Attenuation circuit, signal conditioning device, signal measuring equipment and oscilloscope

Abstract

The utility model discloses an attenuation circuit, a signal conditioning device, a signal measuring device and an oscilloscope, the attenuation circuit comprises a first impedance circuit, the first end of the first impedance circuit is connected with an input signal, and the second end of the first impedance circuit is connected with the output end of the attenuation circuit; the first end of the second impedance circuit is connected with the second end of the first impedance circuit, and the second end of the second impedance circuit is grounded; the impedance adjusting circuit comprises an impedance device and a control piece; the first end of the control piece is connected with the second end of the first impedance circuit through the impedance device, and the second end of the control piece is grounded; or, the first end of the control piece is connected with the second end of the first impedance circuit, and the second end of the control piece is connected with the ground through the impedance device; the control part is used for controlling the impedance device to be connected to the impedance adjusting circuit or disconnecting the impedance device from the impedance adjusting circuit. According to the technical scheme, the stability of the attenuation proportion of the attenuation circuit can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of signal attenuation, in particular to an attenuation circuit, a signal conditioning device, a signal measuring device and an oscilloscope. Background Art

[0002] The attenuation circuit is usually used as a front-end circuit in the signal measurement equipment to perform preliminary attenuation on the connected signal according to a certain attenuation ratio. However, due to the precision errors of the devices (resistance devices and capacitance devices) and the influence of parasitic capacitance in actual operation, the actual attenuation ratio of the attenuation circuit after actual welding cannot be uniformly achieved to the expected attenuation ratio. At present, a mechanically structured adjustable parameter impedance device (such as an adjustable capacitor) is usually set in the attenuation circuit to facilitate further adjustment of its attenuation ratio so that it can achieve the expected attenuation ratio.

[0003] However, the parameter values ​​of the mechanical adjustable impedance device are unstable and will change after a period of time, resulting in the need for subsequent continuous calibration and maintenance of the attenuation circuit to maintain the expected attenuation ratio, which is not conducive to practical use. Utility Model Content

[0004] The main purpose of the utility model is to provide an attenuation circuit, aiming to solve the problem that the attenuation ratio of the attenuation circuit using an impedance device with adjustable parameters cannot be kept stable for a long time.

[0005] In order to achieve the above-mentioned object, the utility model proposes an attenuation circuit, wherein the attenuation circuit comprises:

[0006] a first impedance circuit, wherein a first end of the first impedance circuit is connected to an input signal, and a second end of the first impedance circuit is connected to an output end of the attenuation circuit;

[0007] a second impedance circuit, wherein a first end of the second impedance circuit is connected to a second end of the first impedance circuit, and a second end of the second impedance circuit is grounded;

[0008] An impedance adjustment circuit comprises an impedance device and a control device; a first end of the control device is connected to a second end of the first impedance circuit via the impedance device, and a second end of the control device is connected to ground; or a first end of the control device is connected to a second end of the first impedance circuit, and a second end of the control device is connected to ground via the impedance device;

[0009] The control element is used to control the connection of the impedance device to the impedance adjustment circuit, or to disconnect the impedance device from the impedance adjustment circuit.

[0010] Optionally, there are multiple impedance adjustment circuits.

[0011] Optionally, the control element includes a switch device; the switch device connects the impedance device to the impedance adjustment circuit when turned on, and disconnects the impedance device from the impedance adjustment circuit when turned off.

[0012] Optionally, the control member includes a first conductive member and a second conductive member;

[0013] The first conductive member and the second conductive member connect the impedance device to the impedance adjustment circuit when they are electrically connected, and disconnect the impedance device from the impedance adjustment circuit when they are not electrically connected.

[0014] Optionally, the second impedance circuit includes: a first resistor, a second resistor and a first capacitor, the first end of the first resistor and the first end of the first capacitor are respectively connected to the second end of the first impedance circuit, the second end of the first resistor is grounded, and the second end of the first capacitor is grounded via the second resistor.

[0015] Optionally, the first impedance circuit includes: a resistance circuit and a second capacitor, the first end of the resistance circuit is connected to the input signal, the second end of the resistance circuit is connected to the first end of the second impedance circuit, and the second capacitor is respectively connected to the two ends of the resistance circuit.

[0016] Optionally, the impedance device is a capacitor device or a resistor device.

[0017] The utility model also provides a signal conditioning device, characterized in that the signal conditioning device comprises the attenuation circuit as described above.

[0018] The utility model also provides a signal measuring device, the signal measuring device comprising the attenuation circuit as described above;

[0019] Alternatively, the signal measuring device comprises the signal conditioning device as described above.

[0020] The utility model also provides an oscilloscope, the oscilloscope device comprising the attenuation circuit as described above;

[0021] Alternatively, the oscilloscope comprises a signal conditioning device as described above.

[0022] The technical solution of the utility model uses a control component to control the connection relationship between the impedance device and the first impedance circuit, so that the attenuation circuit can present two different attenuation ratios. Therefore, it is only necessary to use an impedance device with a fixed parameter value that meets the accuracy standard, such as a fixed resistance resistor or a ceramic capacitor, to adjust the attenuation ratio of the attenuation circuit to the expected attenuation ratio. Moreover, since the parameter value of the impedance device with a fixed parameter value can remain stable for a long time, the attenuation ratio of the attenuation circuit can be maintained unchanged for a long time, thereby solving the problem that the attenuation ratio of the attenuation circuit using the impedance device 31 with adjustable parameters cannot remain stable for a long time.

[0023] In addition, the mechanically structured adjustable impedance device 31 has the disadvantages of high cost and large size, which makes it inconvenient to design portable devices. The attenuation circuit proposed in the utility model can use commonly used fixed-resistance resistors or ceramic capacitors, which is also beneficial to reducing the circuit cost of the attenuation circuit and facilitating the design of portable devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0025] Figure 1 This is a module schematic diagram of an embodiment of the attenuation circuit of the utility model;

[0026] Figure 2 This is a circuit diagram of an embodiment of the attenuation circuit of the utility model;

[0027] Figure 3 This is a schematic structural diagram of another embodiment of the attenuation circuit of the utility model in which the first conductive member and the second conductive member are connected by conductive silver paste;

[0028] Figure 4 This is a circuit diagram of another embodiment of the attenuation circuit of the utility model;

[0029] Figure 5 This is a module diagram of another embodiment of the attenuation circuit of the utility model.

[0030] Description of Figure Numbers:

[0031]

[0032] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0034] In addition, in the present utility model, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0035] The utility model provides an attenuation circuit.

[0036] Reference Figures 1 to 4 , the attenuation circuit comprises:

[0037] A first impedance circuit 10, wherein a first end of the first impedance circuit 10 is grounded;

[0038] A first impedance circuit 10, wherein a first end of the first impedance circuit 10 is connected to an input signal Vin, and a second end of the first impedance circuit 10 is connected to an output end of the attenuation circuit;

[0039] A second impedance circuit 20, wherein a first end of the second impedance circuit 20 is connected to a second end of the first impedance circuit 10, and a second end of the second impedance circuit 20 is grounded;

[0040] The impedance adjustment circuit 30 includes an impedance device 31 and a control device 32; the first end of the control device 32 is connected to the second end of the first impedance circuit 10 via the impedance device 31, and the second end of the control device 32 is connected to the ground; or the first end of the control device 32 is connected to the second end of the first impedance circuit 10, and the second end of the control device 32 is connected to the ground via the impedance device 31.

[0041] The control element 32 is used to control the impedance device 31 to be connected to the impedance adjustment circuit 30 , or to control the impedance device 31 to be disconnected from the impedance adjustment circuit 30 .

[0042] In this embodiment, both the first impedance circuit 10 and the second impedance circuit 20 can be constructed by using resistor devices and capacitor devices. The circuit structures of the first impedance circuit 10 and the second impedance circuit 20 can be the same or different, and the impedance values ​​of the first impedance circuit 10 and the second impedance circuit 20 can be the same or different, which is not limited to this embodiment. The first impedance circuit 10 and the second impedance circuit 20 constitute a voltage divider circuit structure, which is used to divide and attenuate the input signal Vin connected to the first impedance circuit 10 (that is, the input signal Vin connected to the attenuation circuit) according to the impedance ratio of the two and then output it.

[0043] The impedance device 31 may be at least one of a resistor device or a capacitor device. The impedance device 31 and the control device 32 have two connection relationships with the second impedance adjustment circuit 30, wherein the first connection relationship is: the first end of the control device 32 is connected to the first end of the second impedance circuit 20 via the impedance device 31, and the second end of the control device 32 is connected to the second end of the second impedance circuit 20 (that is, grounded); the second connection relationship is: the first end of the control device 32 is connected to the first end of the second impedance circuit 20, and the second end of the control device 32 is connected to the second end of the second impedance circuit 20 via the impedance device 31. In short, the difference between the above two connection relationships is that: the first connection relationship (refer to Figure 5 ) wherein the second end of the control element 32 is grounded via the impedance element 31, and the second connection relationship (refer to Figure 1 ) The second end of the control element 32 is directly grounded.

[0044] The control element 32 can realize the electrical connection between its first end and the second end under the triggering of an electrical signal (current signal or voltage signal) or when there is a conductive path between the first end and the second end, so that the impedance device 31 can be connected in parallel to the two ends of the second impedance circuit 20. Of course, the control element 32 can disconnect the electrical connection between its first end and the second end under the triggering of another electrical signal (current signal or voltage signal) or when there is no conductive path between the first end and the second end, so that the parallel connection relationship between the impedance device 31 and the second impedance circuit 20 can be disconnected. When the impedance device 31 is connected to the second impedance circuit 20 in parallel, the attenuation ratio of the attenuation circuit as a whole in this solution is jointly determined by the first impedance circuit 10, the second impedance circuit 20, and the impedance components in the impedance adjustment circuit 30; when the impedance device 31 is disconnected from the impedance adjustment circuit 30, the attenuation ratio of the attenuation circuit as a whole is jointly determined by the first impedance circuit 10 and the second impedance circuit 20.

[0045] In this way, the technical solution of the utility model controls the connection relationship between the impedance device 31 and the first impedance circuit 10 through the control component 32, so that the attenuation circuit can present two different attenuation ratios. Therefore, it is only necessary to use an impedance device with a fixed parameter value that meets the accuracy standard, such as a fixed resistance resistor or a ceramic capacitor, to adjust the attenuation ratio of the attenuation circuit to the expected attenuation ratio. Moreover, since the parameter value of the impedance device with a fixed parameter value can remain stable for a long time, the attenuation ratio of the attenuation circuit can be maintained unchanged for a long time, thereby solving the problem that the attenuation ratio of the attenuation circuit using the impedance device 31 with adjustable parameters cannot remain stable for a long time.

[0046] In addition, the mechanically structured adjustable impedance device 31 has the disadvantages of high cost and large size, which makes it inconvenient to design portable devices. The attenuation circuit proposed in the utility model can use commonly used fixed-resistance resistors or ceramic capacitors, which is also beneficial to reducing the circuit cost of the attenuation circuit and facilitating the design of portable devices.

[0047] Reference Figure 2 and Figure 4 , the number of the impedance adjustment circuits 30 is multiple.

[0048] In this embodiment, the specific number of impedance adjustment circuits 30 can be determined according to actual needs, and this embodiment does not limit this. It can be understood that the number of attenuation ratio gears that the attenuation circuit can present at this time should be 2 to the power of N, where N is the number of impedance adjustment circuits 30, for example: 2-way impedance adjustment circuits 30 can allow the attenuation circuit to have 4-level attenuation ratios, and 3-way impedance adjustment circuits 30 can allow the attenuation circuit to have 8-level attenuation ratios. It should be noted that the parameters of the impedance device 31 in different impedance adjustment circuits 30 can be different, and the impedance device 31 and the control element 32 in different impedance adjustment circuits 30 can adopt different connection relationships (i.e., the above two connection relationships) to achieve connection with the first impedance circuit 10.

[0049] The technical solution of the utility model can make it easier to adjust the accuracy of the impedance device 31 of the adjustable parameter of the multi-channel impedance adjustment circuit 30 by designing the number of impedance adjustment circuits 30 to be multiple. Figure 2 Take this as an example to explain the regulation principle. Figure 2The figure shows a situation where the number of impedance adjustment circuits 30 is two, the impedance device 31 is a capacitor (third capacitor C3, fourth capacitor C4), and the two impedance adjustment circuits 30 are connected to the first impedance circuit 10 using the second connection relationship. If the overall capacitance value of the two impedance adjustment circuits 30 and the first impedance circuit 10 is required to be 200pF, and the accuracy of the capacitor used is 1%, the value of the first capacitor C1 can be set as close to the calculated value of 200pF as possible. However, combined with the capacitance accuracy, the actual overall capacitance value of the two impedance adjustment circuits 30 is (200±2)pF, then a 198pF capacitor can be selected as the first capacitor C1, a 1pF capacitor can be selected as the third capacitor C3, and a 2pF capacitor can be selected as the fourth capacitor C4. The relationship between the capacitance value of C3 and C4 in parallel and the state of the control element 32 can be shown in the following table:

[0050] As can be seen from the above table, the capacitance of the third capacitor C3 and the fourth capacitor C4 in parallel can be set in a range of 0~3pF with a precision step of 1pF, so as to meet the above requirement of (200±2)pF. If there is a need for precision adjustment in a larger range, it is only necessary to continue to increase the number of impedance adjustment circuits 30 and use the capacitor device with a small capacitance value as the impedance device 31 of the additional impedance adjustment circuit 30. Of course, the entire adjustable precision can also be improved by using a capacitor with a smaller capacitance value as the impedance device 31.

[0051] Optionally, the control element 32 includes a switch device; the switch device connects the impedance device 31 to the impedance adjustment circuit 30 when turned on, and disconnects the impedance device 31 from the impedance adjustment circuit 30 when turned off.

[0052] In this embodiment, the switch device can be any one or more combinations of MOS switch, triode, thyristor, relay, dip switch, etc. For example, Figure 4 In the embodiment, the control element 32 is an N-MOS tube (Q1, Q2), the drain of the N-MOS tube (Q1, Q2) is connected to the impedance device 31 (the third capacitor C3, the fourth capacitor C4), and the source is connected to the second impedance circuit 20. The control element 32 (Q1, Q2) can be turned on when the gate receives a high-level signal, and the third capacitor C3 or the fourth capacitor C4 is connected to the second impedance circuit 20, thereby changing the attenuation ratio of the attenuation circuit; when the gate receives a low-level signal, it is turned off to disconnect the third capacitor C3 or the fourth capacitor C4 from the second impedance circuit 20.

[0053] Optionally, refer to Figure 2 and Figure 3 , the control member 32 includes a first conductive member A and a second conductive member B;

[0054] The first conductive member A and the second conductive member B connect the impedance device 31 to the impedance adjustment circuit 30 when they are electrically connected, and disconnect the impedance device 31 from the impedance adjustment circuit 30 when they are not electrically connected.

[0055] In this embodiment, the first conductive member A and the second conductive member B may be a reserved pad or solder point. During the factory calibration stage of the product, the first conductive member A and the second conductive member B may be electrically connected by using a quick-drying silver paint pen to apply conductive paste (e.g., conductive silver paste) or fly wires, and the first conductive member A and the second conductive member B may be electrically disconnected by removing the conductive paste or the wire of the fly wire between the first conductive member A and the second conductive member B.

[0056] In another optional embodiment, the first conductive member A and the second conductive member B may also be implemented using a signal slot (not shown in the figure). In this case, the first conductive member A and the second conductive member B may be electrically connected by inserting the signal plugs at both ends of the signal line into the first conductive member A and the second conductive member B respectively, and the electrical connection between the first conductive member A and the second conductive member B may also be disconnected by pulling out the signal plugs at both ends of the signal line.

[0057] Reference Figure 2 and Figure 4 The second impedance circuit 20 includes: a first resistor R1, a second resistor R2 and a first capacitor C1, the first end of the first resistor R1 and the first end of the first capacitor C1 are respectively connected to the second end of the first impedance circuit 10, the second end of the first resistor R1 is grounded, and the second end of the first capacitor C1 is grounded via the second resistor R2.

[0058] Optionally, the first impedance circuit 10 includes: a resistance circuit and a second capacitor C2, the first end of the resistance circuit is connected to the input signal Vin, the second end of the resistance circuit is connected to the first end of the second impedance circuit 20, and the second capacitor C2 is connected to both ends of the resistance circuit. Figure 2 and Figure 4 The resistor circuit includes two third resistors R3 connected in series.

[0059] The utility model also proposes a signal conditioning device, which includes an attenuation circuit. The specific structure of the attenuation circuit refers to the above-mentioned embodiment. Since the signal conditioning device adopts all the technical solutions of all the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0060] The utility model also proposes a signal measuring device, which includes an attenuation circuit or a signal conditioning device. The specific structure of the attenuation circuit or the signal conditioning device refers to the above-mentioned embodiment. Since the signal measuring device adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0061] The utility model also provides an oscilloscope, which includes an attenuation circuit or a signal conditioning device. The specific structure of the attenuation circuit or the signal conditioning device refers to the above embodiment. Since the oscilloscope adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0062] The above description is only an optional embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An attenuation circuit, characterized in that: The attenuation circuit comprises: a first impedance circuit, wherein a first end of the first impedance circuit is connected to an input signal, and a second end of the first impedance circuit is connected to an output end of the attenuation circuit; a second impedance circuit, wherein a first end of the second impedance circuit is connected to a second end of the first impedance circuit, and a second end of the second impedance circuit is grounded; An impedance adjustment circuit comprises an impedance device and a control device; a first end of the control device is connected to a second end of the first impedance circuit via the impedance device, and a second end of the control device is connected to ground; or a first end of the control device is connected to a second end of the first impedance circuit, and a second end of the control device is connected to ground via the impedance device; The control element is used to control the connection of the impedance device to the impedance adjustment circuit, or to disconnect the impedance device from the impedance adjustment circuit.

2. The attenuation circuit according to claim 1, characterized in that: The number of the impedance adjustment circuits is multiple.

3. The attenuation circuit according to claim 1, characterized in that: The control element includes a switch device; when the switch device is turned on, the impedance device is connected to the impedance adjustment circuit, and when the switch device is turned off, the impedance device is disconnected from the impedance adjustment circuit.

4. The attenuation circuit according to claim 1, characterized in that: The control member includes a first conductive member and a second conductive member; The first conductive member and the second conductive member connect the impedance device to the impedance adjustment circuit when they are electrically connected, and disconnect the impedance device from the impedance adjustment circuit when they are not electrically connected.

5. The attenuation circuit according to claim 1, characterized in that: The second impedance circuit includes: a first resistor, a second resistor and a first capacitor, the first end of the first resistor and the first end of the first capacitor are respectively connected to the second end of the first impedance circuit, the second end of the first resistor is grounded, and the second end of the first capacitor is grounded via the second resistor.

6. The attenuation circuit according to claim 1, characterized in that: The first impedance circuit includes: a resistance circuit and a second capacitor, the first end of the resistance circuit is connected to the input signal, the second end of the resistance circuit is connected to the first end of the second impedance circuit, and the second capacitor is respectively connected to the two ends of the resistance circuit.

7. The attenuation circuit according to any one of claims 1 to 6, characterized in that: The impedance device is a capacitor device or a resistor device.

8. A signal conditioning device, characterized in that: The signal conditioning device comprises an attenuation circuit as described in any one of claims 1-7.

9. A signal measuring device, characterized in that: The signal measuring device comprises an attenuation circuit as claimed in any one of claims 1 to 7; Alternatively, the signal measuring device comprises the signal conditioning apparatus as claimed in claim 8.

10. An oscilloscope, characterized in that: The oscilloscope comprises the attenuation circuit according to any one of claims 1 to 7; Alternatively, the oscilloscope comprises the signal conditioning device as claimed in claim 8.

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