Filter device for multiple signal single line entering darkroom

Abstract

The embodiment of the present invention provides a filtering device for a multi-signal single line to enter a darkroom, belonging to the field of filtering technology. The device comprises: a metal shell; a darkroom shielding body; the metal shell and the darkroom shielding body enclose a box structure with a sealed cavity, and metal sand is encapsulated in the sealed cavity; the darkroom shielding body is used to connect a single-core wire coated with a metal shielding layer and allow the single-core wire that has been stripped of the metal shielding layer to pass through the sealed cavity and enter the darkroom, and the metal shielding layer section of the single-core wire contacts the darkroom shielding body to consume interference signals through the conductive plane formed by the darkroom shielding body, the metal shell and the metal sand. The scheme of the present invention not only ensures that various useful signals on the single-core wire can enter the radio wave darkroom smoothly, but also prevents other interference signals from entering the radio wave darkroom, and meets the relevant requirements for multiple signals on the same line to enter the darkroom.

Description

Technical Field

[0001] The invention relates to the field of filtering technology, in particular to a filtering device used for a multi-signal single line entering a darkroom. Background Art

[0002] Darkrooms are of great significance in the field of measurement. In order to avoid deviations in measurement results caused by external electromagnetic radiation, the device under test is placed in a darkroom that shields external electromagnetic waves for testing, so that the device under test is not affected by the external electromagnetic environment during the test, and all test results are related to the device under test itself. Therefore, in addition to the shielding performance of the darkroom shell itself, in order to avoid the influence of interference signals from the power and communication signals that power and transmit signals to the device under test on the test results, preferably, based on the special requirements of the darkroom for the electromagnetic environment, all power and communication signals entering the darkroom must be filtered accordingly before they can enter the darkroom and be used by the test product during the test process.

[0003] In the prior art, when the power signal enters the darkroom, it is generally filtered by installing a power filter, while when various communication signals enter the darkroom, they enter by photoelectric conversion. When the power signal and the communication signal enter the darkroom independently, the corresponding interference signal processing will have a better effect. However, when multiple signals of different frequency bands are superimposed on a line at the same time, for example, when a single-core wire is used to carry both the power signal and the carrier signal, there is no corresponding filtering method available. The main reason is that the existing filters used for darkroom construction can only filter signals of a single frequency band, such as the power filter commonly used in the darkroom construction process. The power filter is a passive bidirectional network, which is essentially a low-pass filter. It allows DC or 50Hz power signals to flow through, but does not allow high-frequency signals to flow through. However, the photoelectric conversion technology for high-frequency communication signals cannot realize the conversion of low-frequency electrical signals into optical signals. Based on the problem that the prior art cannot meet the problem of multiple signals entering the darkroom on the same line, it is necessary to create a filtering device for multiple signals to enter the darkroom on a single line. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a filtering device for multiple signals entering a darkroom on a single line, so as to at least solve the problem that the prior art cannot satisfy the requirement of multiple signals on the same line entering a darkroom.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides a filtering device for a multi-signal single line entering a darkroom, the device comprising: a metal shell; a darkroom shielding body; the metal shell and the darkroom shielding body enclose a box structure with a sealed cavity, and metal sand is enclosed in the sealed cavity; the darkroom shielding body is used to connect a single-core wire coated with a metal shielding layer and allow the single-core wire with the metal shielding layer stripped to pass through the sealed cavity and enter the darkroom, the metal shielding layer section of the single-core wire is in contact with the darkroom shielding body, so as to consume interference signals through the conductive plane formed by the darkroom shielding body, the metal shell and the metal sand.

[0006] Optionally, the metal shell is a rectangular funnel-shaped structure with an opening, and the darkroom shielding body covers the opening of the metal shell to form the sealed cavity.

[0007] Optionally, the five planes of the metal shell are made of the same metal material.

[0008] Optionally, the five planes of the metal shell are made of galvanized steel sheets.

[0009] Optionally, the metal shell and the darkroom shielding body are fixed by metal screws.

[0010] Optionally, the metal sand has a resistivity of less than 9.78×10 -8 Ω·m material.

[0011] Optionally, the particle diameter of the metal sand is less than or equal to 2 mm.

[0012] Optionally, the metal shell, the darkroom shielding body and the metal sand are in conductive contact with each other.

[0013] Optionally, the metal shielding layer is a wire shielding layer made of conductive metal.

[0014] Optionally, a portion of the single-core wire located in the sealed cavity is not covered with the wire shielding layer.

[0015] Through the above technical scheme, a conductive plane is formed by a metal shell, a darkroom shielding body and metal sand. When an external interference signal is coupled into the metal shielding layer of the single-core conductor, the interference signal will eventually flow into the constructed conductive plane and be consumed, and will not enter the radio wave darkroom. This ensures that various useful signals on the conductor enter the radio wave darkroom smoothly, and prevents other interference signals from entering the radio wave darkroom, thereby meeting the relevant requirements for multiple signals on the same line to enter the darkroom.

[0016] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0018] Figure 1 It is a device structure diagram of a filtering device for multiple signals entering a darkroom through a single line, provided in one embodiment of the present invention.

[0019] Description of Reference Numerals

[0020] 10-metal casing; 20-darkroom shielding body; 30-metal shielding layer; 40-metal sand; 50-single-core conductor. DETAILED DESCRIPTION

[0021] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0022] Figure 1 This is a device diagram of a filtering device for multiple signals entering a darkroom through a single line provided by an embodiment of the present invention. Figure 1 As shown, an embodiment of the present invention provides a filtering device for multiple signals entering a darkroom through a single line, which is applied to filtering when multiple signals enter the darkroom through a line at the same time. The device comprises: a metal shell 10; a darkroom shielding body 20; the metal shell 10 and the darkroom shielding body 20 are enclosed to form a box structure with a sealed cavity, and the sealed cavity is enclosed with metal sand 40; the darkroom shielding body 20 is used to connect a single-core wire 50 coated with a metal shielding layer and allow the single-core wire 50 with the metal shielding layer stripped to pass through the sealed cavity and enter the darkroom, and the metal shielding layer section of the single-core wire 50 is in contact with the darkroom shielding body, so as to consume interference signals through the conductive plane formed by the darkroom shielding body 20, the metal shell 10 and the metal sand 40.

[0023] In the embodiment of the present invention, the darkroom has significant significance in the field of measurement. In order to avoid the deviation of the measurement results caused by external electromagnetic wave radiation, the device to be tested is placed in a darkroom that shields external electromagnetic waves for testing, so that the device to be tested is not affected by the external electromagnetic environment during the test process, and all test results are related to the device to be tested itself. Therefore, in addition to the shielding performance of the darkroom shell itself, in order to avoid the influence of interference signals in the power and communication signals that power and transmit signals to the device to be tested on the test results, preferably, based on the special requirements of the darkroom for the electromagnetic environment, all power and communication signals entering the darkroom must be filtered accordingly before entering the darkroom and being used by the test product during the test process.

[0024] In the prior art, when the power signal enters the darkroom, it is generally filtered by installing a power filter, while when various communication signals enter the darkroom, they enter by photoelectric conversion. When the power signal and the communication signal enter the darkroom independently, independent corresponding interference signal processing will have a better effect. However, when multiple signals of different frequency bands are superimposed on a line at the same time, for example, when a single-core wire is used to carry both the power signal and the carrier signal, there is no corresponding filtering method available. The main reason is that the existing filters used for darkroom construction can only filter signals of a single frequency band, such as the power filter commonly used in the darkroom construction process. The power filter is a passive bidirectional network, which is essentially a low-pass filter. It allows DC or 50Hz power signals to flow through, but does not allow high-frequency signals to flow through. However, the photoelectric conversion technology for high-frequency communication signals cannot convert low-frequency electrical signals into optical signals.

[0025] The solution of the present invention is based on the fact that the existing technology cannot realize the simultaneous transmission of low-frequency and high-frequency multiple frequency points or frequency band signals on the same line while ensuring that interference signals are prevented from entering the darkroom. A filtering device for multiple signals entering the darkroom through a single line is proposed, which is used for filtering when multiple signals enter the darkroom through one line at the same time.

[0026] Shielded grounding is a grounding method that makes a permanent and good electrical connection between the shielding body and the ground or the metal shell of the interference source in order to prevent electromagnetic interference. It has the ability to consume interference signals and is not affected by the frequency of the processed signal. It is highly applicable to the processing of a single-core conductor 50 with multiple frequency signals superimposed. The scheme of the present invention is constructed based on shielded grounding, creating a "ground" on the line through which the signal flows, that is, a conductive plane for consuming interference signals. Therefore, the scheme of the present invention proposes a filtering device based on metal sand 40. The reason for choosing metal sand 40 as the main conductive plane material is determined based on electromagnetic shielding theory.

[0027] Specifically, electromagnetic shielding refers to the use of components made of conductive materials or ferromagnetic materials to shield the ends of the stator core of large-capacity steam turbine generators to reduce the additional losses and local heating caused by the leakage magnetic flux of the stator winding ends in the structural parts. In terms of communication, shielding is the metal isolation between two spatial regions to control the induction and radiation of electric fields, magnetic fields and electromagnetic waves from one region to another. Specifically, it is to surround the interference source of components, circuits, assemblies, cables or the entire system with a shielding body to prevent the interference electromagnetic field from spreading outward; and to surround the receiving circuit, equipment or system with a shielding body to prevent them from being affected by the external electromagnetic field. When selecting electromagnetic shielding materials, because electromagnetic waves decay quickly in good conductors, the thickness from the conductor surface to 1 / e (about 36.8%) of the surface value is called the skin thickness (also known as the penetration depth), which is represented by d. The selection formula is:

[0028] SE R =168-101lg(fu r / σ r )

[0029]

[0030] Among them, u r is the relative magnetic permeability of the shielding material relative to air; σ r is the relative conductivity of the shielding material relative to copper; f is the electromagnetic wave frequency. Because the frequencies of most electromagnetic wave interference signals in space are less than 5 GHz, 5 GHz is used for estimation when selecting materials. Then λ / 20 is 3 mm, so the pure metal sand 40 with a diameter of 2 mm fully meets the requirement of s < λ / 20 in the electromagnetic field shielding theory. S is the gap size. Based on this, the selected metal sand 40 only needs to meet this condition to achieve the requirements for interference signal processing. Therefore, as long as the diameter of the selected metal sand 40 is less than or equal to 2 mm, it can meet the requirements for most interference signal processing.

[0031] Preferably, the metal shell 10 is a rectangular funnel-shaped structure with an opening, and the darkroom shielding body 20 covers the opening of the metal shell 10 to form the sealed cavity; the five planes of the metal shell 10 are made of the same metal material.

[0032] In an embodiment of the present invention, in order to store the metal sand 40, a corresponding container needs to be created. And in order to avoid affecting the conductive properties, the material of the corresponding container also needs to be a metal with good conductive properties. Preferably, the five planes of the metal shell are made of galvanized steel plates. Galvanized steel plates are welded steel plates with hot-dip or electroplated zinc layers on the surface. They are widely used and are mainly used for parts of small household appliances that require a good appearance. Because it has good plasticity and conductivity, it becomes an excellent grounding material. The manufacture of metal shells using galvanized steel plates not only reduces the manufacturing difficulty, but also improves the performance of consuming interference signals.

[0033] Preferably, the metal shell 10 is an open shell, and except for the top, the other five surfaces are covered by the same metal. The reason for setting it as an open shell is to facilitate the storage and removal of the metal sand 40. When the metal sand 40 needs to be replaced, the open shell is more convenient to use.

[0034] Preferably, the metal shell 10 and the darkroom shielding body 20 are fixed by metal screws.

[0035] In the real-time example of the present invention, it is impossible to keep the shell open during actual use, which may cause the metal sand 40 to leak during handling and use. Therefore, after the metal sand 40 is stored, the metal shell needs to be packaged. The anechoic chamber shielding body 20 is used to open and package the metal shell 10. In order to ensure the conductivity of the entire conductive plane, it is necessary to ensure that the anechoic chamber shielding body 20 is in conductive contact with the metal shell 10. Therefore, preferably, when fixing the anechoic chamber shielding body 20, it is fixed with metal screws with good conductivity. In order to ensure the conductive contact between the anechoic chamber shielding body 20 and the metal sand 40, if the surface of the anechoic chamber shielding body 20 is painted, before fixing the anechoic chamber shielding body 20, it is first necessary to polish the contact part between the anechoic chamber shielding body 20 and the metal sand 40, so that the conductive layer of the anechoic chamber shielding body 20 is exposed and in conductive contact with the metal sand 40.

[0036] Preferably, the metal sand 40 has a resistivity of less than 9.78×10 -8 Ω·m material.

[0037] In the embodiment of the present invention, in order to ensure that the metal sand 40 has sufficient conductivity and ensure timely processing of interference signals, preferably, the resistivity of the metal sand 40 needs to be less than a preset threshold. After adaptive training, the maximum resistivity value is set to 9.78×10-8Ω·m.

[0038] Preferably, the metal shell 10, the darkroom shielding body 20 and the metal sand 40 are in conductive contact with each other. The metal shielding layer is a wire shielding layer made of conductive metal.

[0039] In the embodiment of the present invention, although the metal sand 40 is the main grounding material, the metal shell 10 and the anechoic chamber shield 20 in contact therewith are both ideal shielding bodies. Therefore, these three parts are selected from materials with good conductive properties, and then connected through conductive contact, so that the three form a unified conductive plane, thereby improving the interference signal absorption performance of the conductive plane.

[0040] The conductive plane obtained above is used to filter the interference signal in the wire before it flows into the darkroom. Therefore, the single-core wire 50 is the carrier of the conductive signal, including signals with multiple frequencies stacked. Among them, the core wire of the wire is the main carrier of the electrical signal. In order to prevent the core wire of the wire from directly contacting the outside world, the surface of the core wire of the wire is covered with a layer of wire insulation layer. When the electrical signal flows through the conductive plane, the coupled interference signal needs to flow into the conductive plane for consumption. Therefore, in the conductive plane, in order to ensure that the interference signal enters the conductive plane smoothly, the single signal line segment connected to the conductive plane is no longer provided with a wire shielding layer. In order to avoid interference of the external magnetic field on the signal core wire in the place not connected to the conductive plane, a metal shielding layer 30 needs to be provided. The portion of the single-core wire located in the sealed cavity is not covered with the metal shielding layer 30.

[0041] In the embodiment of the present invention, after the single-core wire 50 flows through the conductive plane, the interference signal therein is completely consumed. In order to avoid the external magnetic field from being re-coupled into the single signal line, the single signal line is connected to the darkroom after passing through the conductive plane. The distance between the darkroom and the conductive plane can be reduced, and the processing effect and use effect of the conductive signal can be improved.

[0042] Those skilled in the art will understand that all or part of the steps in the method for implementing the above-mentioned embodiments can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions for making a single-chip microcomputer, a chip or a processor (processor) perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0043] The optional embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept of the embodiments of the present invention, the technical scheme of the embodiments of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0044] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. A filtering device for multiple signals entering a darkroom through a single line, characterized in that: The device comprises: The metal shell and the darkroom shielding body are combined to form a box structure with a sealed cavity, and the sealed cavity is filled with metal sand; wherein, The metal shell is a rectangular funnel-shaped structure with an opening, and the darkroom shielding body covers the opening of the metal shell to form the sealed cavity; The five planes of the metal shell are made of the same metal material; The five planes of the metal shell are made of galvanized steel sheets; The metal shell and the darkroom shielding body are fixed by metal screws; The metal sand has a resistivity of less than 9.78×10 -8 Ω·m materials; The particle diameter of the metal sand is less than or equal to 2 mm; Darkroom shielding body; The darkroom shielding body is used to connect a single-core wire coated with a metal shielding layer and allow the single-core wire with the metal shielding layer stripped off to pass through the sealed cavity and enter the darkroom. The cross-section of the metal shielding layer of the single-core wire is in contact with the darkroom shielding body to consume interference signals through the conductive plane formed by the darkroom shielding body, the metal shell and the metal sand.

2. The device according to claim 1, characterized in that The metal shell, the darkroom shielding body and the metal sand are in conductive contact with each other.

3. The device according to claim 1, characterized in that The metal shielding layer is a wire shielding layer made of conductive metal.

4. The device according to claim 3, characterized in that The portion of the single-core wire located in the sealed cavity is not covered with the wire shielding layer.

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