A calibration method for radio frequency test equipment

Abstract

A calibration method for a radio frequency test fixture, the radio frequency test fixture comprising a test instrument and a shielding box, the test instrument having a first signal interface and a second signal interface, a fixing table provided in the shielding box, a coupling plate installed on the fixing table, a first connection point and a second connection point provided on the side wall of the shielding box, the second signal interface and the second connection point being connected via a third cable, and the second connection point and the coupling plate being connected via a fourth cable. The calibration method comprises the following steps: measuring the line loss of the entire loop, measuring the line loss of the fifth cable, measuring the sum of the line losses of the first cable and the second cable; and calculating the line loss of the radio frequency test fixture. The calibration method can significantly improve the efficiency of the calibration of the radio frequency test fixture, while significantly reducing the cost.

Description

Technical Field

[0001] The invention relates to the field of electronic equipment manufacturing and testing, and specifically to a calibration method for radio frequency testing tooling. Background Art

[0002] In the process of R&D and production of RF products, it is essential to test the relevant parameters of RF products (such as transmission power, frequency error, phase error, receiving sensitivity, etc.). In the prior art, the RF indicators of the RF signal of the product are tested by a comprehensive tester. When testing, the comprehensive tester needs to be connected to the product through an RF cable, and the RF cable also has signal attenuation. Therefore, when testing the RF indicators of the RF signal of the product, the RF cable needs to be calibrated.

[0003] At present, the industry generally uses the golden machine mode for calibration. Here, the golden machine is a product with all indicators and parameters adjusted to fixed optimal values. When testing, the golden machine is connected to the comprehensive tester through the RF line. The RF indicators of the golden machine are fixed, so the golden machine can be used as the standard to calibrate the RF line and the comprehensive tester at the same time. The biggest disadvantages of this calibration method are:

[0004] 1) In the NPI stage, it is usually too late to generate gold machine, which leads to obvious shortcomings in production timeliness;

[0005] 2) During the NPI stage, it is usually necessary to frequently replace the gold machine, resulting in high R&D and production of finished products. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a calibration method for a radio frequency test tool, aiming to solve the problems of low efficiency and high cost of radio frequency testing in the NPI stage of existing radio frequency products.

[0007] In order to solve the above technical problems, the technical solution adopted by the invention is to provide a calibration method for a radio frequency test fixture, wherein the radio frequency test fixture includes a test instrument and a shielding box, wherein the test instrument has a first signal interface and a second signal interface, a fixing table is provided in the shielding box, a coupling plate is installed on the fixing table, a first connection point and a second connection point are provided on the side wall of the shielding box, the second signal interface and the second connection point are connected by a third cable, and the second connection point and the coupling plate are connected by a fourth cable; the calibration method comprises the following steps:

[0008] Step S1, installing the device under test on the fixing table, connecting the first signal interface to the first connection point with the first cable, connecting a fifth cable to one end of the device under test, connecting the fifth cable to the first cable with the second cable, measuring the line loss of the entire loop, and recording the measurement result as Loss1;

[0009] Step S2, measuring the line loss of the fifth cable, and recording the measurement result as Loss2;

[0010] Step S3, separating the first cable from the first connection point, separating the third cable from the second signal interface, taking out the second cable, connecting two ends of the second cable to an end of the first cable and the second signal interface respectively, measuring the line loss of the first cable and the second cable, and recording the measurement result as Loss3;

[0011] Step S4, calculating the line loss of the radio frequency test tooling according to the following formula: Loss=Loss1-Loss2-Loss3, wherein Loss is the line loss of the radio frequency test tooling.

[0012] In the above technical solution, the line loss Loss1 of the entire loop, the line loss Loss2 of the fifth cable, the line loss and Loss3 of the first cable and the second cable are measured in sequence through the above steps, and then the line loss Loss of the RF test fixture is calculated according to the formula to achieve rapid calibration of the RF test fixture. The entire calibration process has simple operation steps and is easy to implement. Most importantly, there is no need to use a gold machine, which can greatly improve the efficiency of RF test fixture calibration and greatly reduce costs.

[0013] In the calibration method of the radio frequency test fixture provided by the present invention, the device to be tested includes a PCB board, and an antenna and an antenna matching element mounted on the PCB board.

[0014] In the calibration method of radio frequency testing tool provided by the present invention, the testing instrument is an RF testing instrument.

[0015] In the calibration method of the radio frequency test tool provided by the present invention, a first mounting cavity is provided on the solid-state table, and the coupling plate is fixed in the first mounting cavity.

[0016] In the calibration method of the radio frequency test tool provided by the present invention, the solid table is provided with a second installation cavity; in the step S1, the step of "installing the device under test on the fixed table" is to fix the device under test in the second installation cavity.

[0017] In the calibration method of the radio frequency testing tool provided by the present invention, the fifth cable includes a radio frequency line and a radio frequency terminal.

[0018] The calibration method of the RF test fixture of the present invention can at least achieve the following beneficial effects: through the above steps, the line loss Loss1 of the entire loop, the line loss Loss2 of the fifth cable, the line loss and Loss3 of the first cable and the second cable are measured in sequence, and then the line loss Loss of the RF test fixture is calculated according to the formula, so as to realize the rapid calibration of the RF test fixture. The operation steps of the entire calibration process are simple and easy to implement. Most importantly, there is no need to use a gold machine, which can greatly improve the efficiency of the calibration of the RF test fixture and greatly reduce the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings in the following description are only embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without creative work:

[0020] Figure 1 A schematic diagram of line connection when measuring line loss of the entire loop in the calibration method provided in an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of line connections when measuring the line losses of a first cable and a second cable in a calibration method provided in an embodiment of the present invention;

[0022] Figure 3 A flowchart of the steps of the calibration method provided in an embodiment of the present invention.

[0023] Description of the accompanying drawings in the specific implementation manner:

[0024] Shielding box 11 Test Equipment 12 First signal interface 121 Second signal interface 122 Fixed platform 111 Coupling plate 1111 First connection point 112 Second connection point 113 First Cable 13 Second cable 14 The third cable 15 Fourth Cable 16 Device under test 2 Fifth Cable 3 DETAILED DESCRIPTION

[0025] In order to facilitate understanding of the invention, the invention will be described more fully below with reference to the relevant drawings. Typical embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the invention more thorough and comprehensive.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the invention belongs. The terms used in the specification of the invention herein are only for the purpose of describing specific embodiments and are not intended to limit the invention.

[0027] This embodiment provides a calibration method for a radio frequency testing tool.

[0028] In order to facilitate understanding of the calibration method provided in this embodiment, it is necessary to first introduce and explain the radio frequency test tooling. Figure 1 , the radio frequency test tooling includes a test instrument 12 and a shielding box 11. The test instrument 12 is an RF test instrument 12. Here, we choose an RF test instrument 12 of model CMW500. The test instrument 12 has a first signal interface 121 and a second signal interface 122. Here, the first signal interface 121 is a signal transmitting end, and the second signal interface 122 is a signal receiving end. The shielding box 11 is a hollow rectangular structure and can be made of aluminum. A fixed platform 111 is provided inside it, and a coupling plate 1111 is installed on the fixed platform 111. Here, the fixed platform is provided with a first installation cavity and a second installation cavity, and the coupling plate 1111 is fixed in the first installation cavity. The vertical side walls of the shielding box 11 are provided with a first connection point 112 and a second connection point 113. Here, the first connection point 112 and the second connection point 113 are respectively the first metal terminal and the second metal terminal that pass through the side walls. The second signal interface 122 is connected to the second connection point 113 via a third cable 15 , and the second connection point 113 is connected to the coupling plate 1111 via a fourth cable 16 disposed in the shielding box 11 .

[0029] The second cable 14 connected to the first connection point 112, the first signal interface 121 and the first connection point 112 are connected via a first cable 13,

[0030] See also Figure 1 In the figure, the point indicated by A is the end of the second cable 14 connected to the fifth cable 3, the point indicated by B is the end of the fourth cable 16 connected to the coupling plate 1111, the point indicated by C is the end of the third cable 15 connected to the second signal interface 122, and the point indicated by D is the end of the first cable 13 connected to the first signal interface 121. Figure 2 , the calibration method provided in this embodiment includes the following steps:

[0031] Step S1, see Figure 1 , install the device under test 2 on the fixing platform 111, connect the first signal interface 121 with the first connection point 112 with the first cable 13, connect the fifth cable 3 at one end of the device under test 2, and connect the fifth cable 3 with the first cable 13 with the second cable 14, so that the line loss of the entire loop can be measured, and the measurement result is recorded as Loss1;

[0032] Step S2, measuring the line loss of the fifth cable 3, and recording the measurement result as Loss2; here, we use a common method in the art to measure the line loss of the fifth cable 3;

[0033] Step S3, see Figure 2 , separate the first cable 13 and the first connection point 112, separate the third cable 15 and the second signal interface 122, take out the second cable 14, and connect the two ends of the second cable 14 to the end of the first cable 13 and the second signal interface 122 respectively, so that the line loss of the first cable 13 and the second cable 14 can be measured, and the measurement result is recorded as Loss3;

[0034] Step S4, calculate the line loss of the RF test fixture according to the following formula: Loss = Loss1-Loss2-Loss3, where Loss is the line loss of the RF test fixture. In fact, the line loss Loss of the RF test fixture is the sum of the line loss between the device under test 2 and the coupling plate 1111, the line loss of the third cable 15, and the line loss of the fourth cable.

[0035] In the step S1 , the device under test 2 includes a PCB board, and an antenna and an antenna matching element mounted on the PCB board. The device under test 2 is fixed in the second mounting cavity on the fixing platform 111 .

[0036] In the step S2, the fifth cable 3 includes a radio frequency line and a radio frequency terminal. Of course, the radio frequency line and the radio frequency terminal are matched with the antenna.

[0037] By adopting the calibration method provided in this embodiment, it is only necessary to successively measure the line loss Loss1 of the entire loop, the line loss Loss2 of the fifth cable, the line loss and Loss3 of the first cable and the second cable through the above steps, and then calculate according to the formula to obtain the line loss Loss of the RF test tooling, thereby realizing rapid calibration of the RF test tooling. The operation steps of the entire calibration process are simple and easy to implement. Most importantly, there is no need to use a gold machine, which can greatly improve the efficiency of the RF test tooling calibration and greatly reduce the cost.

[0038] In addition, an adjacent first mounting cavity and a second mounting cavity are provided on the fixing platform 111, and the coupling plate 1111 and the device under test 2 are fixed in the first mounting cavity and the second mounting cavity respectively, so as to ensure that the relative positions of the coupling plate 1111 and the device under test 2 will not change during the measurement process, so as to ensure that the measurement results are accurate and reliable.

[0039] In some other embodiments, the RF test instrument 12 may also adopt other models, as long as an instrument with RF transmission / reception function is selected.

[0040] The embodiments of the invention are described above in conjunction with the accompanying drawings, but the invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the inspiration of the invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the invention and the claims, all of which are within the protection of the invention.

Claims

1. A calibration method for a radio frequency test tool, characterized in that: The radio frequency test tool comprises a test instrument (12) and a shielding box (11), the test instrument (12) having a first signal interface (121) and a second signal interface (122), a fixing platform (111) is provided inside the shielding box (11), a coupling plate (1111) is installed on the fixing platform (111), a first connection point (112) and a second connection point (113) are provided on the side wall of the shielding box (11), the second signal interface (122) and the second connection point (113) are connected via a third cable (15), and the second connection point (113) and the coupling plate (1111) are connected via a fourth cable (16); the calibration method comprises the following steps: Step S1, installing the device under test (2) on the fixing platform (111), connecting the first signal interface (121) to the first connection point (112) using the first cable (13), connecting a fifth cable (3) to one end of the device under test (2), connecting the fifth cable (3) to the first cable (13) using a second cable (14), measuring the line loss of the entire loop, and recording the measurement result as Loss1; Step S2, measuring the line loss of the fifth cable (3), and recording the measurement result as Loss2; Step S3, separating the first cable (13) from the first connection point (112), separating the third cable (15) from the second signal interface (122), taking out the second cable (14), connecting the two ends of the second cable (14) to the end of the first cable (13) and the second signal interface (122), respectively, measuring the line loss of the first cable (13) and the second cable (14), and recording the measurement result as Loss3; Step S4, calculating the line loss of the RF test tool according to the following formula: Loss=Loss1-Loss2-Loss3, wherein Loss is the line loss of the RF test tool.

2. The calibration method of the radio frequency test fixture according to claim 1, characterized in that: The device to be tested (2) comprises a PCB board, and an antenna and an antenna matching element mounted on the PCB board.

3. The calibration method of radio frequency test fixture according to claim 1, characterized in that: The test instrument (12) is an RF test instrument (12).

4. The calibration method of radio frequency test fixture according to claim 1, characterized in that: The solid-state platform is provided with a first mounting cavity, and the coupling plate (1111) is fixed in the first mounting cavity.

5. The calibration method of radio frequency test fixture according to claim 1, characterized in that: The solid-state platform is provided with a second mounting cavity; in the step S1, the step of "mounting the device under test (2) on the fixing platform (111)" is to fix the device under test (2) in the second mounting cavity.

6. The calibration method of radio frequency test fixture according to claim 1, characterized in that: The fifth cable (3) comprises a radio frequency line and a radio frequency terminal.

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