Distance-adjustable differential probe and digital oscilloscope
By adding short-connected wires and parasitic isolation capacitors to the signal transmission line of the differential probe, the problem of parasitic electrical parameters interference of the differential probe is solved, and the measurement accuracy and accuracy of the digital oscilloscope are improved.
Patent Information
- Application Number
- CN202420961752.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-07
- Publication Date
- 2025-03-04
- Estimated Expiration
- 2034-05-07
AI Technical Summary
The parasitic electrical parameters of the differential probe cause interference to the signal to be measured, affecting the measurement accuracy and accuracy of the digital oscilloscope.
By adding short-connected wires and parasitic isolation capacitors between the shielded grid lines of the signal transmission line of the differential probe, the parasitic inductance and capacitance are reduced, the resonance frequency is increased, and the parasitic signal interference is reduced.
It effectively reduces parasitic signal interference from differential probes and improves the measurement accuracy and accuracy of high-frequency signals by digital oscilloscopes.
Smart Images
Figure CN222561670U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of digital signal detection, and in particular to a differential probe with adjustable spacing and a digital oscilloscope. Background Art
[0002] The probe is an electronic component that connects the circuit under test to the input of the digital oscilloscope. It is crucial to the accuracy and correctness of its measurement results. The simplest probe is a wire that connects the circuit under test to the input of the electronic oscilloscope. The complex probe is composed of resistors and capacitors and active devices. Simple probes without shielding measures are easily interfered by external electromagnetic fields, and their equivalent capacitance is large, which increases the load of the circuit under test and distorts the measured signal.
[0003] Currently, when using an active differential probe to measure signals, in order to adapt the distance between the two measured points, it is often necessary to use a probe with adjustable probe distance. Figure 1 , which is a schematic diagram of the structure of a differential probe with adjustable spacing. The differential probe includes a probe housing 1, a connecting adapter 2, a signal transmission line 3, a spacing adjustment mechanism 4, a tip matching circuit 5 and a tip contact 6. The two tip contacts 6 (a positive terminal contact and a negative terminal contact) of the differential probe are respectively fixed and moved by the spacing adjustment mechanism 4. Since the signal transmission line 3 increases the return path of the high-frequency signal transmission between the positive terminal contact and the negative terminal contact, its parasitic capacitance and parasitic inductance will resonate, resulting in uneven gain within a certain frequency band, thereby affecting the measurement precision and accuracy of the digital oscilloscope. Summary of the invention
[0004] The technical problem to be solved by the present application is how to reduce the interference of parasitic electrical parameters of the differential probe on the signal to be measured.
[0005] According to the first aspect, an embodiment provides a differential probe with adjustable spacing, comprising a housing, a first tip contact and a second tip contact for electrical connection are disposed outside the housing, and a spacing adjustment mechanism, a first tip matching circuit, a second tip matching circuit, a first signal transmission line, a second signal transmission line, and a probe amplification circuit are disposed inside the housing;
[0006] The spacing adjustment mechanism is used to fix and adjust the distance between the first tip contact and the second tip contact;
[0007] The first tip matching circuit is electrically connected to the first tip contact, and the second tip matching circuit is electrically connected to the second tip contact;
[0008] The first signal transmission line is connected between the first tip matching circuit and the probe amplification circuit, and the second signal transmission line is connected between the second tip matching circuit and the probe amplification circuit;
[0009] The first signal transmission line includes a first shielding grid line and a first battery conductor, one end of the first battery conductor is electrically connected to the first tip matching circuit, and the other end is electrically connected to the probe amplification circuit; the second signal transmission line includes a second shielding grid line and a second battery conductor, one end of the second battery conductor is electrically connected to the second tip matching circuit, and the other end is electrically connected to the probe amplification circuit; the first shielding grid line and the second shielding grid line both include a first connection end and a second connection end, and the first connection end of the first shielding grid line and the first connection end of the second shielding grid line are both electrically connected to the ground end of the probe amplification circuit;
[0010] The differential probe further includes a parasitic reduction circuit, wherein the parasitic reduction circuit includes at least one short-circuit wire, each of which electrically connects the first shielding grid line and the second shielding grid line;
[0011] In one embodiment, the electrical connection points between the short-circuit wire and the first shielding grid wire and the second shielding grid wire do not include the first connection end of the first shielding grid wire and the first connection end of the second shielding grid wire.
[0012] In one embodiment, the parasitic reduction circuit further includes at least one parasitic isolation capacitor, and two ends of each of the parasitic isolation capacitors are electrically connected to the first shielding grid line and the second shielding grid line, respectively.
[0013] In one embodiment, the parasitic reduction circuit includes a short-circuit wire, and two ends of the short-circuit wire are respectively arranged at the front connection ends of the first shielding grid line and the second shielding grid line.
[0014] In one embodiment, the parasitic reduction circuit includes at least two short-circuit wires, and the electrical connection point between each short-circuit wire and the first shielding grid line is at a different position.
[0015] In one embodiment, the electrical connection point between each of the short-circuit wires and the second shielding grid wires is located at a different position.
[0016] In one embodiment, the short-circuit wire is a wire mesh.
[0017] In one embodiment, the first tip matching circuit includes a first resistor R1 and a first capacitor C1 connected in parallel, one end of the parallel connection is electrically connected to the first tip contact, and the other end of the parallel connection is electrically connected to the first battery core wire.
[0018] In one embodiment, the second tip matching circuit includes a first resistor R1 and a first capacitor C1 connected in parallel, one end of the parallel connection is electrically connected to the second tip contact, and the other end of the parallel connection is electrically connected to the second battery core wire.
[0019] In one embodiment, the probe amplification circuit includes an amplifier, a positive input terminal of the amplifier is electrically connected to the first battery core wire, and a negative input terminal of the amplifier is electrically connected to the second battery core wire.
[0020] According to the second aspect, an embodiment provides a digital oscilloscope, comprising the differential probe described in the first aspect.
[0021] According to the differential probe of the above embodiment, since the parasitic inductance is reduced by adding a short-circuit wire between two separated tip matching circuits, the resonant frequency of the parasitic device generated by the differential probe is increased, thereby achieving the purpose of reducing and lowering parasitic signal interference. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 It is a schematic diagram of the structure of a differential probe with adjustable spacing;
[0023] Figure 2 A schematic diagram of the electrical connection of an adjustable spacing differential probe in one embodiment;
[0024] Figure 3 A schematic diagram of a parasitic equivalent circuit of a differential probe in an embodiment;
[0025] Figure 4 is a schematic diagram of electrical connections of a parasitic reduction circuit in one embodiment;
[0026] Figure 5 A schematic diagram of the circuit structure of a parasitic reduction circuit in an embodiment;
[0027] Figure 6 A schematic diagram of the circuit structure of a parasitic reduction circuit in another embodiment;
[0028] Figure 7 FIG. 4 is a schematic diagram of a parasitic equivalent circuit of a differential probe in another embodiment. DETAILED DESCRIPTION
[0029] The present application is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are intended to enable the present application to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, and methods. In some cases, some operations related to the present application are not shown or described in the specification, in order to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.
[0030] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.
[0031] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).
[0032] Please refer to Figure 2, is a measurement electrical connection diagram of an adjustable spacing differential probe in an embodiment, including a first tip matching circuit 10, a second tip matching circuit 20, a first signal transmission line 30, a second signal transmission line 40, a probe amplification circuit 50, an extension wire 60 and a digital oscilloscope 70. The digital oscilloscope 70 is connected to the differential probe through the extension wire 60. The two tips of the differential probe are respectively provided with a first tip matching circuit 10 and a second tip matching circuit 20, both of which include a first resistor R1 (input resistor) and a first capacitor C1 (compensation capacitor). The first tip matching circuit 10 and the second tip matching circuit 20 are respectively connected to the amplifier 51 of the probe amplifying circuit 50 through a 50-ohm coaxial cable (the first signal transmission line 30 and the second signal transmission line 40). One end of the second resistor R2 (50-ohm output matching resistor) of the probe amplifying circuit 50 is connected to the output end of the amplifier 51, and the other end is connected to the digital oscilloscope 70 through an extension wire 60 (50-ohm coaxial cable), wherein the extension wire 60 includes a shielded mesh wire 61 and a core inner wire 62. One end of the shielded mesh wire 61 of the extension wire 60 is connected to the second resistor R2, and the other end is grounded through the third resistor R3 (50-ohm matching resistor) of the digital oscilloscope 70. The shielded mesh wire 61 is electrically connected to the grounding points of the differential probe and the digital oscilloscope, respectively. In addition, the first signal transmission line 30 includes a first shielding grid line 31 and a first battery conductor 32, one end of the first battery conductor 32 is electrically connected to the first tip matching circuit 10, and the other end is connected to the positive input terminal of the amplifier 51, and the first shielding grid line 31 is electrically connected to the ground terminal of the probe amplification circuit 50; the second signal transmission line 40 includes a second shielding grid line 41 and a second battery conductor 42, one end of the second battery conductor 42 is electrically connected to the second tip matching circuit 20, and the other end is connected to the negative input terminal of the amplifier 51, and the second shielding grid line 41 is electrically connected to the ground terminal of the probe amplification circuit 50.
[0033] like Figure 1 The differential probe of the structure shown has a problem at high frequencies because the positive and negative input terminals are grounded only at the position where they are connected to the amplifier circuit 50 (the differential signal return flows in from one end and out from the other end), and the parasitic capacitance of the PCB or coaxial cable (the first battery core conductor 32 and the second battery core conductor 42) and the parasitic inductance of the coaxial cable shielding layer (the first shielding grid line 31 and the second shielding grid line 41) form an LC resonance. If the resonance frequency falls within the probe bandwidth, it will affect the frequency response performance of the probe.
[0034] Please refer to Figure 3, is a schematic diagram of a parasitic equivalent circuit of a differential probe in an embodiment. The second capacitor C2 and the third capacitor C3 are parasitic capacitors before the coaxial cable input, and are composed of PCB parasitic capacitance and cable (first battery conductor 32 and second battery conductor 42) parasitic capacitance, which is generally at the fF level. Inductors L11, L12, L13, L21, L22 and L23 are parasitic inductors of the cable shielding layer (first shielding grid line 31 and second shielding grid line 41), wherein the first shielding grid line 31 and the second shielding grid line 41 are respectively equivalent to three inductors, one inductor represents a parasitic inductance of 1 / 3 of the length, and inductors L10 and L20 are parasitic inductors of the first battery conductor 32 and the second battery conductor 42, respectively. Figure 3 Only parasitic parameters that affect the resonance phenomenon are identified. The measured signal source is input through the first tip Vin1 and the second tip Vin2, forming two return loops. The one passing through the inductor L10 and the inductor L20 is the measurement loop, and the one passing through the first shielding grid line 31 and the second shielding grid line 41 (inductor L11, inductor L12, inductor L13, inductor L21, inductor L22 and inductor L23) is the return loop brought by the parasitic parameters. Because the parasitic parameters have capacitance and inductance, resonance will occur. The resonant frequency fo can be obtained according to the following formula:
[0035] Lp=L11+L12+L13+L21+L22+L23;
[0036] Cp=C3*C4 / (C3+C4);
[0037] Among them, Cp is the parasitic loop capacitance, Lp is the total parasitic loop inductance, Cp is generally 500fF, when the parasitic loop inductance is 10nH, the fo resonant frequency is 2.25GHz, assuming that the bandwidth of the differential probe is 4GHz, this resonant frequency falls within the bandwidth of the probe.
[0038] In engineering, parasitic electrical parameters cannot be completely eliminated, but their impact can be reduced as much as possible. Therefore, as long as Lp and Cp are reduced as much as possible, the resonant frequency fo can be increased and fo can be moved outside the probe bandwidth.
[0039] In an embodiment of the present application, a parasitic reduction circuit is electrically connected between the shielding grid lines of the first signal transmission line 30 and the second signal transmission line 40, so that the outer shielding layer of the coaxial cable is also connected to the same grounding network, and the parasitic inductance of the outer shielding layer of the coaxial cable is bypassed, so there is no resonant frequency.
[0040] Embodiment 1:
[0041] like Figure 1 and Figure 2As shown, the differential probe with adjustable spacing includes a housing, a first tip contact and a second tip contact for electrical connection are disposed outside the housing, and a spacing adjustment mechanism, a first tip matching circuit 10, a second tip matching circuit 20, a first signal transmission line 30, a second signal transmission line 40 and a probe amplifier circuit 50 are disposed inside the housing. The spacing adjustment mechanism is used to fix and adjust the distance between the first tip contact and the second tip contact, the first tip matching circuit 10 is electrically connected to the first tip contact, and the second tip matching circuit 20 is electrically connected to the second tip contact. The first signal transmission line 30 is connected between the first tip matching circuit 10 and the probe amplifier circuit 50, and the second signal transmission line 40 is connected between the second tip matching circuit 20 and the probe amplifier circuit 50. The first signal transmission line 30 includes a first shielding grid line 31 and a first battery conductor 32, one end of the first battery conductor 32 is electrically connected to the first tip matching circuit 10, and the other end is electrically connected to the probe amplification circuit 50. The second signal transmission line 40 includes a second shielding grid line 41 and a second battery conductor 42, one end of the second battery conductor 42 is electrically connected to the second tip matching circuit 20, and the other end is electrically connected to the probe amplification circuit 50. The first shielding grid line 31 and the second shielding grid line 41 both include a first connection end and a second connection end, and the first connection end of the first shielding grid line 31 and the first connection end of the second shielding grid line 41 are both electrically connected to the ground end of the probe amplification circuit 50.
[0042] Please refer to Figure 4 , is a schematic diagram of electrical connection of a parasitic reduction circuit in an embodiment, the differential probe further includes a parasitic reduction circuit 80, the parasitic reduction circuit 80 includes at least one short-circuit wire, each short-circuit wire electrically connects the first shielding grid line 31 and the second shielding grid line 41. In one embodiment, the electrical connection point between the short-circuit wire and the first shielding grid line 31 and the second shielding grid line 41 does not include the first connection end of the first shielding grid line 31 and the first connection end of the second shielding grid line 41.
[0043] Please refer to Figure 5 , is a schematic diagram of a circuit structure of a parasitic reduction circuit in an embodiment. The parasitic reduction circuit 80 includes a short-circuit wire D1, and the two ends of the short-circuit wire D1 are respectively arranged at the front connection ends of the first shielding grid line 31 and the second shielding grid line 41. The parasitic reduction circuit 80 also includes at least one parasitic isolation capacitor C 11 , each parasitic isolation capacitor C 11 The two ends of the differential probe are respectively electrically connected to the first shielding grid line 31 and the second shielding grid line 41. In one embodiment, the housing of the differential probe is a metal shielding shell or a plastic shielding shell coated with conductive paint, and the first shielding grid line 31 and the second shielding grid line 41 form a flat plate capacitor and are connected in series.
[0044] Please refer to Figure 6, which is a schematic diagram of the circuit structure of the parasitic reduction circuit in another embodiment. In one embodiment, the parasitic reduction circuit 80 includes at least two shorting wires, and the positions of the electrical connection points of each shorting wire with the first shielding grid line 31 are different. In one embodiment, the positions of the electrical connection points of each shorting wire with the second shielding grid line 41 are different.
[0045] In one embodiment, the shorting wires in the parasitic reduction circuit 80 are wire meshes. In one embodiment, the shorting wires in the parasitic reduction circuit 80 are conductors with stretchable characteristics such as metal wires, flexible PCBs, metal shrapnel, and conductive foam.
[0046] In one embodiment, the first tip matching circuit 10 includes a first resistor R1 and a first capacitor C1 connected in parallel. One end of the parallel connection is electrically connected to the first tip contact, and the other end of the parallel connection is electrically connected to the first cell wire 32. In one embodiment, the second tip matching circuit 20 includes a first resistor R1 and a first capacitor C1 connected in parallel. One end of the parallel connection is electrically connected to the second tip contact, and the other end of the parallel connection is electrically connected to the second cell wire 42. In one embodiment, the probe amplifier circuit 50 includes an amplifier 51. The positive input terminal of the amplifier 51 is electrically connected to the first cell wire 32, and the negative input terminal of the amplifier 51 is electrically connected to the second cell wire 42.
[0047] In one embodiment of the present application, a digital oscilloscope is also disclosed, which includes the differential probe described above.
[0048] Conductors are added to the grounding ends of the two PCBs of the first and second tip matching circuits of the differential probe. The conductor itself also has parasitic inductance, and the inductance value is related to the cross-sectional area and length of the conductor. The larger the cross-sectional area, the smaller the parasitic inductance; the shorter the length, the smaller the parasitic inductance. However, the larger the cross-sectional area, the worse the flexibility of the conductor, which is not conducive to adjusting the spacing. The length selection will affect the opening angle of the first and second tip contacts. Therefore, it is difficult to eliminate the parasitic parameters of the conductor. Please refer to Figure 7 , which is a schematic diagram of the parasitic equivalent circuit of the differential probe in another embodiment. After adding the shorting wires of the parasitic reduction circuit, if the parasitic inductance of the shorting wire as a conductor is L1, then the total inductance Lp1 of the parasitic loop is:
[0049] Lp1 = L1 * Lp / (L1 + Lp);
[0050] Lp = L11 + L12 + L13 + L21 + L22 + L23;
[0051] Among them, it is certain that Lp1 < Lp. Then, after adding conductors to the grounding ends of the two PCBs of the first and second tip matching circuits, the resonance frequency of the parasitic device will increase. As long as L1 is small enough, the resonance frequency of the parasitic device will be higher than the probe bandwidth.
[0052] If the differential probe has a higher bandwidth and the resonant frequency of the parasitic device is still within the probe bandwidth after adding a conductor (shorting the wire), the following measures can be taken to further increase the resonant frequency, including:
[0053] The equivalent inductance L1 is affected by the cross-sectional area and length of the conductor. In order to meet the basic function of adjusting the probe spacing, L1 cannot be infinitely small. Inductance L11 to inductance L21 are the parasitic inductance of the coaxial cable shielding layer. There is also an insulating layer on the outer layer, and conductor connections cannot be added. However, the resonant frequency can be increased by increasing the capacitance, such as Figure 7 As shown, the capacitor C10 can also be added between the inductors L12, L13 and the inductors L22, L23, or both. It should be noted how the capacitor C10 increases the resonant frequency of the parasitic loop. When the parasitic reduction circuit is equipped with multiple capacitors and inductors, the calculation of the resonant frequency is relatively complicated. This application only analyzes the change of the resonant frequency from a qualitative method. Figure 7 As shown, the equivalent capacitor C2, the equivalent capacitor C3 and the added capacitor C10 are in series relationship, and the total capacitance Cp of the parasitic loop is larger than Figure 3 The circuit shown is small. If the total inductance remains unchanged, the resonant frequency increases. In addition, the capacitor passes AC and blocks DC. In the high frequency band, the capacitor is equivalent to a short circuit. As long as the value of the capacitor C10 is large enough, in the high frequency band, the addition of capacitor C10 can bypass the inductors L12, L13, L22 and L23, so the total inductance Lp of the parasitic loop becomes L1||(L1+L21), the inductance Lp becomes smaller, and the resonant frequency increases. Figure 7 Compared with the circuit shown Figure 3 In the parasitic equivalent circuit shown in the circuit, both Cp and Lp are reduced, but the resonant frequency increases according to the formula obtained based on the total inductance of the parasitic loop.
[0054] In one embodiment, the method of increasing the capacitance C10 is to install a conductor on two coaxial cables (a first signal transmission line 30 and a second signal transmission line 40), and the conductor is close to the two coaxial cables. Then, the conductor and the outer conductor shielding layers of the two coaxial cables form two series-connected flat-plate capacitors Ca (with the first signal transmission line 30) and Cb (with the second signal transmission line 40), and the increased capacitance C10=Ca*Cb / (Ca+Cb).
[0055] In one embodiment, the capacitor C10 is added by using an internally conductive housing, such as a metal housing or spraying conductive paint on a plastic housing, in order to form a flat plate capacitor between the insulation layers and conductors of the two coaxial cables and connect them in series.
[0056] The differential probe disclosed in the embodiment of the present application includes a shell, a first tip contact and a second tip contact for electrical connection are externally arranged on the shell, and a spacing adjustment mechanism, a first tip matching circuit, a second tip matching circuit, a first signal transmission line, a second signal transmission line, a probe amplification circuit and a parasitic reduction circuit are arranged inside the shell. The parasitic reduction circuit includes a short-circuit wire, and the short-circuit wire is electrically connected between the first and second shielding grid lines. Since the induced inductance is reduced by adding a conductor between the two separated tip matching circuits, the resonant frequency of the parasitic device generated by the differential probe is increased, so as to achieve the purpose of reducing and lowering the interference of parasitic signals, thereby improving the measurement precision and accuracy of the digital oscilloscope in measuring high-frequency signals.
[0057] The above specific examples are used to illustrate the present invention, which is only used to help understand the present application and is not intended to limit the present application. For technicians in the technical field to which the present application belongs, they can also make some simple deductions, deformations or substitutions based on the ideas of the present application.
Claims
1. A differential probe with adjustable spacing, characterized in that: The invention comprises a shell, wherein a first tip contact and a second tip contact for electrical connection are disposed outside the shell, and a spacing adjustment mechanism, a first tip matching circuit, a second tip matching circuit, a first signal transmission line, a second signal transmission line and a probe amplification circuit are disposed inside the shell; The spacing adjustment mechanism is used to fix and adjust the distance between the first tip contact and the second tip contact; The first tip matching circuit is electrically connected to the first tip contact, and the second tip matching circuit is electrically connected to the second tip contact; The first signal transmission line is connected between the first tip matching circuit and the probe amplification circuit, and the second signal transmission line is connected between the second tip matching circuit and the probe amplification circuit; The first signal transmission line includes a first shielding grid line and a first battery conductor, one end of the first battery conductor is electrically connected to the first tip matching circuit, and the other end is electrically connected to the probe amplification circuit; the second signal transmission line includes a second shielding grid line and a second battery conductor, one end of the second battery conductor is electrically connected to the second tip matching circuit, and the other end is electrically connected to the probe amplification circuit; the first shielding grid line and the second shielding grid line both include a first connection end and a second connection end, and the first connection ends of the first shielding grid line and the second shielding grid line are both electrically connected to the ground end of the probe amplification circuit; The differential probe further includes a parasitic reduction circuit, wherein the parasitic reduction circuit includes at least one short-circuit conductor, each of which electrically connects the first shielding grid line and the second shielding grid line.
2. The differential probe according to claim 1, characterized in that: The parasitic reduction circuit further includes at least one parasitic isolation capacitor, and two ends of each of the parasitic isolation capacitors are electrically connected to the first shielding grid line and the second shielding grid line respectively.
3. The differential probe according to claim 1, characterized in that: The parasitic reduction circuit includes a short-circuit wire, and two ends of the short-circuit wire are respectively arranged at the front connection ends of the first shielding grid line and the second shielding grid line.
4. The differential probe according to claim 1, characterized in that: The parasitic reduction circuit includes at least two short-circuit conductors, and the electrical connection point between each short-circuit conductor and the first shielding grid line is at a different position.
5. The differential probe according to claim 4, characterized in that: The positions of the electrical connection points between each of the short-circuit wires and the second shielding grid lines are different.
6. The differential probe according to claim 1, wherein: The short-circuit wire is a wire mesh.
7. The differential probe according to claim 1, wherein: The first tip matching circuit includes a first resistor R1 and a first capacitor C1 connected in parallel, one end of which is electrically connected to the first tip contact, and the other end of which is electrically connected to the first battery core wire.
8. The differential probe according to claim 1, wherein: The second tip matching circuit includes a first resistor R1 and a first capacitor C1 connected in parallel, one end of which is electrically connected to the second tip contact, and the other end of which is electrically connected to the second battery core wire.
9. The differential probe according to claim 1, characterized in that: The probe amplification circuit comprises an amplifier, a positive input terminal of the amplifier is electrically connected to the first battery core wire, and a negative input terminal of the amplifier is electrically connected to the second battery core wire.
10. A digital oscilloscope, characterized in that: Comprising a differential probe as claimed in any one of claims 1 to 9.