TDR impedance tester

Abstract

The utility model relates to the technical field of electronic technology testing, solves the technical problems that pulse signals generated in the prior art are low in accuracy and poor in filtering effect, and particularly relates to a TDR impedance tester. The tester comprises a probe used for collecting pulse signals, a front-end circuit and a rear-end circuit used for processing the returned pulse signals, and the front-end circuit is composed of a pulse generation circuit used for generating the pulse signals, a compensation circuit, an amplification circuit and a filter circuit. The pulse generating circuit is composed of an input signal, a current-limiting resistor R1, a shunt resistor R4, an operational amplifier D1 and a pulse signal, the accuracy of the returned pulse signal can be improved through the cooperation of the pulse generating circuit and the compensation circuit, and the accuracy of the measurement result is further improved through the cooperation of the filter circuit. Moreover, the interference of high-frequency signals can be effectively suppressed, and the anti-interference capability of the tester is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic technology testing, in particular to a TDR impedance tester. Background Art

[0002] The TDR-Z3800 impedance tester is an instrument that measures the impedance of an electronic circuit by measuring and analyzing the reflected pulse signal of the electrical parameters of the AC signal in the electronic circuit. This tester can help users quickly and accurately measure the impedance of different components in the electronic circuit, as well as analyze various problems and abnormal phenomena in the electronic circuit. Therefore, it is widely used in power systems, communication systems, medical equipment, industrial automation and other fields. The impedance tester in the existing technology has low accuracy because the pulse signal emitted by the pulse generating circuit is easily interfered by high-frequency signals. The oscilloscope has poor filtering effect on the returned pulse signal, resulting in low signal accuracy. In addition, the operator needs to follow complicated steps, which seriously affects work efficiency. Utility Model Content

[0003] In view of the shortcomings of the existing technology, the utility model provides a TDR impedance tester, which solves the technical problems of low pulse signal accuracy and poor filtering effect generated by the existing technology, thereby achieving the purpose of improving the accuracy of the pulse signal and optimizing the filtering effect.

[0004] To solve the above technical problems, the present invention provides the following technical solutions: a TDR impedance tester, comprising a probe for collecting pulse signals, a front-end circuit and a back-end circuit for processing the returned pulse signals, wherein the front-end circuit is composed of a pulse generating circuit, a compensation circuit, an amplifying circuit and a filtering circuit for generating pulse signals.

[0005] Preferably, the pulse generating circuit is composed of an input signal, a current limiting resistor R1, a shunt resistor R4, an op amp D1 and a pulse signal. The input signal is connected to the positive input terminal of the op amp D1 through the current limiting resistor R1. The positive input terminal and the output terminal of the op amp D1 are connected in parallel with the shunt resistor R4. The negative input terminal and the output terminal of the op amp D1 are connected in parallel with the shunt resistor R2 and the diode P1 connected in series in sequence. The shunt resistor R2 and the diode P1 are connected in parallel with the shunt resistor R3 and the diode P2 connected in series in sequence.

[0006] Preferably, the compensation circuit is composed of a current limiting resistor R8, an inductor L1, a shunt resistor R9, a capacitor C2 and a return signal. The pulse signal is connected to the A end of the probe through the current limiting resistor R8 and the inductor L1, and the B end of the probe receives the return signal. A shunt resistor R9 and a capacitor C2 are respectively connected in parallel between the pulse signal and the return signal.

[0007] Preferably, the amplification circuit consists of a current limiting resistor R6, a 5V power supply, an op amp D2 and an amplified signal. The return signal is connected to the op amp D2 through the current limiting resistor R6, and the output end of the op amp D2 transmits the amplified signal. The 5V power supply is connected to the positive input end of the op amp D2 through the current resistor R5, and the positive input end of the op amp D2 is grounded through the resistor R7.

[0008] Preferably, the filtering circuit consists of a 5V filtering power supply, a voltage dividing resistor R11, a variable resistor R12, an op amp D3, a current limiting resistor R16 and a filtering signal. The 5V filtering power supply is connected to the negative input terminal of the op amp D3 through the voltage dividing resistor R11 and the variable resistor R12, the amplified signal is connected to the positive input terminal of the op amp D3, the output terminal of the op amp D3 outputs the filtering signal through the current limiting resistor R16, the positive input terminal and the output terminal of the op amp D3 are connected in parallel with the current limiting resistor R15 and the capacitor C4 connected in series in sequence, the negative input terminal and the output terminal of the op amp D3 are connected in parallel with the fixed resistor R13 and the variable resistor R14 connected in series in sequence, and the 5V filtering power supply is connected to the filtering signal through the current limiting resistor R10 and the shunt resistor R17 in sequence.

[0009] Preferably, the back-end circuit consists of a high-speed sampling oscilloscope, a microprocessor module and a display screen.

[0010] Preferably, the model of the high-speed sampling oscilloscope is 86100C, the model of the microprocessor module is TMS320F2812, and the model of the display screen is JY-J302.

[0011] By means of the above technical solution, the present invention provides a TDR impedance tester, which has at least the following beneficial effects:

[0012] 1. The utility model can generate a high-precision pulse signal while performing preliminary filtering on the returned pulse signal through the cooperation of the pulse generating circuit and the compensation circuit, thereby improving the accuracy of the returned pulse signal. The cooperation with the filtering circuit further improves the accuracy of the measurement result. In addition, in the process of transmitting the pulse signal, the interference of the high-frequency signal can be effectively suppressed through the action of multiple resistance elements, thereby improving the anti-interference ability of the tester.

[0013] 2. The utility model can effectively simplify the operation complexity of the staff through the cooperation of the microprocessor module and the display screen, so that the staff can quickly operate on the online video when using the tester. It is simple and easy to get started, which improves the convenience of using the tester. The graphical interface of the display screen makes the operation simple and efficient, thereby improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0015] Figure 1 This is a structural block diagram of a TDR impedance tester of the present utility model;

[0016] Figure 2 This is a circuit diagram of a pulse generating circuit of the present utility model;

[0017] Figure 3 This is a circuit diagram of the compensation circuit of the utility model;

[0018] Figure 4 This is a circuit diagram of the amplifier circuit of the utility model;

[0019] Figure 5 This is a circuit diagram of the filter circuit of the utility model.

[0020] In the figure: 1. Probe; 2. Front-end circuit; 21. Pulse generating circuit; 22. Compensation circuit; 23. Amplifying circuit; 24. Filtering circuit; 3. Back-end circuit; 31. High-speed sampling oscilloscope; 32. Microprocessing module; 33. Display screen. DETAILED DESCRIPTION

[0021] To make the above-mentioned objectives, features, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. This will enable a full understanding of how the present invention applies technical means to solve technical problems and achieve technical effects, and to implement the invention accordingly.

[0022] Due to the technical problems of low accuracy of pulse signals and poor filtering effect generated by existing technologies, please refer to Figure 1 - Figure 5, this embodiment provides a TDR impedance tester, which can improve the accuracy of pulse signals and optimize the filtering effect. The impedance tester includes a probe 1 for collecting pulse signals, a front-end circuit 2 and a back-end circuit 3 for processing the returned pulse signals. The front-end circuit 2 is composed of a pulse generating circuit 21 for generating pulse signals, a compensation circuit 22, an amplifying circuit 23 and a filtering circuit 24. The pulse generating circuit 21 is composed of an input signal, a current limiting resistor R1, a shunt resistor R4, an operational amplifier D1 and a pulse signal. The input signal is transmitted through the current limiting circuit Resistor R1 is connected to the positive input terminal of op amp D1, shunt resistor R4 is connected in parallel to the positive input terminal and output terminal of op amp D1, shunt resistor R2 and diode P1 are connected in series in parallel to the negative input terminal and output terminal of op amp D1, shunt resistor R3 and diode P2 are connected in series in parallel to the shunt resistor R2 and diode P1, compensation circuit 22 is composed of current limiting resistor R8, inductor L1, shunt resistor R9, capacitor C2 and return signal, pulse signal is connected to terminal A of probe 1 through current limiting resistor R8 and inductor L1, and terminal B of probe 1 receives the return signal. A shunt resistor R9 and a capacitor C2 are connected in parallel between the pulse signal and the return signal respectively. The amplifier circuit 23 consists of a current limiting resistor R6, a 5V power supply, an op amp D2 and an amplified signal. The return signal is connected to the op amp D2 through the current limiting resistor R6, and the output end of the op amp D2 transmits the amplified signal. The 5V power supply is connected to the positive input end of the op amp D2 through the current resistor R5, and the positive input end of the op amp D2 is grounded through the resistor R7. The filter circuit 24 consists of a 5V filter power supply, a voltage divider resistor R11, a variable resistor R12, an op amp D3, a current limiting resistor R16 and a filter signal. The 5V filter power supply is connected to the negative input terminal of the operational amplifier D3 through the voltage divider resistor R11 and the variable resistor R12, the amplified signal is connected to the positive input terminal of the operational amplifier D3, and the output terminal of the operational amplifier D3 outputs the filtered signal through the current limiting resistor R16. The positive input terminal and output terminal of the operational amplifier D3 are connected in parallel with the current limiting resistor R15 and the capacitor C4 connected in series in sequence. The negative input terminal and output terminal of the operational amplifier D3 are connected in parallel with the fixed resistor R13 and the variable resistor R14 connected in series in sequence. The 5V filter power supply is connected to the filtered signal through the current limiting resistor R10 and the shunt resistor R17 in sequence.

[0023] In the present invention, the microprocessor module 32 of the back-end circuit 3 sends an input signal to the pulse generating circuit 21. The pulse generating circuit 21 suppresses interference to the signal to a certain extent through the action of the current limiting resistor R1 and the shunt resistor R4, and outputs a pulse signal through the operational amplifier D1. The protection circuit is composed of the shunt resistor R2, the diode P1, the shunt resistor R3 and the diode P2. The main function is to protect the components in the circuit and prevent the reverse voltage from damaging the operational amplifier D1 chip. The operational amplifier D1 generally uses the LM358 signal chip. The generated pulse signal is first transmitted to the probe 1A end through the compensation circuit 22, and returns from the probe 1B end after passing through the circuit to be detected and passes through the compensation circuit 22 again. The compensation circuit 22 can correct the measurement error between the instrument and the object to be measured, so that the measurement result is more accurate. The return signal output by the compensation circuit 22 is amplified through the amplifier circuit 23. Since the returned pulse signal is small, the pulse signal needs to be further amplified. The return signal is amplified through the operational amplifier D2 in the amplifier circuit. The amplified signal is generated and transmitted to the filter circuit 24. The operational amplifier D3 in the filter circuit 24 is composed of a non-inverting proportional amplifier of model LM358. The other passive components are connected to the non-inverting input terminal of the operational amplifier D3. The output voltage of the non-inverting amplifier is fed back to the passive network. The function of the entire filter circuit is to filter out the harmonics of the pulse signal and double the ideal 0-5V PWM signal to convert it into a 0-10V analog signal. Practice has shown that when the signal frequency is about 0.02MHz, the filtering effect is best. The filtered signal generated by the filter circuit 24 is transmitted to the high-speed sampling oscilloscope 31. Through the coordinated action of the pulse generating circuit and the compensation circuit, it is possible to generate a high-precision pulse signal while performing preliminary filtering on the returned pulse signal, thereby improving the accuracy of the returned pulse signal. The action of the filter circuit further improves the accuracy of the measurement result. In addition, in the process of transmitting the pulse signal, the interference of the high-frequency signal can be effectively suppressed by the action of multiple resistor elements, thereby improving the anti-interference ability of the tester.

[0024] Since the operation steps of the existing impedance tester are very complicated, which seriously affects the work efficiency, please refer to Figure 1 The back-end circuit 3 consists of a high-speed sampling oscilloscope 31, a microprocessor module 32 and a display screen 33. The model of the high-speed sampling oscilloscope 31 is 86100C, the model of the microprocessor module 32 is TMS320F2812, and the model of the display screen 33 is JY-J302.

[0025] The high-speed sampling oscilloscope 31 in the present invention needs to be able to match the pulse signal frequency of the pulse generating circuit 21, and has a built-in matching synchronization trigger so that the pulse signal can be triggered and synchronized to increase signal accuracy. The present invention adopts a high-speed sampling oscilloscope of model 86100C to achieve high-speed sampling and improve measurement accuracy and sensitivity. When processing pulse signals, a processing chip with strong computing power and higher accuracy is required to process high-precision pulse signals to ensure that the pulse signals still maintain high accuracy after processing. Through the microprocessor of model TMS320F2812, not only high processing speed and high calculation accuracy can be achieved, but also different Under demand conditions, a variety of processing equipment and instruments can be added, and each instrument can be precisely controlled. Simple operation can be performed through the display screen model JY-J302. The graphical operation interface is used to simplify the operation process and reduce the difficulty of operation. At the same time, it provides rich data analysis functions to help users better understand the test results. Through the cooperation of the microprocessor module and the display screen, the operation complexity of the staff can be effectively simplified, so that the staff can quickly operate on the online video when using the tester. It is simple and easy to get started, which improves the convenience of using the tester. The graphical interface of the display screen makes the operation simple and efficient, thereby improving work efficiency.

[0026] The above embodiments provide a detailed introduction to the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A TDR impedance tester, comprising a probe (1) for collecting pulse signals, a front-end circuit (2) and a back-end circuit (3) for processing the returned pulse signals, characterized in that: The front-end circuit (2) is composed of a pulse generating circuit (21) for generating a pulse signal, a compensation circuit (22), an amplifying circuit (23) and a filtering circuit (24); The pulse generating circuit (21) is composed of an input signal, a current limiting resistor R1, a shunt resistor R4, an op amp D1, and a pulse signal. The input signal is connected to the positive input terminal of the op amp D1 through the current limiting resistor R1. The positive input terminal and the output terminal of the op amp D1 are connected in parallel with the shunt resistor R4. The negative input terminal and the output terminal of the op amp D1 are connected in parallel with the shunt resistor R2 and the diode P1 which are connected in series in sequence. The shunt resistor R2 and the diode P1 are connected in parallel with the shunt resistor R3 and the diode P2 which are connected in series in sequence.

2. The impedance tester according to claim 1, wherein: The compensation circuit (22) is composed of a current limiting resistor R8, an inductor L1, a shunt resistor R9, a capacitor C2 and a return signal. The pulse signal is connected to the A end of the probe (1) through the current limiting resistor R8 and the inductor L1, and the B end of the probe (1) receives the return signal. The shunt resistor R9 and the capacitor C2 are respectively connected in parallel between the pulse signal and the return signal.

3. The impedance tester according to claim 1, wherein: The amplifying circuit (23) is composed of a current limiting resistor R6, a 5V power supply, an op amp D2 and an amplified signal. The return signal is connected to the op amp D2 through the current limiting resistor R6, and the output end of the op amp D2 transmits the amplified signal. The 5V power supply is connected to the positive input end of the op amp D2 through the current resistor R5, and the positive input end of the op amp D2 is grounded through the resistor R7.

4. The impedance tester according to claim 1, wherein: The filtering circuit (24) is composed of a 5V filtering power supply, a voltage dividing resistor R11, a variable resistor R12, an op amp D3, a current limiting resistor R16 and a filtering signal. The 5V filtering power supply is connected to the negative input terminal of the op amp D3 through the voltage dividing resistor R11 and the variable resistor R12, and the amplified signal is connected to the positive input terminal of the op amp D3. The output terminal of the op amp D3 outputs the filtering signal through the current limiting resistor R16. The positive input terminal and the output terminal of the op amp D3 are connected in parallel with a current limiting resistor R15 and a capacitor C4 connected in series in sequence. The negative input terminal and the output terminal of the op amp D3 are connected in parallel with a fixed resistor R13 and a variable resistor R14 connected in series in sequence. The 5V filtering power supply is connected to the filtering signal through the current limiting resistor R10 and the shunt resistor R17 in sequence.

5. The impedance tester according to claim 1, characterized in that: The back-end circuit (3) is composed of a high-speed sampling oscilloscope (31), a microprocessor module (32) and a display screen (33).

6. The impedance tester according to claim 5, characterized in that: The model of the high-speed sampling oscilloscope (31) is 86100C, the model of the microprocessor module (32) is TMS320F2812, and the model of the display screen (33) is JY-J302.

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