Attenuator external differential probe and detection device

Abstract

The utility model provides an attenuator external differential probe, which comprises an attenuator module, a differential amplification module and a coaxial shielding cable, two ends of the coaxial shielding cable are respectively connected with the attenuator module and the differential amplification module, and the attenuator module and the differential amplification module are respectively provided with a shielding shell. According to the external differential probe of the attenuator provided by the utility model, the attenuator module and the differential amplification module are separately arranged, so that the attenuator module can be set as a miniaturized independent module and is easier to be close to a circuit board to be tested, thereby improving the anti-interference capability of the external differential probe of the attenuator. Meanwhile, according to the detection device provided by the utility model, the testing accuracy can be effectively improved by adopting the external differential probe of the attenuator. The utility model also provides a detection device.

Description

[Technical Field]

[0001] This utility model relates to the field of electronic circuit testing technology, and in particular to an external differential probe for attenuators and a testing device. [Background Technology]

[0002] In the field of electronic measurement, a differential probe is an electronic measuring device specifically designed for measuring differential signals in high-voltage circuits. It can convert the differential mode of a high-voltage signal into a low-voltage signal, enabling accurate measurement and analysis by an oscilloscope.

[0003] However, as Figure 1 As shown, existing differential probes combine the attenuator module and differential amplifier module, resulting in a relatively large probe body. Therefore, the probe body cannot be placed directly near the circuit board; two signal lines must be connected to the circuit under test, and these lines have a certain length (50-100mm). Since these signal lines are ordinary wires, they cannot shield against electromagnetic interference. In environments with complex electromagnetic interference, the signal lines absorb a lot of interference, thus affecting the accuracy of the test. [Utility Model Content]

[0004] This invention provides an external differential probe and detection device for attenuators that are susceptible to interference and have low accuracy, thereby improving detection accuracy.

[0005] This utility model provides an external differential probe for an attenuator, including an attenuator module, a differential amplifier module, and a coaxial shielded cable. The two ends of the coaxial shielded cable are respectively connected to the attenuator module and the differential amplifier module. Both the attenuator module and the differential amplifier module are provided with shielded shells.

[0006] This utility model provides a testing device, including an oscilloscope and an external differential probe for attenuators. The oscilloscope and the external differential probe for attenuators are detachably electrically connected. The external differential probe for attenuators includes an attenuator module, a differential amplifier module, and a coaxial shielded cable. The two ends of the coaxial shielded cable are respectively connected to the attenuator module and the differential amplifier module. Both the attenuator module and the differential amplifier module are provided with shielded housings.

[0007] Compared with existing technologies, the external differential probe for attenuators provided by this invention separates the attenuator module from the differential amplification module, allowing the attenuator module to be configured as a miniaturized, standalone module that is easier to place close to the circuit board under test, thereby improving the anti-interference capability of the external differential probe. Furthermore, the detection device provided by this invention, employing the external differential probe for attenuators, can effectively improve the accuracy of the test. [Attached Image Description]

[0008] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0009] Figure 1 is a schematic diagram of the connection structure of the differential probe and the detection device in the prior art;

[0010] Figure 2 is a schematic diagram of the structure of the detection device provided by the present application;

[0011] Figure 3 is a schematic diagram of the connection of the first embodiment of the attenuator external differential probe;

[0012] Figure 4 is a schematic diagram of the connection of the second embodiment of the attenuator external differential probe; and

[0013] Figure 5 is a schematic diagram of the connection of the third embodiment of the attenuator external differential probe.

DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only constitute some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort fall within the scope of protection of the present application.

[0015] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between the components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications will also change accordingly.

[0016] In addition, the description of "first", "second", etc. in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0017] In the utility model, unless another definite provision and limitation, the terms "connect", "fix" and the like should do the broad sense understanding, for example, "fix" can be fixed connection, also can be detachable connection, or be integrated;Can be mechanical connection, also can be electrical connection;Can be directly connected, also can be indirectly connected through the intermediate medium, can be the communication of two elements or the interaction of two elements, unless another definite limitation.For the ordinary skilled person in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0018] In addition, the technical solutions of various embodiments of the utility model can be combined with each other, but it must be based on that the ordinary skilled person in the art can realize, when the combination of technical solutions appears mutual contradiction or cannot be realized, it should be considered that the combination of technical solutions does not exist, also not within the protection scope required by the utility model.

[0019] Please refer to Figure 2 And Figure 3 A detection device 100, including oscilloscope 30 and attenuator external differential probe, the oscilloscope 30 with the attenuator external differential probe 10 detachable electrical connection.The attenuator external differential probe 10 includes attenuator module 1, differential amplification module 3 and coaxial shielded cable 5, the coaxial shielded cable 5 both ends are connected with attenuator module 1 and differential amplification module 3, attenuator module 1 and differential amplification module 3 are both provided with shielded shell 7.

[0020] The attenuator external differential probe 10 is set by separating the attenuator module 1 and the differential amplification module 3, so that the attenuator module 1 can be set as a small-sized separate module, which is more easily arranged close to the measured circuit 50, thereby improving the anti-interference capability of the attenuator external differential probe 10.The detection device 100 adopts the attenuator external differential probe 10, which can avoid connecting the measured circuit 50 by signal lines, thereby effectively improving the accuracy of the test.

[0021] In the first embodiment, the attenuator module 1 includes a positive attenuation branch 11 and a negative attenuation branch 13, the positive attenuation branch 11 and the negative attenuation branch 13 are connected with the differential amplification module 3 through the coaxial shielded cable 5 respectively. Among them, the positive attenuation branch 11 and the negative attenuation branch 13 are arranged in the same shielded shell 7, which is convenient for production packaging.

[0022] The positive attenuation branch 11 is provided with a positive connector 111, and the negative attenuation branch 13 is provided with a negative connector 131, the positive connector 111 and the negative connector 131 are arranged through the shielding shell 7, and are mainly used for connecting the measured circuit 50. It should be noted that the positive connector 111 and the negative connector 131 can be selected from BNC, SMA, SMB, MMCX or equal-interval jacks, sockets and the like. By arranging the positive connector 111 and the negative connector 131, the attenuator module 1 can be more convenient to connect the measured circuit 50, and even can be directly installed on the measured circuit 50, so that the distance from the signal in the measured circuit 50 to the attenuator module 1 is very short, which can be controlled to be less than 5mm, therefore, the input signal will not be absorbed by electromagnetic interference, effectively improving the anti-interference ability of the attenuator module 1 and improving the detection accuracy.

[0023] The coaxial shielding cable 5 includes a positive shielding line 51 and a negative shielding line 53, the positive shielding line 51 is connected with the positive attenuation branch 11, and the negative shielding line 53 is connected with the negative attenuation branch 13. Wherein, the positive shielding line 51 and the negative shielding line 53 are arranged in a spaced manner. The positive shielding line 51 and the negative shielding line 53 are coaxially arranged shielding lines, which can shield radiation, so that the attenuator external differential probe 10 can maintain good transmission performance in an electromagnetic interference environment.

[0024] Please continue to refer to Figure 4 , in order to further improve the anti-interference ability, the positive shielding line 51 and the negative shielding line 53 are twisted and arranged. Specifically, the positive shielding line 51 and the negative shielding line 53 are twisted together and then sleeved in the shielding layer, thereby reducing electromagnetic interference and improving signal transmission quality. By twisting, the overall distributed capacitance and distributed inductance of the coaxial shielding cable 5 can be small, and the impedance of the attenuator module 1 can be matched, so that high-frequency signals can be more stably transmitted, and the highest can stably transmit 500M high-frequency signals.

[0025] Further, a magnetic ring 9 is sleeved outside the coaxial shielded cable 5 to absorb common mode interference. No matter whether the coaxial shielded cable 5 is arranged in a manner of spacing the positive shield line 51 and the negative shield line 53 in the first embodiment or in a manner of twisting the positive shield line 51 and the negative shield line 53 in the second embodiment, the magnetic ring 9 can be sleeved outside. The magnetic ring 9 cooperates with the coaxial shielded cable 5 to effectively improve the clarity of the signal and the transmission distance. Since the attenuator module 1 and the differential amplification module 3 are arranged separately, when the environment space of the measured circuit 50 is small, the attenuator module 1 can be arranged on the measured circuit 50, the differential amplification module 3 is arranged on the oscilloscope 30, and the distance of the coaxial shielded cable 5 can be extended by adding the magnetic ring 9, so that the attenuator external differential probe 10 can adapt to more use scenarios. Of course, the magnetic ring 9 can be one of amorphous magnetic ring 9, manganese-zinc ferrite magnetic ring 9 or nickel-zinc magnetic ring 9, which is not limited here.

[0026] The positive attenuation branch 11 includes a first resistor R1, a first capacitor C1 and a third resistor R3, the first resistor R1 and the third resistor R3 are connected in series between the positive connector 111 and the ground, the connection point of the first resistor R1 and the third resistor R3 is connected to the positive shield line 51, and the first capacitor C1 is arranged in parallel with the first resistor R1; the negative attenuation branch 13 is symmetrically provided with a second resistor R2, a second capacitor C2 and a fourth resistor R4 relative to the positive attenuation branch 11, the second resistor R2 and the fourth resistor R4 are connected in series between the negative connector 131 and the ground, the connection point of the second resistor R2 and the fourth resistor R4 is connected to the negative shield line 53, and the second capacitor C2 is arranged in parallel with the second resistor R2.

[0027] The positive attenuation branch 11 and the negative attenuation branch 13 are symmetrically arranged, and attenuation of a certain proportion multiple is realized through the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4, so as to reduce the amplitude or power of the input signal, and the attenuated signal is transmitted to the differential amplification module 3 through the coaxial shielded cable 5 for further processing. And, the first capacitor C1 and the second capacitor C2 are cooperatively arranged, so that the impedance of the attenuator module 1 matches the impedance of the coaxial shielded cable 5, so that the high-frequency signal can be more stably transmitted. In addition, the circuit arrangement structure is simple, only a few passive resistors and capacitors are arranged, the overall space is small, the overall volume of the attenuator module 1 is very small, the attenuator module 1 can be arranged in a position close to the measured circuit 50 or directly installed on the measured circuit 50, so as to improve the anti-interference ability and increase the application range.

[0028] Correspondingly, the differential amplification module 3 includes a differential amplifier 31, a fifth resistor R5 and a third capacitor C3 connected in parallel between the positive input end of the differential amplifier 31 and the ground, and a sixth resistor R6 and a fourth capacitor C4 connected in parallel between the negative input end of the differential amplifier 31 and the ground. The output end of the differential amplifier 31 penetrates the shielded shell 7, the positive input end of the differential amplifier 31 is connected with the positive shielded line 51, the negative input end of the differential amplifier 31 is connected with the negative shielded line 53, and the sixth resistor R6 and the fourth capacitor C4 are symmetrically arranged with the fifth resistor R5 and the third capacitor C3. The differential amplifier 31, the fifth resistor R5, the sixth resistor R6, the third capacitor C3 and the fourth capacitor C4 are arranged in the shielded shell 7, and the output end of the differential amplifier 31 penetrates the shielded shell 7, so as to realize the connection with the oscilloscope 30 and display the measurement result through the oscilloscope 30. The differential amplification module 3 amplifies the signal transmitted from the coaxial shielded cable 5 through the differential amplifier 31, inputs into the oscilloscope 30, and realizes the suppression of common-mode noise.

[0029] Please continue to refer to Figure 5In order to improve the use scene of the attenuator external differential probe 10, the attenuator module 1 can also be split and arranged, the positive attenuation branch 11 and the negative attenuation branch 13 are arranged in opposite intervals, and are respectively arranged in two isolated shielding shells 7. This arrangement mode is equivalent to splitting the attenuator module 1 into two parts that can be independently installed and placed. In some special measured circuits 50, the positions of the positive and negative signals are not completely matched with the attenuator module 1. At this time, the positive connector 111 and the negative connector 131 can be respectively installed at the corresponding test points, so as to realize the connection between the attenuator external differential probe 10 and the measured circuit 50.

[0030] The positive attenuation branch 11 and the negative attenuation branch 13 are arranged separately, mainly due to the separate arrangement idea of the attenuator module 1 and the differential amplification module 3. In the case of ensuring stable transmission signal and low interference, the attenuator external differential probe 10 has higher adaptability and can be used in different test environments, which is very convenient.

[0031] The above is only an embodiment of the present application, and it should be pointed out that, for those skilled in the art, improvements can be made without departing from the inventive concept of the present application, but these all belong to the protection scope of the present application.

Claims

1. An attenuator off-the-difference probe, characterized by, It comprises: an attenuator module; a differential amplifier module; and a coaxial shielded cable, which is connected with the attenuator module and the differential amplifier module at both ends, and the attenuator module and the differential amplifier module are both provided with a shielded shell. The attenuator module comprises:

2. The attenuator off-the-shelf differential probe of claim 1, wherein, a positive attenuator branch; and a negative attenuator branch, which are connected with the differential amplifier module through the coaxial shielded cable respectively; wherein, the positive attenuator branch and the negative attenuator branch are arranged in the same shielded shell, or are oppositely spaced and arranged in two isolated shielded shells respectively. The coaxial shielded cable comprises:

3. The attenuator off-the-shelf differential probe of claim 2, wherein, a positive shielded line, which is connected with the positive attenuator branch; and a negative shielded line, which is connected with the negative attenuator branch; wherein, the positive shielded line and the negative shielded line are spaced or twisted. The positive attenuator branch is provided with a positive connector, and the negative attenuator branch is provided with a negative connector, and the positive connector and the negative connector are selected from BNC, SMA, SMB, MMCX or equal-interval jacks and sockets of radio frequency.

4. The attenuator off-the-shelf differential probe of claim 3, wherein, The positive attenuator branch comprises a first resistor, a first capacitor and a third resistor, the first resistor and the third resistor are connected in series between the positive connector and the ground, the connection point of the first resistor and the third resistor is connected with the positive shielded line, and the first capacitor is connected in parallel with the first resistor; 5. The attenuator off-the-shelf differential probe of claim 4, wherein, The negative attenuator branch is symmetrically provided with a second resistor, a second capacitor and a fourth resistor relative to the positive attenuator branch, the second resistor and the fourth resistor are connected in series between the negative connector and the ground, the connection point of the second resistor and the fourth resistor is connected with the negative shielded line, and the second capacitor is connected in parallel with the second resistor. The differential amplifier module comprises:

6. The attenuator off-the-shelf differential probe of claim 3, wherein, a differential amplifier, the output end of which penetrates the shielded shell, the positive input end of which is connected with the positive shielded line, and the negative input end of which is connected with the negative shielded line; a fifth resistor and a third capacitor, which are connected in parallel between the positive input end of the differential amplifier and the ground; and a sixth resistor and a fourth capacitor, which are connected in parallel between the negative input end of the differential amplifier and the ground, and the sixth resistor, the fourth capacitor, the fifth resistor and the third capacitor are symmetrically arranged. The coaxial shielded cable is provided with a magnetic ring, which is used for absorbing common-mode interference, and the magnetic ring is made of amorphous magnetic ring, manganese-zinc ferrite magnetic ring or nickel-zinc magnetic ring.

7. The attenuator off-the-shelf differential probe of claim 1, wherein, It comprises an oscilloscope and at least one differential probe as claimed in any one of claims 1 to 7, and the oscilloscope and the differential probe are detachably electrically connected.

8. A detection device, characterized in that ​

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