A method for measuring the interface impedance of a PCB board to be connected to an optical device

Abstract

This invention discloses a method for measuring the impedance of an interface for an optical device to be connected to a PCB board. The method includes: setting a test impedance range; dividing the test impedance range into zones according to a preset gradient impedance; configuring test strips with corresponding impedances; sequentially connecting a test rigid board, test strips, and the PCB board to form an electrical series connection; testing the impedance of the test rigid board, test strips, and the interface for the optical device to be connected to the PCB board using a measuring instrument, and obtaining the corresponding test relationships; by comparing the influence of test strips with different impedances within the impedance range on the impedance of the interface for the optical device to be connected to the PCB board, obtaining the optimal matching impedance of the test strip corresponding to the impedance of the interface for the optical device to be connected to the PCB board; and obtaining the true impedance of the interface for the optical device to be connected to the PCB board using the optimal matching impedance. This invention, based on the characteristics of the measuring instrument, sets test strips with gradient impedances, obtains the impedance test relationships of all test strips, and derives the impedance of the interface for the optical device to be connected to the PCB board from the test relationships.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, and in particular to a method for measuring the interface impedance of optical devices to be connected to a PCB board. Background Technology

[0002] As optical module speeds increase and optical port signals become more sensitive, impedance matching between the PCB board interface and the optical device becomes increasingly important. Current technology typically involves placing probes at the PCB board interface of the optical device to be connected, then connecting a measuring instrument to measure the impedance of the interface, and using the impedance measurement value to match the corresponding optical device.

[0003] When using probes to perform impedance testing on the interface of optical devices to be connected to a PCB board, manual probe insertion can easily prevent the probe from being inserted into the optimal position of the interface. Furthermore, the different insertion positions of the probes by different individuals can lead to significant deviations in the impedance measurement values ​​of the interface, resulting in inaccurate impedance testing, severely impacting testing efficiency and the selection of suitable optical devices for the interface impedance.

[0004] Therefore, overcoming the shortcomings of the existing technology is an urgent problem to be solved in this technical field. Summary of the Invention

[0005] The technical problem to be solved by the embodiments of the present invention is that the prior art uses probes to measure the interface impedance of the optical device to be connected to the PCB board, which is inaccurate and makes it difficult to accurately select the optical device whose impedance is compatible with the interface impedance of the optical device to be connected to the PCB board.

[0006] The embodiments of the present invention adopt the following technical solutions:

[0007] This invention provides a method for measuring the interface impedance of an optical device to be connected to a PCB board, comprising:

[0008] Set the test impedance range of the test softband, divide the test impedance range into zones according to the preset gradient impedance, and configure the test softband with the corresponding impedance.

[0009] The test hard board, test soft tape, and PCB board are connected in sequence to form an electrical series connection. The impedance of the optical device interface to be connected to the test hard board, test soft tape, and PCB board is tested by a measurement and analysis instrument, and the corresponding test relationship is obtained.

[0010] By comparing the impact of the test softband configured with impedance within the impedance range on the impedance interface of the optical device to be connected on the PCB board, the optimal matching impedance of the test softband corresponding to the impedance of the optical device interface to be connected on the PCB board is obtained, and the true impedance of the optical device interface to be connected on the PCB board is obtained through the optimal matching impedance.

[0011] Preferably, before setting the test impedance of the test softband, the method further includes obtaining the apparent impedance of the interface of the optical device to be connected on the PCB board, and setting the test impedance range of the test softband based on the apparent impedance, specifically:

[0012] Based on the calibration impedance of the test softband corresponding to the apparent impedance of the optical device interface to be connected to the PCB board, the upper limit threshold of the test impedance of the test softband is set according to the allowable error accuracy of the actual optical device interface impedance to be connected to the PCB board.

[0013] Using the displayed impedance of the test softband corresponding to the displayed impedance of the optical device interface to be connected to the PCB board as a benchmark, the lower limit threshold of the test impedance of the test softband is set according to the allowable error accuracy of the actual optical device interface impedance to be connected to the PCB board.

[0014] Preferably, the step of dividing the test impedance range into zones according to a preset gradient impedance and configuring test soft bands with corresponding impedances specifically includes:

[0015] The range of test impedance is determined by setting the difference between the upper and lower threshold values ​​of the test impedance of the test softband based on the allowable error accuracy of the interface impedance of the optical device to be connected on the actual PCB board.

[0016] Based on the test impedance range, preset gradient impedance, and the allowable error accuracy of the interface impedance of the optical device to be connected on the actual PCB board, the lower limit threshold of the test impedance of the test softband is set, and all test impedance values ​​set within the test impedance range are obtained.

[0017] Configure the corresponding impedance test strip according to all the set test impedance values.

[0018] Preferably, before comparing the impact of different impedance test strips within the impedance range on the impedance of the optical device interface to be connected to the PCB board, the method further includes testing all test strips configured within the impedance range one by one. Specifically, this involves replacing the corresponding test strips one by one, obtaining the impedance test relationship between the test board, the test strips, and the optical device interface to be connected to the PCB board through the network analyzer, until all test strips within the impedance range have been tested.

[0019] Preferably, after obtaining the actual impedance of the interface of the optical device to be connected to the PCB board, the method further includes selecting a suitable optical device using the compensation amount of the impedance of the interface of the optical device to be connected to the PCB board, specifically:

[0020] The compensation impedance of the PCB board is obtained by measuring the difference between the actual impedance value of the optical device interface to be connected on the PCB board and the apparent impedance of the optical device interface to be connected on the PCB board.

[0021] Select the appropriate optical device based on the compensation impedance and the apparent impedance of the optical device interface to be connected on the PCB board.

[0022] Preferably, the preset gradient impedance is set indirectly according to the allowable error accuracy of the interface impedance of the optical device to be connected on the PCB board, specifically:

[0023] Based on actual needs, the maximum permissible error of the corresponding test soft band is calculated according to the maximum permissible error accuracy of the impedance of the optical device connected to the PCB board that the customer can accept.

[0024] The gradient impedance is set according to the maximum permissible error accuracy of the test softband, wherein the preset gradient impedance is less than or equal to the maximum permissible error accuracy of the test softband.

[0025] Preferably, the step of setting the test impedance range of the test softband based on the displayed impedance is as follows:

[0026] Obtain the apparent impedance of the interface of the optical device to be connected on the PCB board;

[0027] The test softband impedance corresponding to the displayed impedance of the optical device interface to be connected to the PCB board is obtained based on the displayed impedance of the optical device interface to be connected to the PCB board.

[0028] Use the test impedance displayed on the soft band as the reference impedance to set the test impedance range.

[0029] Preferably, the step of obtaining the optimal matching impedance of the test softband corresponding to the impedance of the optical device interface to be connected on the PCB board by comparing the impedance effects of test softbands with different impedances within the impedance range on the interface of the optical device to be connected on the PCB board is specifically as follows:

[0030] Based on the characteristics of the measuring instrument, from all the test relationships of the test soft bands within the test impedance range, identify the test soft bands that cause the measured value of the interface impedance of the optical device to be connected to the PCB board to be too high, identify the test soft bands that cause the measured value of the interface impedance of the optical device to be connected to the PCB board to be too low, and identify the test soft bands whose measured values ​​of the interface impedance of the optical device to be connected to the PCB board are close.

[0031] The optimal fitting impedance of the test flexible tape is obtained by taking the average value.

[0032] Preferably, the characteristics of the measuring instrument are as follows:

[0033] When the impedance value of the test softband being tested is greater than the optimal matching impedance value of the test softband for the interface impedance of the optical device to be connected on the PCB board, the measured impedance value of the interface impedance of the optical device to be connected on the PCB board is higher than the actual impedance value.

[0034] When the impedance value of the test softband being tested is equal to the optimal matching impedance value of the test softband for the interface impedance of the optical device to be connected on the PCB board, the measured impedance value of the interface impedance of the optical device to be connected on the PCB board is equal to the actual impedance value.

[0035] When the impedance value of the test softband being tested is less than the optimal matching impedance value of the test softband for the interface impedance of the optical device to be connected to the PCB board, the measured impedance value of the interface impedance of the optical device to be connected to the PCB board is less than the actual impedance value.

[0036] Preferably, obtaining the apparent impedance of the optical device interface to be connected to the PCB board specifically involves:

[0037] The test rigid board and the PCB board are connected to form an electrical series connection.

[0038] The impedance of the optical device interface to be connected to the test board and PCB board is tested using a measurement analyzer to obtain the apparent impedance of the optical device interface to be connected to the PCB board.

[0039] Compared with the prior art, the beneficial effects of the embodiments of the present invention are as follows: The present invention uses a test soft strip to replace the traditional probe for measuring the impedance of the interface of the optical device to be connected to the PCB board. The test soft strip can be well connected to the interface of the optical device to be connected to the PCB board, which can effectively avoid the problem of inaccurate impedance measurement of the interface of the optical device to be connected to the PCB board due to the probe not being able to be inserted into the optimal position or the probe being manually inserted. In addition, the present invention uses a test soft strip with a corresponding impedance set according to a preset gradient impedance within the test impedance range. By measuring the influence of the test soft strip on the impedance of the interface of the optical device to be connected to the PCB board, the optimal matching impedance of the test soft strip corresponding to the current impedance of the interface of the optical device to be connected to the PCB board is determined. The true impedance of the interface of the optical device to be connected to the PCB board is obtained by measuring the impedance of the interface of the optical device to be connected to the PCB board and the trend of the impedance test image of the interface of the optical device to be connected to the PCB board. The difference between the measured value and the true value can be judged by the measured value of the interface impedance of the optical device to be connected to the PCB board and compensated for, so as to facilitate the replacement of the optical device with a more suitable one on the PCB board. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a flowchart of a method for measuring the interface impedance of an optical device to be connected to a PCB board, provided by an embodiment of the present invention.

[0042] Figure 2 This is a schematic diagram of the connection between a test rigid board, a test flexible tape, and a PCB board for measuring the interface impedance of an optical device to be connected to a PCB board, provided by an embodiment of the present invention.

[0043] Figure 3 This is a flowchart of a method for measuring the interface impedance of an optical device to be connected to a PCB board, provided by an embodiment of the present invention.

[0044] Figure 4 This is a flowchart of a method for measuring the interface impedance of an optical device to be connected to a PCB board, provided by an embodiment of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0046] In the description of this invention, the terms "inner", "outer", "longitudinal", "lateral", "upper", "lower", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and do not require that this invention must be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0047] Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0048] Example 1:

[0049] Embodiment 1 of the present invention provides a method for measuring the interface impedance of optical devices to be connected on a PCB board, such as... Figure 1 As shown, it includes:

[0050] Step 201: Set the test impedance range of the test softband, divide the test impedance range into zones according to the preset gradient impedance, and configure the test softband with the corresponding impedance.

[0051] In the process of measuring the interface impedance of optical devices to be connected to a PCB board using measuring instruments, this invention discovered that different impedance test strips produce different measurement deviations for the measured interface impedance. When a test strip with an impedance higher than the optimal match for the interface impedance of the optical device to be connected to the PCB board is selected for measurement, the measured impedance value will be higher than the true value; when a test strip with an impedance lower than the optimal match for the interface impedance of the optical device to be connected to the PCB board is selected for measurement, the measured impedance value will be lower than the true value; when a test strip with an impedance optimally matched to the interface impedance of the optical device to be connected to the PCB board is selected for measurement, the measured impedance value will be approximately equal to the true value. Furthermore, continuously adjustable test strips cannot be used during the testing process, as the resistance value of the test strip is difficult to change once set; even if a series of test strips are set, the optimal impedance of the interface impedance of the optical device to be connected to the PCB board cannot be continuously adjusted. The provided test tape may not be among the test tapes with the set resistance values. For example, suppose we set test tapes with resistance values ​​of 40Ω, 45Ω, 50Ω, 55Ω, and 60Ω for measurement, but the actual optimal impedance of the compatible test tape is 43Ω. In this case, we can compare the test results of 40Ω and 45Ω, take the average to obtain the optimal test tape measurement impedance of 42.5Ω, and then set the 42.5Ω test tape to test the impedance of the optical device interface to be connected to the PCB board. Within the allowable error range, this makes the measurement of the interface impedance of the optical device to be connected to the PCB board more accurate. In addition, according to customer needs, the 40Ω to 45Ω range can be further subdivided into test tapes with 1Ω intervals to further improve the accuracy of the interface impedance of the optical device to be connected to the PCB board. The measurement relationship obtained by the measuring instrument in this invention can be obtained through analysis of measurement charts or measurement curves.

[0052] Based on this, in order to measure the interface impedance of the optical devices to be connected to the PCB board relatively accurately, this invention first sets the test impedance range, divides the test impedance range into zones according to a preset gradient impedance, and configures test soft bands with corresponding impedances for easy replacement during the test. The preset gradient impedance of this invention is indirectly set according to the allowable error accuracy of the interface impedance of the optical devices to be connected to the PCB board. Specifically: based on actual needs, the maximum allowable error accuracy of the corresponding test soft band is calculated according to the maximum allowable error accuracy of the PCB board connection to the optical devices that the customer can accept; the gradient impedance is set according to the maximum allowable error accuracy of the test soft band, wherein the preset gradient impedance is less than or equal to the maximum allowable error accuracy of the maximum test soft band. For ease of understanding, a specific example is given below. For instance, when the test impedance range is between 40Ω and 60Ω, if the preset gradient impedance is 5Ω, then four zones are correspondingly divided: 40Ω to 45Ω, 45Ω to 50Ω, 50Ω to 55Ω, and 55Ω to 60Ω, and test soft bands with resistance values ​​of 40Ω, 45Ω, 50Ω, 55Ω, and 60Ω are set respectively. It is worth noting that two principles should generally be followed when setting corresponding resistance values ​​for test strips within each zone after partitioning: First, the resistance intervals between test strips should be equal; second, the preset gradient impedance should be less than or equal to the minimum allowable error accuracy of the test strip. The minimum allowable error accuracy of the test strip is usually determined by the minimum allowable error accuracy of the interface impedance of the optical device to be connected to the PCB board. The corresponding minimum allowable error accuracy of the interface impedance of the optical device to be connected to the PCB board can be determined according to customer requirements or actual conditions.

[0053] For this invention, the test impedance range is not arbitrarily set. The test impedance range needs to include the optimal matching impedance value of the test softband corresponding to the interface impedance of the optical device to be connected to the PCB board. A preset gradient impedance is used to set the resistance value of the test softband for measurement, fluctuating around the optimal matching impedance value, to eliminate measurement errors caused by the test softband being greater or less than the optimal matching value. Typically, the influence of the test softband on the interface impedance of the optical device to be connected to the PCB board is within 5Ω. Therefore, before setting the test impedance range, a calibration impedance of the test softband (referred to as the apparent impedance in this invention) needs to be set as a reference, and the test impedance range is set based on this calibration impedance. Before setting the test impedance of the test softband, the method further includes obtaining the apparent impedance of the interface of the optical device to be connected to the PCB board, and using the apparent impedance as a reference to set the test impedance range of the test softband. Specifically, the upper limit threshold of the test impedance of the test softband is set based on the apparent impedance of the interface of the optical device to be connected to the PCB board, according to the allowable error accuracy of the actual interface impedance of the optical device to be connected to the PCB board; the lower limit threshold of the test impedance of the test softband is set based on the apparent impedance of the interface of the optical device to be connected to the PCB board, according to the allowable error accuracy of the actual interface impedance of the optical device to be connected to the PCB board. This invention measures the test softband by connecting any test softband to the interface of the optical device to be connected to the PCB board, and uses this measured value as the apparent impedance. The matching impedance of the test softband is obtained based on the apparent impedance of the interface of the optical device to be connected to the PCB board. At this time, the matching impedance of the test softband is the calibration impedance, and the test impedance range of the test softband is set based on the calibration impedance of the test softband. For example, the impedance of the optical device interface to be connected on the PCB board is converted to a test softband adaptation value of 50Ω. The corresponding maximum allowable error accuracy is 5Ω, and the test impedance range can be selected between 40Ω and 60Ω (or other reasonable ranges). It is important to note that when setting the test range of the test softband based on the impedance of the optical device interface to be connected on the PCB board, this invention does not directly set the test range. It requires obtaining the corresponding adaptation value of the test softband from the impedance and then using this adaptation value to set the test range. Furthermore, the adaptation value of the test softband corresponding to the impedance is not the optimal adaptation value; the optimal adaptation value is the test softband adaptation value corresponding to the actual impedance of the optical device interface to be connected on the PCB board.

[0054] Step 202: Connect the test rigid board, test flexible tape, and PCB board in sequence to form an electrical series connection. Use a measurement analyzer to test the impedance of the optical device interface to be connected to the test rigid board, test flexible tape, and PCB board, and obtain the corresponding test relationship.

[0055] like Figure 2The diagram illustrates the connection of the test rigid board, test flexible tape, and PCB board. The PCB board has ROSA and TOSA ports for connecting to the flexible tape (corresponding to the optical device interface to be connected to the PCB board in this invention), used to connect the optical device. This embodiment of the invention uses an oscilloscope, TDR (Time-domain-reflectometry), or network analyzer to test the impedance of the test rigid board, test flexible tape, and the optical device interface to be connected to the PCB board. The test rigid board, test flexible tape, and PCB board are connected sequentially to form a series connection in the electrical system. The measuring instrument is connected to this system, and the impedance of the test rigid board, test flexible tape, and the optical device interface to be connected to the PCB board is scanned and tested using the radio wave signal emitted by the measuring instrument. Because the instrument scans the test rigid board, test flexible tape, and PCB board continuously, the impedance of the optical device interface to be connected to the PCB board measured by the instrument is affected not only by its true impedance but also by the impedance of the test flexible tape and test rigid board. This effect is introduced by the testing instrument. For oscillating measuring instruments, a test softband resistance that is too high (above the optimal matching impedance) will result in an overestimation of the impedance of the interface of the optical device to be connected to the PCB board, while a test softband resistance that is too low (below the optimal matching impedance) will result in an underestimation of the impedance of the interface of the optical device to be connected to the PCB board.

[0056] Step 203: By comparing the impact of the test softband configured within the impedance range on the impedance interface of the optical device to be connected on the PCB board, obtain the optimal matching impedance of the test softband corresponding to the impedance of the optical device interface to be connected on the PCB board, and obtain the true impedance of the optical device interface to be connected on the PCB board through the optimal matching impedance.

[0057] This invention, through the measurement and testing relationship output by the measuring instrument, allows us to determine the range of the true impedance of the interface of the optical device to be connected to the PCB board. Within the allowable error range, the average value within this range is taken as the measured impedance of the interface of the optical device to be connected to the PCB board, which can effectively improve the measurement accuracy of the interface impedance of the optical device to be connected to the PCB board. It is worth noting that this invention first determines the optimal matching test softband impedance value of the interface impedance of the optical device to be connected to the PCB board. After determining the optimal matching test softband impedance value, the test softband with the optimal impedance value is used to measure the impedance of the interface of the optical device to be connected to the PCB board. Within the allowable error range, the measured value at this time can be considered as the true value of the interface impedance of the optical device to be connected to the PCB board (since human operation inherently has errors, even measuring instruments will have errors).

[0058] To illustrate the complete solution of the invention, the details of the invention will be explained in detail below. Furthermore, the test impedance range is divided into zones according to a preset gradient impedance, and corresponding test soft bands are configured, such as... Figure 3As shown, it specifically includes:

[0059] Step 301: Use the error accuracy of the interface impedance of the optical device to be connected on the actual PCB board to set the difference between the upper and lower threshold values ​​of the test impedance of the test softband to determine the range of test impedance.

[0060] In this invention, after obtaining the measured impedance of the interface of the optical device to be connected to the PCB board, the measured value is used as a benchmark. The corresponding test impedance range of the interface is set according to the actual situation or the customer's required error accuracy. The test impedance range of the test softband is then deduced from the test impedance range of the interface. The span of the test impedance range (upper threshold minus lower threshold) is obtained through the test impedance range of the test softband. Typically, after obtaining the apparent impedance of the PCB board, approximately five test areas are set within the upper and lower thresholds of the apparent impedance (the number of areas can be determined according to specific circumstances) based on the actual situation or the maximum allowable error accuracy by the customer, to determine the test impedance range of the interface of the optical device to be connected to the PCB board.

[0061] Step 302: Based on the test impedance range, preset gradient impedance, and error accuracy of the interface impedance of the optical device to be connected on the actual PCB board, set the lower limit threshold of the test impedance of the test softband, and obtain all the test impedance values ​​set within the test impedance range.

[0062] Once the test impedance range of the test softband is known, test softbands with corresponding impedances are configured by dividing the area into zones. The method for configuring the test softband has already been explained with an example in step 201, and will not be discussed further here.

[0063] Step 303: Configure the corresponding impedance test strip according to all the set test impedance values.

[0064] Once the corresponding impedance is determined, test strips with the corresponding impedance are configured, and the test strips, test rigid board, and PCB board are connected in series to form an electrical series connection. Measurements are then performed using measuring instruments to obtain the measurement relationship. The test strips are continuously replaced to obtain the measurement relationship for all test strips. Before comparing the impact of test strips with different impedances within the impedance range on the impedance of the optical device interface to be connected to the PCB board, all test strips configured within the impedance range are tested one by one. Specifically, the corresponding test strips are replaced one by one, and the impedance relationship of the test rigid board, test strips, and the optical device interface to be connected to the PCB board is obtained using the network analyzer until all test strips within the impedance range have been tested.

[0065] Furthermore, after obtaining the true impedance of the interface of the optical device to be connected to the PCB board, the method further includes selecting a suitable optical device using the compensation amount of the impedance of the interface of the optical device to be connected to the PCB board. Specifically, the compensation impedance of the PCB board is obtained based on the difference between the measured true impedance value of the interface of the optical device to be connected to the PCB board and the apparent impedance of the interface of the optical device to be connected to the PCB board; and a suitable optical device is selected based on the compensation impedance and the apparent impedance of the interface of the optical device to be connected to the PCB board.

[0066] The purpose of this invention is to select an optical module with appropriate impedance matching based on the measured impedance of the interface of the optical device to be connected to the PCB board. The more accurate the impedance measurement of the interface of the optical device to be connected to the PCB board, the higher the compatibility of the selected optical module. Before actual assembly and packaging, the impedance test relationship of the interface of the optical device to be connected to the PCB board can be obtained by measuring the impedance test relationship. According to the law of the test relationship, the difference between the impedance of the interface of the optical device to be connected to the PCB board and the displayed impedance is measured, and the impedance of the internal softband of the corresponding optical module is compensated by the difference to achieve the best matching effect. It is worth noting that the test softband of this invention can be understood as simulating the impedance of the corresponding optical device, obtaining the optimal matching impedance of the optical device while measuring the actual impedance of the interface of the optical device to be connected to the PCB board.

[0067] Furthermore, the test impedance range of the test softband is set based on the displayed impedance as follows: Figure 4 As shown, specifically:

[0068] Step 401: Obtain the apparent impedance of the interface of the optical device to be connected on the PCB board.

[0069] Step 402: Obtain the test softband calibration impedance corresponding to the displayed impedance of the optical device interface to be connected on the PCB board based on the displayed impedance of the optical device interface to be connected on the PCB board.

[0070] Step 403: Using the test softband calibration impedance as a reference, set the test impedance range.

[0071] In this invention, the test rigid board and PCB board do not need to be replaced during the measurement process. First, the apparent impedance of the interface of the optical device to be connected to the PCB board is obtained using a measuring instrument (the principle of obtaining the apparent impedance has been explained above and will not be repeated here). By assessing the compatibility between the interface of the optical device to be connected to the PCB board and the test softband, the optimal matching impedance of the test softband can be determined. Based on the optimal matching impedance of the test softband, the test impedance range of the test softband is set according to the allowable error accuracy and test impedance range of the impedance of the interface of the optical device to be connected to the PCB board. Within the allowable error range, this measured value can be considered the true value.

[0072] This invention, after obtaining the measurement relationships of all test softbands, eliminates the influence of test softbands on the measurement of the interface of the optical device to be connected to the PCB board by selecting appropriate test softbands. Specifically, by comparing the impedance influence of test softbands with different impedances within the impedance range on the interface of the optical device to be connected to the PCB board, the optimal matching impedance of the test softband corresponding to the impedance of the interface of the optical device to be connected to the PCB board is obtained. This is done by: based on the characteristics of the measuring instrument, identifying the test softbands that cause the measured impedance value of the interface of the optical device to be connected to the PCB board to be too high from all the test relationships of the test softbands within the test impedance range; identifying the test softbands that cause the measured impedance value of the interface of the optical device to be connected to the PCB board to be too low; and identifying the test softbands whose measured impedance values ​​of the interface of the optical device to be connected to the PCB board are close; and obtaining the optimal matching impedance of the test softband by averaging. Using the averaging method makes the error of this invention smaller, achieving an accuracy within the allowable error range. It is worth noting that measuring instruments have their own measurement characteristics, specifically: when the impedance value of the test softband being tested is greater than the optimal matching impedance value of the test softband for the interface impedance of the optical device to be connected to the PCB board, the measured impedance value of the interface impedance of the optical device to be connected to the PCB board is higher than the actual impedance value; when the impedance value of the test softband being tested is equal to the optimal matching impedance value of the test softband for the interface impedance of the optical device to be connected to the PCB board, the measured impedance value of the interface impedance of the optical device to be connected to the PCB board is equal to the actual impedance value; when the impedance value of the test softband being tested is less than the optimal matching impedance value of the test softband for the interface impedance of the optical device to be connected to the PCB board, the measured impedance value of the interface impedance of the optical device to be connected to the PCB board is less than the actual impedance value. Based on the characteristics of the measuring instrument, this invention sets test softbands with corresponding gradient impedances within the test impedance range. By obtaining the impedance test relationships of all set test softbands through the testing instrument, the optimal matching impedance value of the test softband corresponding to the current interface impedance of the optical device to be connected to the PCB board is obtained. The impedance of the interface of the optical device to be connected to the PCB board is then obtained through the test softband with the optimal matching impedance value. The method of this invention can accurately measure the impedance of the interface of the optical device to be connected to the PCB board within the allowable error range, and can also obtain the optimal matching impedance value of the optical device that is compatible with the impedance of the interface of the optical device to be connected to the PCB board.

[0073] It is worth noting that a test board is involved in the testing process of this invention. To eliminate the influence of the test board on the measurement, within the limits of permissible conditions, this invention can eliminate the influence of the test board and the PCB board. Specifically, obtaining the apparent impedance of the optical device interface to be connected to the PCB board involves connecting the test board and the PCB board to form an electrical series connection, and then using a measurement analyzer to test the impedance of the optical device interface to be connected to the test board and the PCB board to obtain the apparent impedance of the optical device interface to be connected to the PCB board. This method allows for more accurate measurement of the impedance of the optical device interface to be connected to the PCB board.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of measuring the interface impedance of a PCB board to be connected to an optical device, characterized in that, The method comprises the following steps: Setting a test impedance range of the test soft band, dividing the test impedance range according to preset gradient impedances, and configuring the test soft band of the corresponding impedance; Connecting the test hard board, the test soft band, and the PCB board in sequence to form a series connection relationship under electricity, scanning and testing the impedance of the interface of the optical device to be connected of the PCB board by measuring the electric wave signal emitted by the measuring analyzer, and obtaining the corresponding test relationship; By comparing the influence of the test soft band of the configured impedance in the impedance range on the impedance of the interface of the optical device to be connected of the PCB board, the optimal adaptive impedance of the test soft band corresponding to the impedance of the interface of the optical device to be connected of the PCB board is obtained, and the real impedance of the interface of the optical device to be connected of the PCB board is obtained through the optimal adaptive impedance; comprising: according to the characteristics of the measuring instrument, finding out the test soft band that affects the measurement value of the impedance of the interface of the optical device to be connected of the PCB board to be connected to be high, finding out the test soft band that affects the measurement value of the impedance of the interface of the optical device to be connected of the PCB board to be connected to be low, and finding out the test soft band that affects the measurement value of the impedance of the interface of the optical device to be connected of the PCB board to be connected to be close; the optimal adaptive impedance of the test soft band is obtained by taking the average value.

2. The method of claim 1, wherein the method further comprises: Before setting the test impedance of the test soft band, the method further comprises obtaining the apparent impedance of the interface of the optical device to be connected of the PCB board, and setting the test impedance range of the test soft band based on the apparent impedance, specifically: Taking the test soft band calibration impedance corresponding to the apparent impedance of the interface of the optical device to be connected of the PCB board as a reference, setting the upper limit threshold of the test impedance of the test soft band according to the error precision allowed by the actual impedance of the interface of the optical device to be connected of the PCB board; Taking the apparent impedance of the test soft band corresponding to the apparent impedance of the interface of the optical device to be connected of the PCB board as a reference, setting the lower limit threshold of the test impedance of the test soft band according to the error precision allowed by the actual impedance of the interface of the optical device to be connected of the PCB board.

3. The method of claim 2, wherein the method further comprises: The method further comprises the following steps: Determining the test impedance range span by using the difference between the upper limit threshold and the lower limit threshold of the test impedance of the test soft band set according to the error precision allowed by the actual impedance of the interface of the optical device to be connected of the PCB board; Setting all test impedance values in the test impedance range according to the test impedance range span, the preset gradient impedance, and the error precision allowed by the actual impedance of the interface of the optical device to be connected of the PCB board; Configuring the test soft band of the corresponding impedance according to the set all test impedance values.

4. The method of claim 1, wherein the method further comprises: Before comparing the influence of the test soft band of different impedances in the impedance range on the impedance of the interface of the optical device to be connected of the PCB board, the method further comprises testing all test soft bands configured in the impedance range one by one, specifically: replacing the corresponding test soft band one by one, obtaining the impedance test relationship of the test hard board, the test soft band, and the interface of the optical device to be connected of the PCB board through the network analyzer, until all test soft bands in the test impedance range are tested.

5. The method of claim 1, wherein the method further comprises: measuring the interface impedance of the PCB board to be connected to the optical device. After obtaining the real impedance of the PCB board to be connected with the optical device interface, the method further comprises selecting an adaptive optical device by using the compensation amount of the impedance of the PCB board to be connected with the optical device interface, specifically comprising: According to the difference between the measured real impedance value of the PCB board to be connected with the optical device interface and the apparent impedance of the PCB board to be connected with the optical device interface, the compensation impedance of the PCB board is obtained. According to the compensation impedance and the apparent impedance of the PCB board to be connected with the optical device interface, an adaptive optical device is selected.

6. The method of claim 1, wherein the method further comprises: applying a voltage to the interface of the optical device to be connected to the PCB board; and measuring the impedance of the interface of the optical device to be connected to the PCB board. The preset gradient impedance is indirectly set according to the impedance error tolerance of the PCB board to be connected with the optical device interface, specifically comprising: According to the actual demand, the maximum allowed error accuracy of the corresponding test soft band is converted according to the maximum allowed error accuracy of the PCB board to be connected with the optical device interface that the customer can accept; According to the maximum allowed error accuracy of the test soft band, the gradient impedance is set, wherein the preset gradient impedance is less than or equal to the maximum test soft band maximum allowed error accuracy.

7. The method of measuring the interface impedance of a PCB board to be connected to an optical device according to claim 2, wherein, The test impedance range of the test soft band is set based on the apparent impedance, specifically comprising: Obtaining the apparent impedance of the PCB board to be connected with the optical device interface; According to the apparent impedance of the PCB board to be connected with the optical device interface, the calibration impedance of the test soft band corresponding to the apparent impedance of the PCB board to be connected with the optical device interface is obtained; The test impedance range is set based on the calibration impedance of the test soft band.

8. The method of claim 7, wherein the method further comprises: applying a voltage to the interface of the optical device to be connected to the PCB board; and measuring the impedance of the interface of the optical device to be connected to the PCB board. The characteristics of the measuring instrument are specifically: When the impedance value of the test soft band for testing is greater than the optimal adaptive test soft band impedance value of the PCB board to be connected with the optical device interface, the measured impedance value of the PCB board to be connected with the optical device interface is higher than the actual impedance value; When the impedance value of the test soft band for testing is equal to the optimal adaptive test soft band impedance value of the PCB board to be connected with the optical device interface, the measured impedance value of the PCB board to be connected with the optical device interface is equal to the actual impedance value; When the impedance value of the test soft band for testing is less than the optimal adaptive test soft band impedance value of the PCB board to be connected with the optical device interface, the measured impedance value of the PCB board to be connected with the optical device interface is less than the actual impedance value.

9. The method of claim 7, wherein the method further comprises: applying a voltage to the interface of the optical device to be connected to the PCB board; and measuring the impedance of the interface of the optical device to be connected to the PCB board. The apparent impedance of the PCB board to be connected with the optical device interface is obtained, specifically comprising: The test hard board and the PCB board are connected in series under the electrical connection, The impedance of the test hard board and the PCB board to be connected with the optical device interface is tested by the measuring analyzer, and the apparent impedance of the PCB board to be connected with the optical device interface is obtained.

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