CN219737650U

CN219737650U - Testing device and signal testing system

Info

Publication number: CN219737650U
Application number: CN202222428303.6U
Authority: CN
Inventors: 梁远曦
Original assignee: Honor Device Co Ltd
Current assignee: Honor Device Co Ltd
Priority date: 2022-09-09
Filing date: 2022-09-09
Publication date: 2023-09-22
Anticipated expiration: 2032-09-09

Abstract

The utility model provides a testing device and a signal testing system, which comprises a testing board, wherein the testing board comprises at least one pair of transmission lines, each pair of transmission lines comprises a first transmission line and a second transmission line, the first transmission line is used for transmitting a first signal, the second transmission line is used for transmitting a second signal, and the first signal and the second signal are a pair of differential signals; the first transmission line comprises a first input end, a first output end, a first adjustable resistor and a first transmission line; the first input end is connected with a first adjustable resistor, the first adjustable resistor is connected with a first transmission line, and the first transmission line is connected with the first output end; the second transmission line comprises a second input end, a second output end, a second adjustable resistor and a second transmission line; the second input end is connected with a second adjustable resistor, the second adjustable resistor is connected with the second transmission line, and the second transmission line is connected with the second output end.

Description

Testing device and signal testing system

Technical Field

The present utility model relates to the field of signal testing, and in particular, to a testing apparatus and a signal testing system.

Background

In order to ensure the transmission quality of signals in electronic equipment, experiments are needed to be carried out in advance so as to obtain the optimal resistance value of the series resistance in the signal wiring. How to design test fixtures is a growing concern for the skilled artisan.

Disclosure of Invention

The utility model provides a testing device and a signal testing system, which can flexibly adjust the resistance of a series resistor in the testing device, so that the optimal resistance of the resistor connected in series with a signal transmitting end can be obtained during signal testing, and the quality of signal transmission is improved.

In a first aspect, the present utility model provides a test apparatus comprising: a test board including at least one pair of transmission lines, each pair of transmission lines including a first transmission line for transmitting a first signal and a second transmission line for transmitting a second signal, the first signal and the second signal being a pair of differential signals; the first transmission line comprises a first input end, a first output end, a first adjustable resistor and a first transmission line; the first input end is connected with a first adjustable resistor, the first adjustable resistor is connected with a first transmission line, and the first transmission line is connected with the first output end; the second transmission line comprises a second input end, a second output end, a second adjustable resistor and a second transmission line; the second input end is connected with a second adjustable resistor, the second adjustable resistor is connected with the second transmission line, and the second transmission line is connected with the second output end.

According to the testing device provided by the embodiment of the utility model, the adjustable resistor is connected in series between the input end and the output end of each transmission line on the testing board, so that the resistance value of the adjustable resistor can be dynamically adjusted according to the eye pattern of the signal displayed by the signal receiving end when the signal is tested. Therefore, the resistance value of the transmission line for transmitting the signal on the test board can be obtained under the condition that the quality of the signal eye diagram is best, and the accuracy of the obtained resistance value is improved. Therefore, when the resistor with the resistance value is connected in series on the signal transmitting end of the electronic equipment, the reflection of the signal transmitting end can be effectively reduced, and the transmission quality of the signal is improved. In addition, as the resistance value of the resistor on the transmission line can be adjusted, compared with the resistance type fixed resistor on the transmission line of the traditional testing device, the utility model can complete the test on one transmission line by using the novel testing device when testing signals and the test is needed to be carried out on the transmission line connected with circuits with different resistance values in series. The space of the testing device is greatly saved, and the testing flow is simplified.

With reference to the first aspect, in one possible implementation manner, the resistance adjustment ranges of the adjustable resistors in each pair of transmission lines are the same or different.

With reference to the first aspect, in one possible implementation manner, the output terminals in each pair of transmission lines are further configured to: the transmission line is connected with the target wiring terminal, and the target wiring terminal is any input end through which no signal passes or any output end through which no signal passes in the test device.

With reference to the first aspect, in one possible implementation manner, the input terminal in the transmission line is further configured to: the transmission line is connected with the target wiring terminal, and the target wiring terminal is any input end through which no signal passes or any output end through which no signal passes in the testing device.

With reference to the first aspect, in a possible implementation manner, in a case that the testing device has a signal path for transmitting a signal, if the signal sequentially passes through at least two adjustable resistors in the signal path, resistance values of other adjustable resistors except a first adjustable resistor through which the signal passes are first resistance values; the first resistance value is a characteristic impedance value of a transmission line in the testing device.

In a second aspect, the utility model provides a signal testing system, comprising a signal generator, a testing device and an oscilloscope; the signal generator is used for generating a first signal and a second signal, the first signal and the second signal are a pair of differential signals, and the oscilloscope is used for displaying an eye pattern of the received signals; the signal generator comprises a first transmitting end and a second transmitting end, the first transmitting end is used for transmitting a first signal, the second transmitting end is used for transmitting a second signal, the oscilloscope comprises a first receiving end and a second receiving end, the first receiving end is used for receiving the first signal, and the second receiving end is used for receiving the second signal; the testing device comprises a testing board, wherein the testing board comprises at least one pair of transmission lines, and the first transmission line comprises a first input end, a first output end, a first adjustable resistor and a first transmission line; the first input end is connected with the first adjustable resistor, the first adjustable resistor is connected with the first transmission line, and the first transmission line is connected with the first output end; the second transmission line comprises a second input end, a second output end, a second adjustable resistor and a second transmission line; the second input end is connected with a second adjustable resistor, the second adjustable resistor is connected with a second transmission line, and the second transmission line is connected with the second output end; the first transmitting end is connected with the first input end, the first output end is connected with the first receiving end, the second transmitting end is connected with the second input end, and the second output end is connected with the second receiving end.

With reference to the second aspect, in one possible implementation manner, the resistance adjustment ranges of the adjustable resistors in each pair of transmission lines are the same or different.

With reference to the second aspect, in one possible implementation manner, the output terminals in each pair of transmission lines are further configured to: the transmission line is connected with the target wiring terminal, and the target wiring terminal is any input end through which no signal passes or any output end through which no signal passes in the test device.

With reference to the second aspect, in one possible implementation manner, the input terminals in each pair of transmission lines are further configured to: the transmission line is connected with the target terminal, and the target terminal is any input end through which no signal passes or any output end through which no signal passes in the testing device.

With reference to the second aspect, in a possible implementation manner, in a case that a signal path for transmitting a signal exists in the test device, if the signal sequentially passes through at least two adjustable resistors in the signal path, the resistance value of the other adjustable resistors except the first adjustable resistor through which the signal passes is a first resistance value; the first resistance value is a characteristic impedance value of a transmission line in the testing device.

Drawings

For a clearer description of the technical solutions of the embodiments of the present utility model, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1A is a diagram illustrating a signaling example provided by an embodiment of the present utility model;

FIG. 1B is a waveform diagram of a signal voltage according to an embodiment of the present utility model;

FIG. 2 is a diagram showing an exemplary structure of a testing device 22 according to an embodiment of the present utility model;

FIG. 3 is a diagram of a signal testing architecture according to an embodiment of the present utility model;

FIG. 4 is a diagram showing another exemplary structure of a testing device 32 according to an embodiment of the present utility model;

FIG. 5 is a diagram of another signal testing architecture according to an embodiment of the present utility model;

FIG. 6 is a diagram of another signal testing architecture according to an embodiment of the present utility model;

fig. 7 is a diagram of another signal testing architecture according to an embodiment of the present utility model.

Detailed Description

In order that those skilled in the art will better understand the present utility model, a technical solution in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present utility model, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present utility model without making any inventive effort, shall fall within the scope of the present utility model.

The following will describe in detail.

The terms "first," "second," "third," and "fourth" and the like in the description and in the claims and drawings are used for distinguishing between different objects and not necessarily for describing a particular sequential or chronological order. Furthermore, the terms "comprising," "including," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may include other steps or elements not listed or inherent to such process, method, article, or apparatus.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the utility model. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

First, terms related to embodiments of the present utility model will be described by way of example, not limitation.

Characteristic impedance: during the transmission of a signal in a transmission line, an electric field is formed between the transmission line and a reference plane at a point where the signal arrives. Due to the presence of the electric field, a momentary small current is generated, which is present at every point in the transmission line. At the same time, a certain voltage exists in the signal, so that each point of the transmission line is equivalent to a resistor in the signal transmission process, and the resistor is the characteristic impedance of the transmission line.

Eye Diagram (Eye Diagram): the digital signal transmission quality display device can display the transmission quality of digital signals, is often used in occasions where testing and verification of serial digital signals or high-speed digital signals in electronic equipment and chips are required, and is a quick and very visual observation means of the digital signal quality. In consumer electronics, high-speed signal transmission is often used inside the chip and between the chips, and if the corresponding signal quality is poor, unstable electronic equipment, wrong function execution and even faults are caused. The eye diagram reflects the influence of the physical devices and the channels on the digital signals, and engineers can quickly obtain the actual measurement parameters of the signals in the product to be measured through the eye diagram and can predict the problems possibly happening on site.

For square waves of digital signals, the steeper the edges, the more high frequency components, since they contain rich high frequency harmonic components. When a signal propagates in a transmission line, reflections occur if a discontinuity in the characteristic impedance is encountered. Reflection may occur at the ends, corners, vias, component pins, line width variations, T-leads, etc. of the transmission line. In any case, the impedance of the transmission line is suddenly changed for any reason, and a part of the signal is reflected back to the signal transmitting end along the transmission line.

In the engineering, the magnitude of the signal reflection is calculated by calculating the reflection coefficient, wherein the reflection coefficient refers to the ratio of the amplitude of a reflected signal to the amplitude of an incident signal, and the magnitude is as follows: ρ= (z2—z1)/(z2+z1). Z1 is the characteristic impedance of the first region and Z2 is the characteristic impedance of the second region. When a signal is transmitted from the first region to the second region, abrupt impedance changes occur at the interface, thereby forming a reflection.

Assuming that the characteristic impedance of the transmission line is 50 ohms, a patch resistor of 100 ohms is encountered in the transmission process, and the influence of parasitic capacitance and inductance is not considered temporarily, so that the resistor is regarded as an ideal pure resistor. Then, the reflection coefficient ρ= (100-50)/(100+50) =1/3, and 1/3 of the signal is reflected back to the source. If the voltage of the transmission signal is 3.3V, the reflected voltage is 1.1V. At this time, there are two voltage components at the signal reflection point, one is 3.3V voltage transmitted from the signal transmitting terminal, and the other is 1.1V voltage, and then the voltage at the reflection point is the sum of the two, namely 4.4V.

In practice, the reflection of the signal as it propagates on the circuit board is very complex. The reflected signal is reflected back again, the direction is the same as the transmitting signal, the signal transmitting end is reflected again when reaching the impedance abrupt change, and therefore multiple reflection is formed. Multiple reflections of a signal are the root cause of oscillations of the signal, corresponding to the superposition of a noise on the signal. Therefore, how to reduce noise during signal transmission is a growing concern for the skilled person.

For easy understanding, the above-described process will be described below with reference to the accompanying drawings. Referring to fig. 1A, fig. 1A is a diagram illustrating a signaling example provided by the present novel embodiment. In fig. 1A, a signal transmitting end and a signal receiving end are included. The signal transmitting end transmits signals to the signal receiving end through a transmission line. The resistance value of the signal transmitting end is 10 ohms, the resistance value of the signal receiving end is infinity, and the impedance value of the characteristic impedance of the transmission line is 50 ohms. Assuming that the time for transmitting a signal from a transmitting end to a receiving end is 1 micro nanosecond (nsec), the voltage of the signal transmitted by the signal transmitting end at the initial time is 1v. Then, at the initial time, the voltage of the signal transmitted at the initial time is 0.84v due to the signal loss, and after 1nesc, the signal reaches the transmitting end. Since the characteristic impedance of the transmission line is 50 ohms, the impedance of the signal receiving end is infinite. Therefore, when the signal reaches the signal receiving end, the junction between the transmission line and the signal receiving end has abrupt impedance change. Thus, the signal receiving end will reflect all or part of the signal back to the signal transmitting end. The transmission line can be regarded as the above-described first region throughout the process of transmitting a signal from the transmission line to the signal receiving end. Thus, z1=50 ohms. The signal receiving end can be regarded as the second region, and therefore, z2= infinity. According to the calculation formula of the reflection coefficient, the reflection coefficient of the signal receiving end is 1. Thus, the signal receiving end will totally reflect the received signal. At 1nesc, the voltage at the signal receiving terminal is u=0.84+0.84=1.68 v (signal voltage transmitted by the signal transmitting terminal+signal voltage reflected by the signal receiving terminal). In the whole process that the signal reflected by the signal receiving end is transmitted to the signal transmitting end through the transmission line, the resistance value of the signal transmitting end is 10 ohms because the characteristic impedance of the transmission line is 50 ohms. Therefore, at the moment when the reflected signal reaches the signal transmitting end, an impedance discontinuity occurs at the junction of the transmission line and the signal transmitting end. Thus, the signal transmitting end will reflect all or part of the signal back to the signal receiving end. The transmission line can be regarded as the above-described first region throughout the process of transmitting a signal from the transmission line to the signal transmitting side. Thus, z1=50 ohms. The signal receiving end can be regarded as the second region, and thus z2=10 ohms. According to the calculation formula of the reflection coefficient, the reflection coefficient of the signal transmitting end is-0.67. Therefore, the signal transmitting end will partially reflect the received signal, and at the time of 2nesc, the voltage of the signal reflected by the signal transmitting end is 0.84 x (-0.67) = -0.56v. At the time of 3nesc, the signal receiving end receives the reflected signal sent by the signal sending end and then totally reflects the signal. At this time, the voltage output by the signal receiving end is u=1.68-0.56-0.56=0.56 v (the original voltage of the signal receiving end+the signal voltage sent by the signal sending end+the signal voltage reflected by the signal receiving end). At the time of 4nesc, the signal transmitting end will reflect a signal with a voltage of 0.38v to the signal receiving end based on the reflection coefficient. At the time of 5nesc, the signal receiving end totally reflects the reflected signal received by the signal receiving end, and at this time, the voltage u=0.56+0.38+0.38=1.32 v outputted by the signal receiving end. And the signal transmitting end and the signal receiving end always reflect the received reflected signals, and the voltage output by the signal receiving end also changes after the signal receiving end receives the transmitted signals.

Fig. 1B shows a waveform diagram of the signal voltage at the signal receiving end in fig. 1A. As can be seen from fig. 1B, the signal voltage at the signal receiving end oscillates more significantly in a period of time (in the period of 1 to 16 nesc), and the waveform of the signal becomes gentle after a period of time. If the amplitude of the oscillation of the signal exceeds a certain threshold, the eye diagram of the signal is distorted, which means that the transmission quality of the signal is poor, which may cause unstable operation, wrong function execution and even failure of the electronic device.

Therefore, in order to ensure the signal transmission quality of the electronic device, it is necessary to perform a test to detect the signal. In the signal transmission process, the resistance value of the signal transmitting end may not be consistent with the characteristic impedance value of the transmission line, so that the signal transmitting end may reflect all or part of the reflected signal transmitted by the signal receiving end (the voltage of the signal transmitted by the signal transmitting end is determined by the reflection coefficient of the signal transmitting end) back to the signal receiving end, thereby causing the voltage of the signal received by the signal receiving end to change, further causing the signal received by the signal receiving end to oscillate, and affecting the signal transmission quality. Therefore, how to match a proper resistance value at the signal sending end, so that the resistance value of the matched resistance of the signal sending end is consistent with the characteristic impedance value of the transmission line, thereby reducing the intensity of the signal reflected by the signal sending end to the signal receiving end, improving the quality of signal transmission, and being a problem of increasing attention of technicians.

The test device according to the utility model may be a printed circuit board (Printed Circuit Board, PCB) and the signals may be mobile processor interface (Mobile Industry Processor Interface, MIPI) signals, universal serial bus (Universal Serial Bus, USB) signals, etc.

In order to solve the above problems, an embodiment of the present utility model provides a testing device. Fig. 2 is a schematic diagram showing a structure of a testing device 22 according to an embodiment of the present utility model. The test device 22 includes a test board that includes an input 221, an output 222, an adjustable resistor 223, and a transmission line 224. The input 221 is connected to an adjustable resistor 223, the adjustable resistor 223 is connected to a transmission line 224, and the transmission line 224 is connected to the output 222. The input 221 may be configured to receive a signal, and send the signal to the output 222 through the adjustable resistor 223 and the transmission line 224 in sequence, and then send the signal out through the output 222.

For ease of illustration, the test device 22 is illustrated as testing a signal. Referring to fig. 3, fig. 3 is a schematic diagram of a signal testing structure according to an embodiment of the utility model. The signal received by the test device is assumed to be the signal generated by the signal generator, which sends the signal received by the signal test device to the oscilloscope.

In fig. 3 a signal generator 21, a testing device 22 and an oscilloscope 23 are included. The signal generator 21 is used for generating a signal, the testing device 22 is used for transmitting the signal sent by the signal generator 21 to the oscilloscope 23, and the oscilloscope 23 is used for displaying an eye diagram of the received signal.

As shown in fig. 3, the signal generator 21 includes a transmitting end 211, and the oscilloscope 23 includes a receiving end 231. The transmitting terminal 211 of the signal generator 21 is connected to the input terminal 221 of the testing device 22 via a transmission line 24, the input terminal 221 of the testing device 22 is connected to the output terminal 222 of the testing device 22 via a transmission line 224, and an adjustable resistor 223 is connected in series between the transmission line 224 and the input terminal 221. The output 222 of the test device 22 is connected to the receiving end 231 of the oscilloscope 23 via the transmission line 25.

When transmitting a signal, the signal generator 21 generates a signal and transmits the signal via the input 221 via the transmission line 24 to the input 221 of the test device 22, and further via the adjustable resistor 223 and the transmission line 224 to the output 222 of the test device 22. Then, the signal is sent to the receiving end 231 of the oscilloscope 23 via the transmission line 25 through the output end 222 of the testing device 22, so that the signal is sent to the oscilloscope 23. After receiving the signal, oscilloscope 23 processes the signal and displays the eye diagram of the signal on the display screen. During signal transmission, the resistance value of the adjustable resistor 223 is adjustable, and when the resistance value of the adjustable resistor 223 changes, the eye diagram displayed by the oscilloscope 23 may also change correspondingly. In the case that the quality of the eye diagram displayed by the oscilloscope 23 is optimal, the resistance value of the adjustable resistor 223 can be recorded as the optimal matching resistance of the signal transmitting end so as to match the resistance of the resistance value for the signal transmitting end of the electronic equipment, thereby ensuring that the signal quality transmitted from the signal transmitting end to the signal receiving end of the electronic equipment is optimal.

Referring to fig. 4, fig. 4 is a schematic diagram of another test apparatus 32 according to an embodiment of the utility model. In fig. 4, the test device 32 includes a test board on which at least one pair of transmission lines, respectively a first transmission line and a second transmission line, are included. The first transmission line includes a first input terminal 321, a first output terminal 323, a first adjustable resistor 325, and a first transmission line 327. The first input 321 is connected to a first adjustable resistor 325, the first adjustable resistor 325 is connected to a first transmission line 327, and the first transmission line 327 is connected to the first output 323. The second transmission line includes a second input terminal 322, a second output terminal 324, a second adjustable resistor 326, and a second transmission line 328. The second input terminal 322 is connected to a second adjustable resistor 326, the second adjustable resistor 326 is connected to a second transmission line 328, and the second transmission line 328 is connected to the second output terminal 324. Each pair of transmission lines may be used to transmit a pair of differential signals (e.g., a first signal and a second signal). For example, the first transmission line may transmit the first signal by: the first input end 321 receives the first signal, and transmits the first signal to the first output end 323 through the first adjustable resistor 325 and the first transmission line 327 in sequence, and then the first output end 323 transmits the signal. The second transmission line may transmit a second signal, and the transmission process is: the second input terminal 322 receives the second signal, and transmits the second signal to the second output terminal 324 through the second adjustable resistor 326 and the second transmission line 328 in sequence, and the second output terminal 324 transmits the signal.

For convenience of explanation, the test signal of the test device 32 is exemplified. Referring to fig. 5, fig. 5 is a schematic diagram of another signal testing structure according to an embodiment of the utility model. The signal received by the test device is assumed to be the signal generated by the signal generator, which sends the signal received by the signal test device to the oscilloscope.

Fig. 5 includes a signal generator 31, a test device 32, and an oscilloscope 33. The signal generator 31 is used for generating differential signals, the testing device 32 is used for transmitting signals sent by the signal generator 31 to the oscilloscope 33, and the oscilloscope 33 is used for displaying eye patterns of received signals.

As shown in fig. 5, the signal generator 31 includes a first transmitting terminal 311 and a second transmitting terminal 312, and the testing device 32 includes a first input terminal 321, a second input terminal 322, a first output terminal 323, a second output terminal 324, a first adjustable resistor 325, a second adjustable resistor 326, a first transmission line 327, and a second transmission line 328. Oscilloscope 33 includes a first receiving end 331 and a second receiving end 332.

The first transmitting terminal 311 of the signal generator 31 is connected to a first input terminal 321 of the testing device 32 via a transmission line 341, and the second transmitting terminal 312 of the signal generator 31 is connected to a second input terminal 322 of the testing device 32 via a transmission line 342. The first input 321 of the test device 32 is connected to the first output 323 of the test device 32 via a first transmission line 327, and a first adjustable resistor 325 is connected in series between the first transmission line 327 and the first input 321. The second input 322 of the test device 32 is connected to the second output 324 of the test device 22 via a second transmission line 328, and a second adjustable resistor 326 is connected in series between the second transmission line 328 and the second input 322. The first output 323 of the testing device 32 is connected to the first receiving end 331 of the oscilloscope 33 via a transmission line 351, and the second output 324 of the testing device 32 is connected to the second receiving end 332 of the oscilloscope 33 via a transmission line 352.

When transmitting signals, the signal generator 31 generates a first signal and a second signal. Wherein the first signal and the second signal are a pair of differential signals. The signal generator 31 sends a first signal to the first input 321 of the testing device 32 via the transmission line 341 through the first sending terminal 311, sends the first signal to the first output 323 through the first adjustable resistor 325 and the first transmission line 327, and sends the first signal to the oscilloscope 33 via the first receiving terminal 331 of the oscilloscope 33 via the transmission line 351 through the first output 323. Meanwhile, the signal generator 31 sends the second signal to the second input end 322 of the testing device 32 through the second transmitting end 312 via the transmission line 342, sends the second signal to the second output end 324 through the second adjustable resistor 326 and the second transmission line 328, and sends the second signal to the oscilloscope 33 through the second receiving end 332 of the oscilloscope 33 through the second output end 324 via the transmission line 352. The oscilloscope 33, upon receiving the first signal and the second signal, processes the first signal and the second signal and displays the eye pattern of the pair of differential signals. During the transmission of the first signal and the second signal, the resistance value of the first adjustable resistor 325 and/or the second adjustable resistor 326 may be adjusted, and when the resistance value of the first adjustable resistor 325 and/or the second adjustable resistor 326 changes, the eye diagram displayed by the oscilloscope 33 will also change accordingly. In the case that the quality of the eye diagram displayed by the oscilloscope 33 is optimal, the resistance value of the first adjustable resistor 325 and/or the second adjustable resistor 326 can be recorded as the optimal matching resistance of the differential signal transmitting end, so that the resistances of the corresponding resistance values can be matched for the two transmitting ends of the signal of the electronic device, and the transmission quality of the differential signal transmitted by the electronic device can be improved.

In some embodiments, for different types of electronic devices, the lengths of the transmission lines of the signal transmitting end and the signal receiving end are different, and the different lengths of the transmission lines may cause different transmission times of the signals from the transmitting end to the receiving end, so that waveforms of the signals are changed, and an eye diagram of the signals is affected. Since the length of the transmission lines (e.g., the first transmission line 327 and the second transmission line 328 of fig. 4 described above) on the test device are fixed, a flying line approach may be used between the test device ports to increase the length of the transmission lines. If there is one transmission line (signal path) for transmitting the target signal in the test device, a flying line may be performed between the target terminal (the target terminal is one terminal through which the target signal sequentially passes in the transmission line, and the terminal may be an input terminal or an output terminal) of the transmission line and any one terminal not transmitting the signal in the test device, so as to extend the length of the transmission line. If the target signal sequentially passes through more than one adjustable resistor in the transmission line, the resistance of the other adjustable resistors in the transmission line is the same as the characteristic resistance of the transmission line except the first adjustable resistor through which the target signal passes in the test device. Therefore, under the condition that the length of the transmission line on the testing device is fixed, the flying wire is carried out on the testing device, so that the influence of the resistance value of the resistor of the signal input end on the quality of a signal eye diagram under the condition of different lengths of the transmission lines can be measured.

The application scenario of the above 2 routing modes is described below in an exemplary manner with reference to fig. 6 to 7.

Referring to fig. 6, fig. 6 is a schematic diagram of another signal testing structure according to an embodiment of the utility model. In fig. 6, a signal generator 41, a testing device 42 and an oscilloscope 43 are included. The signal generator 41 is used for generating a signal, the testing device 42 is used for transmitting the signal sent by the signal generator 41 to the oscilloscope 43, and the oscilloscope 43 is used for displaying an eye diagram of the received signal. Assuming that the length of the transmission line between the transmitting end of the signal generator 41 and the input end on the testing device 42 is 1 cm, the length of the transmission line before the output end of the testing device 42 and the receiving end of the oscilloscope 43 is 1 cm, the length of the single transmission line fixed between the input end on the testing device 42 and the receiving end is 5 cm, and the target length of the transmission line between the transmitting end 411 of the signal generator 41 and the receiving end 431 of the oscilloscope 43 is 18 cm.

Then, as shown in fig. 6, the signal generator 41 includes a transmitting terminal 411, and the testing device 42 includes a third input terminal 421, a fourth input terminal 422, a third output terminal 423, a fourth output terminal 424, a third adjustable resistor 425, a fourth adjustable resistor 426, a third transmission line 427, and a fourth transmission line 428.

The transmitting terminal 411 of the signal generator 41 is connected to a third input terminal 421 of the testing device 42 via a transmission line 45, the third input terminal 421 is connected to a third output terminal 423 via a third transmission line 427, and a third adjustable resistor 425 is connected in series between the third input terminal 421 and the third transmission line 427. The third output terminal 423 is connected to the fourth input terminal 422 through the first target transmission line 44, and the length of the first target transmission line 44 is 6 cm. The fourth input 422 and the fourth output 424 are connected by a fourth transmission line 428, and a fourth adjustable resistor 426 is connected in series between the fourth input 422 and the fourth transmission line 428. The fourth output 424 is connected to the receiving end 431 of the oscilloscope 43 via the transmission line 46. The resistance value of the fourth adjustable resistor 426 is 50 ohms, and the resistance value of the third adjustable resistor 425 can be arbitrarily adjusted. Thus, by the above connection, the length of the transmission line connecting the signal generator 41 and the oscilloscope 43 is ensured to be 18 cm.

When transmitting a signal, the signal generator 41 generates a signal and transmits the signal via the transmission line 45 to the third input 421 of the test device 42 via the transmission terminal 411. The signal then passes through the third input 421 of the testing device 42 via the third adjustable resistor 425 and the third transmission line 427 to the third output 423 of the testing device 42. The signal then reaches the fourth input 422 of the test device 42 via the third output 423 and the first target transmission line 44. The signal then reaches the fourth output 424 of the test device 42 via the fourth adjustable resistor 426 and the fourth transmission line 428. The signal then passes through transmission line 46 to the receiving end 431 of oscilloscope 43. Oscilloscope 43 displays the eye diagram of the received signal on a display screen. During the signal transmission process, if the resistance of the third adjustable resistor 425 changes, the eye diagram displayed by the oscilloscope 43 also changes.

Referring to fig. 7, fig. 7 is a schematic diagram of another signal testing structure according to an embodiment of the utility model. In fig. 7, a signal generator 51, a testing device 52 and an oscilloscope 53 are included. The signal generator 51 is used for generating a signal, the testing device 52 is used for transmitting the signal sent by the signal generator 51 to the oscilloscope 53, and the oscilloscope 53 is used for displaying an eye diagram of the received signal. Assuming that the length of the transmission line between the transmitting end of the signal generator 51 and the input end on the testing device 52 is 1 cm, the length of the transmission line before the output end of the testing device 52 and the receiving end of the oscilloscope 53 is 1 cm, the length of the single transmission line fixed between the input end on the testing device 52 and the receiving end is 5 cm, and the target length of the transmission line between the transmitting end 511 of the signal generator 51 and the receiving end 531 of the oscilloscope 53 is 10 cm.

Then, as shown in fig. 7, the signal generator 51 includes a transmitting terminal 511, and the testing device 52 includes a fifth input terminal 521, a sixth input terminal 522, a fifth output terminal 523, a sixth output terminal 524, a fifth adjustable resistor 525, a sixth adjustable resistor 526, a fifth transmission line 527, and a sixth transmission line 528. Oscilloscope 53 includes a receiving end 531.

The transmitting terminal 511 of the signal generator 51 is connected to a fifth input terminal 521 of the testing device 52 via a transmission line 55, the fifth input terminal 521 is connected to a fifth output terminal 523 via a fifth transmission line 527, and a fifth adjustable resistor 525 is connected in series between the fifth input terminal 521 and the fifth transmission line 527. The sixth input 522 and the sixth output 524 are connected by a sixth transmission line 528, and a sixth adjustable resistor 526 is connected in series between the sixth input 522 and the sixth transmission line 528. The fifth output terminal 523 is connected to the sixth output terminal 524 through a second target transmission line 54, and the second target transmission line 54 has a length of 3 cm. The sixth output 524 is connected to the receiving end 531 of the oscilloscope 53 via the transmission line 56. Thus, by the above connection, the length of the transmission line connecting the signal generator 51 and the oscilloscope 53 is ensured to be 10 cm.

When transmitting a signal, the signal generator 51 generates a signal and transmits the signal via the transmission line 55 to the fifth input 521 of the test device 52 via the transmission terminal 511. The signal then passes through the fifth input 521 of the test device 52 via the fifth adjustable resistor 525 and the fifth transmission line 527 to the fifth output 523 of the test device 52. The signal then reaches the sixth output 524 of the test device 52 via the second target transmission line 54. The signal then reaches the receiving end 531 of the oscilloscope 53 via the transmission line 56. The oscilloscope 53 displays an eye pattern of the received signal on the display screen. During the signal transmission process, if the resistance of the fifth adjustable resistor 525 changes, the eye pattern displayed by the oscilloscope 53 also changes.

It should be noted that, for simplicity of description, the foregoing method embodiments are all described as a series of acts, but it should be understood by those skilled in the art that the present utility model is not limited by the order of acts described, as some steps may be performed in other orders or concurrently in accordance with the present utility model. Further, those skilled in the art will also appreciate that the embodiments described in the specification are all preferred embodiments, and that the acts and modules referred to are not necessarily required for the present utility model.

In the embodiments provided in the present utility model, it should be understood that the disclosed apparatus may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, such as the division of the modules described above, are merely a logical function division, and may be implemented in other manners, such as multiple units or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, or may be in electrical or other forms.

The modules described above as separate components may or may not be physically separate, and components shown as modules may or may not be physical modules, i.e., may be located in one place, or may be distributed over multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional module in the embodiments of the present utility model may be integrated into one processing module, or each module may exist alone physically, or two or more modules may be integrated into one module. The integrated modules may be implemented in hardware or in software functional modules.

The foregoing has outlined rather broadly the more detailed description of embodiments of the utility model, wherein the principles and embodiments of the utility model are explained in detail using specific examples, the description of the embodiments being merely intended to facilitate an understanding of the utility model and its core concepts; meanwhile, as those skilled in the art will appreciate, the present utility model is not limited to the above description, since modifications may be made in the specific implementation and application scope of the present utility model in accordance with the idea of the present utility model.

Claims

1. A test device, comprising a test board, wherein the test board comprises at least one pair of transmission lines, each pair of transmission lines comprises a first transmission line and a second transmission line, the first transmission line is used for transmitting a first signal, the second transmission line is used for transmitting a second signal, and the first signal and the second signal are a pair of differential signals;

the first transmission line comprises a first input end, a first output end, a first adjustable resistor and a first transmission line; the first input end is connected with the first adjustable resistor, the first adjustable resistor is connected with the first transmission line, and the first transmission line is connected with the first output end;

the second transmission line comprises a second input end, a second output end, a second adjustable resistor and a second transmission line; the second input end is connected with the second adjustable resistor, the second adjustable resistor is connected with the second transmission line, and the second transmission line is connected with the second output end.

2. The test device of claim 1, wherein the adjustable resistors in each pair of transmission lines have the same or different resistance adjustment ranges.

3. The test apparatus of claim 1, wherein the outputs of the pair of pairs of transmission lines are further configured to:

the test device is connected with a target wiring terminal through a transmission line, wherein the target wiring terminal is any input terminal through which no signal passes or any output terminal through which no signal passes in the test device.

4. The test device of claim 1, wherein the inputs in the pair of transmission lines are further configured to:

5. The apparatus of any one of claims 3-4, wherein, in the case where the test apparatus has a signal path through which a signal is transmitted, if the signal sequentially passes through at least two adjustable resistors in the signal path, the resistance value of the other adjustable resistors in the signal path except the first adjustable resistor through which the signal passes is a first resistance value; the first resistance value is a characteristic impedance value of a transmission line in the testing device.

6. The signal testing system is characterized by comprising a signal generator, a testing device and an oscilloscope; the signal generator is used for generating a first signal and a second signal, the first signal and the second signal are a pair of differential signals, and the oscilloscope is used for displaying an eye pattern of the received signals;

the signal generator comprises a first transmitting end and a second transmitting end, the first transmitting end is used for transmitting the first signal, the second transmitting end is used for transmitting the second signal, the oscilloscope comprises a first receiving end and a second receiving end, the first receiving end is used for receiving the first signal, and the second receiving end is used for receiving the second signal; the testing device comprises a testing board, wherein the testing board comprises at least one pair of transmission lines, and the first transmission line comprises a first input end, a first output end, a first adjustable resistor and a first transmission line; the first input end is connected with the first adjustable resistor, the first adjustable resistor is connected with the first transmission line, and the first transmission line is connected with the first output end; the second transmission line comprises a second input end, a second output end, a second adjustable resistor and a second transmission line; the second input end is connected with the second adjustable resistor, the second adjustable resistor is connected with the second transmission line, and the second transmission line is connected with the second output end;

the first transmitting end is connected with the first input end, the first output end is connected with the first receiving end, the second transmitting end is connected with the second input end, and the second output end is connected with the second receiving end.

7. The signal testing system of claim 6, wherein the adjustable resistors in each pair of transmission lines have the same or different resistance adjustment ranges.

8. The signal testing system of claim 6, wherein the outputs of each pair of transmission lines are further configured to:

9. The signal testing system of claim 6, wherein the inputs in each pair of transmission lines are further configured to:

10. A signal testing system according to any one of claims 8-9, wherein in the event that there is a signal path through which a signal is transmitted by the testing device, if the signal passes through at least two adjustable resistors in sequence in the signal path, the resistance value of the other adjustable resistors in the signal path, except the first adjustable resistor through which the signal passes, is the first resistance value; the first resistance value is a characteristic impedance value of a transmission line in the testing device.