filter to be tested. The test fixture is used for connecting the filter to be tested and the radio frequency ports expanded by the radio frequency switch, and the vector network analyzer is connected to the radio frequency switch and used for performing S parameter measurement.

[0074] In the embodiment, the upper computer is configured with a test control program for generating test instructions and processing test data. For example, for a 4-port filter containing two frequency bands of B42 and n78, the upper computer can divide 3 test channels according to the port quantity and test requirements of the filter, wherein Channel1 corresponds to ports 1-2 (B42 frequency band) and Channel2 corresponds to ports 3-4 (n78 frequency band). The digital channel board card is connected to the upper computer and used for receiving the test instructions and driving the radio frequency switch. The radio frequency switch is connected to the digital channel board card and the vector network analyzer and used for expanding the radio frequency ports of the vector network analyzer, so that the number of the radio frequency ports matches the four ports of the filter to be tested. The test fixture is used for connecting the filter to be tested and the radio frequency ports expanded by the radio frequency switch, and the vector network analyzer is connected to the radio frequency switch and used for performing S parameter measurement.

[0075] In specific work, the upper computer configures a corresponding segmented parameter table and calibration parameter for each test channel. Taking Channel1 as an example, the segmented parameter table divides the B42 frequency band (3.4-3.6GHz) into 5 subsegments, and the scanning parameter configuration of each subsegment includes the number of scanning points, the IF bandwidth, the power level, the scanning mode, the scanning delay and the scanning time, wherein the number of scanning points of the passband (3.50-3.54GHz) is set to 300 points, the IF bandwidth is 100kHz, the number of scanning points of the stopband (3.40-3.50GHz, 3.54-3.60GHz) is set to 50 points, the IF bandwidth is 1MHz, and the uniform scanning mode is used in each subsegment. The calibration parameter is uniformly calibrated for the ports corresponding to each test channel, for example, the ports 1 and 2 of Channel1 are jointly calibrated, a calibration file is generated and stored, and in the segmented scanning process, the calibration parameter does not need to be reconfigured when the subsegment is switched.

[0076] The workflow of the system is as follows: the host computer sends instructions, the digital channel board card drives the radio frequency switch to complete port expansion, so that the radio frequency port is connected with the port of the filter to be tested; the host computer sends the segmented parameter table and the calibration parameter of each channel to the vector network analyzer, the vector network analyzer sequentially scans each subsegment according to the order of the segment table of each test channel, for example, Channel1 scans in the order of S1 to S5; after the scanning is completed, the host computer obtains data from the vector network analyzer, processes to generate an S parameter curve, extracts key indicators such as passband insertion loss and stopband attenuation, and completes the S parameter test of the multi-frequency band filter. The system significantly improves the test efficiency through segmented scanning and multi-channel configuration, and is suitable for test requirements in mass production scenarios.

[0077] To sum up, the host computer controls the digital channel board card to drive the radio frequency switch to expand the radio frequency port of the vector network analyzer, solves the problem of mismatched port quantity, and does not need to manually switch frequently; at the same time, the test channel is divided according to the port quantity of the filter to be tested and the test requirement, and the corresponding segmented parameter table and calibration parameter are configured for each test channel, wherein the segmented parameter table can adjust parameters such as the number of scanning points of each subsegment according to the passband and stopband characteristics, more scanning points are set in the passband, less in the stopband, and IF bandwidth and other parameters can also be configured specifically, so that the vector network analyzer can perform segmented scanning based on these parameters, and the calibration parameter does not need to be reconfigured when switching the subsegment, and finally the host computer obtains the S parameter curve, which not only ensures the fineness of passband test and the efficiency of stopband test, reduces the scanning time, avoids the error and time consumption caused by frequent switching of calibration parameters, greatly improves the efficiency and accuracy of the S parameter test of the multi-frequency band filter, and better meets the mass production test requirement.

[0078] The above is only the preferred embodiment of the present application, and does not limit the present application in any way. Any person skilled in the art can make any form of equivalent replacement, modification or change to the technical solutions and technical contents disclosed in the present application without departing from the scope of the technical solutions of the present application, which still belongs to the protection scope of the present application.

Claims

1. A method for testing the S-parameters of a multi-band filter based on segmented scanning, characterized in that, Includes the following steps: The host computer controls the digital channel board to drive the RF switch, thereby expanding the RF ports of the vector network analyzer so that the number of RF ports matches the number of ports of the filter under test. The number of test channels is divided according to the number of ports of the filter under test and the test requirements. A corresponding segmented parameter table and calibration parameters are configured for each test channel of the vector network analyzer. The segmented parameter table includes the scanning parameter configuration for each sub-segment, and the number of scanning points for each sub-segment is adjusted according to its characteristics of being a passband and a stopband. The vector network analyzer performs segmented scanning of each test channel based on the segmented parameter table and calibration parameters of each test channel; The host computer obtains the S-parameter curves obtained from the segmented scanning from the vector network analyzer and completes the S-parameter test of the multi-band filter.

2. The method according to claim 1, characterized in that, The scanning parameter configuration for each sub-segment in the segmented parameter table includes the number of scan points, IF bandwidth, power level, scanning mode, scanning delay, and scanning time.

3. The method according to claim 2, characterized in that, The number of scan points is greater in the passband than in the stopband.

4. The method according to claim 3, characterized in that, Each sub-segment is scanned uniformly.

5. The method according to claim 1, characterized in that, The segmented scanning steps include: The vector network analyzer scans each sub-segment sequentially according to the segment table order of each test channel; After each sub-segment is scanned, the system automatically switches to the next sub-segment. No calibration parameters need to be reconfigured during the switching process until all sub-segments of the test channel have been scanned.

6. The method according to claim 1, characterized in that, The calibration parameters are uniformly calibrated for each test channel.

7. A multi-band filter S-parameter testing system based on segmented scanning, characterized in that, include: The host computer is equipped with a test control program, which is used to generate test instructions and process test data; A digital channel board, connected to the host computer, is used to receive the test commands and drive the RF switch; An RF switch, connected to the digital channel board and the vector network analyzer, is used to expand the RF ports of the vector network analyzer so that the number of RF ports matches the number of ports of the filter under test. A vector network analyzer, connected to the RF switch, is used to perform S-parameter measurements; And a test fixture for connecting the filter under test to the extended RF port of the RF switch; The host computer is configured as follows: The number of test channels is determined according to the number of ports of the filter under test and the test requirements. Each test channel is configured with a corresponding segmented parameter table and calibration parameters. The segmented parameter table includes the scanning parameter configuration for each sub-segment, and the number of scanning points for each sub-segment is adjusted according to its characteristics as a passband or stopband. The vector network analyzer is controlled to perform segmented scanning of each test channel based on the segmented parameter table and calibration parameters of each test channel; The S-parameter curves obtained from the segmented scanning are acquired from the vector network analyzer to complete the S-parameter test of the multi-band filter.

8. The system according to claim 7, characterized in that, The scanning parameter configuration for each sub-segment in the segmented parameter table includes the number of scan points, IF bandwidth, power level, scanning mode, scanning delay, and scanning time. The host computer is configured as follows: Set the number of scan points in the passband sub-segments to a larger number and the number of scan points in the stopband sub-segments to a smaller number; use a uniform scanning method within each sub-segment.

9. The system according to claim 8, characterized in that, The host computer is configured to perform unified calibration on the port corresponding to each test channel, generate calibration parameters, and store them as a calibration file. The vector network analyzer is configured to scan sub-segments sequentially according to the segment parameter table of each test channel during the segmented scanning process, and to keep the calibration parameters of the current test channel unchanged during the sub-segment switching process.

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