A radio frequency test fixture and a radio frequency test method of an electronic product

Abstract

This invention relates to the field of electronic technology and discloses an RF test fixture and an RF testing method for electronic products. The RF testing method includes: setting a first shorting point and a second shorting point on the circuit board; connecting the first shorting point to one end of the antenna and the second shorting point to the other end of the antenna; connecting a first shorting wire of the RF test fixture to the first shorting point, a second shorting wire to the second shorting point, and a test probe to the RF test point, so as to perform RF testing on the RF chip while the antenna is in an open-circuit state. This invention avoids unstable RF test power caused by partial RF signal radiated from the RF chip by the antenna, ultimately ensuring the accuracy of the RF test results; moreover, it is not limited by the size of the internal space of the earphone, facilitating the execution of test operations.

Description

Technical Field

[0001] This invention relates to the field of electronic technology, and in particular to an RF test fixture and an RF test method for electronic products. Background Technology

[0002] With the development of technology, electronic products are becoming more and more diverse. Most products have radio frequency (RF) communication capabilities. When RF signals are transmitted inside electronic products, they are mainly transmitted through the paths on the circuit boards and the internal wires. To ensure the smooth transmission of RF signals, it is necessary to perform RF testing on the circuit boards in electronic products.

[0003] Currently, TWS earphones, or True Wireless Stereo earphones, are one of the electronic products with radio frequency communication capabilities. They are widely used because they bring convenience to many users. The main way to use them is to connect with mobile devices such as mobile phones and computers via Bluetooth radio frequency, then transmit audio information to the earphones, and then decode and output it at the earphone end.

[0004] The form factor of TWS earbuds places high demands on supply chain manufacturers. Key components such as the main control chip, power management IC, wireless charging receiver chip, charging case battery, and earbud battery all require continuous performance improvements and miniaturization to meet the design requirements of TWS earbuds. Therefore, due to space limitations, test sockets cannot be accommodated in TWS earbuds. This necessitates the use of socket-less testing solutions, such as establishing RF test points on the circuit board and using a test fixture with test probes. The test probes of the fixture contact the RF test points on the circuit board to perform RF testing. However, during this RF testing, the antenna of the TWS earbud is not disconnected, essentially resulting in a load test. Some of the energy emitted by the chip is radiated away by the antenna, leading to unstable RF test power values ​​that are highly susceptible to environmental influences and exhibit very poor consistency. Summary of the Invention

[0005] The purpose of this invention is to provide an RF test fixture and an RF test method for electronic products, so as to overcome the problem of inconsistent RF test results in the prior art.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A radio frequency (RF) test fixture is used for RF testing of electronic products. The electronic products include a circuit board, an antenna, and an RF chip disposed on the circuit board. The antenna is RFly connected to the RF chip. The circuit board has RF test points connected to the RF chip, including:

[0008] The test probe is used to dock with the radio frequency test points on the circuit board to perform radio frequency testing on the radio frequency chip;

[0009] A first shorting wire and a second shorting wire are connected, with one end of the first shorting wire connected to one end of the second shorting wire, and the other end of the first shorting wire connected to one end of the antenna, and the other end of the second shorting wire connected to the other end of the antenna, so that the antenna is in an open circuit state.

[0010] Optionally, the test pin, the first jumper wire, and the second jumper wire are all arranged on the process edge of the circuit board.

[0011] A radio frequency (RF) testing method for an electronic product, the electronic product including a circuit board, an antenna, and an RF chip disposed on the circuit board, the antenna being RFly connected to the RF chip, the RF testing method comprising:

[0012] A first shorting point and a second shorting point are provided on the circuit board. The first shorting point is connected to one end of the antenna, and the second shorting point is connected to the other end of the antenna.

[0013] The first shorting wire of the RF test fixture described above is connected to the first shorting point, the second shorting wire is connected to the second shorting point, and the test probe is connected to the RF test point, so that the RF chip can be tested while the antenna is in an open circuit state.

[0014] Optionally, the RF testing method further includes: adjusting the lengths of the first shorting wire and the second shorting wire so that during the RF testing of the RF chip, the passive positions of the first shorting point and the second shorting point are in the high-impedance state position corresponding to the Smith chart.

[0015] Optionally, the method for adjusting the lengths of the first shorting wire and the second shorting wire includes:

[0016] Two shorting wires with a length greater than a preset threshold are installed on the radio frequency test fixture, which serve as the first shorting wire and the second shorting wire, respectively.

[0017] Disconnect the RF path before the RF test point and connect the RF test point to the vector network analyzer;

[0018] Connect the first shorting wire to the first shorting point and the second shorting wire to the second shorting point, and gradually shorten the first shorting wire and the second shorting wire until the passive positions of the first shorting point and the second shorting point reach the high-resistivity position in the Smith chart displayed on the vector network analyzer.

[0019] Optionally, copper tubing can be used to connect the RF test points to the vector network analyzer.

[0020] Optionally, an RF matching unit is connected between the RF chip and the RF test point, and an antenna matching unit is connected between the RF test point and the antenna.

[0021] Optionally, the method of disconnecting the RF path prior to the RF test point includes: disconnecting the RF matching unit.

[0022] Optionally, the radio frequency chip is a Bluetooth chip, and the antenna is a PCB onboard antenna, an FPC antenna, a ceramic antenna, or an LDS antenna.

[0023] Optionally, the electronic product is a TWS Bluetooth headset.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] This invention adds two shorting wires to the RF test fixture for connecting to both ends of the antenna of an electronic product. In application, the test probes, the first shorting wire, and the second shorting wire on the RF test fixture are respectively connected to the RF test points, the first shorting point, and the second shorting point on the circuit board, thereby simultaneously realizing the antenna disconnection operation and the RF chip RF test operation. This avoids the instability of RF test power caused by the antenna radiating part of the RF chip's RF signal, ultimately ensuring the accuracy of the RF test results; moreover, it is not limited by the size of the internal space of the earphone, facilitating the execution of the test operation. Attached Figure Description

[0026] 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.

[0027] Figure 1 This is a schematic diagram of the radio frequency path between the radio frequency chip and the antenna in an electronic product, provided as an embodiment of the present invention.

[0028] Figure 2 The schematic diagram of the circuit board of the electronic product provided in the embodiment of the present invention.

[0029] Figure 3 A flowchart of an electronic product radio frequency testing method provided in an embodiment of the present invention.

[0030] Figure 4 The Smith chart provided for an embodiment of the present invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] Circuit board 1, RF chip 2, RF matching unit 3, antenna matching unit 4, antenna 5, RF test point 6, first shorting point 7, second shorting point 8, high impedance range A. Detailed Implementation

[0033] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0034] To achieve accurate radio frequency (RF) testing, this invention provides a novel RF testing solution. This solution performs RF testing on the RF chip 2 within the electronic product during application testing, while simultaneously controlling the antenna 5 through a short-circuit method. This ensures that the energy emitted by the RF chip 2 is not emitted by the antenna 5 during the RF testing process, thereby guaranteeing the stability of the RF test power value.

[0035] The electronic products to which this invention is applicable can be any product with radio frequency functionality, and are especially suitable for TWS earphones that cannot be tested using conventional test sockets due to limited internal space.

[0036] Typically, an electronic product includes a circuit board 1, an antenna 5, and an RF chip 2 mounted on the circuit board 1. The antenna 5 is RF connected to the RF chip 2. To facilitate RF testing, the circuit board 1 has an RF test point 6, which is connected to the RF chip 2 and used to connect to the test probes of an RF test fixture to perform RF testing.

[0037] Furthermore, the radio frequency path between the radio frequency chip 2 and the antenna 5 within the electronic product can be as follows: Figure 1 As shown, the system specifically includes a Bluetooth chip, an RF matching unit 3, an antenna matching unit 4, and an antenna 5 connected sequentially via radio frequency (RF). RF test point 6 is located on the RF line between the RF matching unit 3 and the antenna matching unit 4. Of course, in other embodiments, the RF path can employ different designs, and this embodiment of the invention does not specifically limit this.

[0038] Taking TWS earphones as an example, the RF chip 2 is specifically a Bluetooth chip, and the antenna 5 can be a PCB-on-board antenna, an FPC antenna, a ceramic antenna, or an LDS antenna. The Bluetooth chip is a type of RF chip 2. Its working principle is as follows: the Bluetooth chip converts the transmitted data into an RF signal, then sends it to the antenna 5. It transmits and receives the signal from the other end of the antenna 5 via a wireless channel, and then converts the signal into a digital signal through an RF receiving circuit before transmitting it to other devices for processing. The Bluetooth chip's signal transmission method employs frequency hopping spread technology, using 79 different frequency bands for frequency hopping, with each band lasting 625μs. Simultaneously, the Bluetooth chip also employs adaptive frequency hopping technology and power control technology to ensure stable data transmission even under conditions of significant interference.

[0039] Specifically, embodiments of the present invention provide an radio frequency test fixture, comprising:

[0040] The test probe is used to dock with the RF test point 6 on the circuit board 1 of the electronic product to perform RF testing on the RF chip 2.

[0041] The first shorting wire and the second shorting wire are connected at one end to the second shorting wire, and the other end of the first shorting wire is used to connect to one end of the antenna 5. The other end of the second shorting wire is used to connect to the other end of the antenna 5, so that the antenna 5 is in an open circuit state.

[0042] Unlike conventional RF test fixtures, this embodiment of the invention adds two shorting wires to the fixture for connecting to both ends of the antenna 5 of the electronic product. This ensures that the antenna 5 is in an open-circuit state during RF testing, preventing instability in RF test power caused by the antenna 5 radiating part of the RF signal of the RF chip 2, and ultimately ensuring the accuracy of the RF test results.

[0043] Please see Figure 2 In order to avoid occupying the effective wiring space of the circuit board 1 and to facilitate testing operations, the test pins, the first shorting point 7 and the second shorting point 8 can all be arranged on the process edge of the circuit board 1.

[0044] Based on the RF test fixtures described above, please refer to... Figure 3 This invention also provides a radio frequency testing method for electronic products, comprising:

[0045] S1. Set a first shorting point 7 and a second shorting point 8 on the circuit board 1, connect the first shorting point 7 to one end of the antenna 5, and connect the second shorting point 8 to the other end of the antenna 5.

[0046] S2. Connect the first shorting wire of the above-mentioned RF test fixture to the first shorting point 7, the second shorting wire to the second shorting point 8, and the test probe to the RF test point 6, so that the RF chip 2 can be tested while the antenna 5 is in an open circuit state.

[0047] In this RF testing method, the test probes, the first shorting wire, and the second shorting wire on the RF test fixture are respectively connected to the RF test point 6, the first shorting point 7, and the second shorting point 8 on the circuit board 1, thereby simultaneously realizing the disconnection operation of the antenna 5 and the RF test operation of the RF chip 2. In this way, the RF test can be completed quickly and accurately, and it is not limited by the size of the internal space of the earphone, which facilitates the execution of the test operation.

[0048] It should be noted that in order to effectively disconnect antenna 5, the first shorting point 7 and the second shorting point 8 need to be in a high-impedance state at their corresponding passive positions on the Smith chart. Since the lengths of the first and second shorting wires will affect the passive position of the corresponding shorting points, in practical applications, two shorting wires of appropriate length can be directly selected based on experience to disconnect antenna 5, or the length of the shorting wire pair can be adjusted before RF testing.

[0049] In one optional embodiment, the method for adjusting the lengths of the first and second shorting wires includes: installing two shorting wires with lengths greater than a preset threshold on an RF test fixture, serving as the first and second shorting wires respectively; disconnecting the RF path before RF test point 6 and connecting RF test point 6 to a vector network analyzer; connecting the first shorting wire to the first shorting point 7 and the second shorting wire to the second shorting point 8, and gradually shortening the first and second shorting wires until the passive positions of the first shorting point 7 and the second shorting point 8 reach the high impedance state in the Smith chart displayed on the vector network analyzer.

[0050] exist Figure 1 In the RF path shown, the method to disconnect the RF path before RF test point 6 can be: disconnect the RF matching unit 3.

[0051] It should be noted that the Smith chart is a calculation diagram plotted on the reflective plane, showing a family of circles representing the normalized input impedance (or admittance). It is a chart used in electrical and electronic engineering, primarily for impedance matching of transmission lines. A vector network analyzer is an instrument that provides Smith chart plotting capabilities; it can be connected to the RF test point 6 via metal components such as copper tubing.

[0052] In this embodiment, two relatively long shorting wires can be selected as the first and second shorting wires. Then, the first and second shorting wires are connected to the corresponding shorting points, and the RF path before RF test point 6 is disconnected. This allows the initial position of the shorting point to be clearly seen on the Smith chart (at which point antenna 5 will not enter a completely open circuit state). Subsequently, as the shorting wires are continuously shortened, the passive position of the shorting point on the Smith chart will rotate counter-clockwise from its initial position until the passive position reaches its maximum value. Figure 4 The high-impedance state range defined by point A. Reaching the high-impedance state indicates that the current length of the jumper wire is sufficient to ensure that antenna 5 enters the open-circuit state.

[0053] Based on this, the embodiments of the present invention can effectively ensure that antenna 5 enters an open circuit state during the radio frequency test by adjusting the length of the two shorting wires, thereby further improving the accuracy of the radio frequency test results.

[0054] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A radio frequency (RF) test fixture, applied to RF testing of electronic products, the electronic products including a circuit board, an antenna, and an RF chip disposed on the circuit board, the antenna being RFly connected to the RF chip, and the circuit board having RF test points connected to the RF chip, characterized in that... include: The test probe is used to dock with the radio frequency test points on the circuit board to perform radio frequency testing on the radio frequency chip; The circuit board is provided with a first shorting point and a second shorting point. The first shorting point is connected to one end of the antenna, and the second shorting point is connected to the other end of the antenna. A first shorting wire and a second shorting wire, one end of the first shorting wire is connected to one end of the second shorting wire, the other end of the first shorting wire is used to connect to the first shorting point, and the other end of the second shorting wire is used to connect to the second shorting point, so that the antenna is in an open circuit state; The lengths of the first and second shorting wires are adjusted and set so that during the radio frequency testing of the radio frequency chip, the passive positions of the first and second shorting points are in the high-impedance state position on the corresponding Smith chart.

2. The radio frequency test fixture according to claim 1, characterized in that, The test pin, the first jumper wire, and the second jumper wire are all located on the process edge of the circuit board.

3. A radio frequency (RF) testing method for an electronic product, the electronic product comprising a circuit board, an antenna, and an RF chip disposed on the circuit board, wherein the antenna is RFly connected to the RF chip, characterized in that, The radio frequency testing method includes: A first shorting point and a second shorting point are provided on the circuit board. The first shorting point is connected to one end of the antenna, and the second shorting point is connected to the other end of the antenna. The first shorting wire of the RF test fixture as described in claim 1 or 2 is connected to the first shorting point, the second shorting wire is connected to the second shorting point, and the test probe is connected to the RF test point, so that the RF chip can be tested while the antenna is in an open circuit state. The radio frequency testing method further includes: adjusting the lengths of the first shorting wire and the second shorting wire so that during the radio frequency testing of the radio frequency chip, the passive positions of the first shorting point and the second shorting point are in the high impedance state position corresponding to the Smith chart.

4. The radio frequency testing method for electronic products according to claim 3, characterized in that, The method for adjusting the lengths of the first shorting wire and the second shorting wire includes: Two shorting wires with a length greater than a preset threshold are installed on the radio frequency test fixture, which serve as the first shorting wire and the second shorting wire, respectively. Disconnect the RF path before the RF test point and connect the RF test point to the vector network analyzer; Connect the first shorting wire to the first shorting point and the second shorting wire to the second shorting point, and gradually shorten the first shorting wire and the second shorting wire until the passive positions of the first shorting point and the second shorting point reach the high-resistivity position in the Smith chart displayed on the vector network analyzer.

5. The radio frequency testing method for electronic products according to claim 4, characterized in that, The RF test points are connected to the vector network analyzer using copper tubing.

6. The radio frequency testing method for electronic products according to claim 4, characterized in that, An RF matching unit is connected between the RF chip and the RF test point, and an antenna matching unit is connected between the RF test point and the antenna.

7. The radio frequency testing method for electronic products according to claim 6, characterized in that, The method for disconnecting the RF path prior to the RF test point includes: disconnecting the RF matching unit.

8. The radio frequency testing method for electronic products according to claim 3, characterized in that, The radio frequency chip is a Bluetooth chip, and the antenna is a PCB onboard antenna, an FPC antenna, a ceramic antenna, or an LDS antenna.

9. The radio frequency testing method for electronic products according to claim 3, characterized in that, The electronic product in question is a TWS Bluetooth headset.

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