CN216771842U

CN216771842U - High frequency PCB characteristic impedance test fixture

Info

Publication number: CN216771842U
Application number: CN202123077935.4U
Authority: CN
Inventors: 唐福现
Original assignee: Shenzhen Jiutong Technology Co ltd
Current assignee: Shenzhen Jiutong Technology Co ltd
Priority date: 2021-12-08
Filing date: 2021-12-08
Publication date: 2022-06-17
Anticipated expiration: 2031-12-08

Abstract

The application discloses a high-frequency PCB characteristic impedance test fixture which comprises a test base, a card edge connector for inserting a high-frequency PCB, a transfer PCB for transferring signals and a patch cord for transmitting the signals on the transfer PCB to the outside; the transfer PCB is fixedly installed on the test base, the card edge connector is installed in the test base, the card edge connector is electrically connected with the transfer PCB, one end of the patch cord is connected to the transfer PCB, and the other end of the patch cord is used for being electrically connected with the time domain analyzer. The technical scheme effectively improves the testing efficiency of the high-frequency PCB characteristic impedance.

Description

High frequency PCB characteristic impedance test fixture

Technical Field

The invention relates to the technical field of PCB (Printed circuit board) testing, in particular to a high-frequency PCB characteristic impedance testing jig.

Background

A PCB (printed Circuit board), also called a printed Circuit board, is an important support for electronic components, and with the advent of the 5G communication era, the electronics and communication industry has rapidly developed, and electronic information products have been continuously developed in the direction of high frequency and high speed, and the demand for PCB signal transmission rate has become higher and higher, and high frequency PCBs have been widely used as special PCBs with higher electromagnetic frequency.

Before and even after all electronic products leave a factory, a series of performance tests are carried out to find and eliminate faults in advance, so that the product quality is ensured, and particularly, the high-frequency PCB is used; the characteristic impedance is an important parameter of the high frequency PCB, and needs to be tested to check the performance of the high frequency PCB.

In the existing field of testing the characteristic impedance of the high-frequency PCB, the mode of the radio frequency probe is the most common, technicians aim at a to-be-tested welding pin on the high-frequency PCB by using the needle point of the radio frequency probe, when the characteristic impedance of the to-be-tested welding pin is tested, one end of the radio frequency probe is connected with the to-be-tested welding pin, and the other end of the radio frequency probe is connected with the time domain analyzer through a connecting wire, so that the electric connection between the to-be-tested welding pin and the time domain analyzer is realized, and the characteristic impedance of the high-frequency PCB is tested.

With the rapid development of social science and technology, the miniaturization and integration of the PCB are in great trend, the number of PCB to-be-tested welding feet which are used for being connected with high-speed pairs on the existing high-frequency PCB is usually up to three or forty pairs, each pair of welding feet to be tested is used for being connected with the corresponding pair of high-speed pairs, and the welding feet to be tested are very dense. The radio frequency probe has a certain diameter, the distance between adjacent to-be-tested welding pins on the high-frequency PCB is too short due to the densification of the to-be-tested welding pins, and in the contact process, because the dense to-be-tested pins also need to distinguish each pair of high-speed pairs of corresponding to-be-tested pins, the characteristic impedance value is difficult to accurately and rapidly test, so that a large amount of time and manpower resources are consumed in the test process, and the efficiency is extremely low.

SUMMERY OF THE UTILITY MODEL

The problem that the efficiency of testing the characteristic impedance of the high-frequency PCB is low in the prior art is solved.

The application provides a high frequency PCB characteristic impedance test fixture adopts following scheme:

a high-frequency PCB characteristic impedance test fixture comprises a test base, a card edge connector for inserting a high-frequency PCB, a transfer PCB for transferring signals and a patch cord for transmitting the signals on the transfer PCB to the outside; the transfer PCB is fixedly installed on the test base, the card edge connector is installed in the test base and is electrically connected with the transfer PCB, one end of the patch cord is connected to the transfer PCB, and the other end of the patch cord is used for being electrically connected with the time domain analyzer; the number of patch cords is many, have on the transfer PCB and be used for corresponding a plurality of transfer fillets that the leg that awaits measuring set up on the high frequency PCB, every patch cord is used for linking to each other with a transfer fillet that corresponds on the transfer PCB.

By adopting the scheme, the high-frequency PCB to be tested can be inserted into the card edge connector, the card edge connector is electrically connected with the transfer PCB, and the transfer PCB is electrically connected with an external time domain analyzer through the patch cord, so that the effect of electrically connecting the high-frequency PCB to be tested with the time domain analyzer is realized; in the traditional technical scheme, probes are commonly used for testing the welding feet to be tested on the high-frequency PCB one by one, and the welding feet to be tested on the existing high-frequency PCB are very dense, so that the problem of inconvenient testing is easy to occur, and in the process of contacting the probes with the welding feet to be tested, each high-speed pair of corresponding different welding feet needs to be distinguished, so that the efficiency is low, and the existing production requirements are difficult to meet; in the technical scheme, a plurality of to-be-tested welding feet on a high-frequency PCB can be switched to the PCB through a card edge connector, each connecting wire is correspondingly connected to one transfer welding foot on the transfer PCB through a plurality of switching wires, so that each connecting wire can correspond to one to-be-tested welding foot on the to-be-tested PCB, and the characteristic impedance of all the to-be-tested welding feet can be measured only by sequentially testing through an external time domain analyzer and the switching wires; only need distinguish the connecting wire and need not to distinguish intensive fillet weld that awaits measuring, test that can be quick, the promotion that is showing efficiency of software testing. On the other hand, the transfer welding wires and the transfer welding pins on the transfer PCB are welded in advance, and each transfer wire is only required to be electrically connected for testing subsequently, so that the problem that in the prior art, the test data is unreliable due to the fact that the welding pins of the high-frequency PCB are dense and probes interfere during testing is solved; in the third aspect, in the technical scheme of the application, the high-frequency PCB to be tested is inserted into the card edge connector, so that the problem that the welding pins to be tested of the high-frequency PCB are easily damaged during the test of the thimble in the prior art is effectively solved, and the effect of reducing loss is achieved.

Optionally, the patch cord is a radio frequency phase-stable micro-coaxial cable.

By adopting the scheme, in the process of testing the high-frequency PCB, the time domain analyzer is sensitive to the microwave phase, and the phase value is required to be kept stable, so that the small signal distortion of the transmission signal is ensured. Besides the phase change of the cable caused by the mechanical bending caused by the outside, the temperature has a great influence on the coaxial cable, mainly because the thermal expansion coefficient of the cable dielectric material is suddenly changed near the room temperature, thereby causing the sudden change of the transmission phase. The phase-stabilizing cable is a low-loss high-phase-stabilizing soft microwave coaxial cable which is mainly used as a low-loss high-phase-stabilizing soft radio frequency connection feeder in electronic equipment such as a phase-controlled radar, a vector network analyzer and the like; the temperature dependent behavior of the materials in the cable and the internal interactions between them will affect the overall phase versus temperature behavior. For example, when the ambient temperature rises, the insulating medium expands with the increase of the temperature and the tightness thereof is reduced, thereby causing the dielectric constant of the dielectric to become small, the propagation rate to increase, and the phase to become small, and at the same time, due to the temperature rise, the cable conductor expands, the physical length thereof also becomes large, and the phase to become large. Due to the special material of the phase-stable cable, the dielectric constant of the phase-stable cable is reduced along with the temperature rise, the dielectric constant of the cable is increased along with the temperature rise of the mechanical structure of the cable, the dielectric constant and the temperature rise can be mutually offset to keep the phase stable, and the phase change value of the phase-stable cable is only 10% of that of a common cable at the ambient temperature of 20-40 ℃. Because the system that this patch cord was used is under the ambient temperature variation range of during operation for the room temperature, consequently the little coaxial cable of radio frequency stationary phase is selected for use to the measured signal in this application technical scheme to further ensure signal transmission's quality.

Optionally, a plurality of adapters used for being connected with the time domain analyzer are fixedly mounted on the testing base, and the number of the adapters is equal to that of the patch cords and the patch cords are arranged in a one-to-one correspondence mode.

By adopting the scheme, the test base is provided with the plurality of adapters which are convenient to plug, so that the effect of quick plug test is realized; in the traditional technical scheme, the probe finds out the appointed welding foot to be detected among the dense welding feet to carry out contact detection, so that the accuracy is difficult to ensure and the efficiency is low; according to the technical scheme, the plurality of adapters are arranged on the adapter part and connected through the connector connected to the time domain analyzer, so that the characteristic impedance is tested; this application technical scheme is equivalent to the adapter that corresponds with the leg transfer of high frequency PCB upper density, from this, external time domain analysis appearance can be fast and accurate link to each other with the adapter to the realization is to the efficiency of software testing of high frequency PCB characteristic impedance and test quality's promotion.

Optionally, one end of each patch cord is provided with a plug, each patch cord is plugged into a corresponding patch head through the plug, and the other end of each patch cord is welded on the transfer welding leg.

Through adopting the above-mentioned scheme, the patch cord passes through the plug and pegs graft on the adapter that corresponds, the other end welding is on the transfer leg, correspond the high frequency PCB of different grade type, this tool only need change different transfer PCB and the card edge connector of cooperation design can, and the patch cord welds well in advance on the transfer PCB that corresponds, only need after the change transfer PCB, card edge connector assembles, and peg graft the patch cord one by one can on the adapter that corresponds, the dismouting of this tool is very convenient, the effectual efficiency that has further promoted.

Optionally, each adapter corresponds to a different identifier.

By adopting the scheme, the welding feet to be tested on the high-frequency PCB are used for being connected with the high-speed pairs, so the welding feet to be tested usually exist in pairs, and when the characteristic impedance of the welding feet to be tested is tested, the data of the welding feet to be tested are recorded after the appointed welding feet to be tested are found for measurement; from this, among the application technical scheme, through will await measuring the leg equivalent to the adapter that corresponds after, correspond the sign with every adapter and have different serial numbers to can be convenient find the required measured leg that awaits measuring, and with the record that its data and serial number correspond. To sum up, above-mentioned technical scheme can be convenient for find appointed leg that awaits measuring, has further promoted the efficiency of this high frequency PCB characteristic impedance test.

Optionally, the card edge connector includes a card slot for being inserted into the high-frequency PCB, a transfer pin is vertically arranged on an inner wall of the card slot, and a slot opening of the card slot is located on the transfer PCB.

By adopting the scheme, when the characteristic impedance of the high-frequency PCB is tested, the switching pin for contact is required to be vertical to the PCB, so that the signal transmission is ensured not to be distorted, the accuracy of the test result is improved, and the effect of preventing the probe from being damaged can be achieved; among this application technical scheme, be used for with the draw-in groove of high frequency PCB grafting through the design, the high frequency PCB of being convenient for inserts to insert the back because switching stitch and draw-in groove inner wall are perpendicular, so the switching stitch can be perpendicular with high frequency PCB, plays the test effect of preferred. And card edge connector's draw-in groove is located the transfer PCB, in the flow of the high frequency PCB of test different grade type, takes out card edge connector and transfer PCB simultaneously and change when can be comparatively convenient, has played the dismouting of being convenient for, further raises the effect of efficiency.

Optionally, the test base includes a base body and a cover plate installed on the base body, and the cover plate is in threaded connection with the base body.

Through adopting above-mentioned scheme, to the inside structure of test base, the tool in this application scheme is provided with the pedestal and installs the apron on the pedestal, when needs are changed or are maintained the inside structure of test base, can contact the bolt on the apron, takes off the apron from the pedestal to the structure that can convenient dismouting test pedestal, thereby carry out the change and the maintenance of spare part, further promoted efficiency of software testing.

Optionally, the cover plate is provided with a positioning pin, and the transfer PCB is provided with a positioning groove; when the cover plate is in threaded connection with the test base, the positioning pin is inserted into the positioning groove, and the end face, far away from the cover plate, of the transfer plate is pressed against the bottom face of the base body.

By adopting the scheme, after the cover plate is covered, the cover plate is inserted on the transfer PCB through the positioning pin so as to position the transfer PCB; in the traditional technical scheme, technical means such as threaded connection and the like are usually adopted for achieving the fixing effect, but the technical means can cause that the assembly and disassembly are not convenient enough and the efficiency is not high enough; in the technical scheme, the positioning pin is inserted into the transfer PCB for positioning, and the end face, far away from the cover plate, of the transfer PCB is pressed against the bottom surface of the base, so that the transfer PCB can be positioned and assembled in the testing base; when the transfer PCB needs to be disassembled and assembled, the positioning pin is separated from the positioning groove along with the disassembly of the cover plate after the cover plate is opened, so that the limitation on the transfer PCB is relieved; the effectual dismouting convenient degree that has promoted transfer PCB of this application technical scheme.

Detachable mode, change transfer PCB and card reason adapter that can be convenient promote work efficiency.

To sum up, the present application includes at least the following beneficial technical effects:

1. in the technical scheme, a plurality of welding feet to be tested on the high-frequency PCB can be switched to the PCB through the card edge connector, each connecting wire is correspondingly connected to one transfer welding foot on the transfer PCB through a plurality of switching wires, so that each connecting wire can correspond to one welding foot to be tested on the PCB to be tested, and the characteristic impedance of all the welding feet to be tested can be tested only by sequentially testing through an external time domain analyzer and the switching wires; only need distinguish the connecting wire and need not to distinguish intensive fillet weld that awaits measuring, test that can be quick, the promotion that is showing efficiency of software testing. On the other hand, the transfer welding wires and the transfer welding pins on the transfer PCB are welded in advance, and each transfer wire is only required to be electrically connected for testing subsequently, so that the problem that in the prior art, the test data is unreliable due to the fact that the welding pins of the high-frequency PCB are dense and probes interfere during testing is solved; in the technical scheme of the application, the high-frequency PCB to be tested is inserted into the card edge connector, so that the problem that the welding pins to be tested of the high-frequency PCB are easily damaged during the thimble test in the prior art is effectively solved, and the effect of reducing loss is achieved;

2. the patch cord is inserted and connected on the corresponding adapter through the plug, another end is welded on the transit leg, correspond to different kinds of high-frequency PCB, the tool only needs to change different transit PCB and card edge connector designed cooperatively, and the patch cord is welded well on the corresponding transit PCB in advance, only need to transfer PCB, card edge connector to assemble well after changing, and insert the patch cord on the corresponding adapter one by one, the disassembling and assembling of the tool is very convenient, have raised the efficiency effectively further;

3. in the technical scheme, the positioning pin is inserted into the transfer PCB for positioning, and the end face, far away from the cover plate, of the transfer PCB is pressed against the bottom surface of the base, so that the transfer PCB can be positioned and assembled in the testing base; when the transfer PCB needs to be disassembled and assembled, the positioning pin is separated from the positioning groove along with the disassembly of the cover plate after the cover plate is opened, so that the limitation on the transfer PCB is relieved; the effectual dismouting convenient degree that has promoted transfer PCB of this application technical scheme.

Drawings

FIG. 1 is an internal structure of a hidden cover plate according to an embodiment of the present application;

FIG. 2 is a top view of an embodiment of the present application;

fig. 3 is a side view of an embodiment of the present application.

Description of reference numerals:

1. testing the base; 11. an adapter; 12. a base body; 13. a cover plate;

2. a card edge connector; 21. a card slot;

3. transferring the PCB; 31. transferring the welding leg; 32. positioning a groove;

4. a patch cord; 41. and (4) a plug.

Detailed Description

The present application will be described in further detail below with reference to the accompanying drawings.

The embodiment of the application discloses high frequency PCB characteristic impedance test fixture.

Referring to fig. 1, a high frequency PCB characteristic impedance test fixture includes a test base 1, a transfer PCB3 for transferring signals from the high frequency PCB to an external time domain analyzer, a card edge connector 2 for plugging the high frequency PCB, and a patch cord 4 for transmitting signals on the transfer PCB3 to the external.

Referring to fig. 1 and 2, the test socket 1 includes a socket body 12 and a cover body, in the embodiment of the present application, the socket body 12 is a square structure and has a mounting cavity for mounting the card edge connector 2 and the transfer PCB3, and an opening of the mounting cavity can be closed by the cover body; specifically, a plurality of threaded blind holes are formed in the end face, far away from the bottom face of the installation cavity, of the seat body 12, a plurality of through holes are formed in the cover plate 13 corresponding to the threaded holes, and the bolts penetrate through the threaded through holes to be fixed in the threaded blind holes, so that the cover plate 13 is installed on the end face, far away from the bottom face, of the seat body 12 in a pressing mode.

Referring to fig. 1 and 2, the card edge connector 2 has a card slot 21 for inserting a high frequency PCB, and it is worth mentioning that in the jig of the present application, different types of high frequency PCBs are designed with different card edge connectors 2 correspondingly, and the slot shape in the corresponding card slot 21 connector is adapted to the shape of the board of the high frequency PCB, so that the high frequency PCB to be tested can be firmly inserted into the card slot 21. The inner wall of the clamping groove 21 is vertically provided with a plurality of switching pins, and when a high-frequency PCB to be tested is inserted into the clamping groove 21, the switching pins can be perpendicular to the high-frequency PCB, so that the better signal accuracy is achieved.

Referring to fig. 1 and 2, in order to install the transfer PCB3 in the installation cavity of base, in the embodiment of the present application, the transfer PCB3 is not a plate-shaped structure, but a three-dimensional structure, and, the transfer PCB3 is provided with a plurality of locating slots 32 on being close to the terminal surface of the cover plate 13, correspondingly, the inner wall of the cover plate 13 is fixed with a plurality of locating pins, when the cover plate 13 is installed on the base 12, the terminal surface that the transfer PCB3 is far away from the cover plate 13 supports and presses on the inner wall of the base 12 of the installation cavity bottom surface, the locating slots 32 on the transfer PCB3 are inserted with the locating pins for positioning, thereby stable assembly to the transfer PCB3 is realized.

Referring to fig. 1 and 2, in order to connect the card edge connector 2 to an external time domain analyzer through the relay PCB3 to test the characteristic impedance of the high frequency PCB plugged in the card edge connector 2, on one hand, the slot of the card slot 21 on the card edge connector 2 is located on the relay PCB3, the card edge connector 2 is fitted in the relay PCB3 of the three-dimensional structure, and the card edge connector 2 is electrically connected to the relay PCB 3; on the other hand, the end face of the transfer PCB3 close to the cover plate 13 is provided with a plurality of transfer solder pins 31, and since the transfer PCB3 is electrically connected to the card edge connector 2, when the high frequency PCB to be tested is plugged into the card slot 21, a plurality of solder pins to be tested of the high frequency PCB correspond to the plurality of transfer solder pins 31 on the transfer PCB 3; the number of the patch cords 4 is multiple, one end of each patch cord 4 is welded with a corresponding transfer welding leg 31, and the other end of each patch cord 4 is used for being electrically connected with an external time domain analyzer; therefore, the transit PCB3 realizes that a plurality of welding feet to be tested on the high-frequency PCB are equivalent to the corresponding patch cord 4, and the patch cord 4 is connected to a time domain analyzer, so that the characteristic impedance of each welding foot to be tested on the high-frequency PCB can be tested. In the embodiment of this application, patch cord 4 is the steady little coaxial cable of looks of radio frequency, adopts micropore polytetrafluoroethylene to insulate, and silvered copper foil adds around the package and weaves the outer conductor, FEP sheath structural style has low-loss, high phase stability and high power electricity performance such as high power, the effectual quality of guaranteeing signal transmission to, little coaxial cable diameter is less, can weld on the leg that awaits measuring on the high frequency PCB and do not produce the interference comparatively conveniently.

Referring to fig. 1 and 3, the other end that every connecting wire kept away from transfer leg 31 all is provided with a plug 41, the fixed adapter 11 that is used for being connected with time domain analyzer that is provided with of correspondence on the test base 1, every plug 41 can peg graft in an adapter 11 that corresponds, so that adapter 11 and patch cord 4 one-to-one, also be the leg one-to-one that awaits measuring on every adapter 11 and the card edge connector 2 high frequency PCB board, thereby only need can test the leg characteristic impedance that awaits measuring that corresponds through external time domain analyzer test adapter 11, the test can not be interfered, data are reliable. In the embodiment of the application, the test base 1 is a fast-plugging type SSMP-K radio frequency female connector, the adapter 11 on the test base 1 can be connected with an external corresponding SSMP-J radio frequency male connector, and is connected to the time domain analyzer through the SSMP-J radio frequency male connector, so that the connection between the adapter 11 and the time domain analyzer is realized.

It is worth mentioning that the test base 1 at the periphery of each adapter 11 is correspondingly provided with a mark, and the mark can be numbers, colors, English letters, patterns and the like; in the embodiment of the application, this sign chooses for use to be the digit, and every switching mouth periphery corresponds the sign and has different numbers to can swiftly learn the fillet weld that awaits measuring on the high frequency PCB that every switching mouth corresponds, with the time of having reduced the appointed fillet weld that awaits measuring of looking for, promote efficiency of software testing.

The implementation principle of the embodiment of the application is as follows: inserting a high-frequency PCB to be tested into the card edge connector 2, wherein the card edge connector 2 is electrically connected to the transfer PCB3, so that a plurality of transfer welding pins 31 arranged on the transfer PCB3 can correspond to the welding pins to be tested on the high-frequency PCB one by one; then, the welding feet to be tested are connected to the adapter 11 one by one through the patch cords 4, so that the welding feet to be tested correspond to the adapter 11 one by one; and finally, testing each adapter 11 through an external time domain analyzer, wherein the testing is equivalent to testing the characteristic impedance of a to-be-tested welding pin on the high-frequency PCB, and the testing efficiency and the testing data reliability are obviously improved.

The embodiments of the present invention are preferred embodiments of the present application, and the protection scope of the present application is not limited thereby, wherein like parts are denoted by like reference numerals. Therefore, the method comprises the following steps: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The utility model provides a high frequency PCB characteristic impedance test fixture which characterized in that: the device comprises a test base (1), a card edge connector (2) for plugging a high-frequency PCB, a transfer PCB (3) for transferring signals and a patch cord (4) for transmitting the signals on the transfer PCB (3) to the outside; the transfer PCB (3) is fixedly installed on the test base (1), the card edge connector (2) is installed in the test base (1), the card edge connector (2) is electrically connected with the transfer PCB (3), one end of the patch cord (4) is connected to the transfer PCB (3), and the other end of the patch cord (4) is used for being electrically connected with the time domain analyzer; the quantity of patch cord (4) is many, have on transit PCB (3) and be used for a plurality of transit leg (31) that a plurality of legs that await measuring set up on corresponding high frequency PCB, every patch cord (4) are used for linking to each other with last one corresponding transit leg (31) of transit PCB (3).

2. The fixture for testing the characteristic impedance of the high-frequency PCB according to claim 1, wherein: the patch cord (4) is a radio frequency phase-stable micro-coaxial cable.

3. The fixture for testing the characteristic impedance of the high-frequency PCB according to claim 1, wherein: a plurality of adapters (11) connected with a time domain analyzer are fixedly mounted on the testing base (1), and the number of the adapters (11) is equal to that of the transfer lines (4) and the adapters are arranged in a one-to-one correspondence mode.

4. The fixture for testing the characteristic impedance of the high-frequency PCB according to claim 3, wherein: one end of each patch cord (4) is provided with a plug (41), each patch cord (4) is plugged into the corresponding adapter (11) through the plug (41), and the other end of each patch cord (4) is welded on the transfer welding leg (31).

5. The fixture for testing the characteristic impedance of the high-frequency PCB according to claim 4, wherein: each adapter (11) is correspondingly marked with different numbers.

6. The fixture for testing the characteristic impedance of the high-frequency PCB according to claim 1, wherein: the card edge connector (2) is including being used for draw-in groove (21) with high frequency PCB grafting, be provided with the switching stitch on draw-in groove (21) inner wall perpendicularly, the notch of draw-in groove (21) is located on transfer PCB (3).

7. The fixture for testing the characteristic impedance of the high-frequency PCB according to claim 1, wherein: the test base (1) comprises a base body (12) and a cover plate (13) arranged on the base body (12), wherein the cover plate (13) is in threaded connection with the base body (12).

8. The fixture for testing the characteristic impedance of the high-frequency PCB according to claim 7, wherein: the cover plate (13) is provided with a positioning pin, and the transfer PCB (3) is provided with a positioning groove (32); when the cover plate (13) is in threaded connection with the test base (1), the positioning pin is inserted into the positioning groove (32), and the end face, far away from the cover plate (13), of the transfer plate is pressed against the bottom face of the base body (12).