CN210536598U - Information leakage prevention filter - Google Patents

Abstract

The utility model discloses an information leakage prevention filter, which consists of a three-level filter circuit; the three-stage filter circuit is positioned in a closed rectangular shell with a cover plate, the cover plate is packaged by screws, three independent cavities are isolated in the rectangular shell by using shielding plates, each stage of filter circuit is positioned in the three cavities respectively, the cavities are isolated by using the shielding plates, common-mode capacitors CF1 and CF2 are arranged on the shielding plate between the two front cavities, common-mode capacitors CF3 and CF4 are arranged on the shielding plate between the two rear cavities, and the three-stage filter circuit is connected by the common-mode capacitors on the shielding plates; after input signals are input from the input port, the three-stage filter circuit carries out filtering processing step by step, interference signals are shielded and attenuated step by step in the totally closed cavity, and finally output from the output port, so that the optimal filtering effect is achieved.

Description

Information leakage prevention filter

Technical Field

The utility model belongs to the technical field of the wave filter, more specifically say, relate to a prevent information disclosure wave filter.

Background

The filter for preventing information leakage is mainly applied to military electronic equipment, along with the continuous development of military and scientific and technological levels in China, the requirements on the space size of the equipment and the performance of the equipment are higher and higher, and the internal data information is prevented from being transmitted to the outside of the equipment through being coupled to a power line to cause information leakage.

However, the existing common filter is usually a low-pass filter, and the performance of the common filter is limited, and in military electronic equipment, the common filter has a certain suppression effect on self-interference of a switching power supply of the equipment, but has a poor suppression effect on electromagnetic interference signals with higher frequency, and cannot realize wide-range effective filtering, so that information leakage cannot be effectively prevented, and the confidentiality of the equipment is improved.

Disclosure of Invention

An object of the utility model is to overcome prior art's is not enough, provides a prevent information disclosure wave filter, when carrying out interference protection to the interference signal of power and coupling, prevents through good shielding effect that information disclosure.

To achieve the above object, the present invention provides an information leakage prevention filter, comprising: cascaded three-level filter circuits;

the three-stage filter circuit is positioned in a closed rectangular shell with a cover plate, the cover plate is packaged by screws, three independent cavities are isolated in the rectangular shell by using shielding plates, each stage of filter circuit is positioned in the three cavities respectively, the cavities are isolated by using the shielding plates, common-mode capacitors CF1 and CF2 are arranged on the shielding plate between the two front cavities, common-mode capacitors CF3 and CF4 are arranged on the shielding plate between the two rear cavities, and the three-stage filter circuit is connected by the common-mode capacitors on the shielding plates; the left end of the rectangular shell is provided with an adapter which is used as the input end of the filter, the right end of the rectangular shell is provided with an output hole, an insulating medium is arranged on the output hole, the output end of the three-stage filter circuit is connected with an output lead, and the lead passes through the insulating medium and then is output;

the first stage filter circuit comprises a filter capacitor C1, a common-mode inductor L1, common-mode capacitors CF1 and CF 2;

an input power supply is connected to the filter through the adapter and then connected in series with the common-mode inductor L1, wherein the anode input end of the common-mode inductor L1 is connected with the anode of the input power supply, and the cathode input end of the common-mode inductor L1 is connected with the cathode of the input power supply; common-mode capacitors CF1 and CF2 are connected in series and then connected in parallel with the output end of the common-mode inductor L1, and the common end of the common-mode capacitors CF1 and CF2 is grounded;

the second stage of filter circuit comprises a filter capacitor C2, a common-mode inductor L2 and common-mode capacitors CF3 and CF 4;

the common-mode inductor L2 is connected in series after the common-mode inductor L1, and the filter capacitor C2 is connected in parallel at the input end of the common-mode inductor L2; common-mode capacitors CF3 and CF4 are connected in series and then connected in parallel with the output end of the common-mode inductor L2, and the common end of the common-mode capacitors CF3 and CF4 is grounded;

the third stage of filter circuit comprises a filter capacitor C3 and a common mode inductor L3;

the common-mode inductor L3 is connected in series behind the common-mode inductor L2, a filter capacitor C3 is connected in parallel with the input end of the common-mode inductor L3, and the positive output end and the negative output end of the common-mode inductor L3 are connected through a shielding wire and serve as the final output end of the filter;

the invention aims to realize the following steps:

the utility model relates to an information leakage prevention filter, which consists of a three-level filter circuit; the three-stage filter circuit is positioned in a closed rectangular shell with a cover plate, the cover plate is packaged by screws, three independent cavities are isolated in the rectangular shell by using shielding plates, each stage of filter circuit is positioned in the three cavities respectively, the cavities are isolated by using the shielding plates, common-mode capacitors CF1 and CF2 are arranged on the shielding plate between the two front cavities, common-mode capacitors CF3 and CF4 are arranged on the shielding plate between the two rear cavities, and the three-stage filter circuit is connected by the common-mode capacitors on the shielding plates; after input signals are input from the input port, the three-stage filter circuit carries out filtering processing step by step, interference signals are shielded and attenuated step by step in the totally closed cavity, and finally output from the output port, so that the optimal filtering effect is achieved.

The utility model relates to a prevent that information from revealing wave filter still has following beneficial effect:

(1) the common-mode capacitors CF1, CF2, CF3 and CF4 are connected among the cavities to replace the common y capacitor, so that the influence of high-frequency parasitic capacitance on the capacitance filtering effect is reduced, and the suppression loss of the CF1, CF2, CF3 and CF4 at the high-frequency end is far greater than that of the common y capacitor;

(2) the filtering frequency range is increased through a multi-stage filtering mode;

(3) the invention has the characteristics of simple structure, few components, high reliability, outstanding filtering performance and the like, and can effectively filter interference signals.

Drawings

Fig. 1 is a circuit diagram of an information leakage prevention filter according to the present invention;

fig. 2 is a structural diagram of the filter for preventing information leakage.

Detailed Description

The following description of the embodiments of the present invention is provided in order to better understand the present invention for those skilled in the art with reference to the accompanying drawings. It is to be expressly noted that in the following description, a detailed description of known functions and designs will be omitted when it may obscure the subject matter of the present invention.

Examples

Fig. 1 is a circuit diagram of the filter for preventing information leakage.

In the present embodiment, as shown in fig. 1, an information leakage prevention filter includes: a three-stage filter circuit;

as shown in fig. 2, the three-stage filter circuit is located in a closed rectangular housing with a cover plate, the cover plate is packaged by screws, three independent cavities are isolated by shielding plates in the rectangular housing, each stage of filter circuit is located in three cavities respectively, the cavities are isolated by shielding plates, common-mode capacitors CF1 and CF2 are mounted on the shielding plate between the first two cavities, common-mode capacitors CF3 and CF4 are mounted on the shielding plate between the last two cavities, and the three-stage filter circuit is connected by the common-mode capacitors on the shielding plates; the left end of the rectangular shell is provided with an adapter which is used as the input end of the filter, the right end of the rectangular shell is provided with an output hole, an insulating medium is arranged on the output hole, the output end of the three-stage filter circuit is connected with an output lead, and the lead passes through the insulating medium and then is output;

the first stage filter circuit comprises a filter capacitor C1, a common-mode inductor L1, common-mode capacitors CF1 and CF 2;

an input power supply is connected to the filter through the adapter and then connected in series with the common-mode inductor L1, wherein the anode input end of the common-mode inductor L1 is connected with the anode of the input power supply, and the cathode input end of the common-mode inductor L1 is connected with the cathode of the input power supply; common-mode capacitors CF1 and CF2 are connected in series and then connected in parallel with the output end of the common-mode inductor L1, and the common end of the common-mode capacitors CF1 and CF2 is grounded;

the first stage of filtering interference signals firstly filters differential mode interference through a capacitor C1, then filters common mode interference signals through a common mode inductor L1, and finally filters high-frequency common mode interference signals through common mode capacitors CF1 and CF 2.

The second stage of filter circuit comprises a filter capacitor C2, a common-mode inductor L2 and common-mode capacitors CF3 and CF 4;

the common-mode inductor L2 is connected in series after the common-mode inductor L1, and the filter capacitor C2 is connected in parallel at the input end of the common-mode inductor L2; common-mode capacitors CF3 and CF4 are connected in series and then connected in parallel with the output end of the common-mode inductor L2, and the common end of the common-mode capacitors CF3 and CF4 is grounded;

the second stage of filtering filters the residual interference signals through a capacitor C2 to remove differential mode interference, then filters the common mode interference signals through a common mode inductor L2, and finally filters the high-frequency common mode interference signals through common mode capacitors CF3 and CF 4.

The third stage of filter circuit comprises a filter capacitor C3 and a common mode inductor L3;

the common-mode inductor L3 is connected in series behind the common-mode inductor L2, a filter capacitor C3 is connected in parallel with the input end of the common-mode inductor L3, and the positive output end and the negative output end of the common-mode inductor L3 are connected through a shielding wire and serve as the final output end of the filter;

the third stage of filtering filters differential mode interference through a capacitor C3, then filters common mode interference signals through a common mode inductor L3, and finally achieves the complete interference suppression function.

In summary, after an input signal is input from the input port, the three-stage filter circuit performs stage-by-stage filtering processing, and in a fully-enclosed cavity, the interference signal is shielded and attenuated stage by stage, and finally the output port outputs the signal, so that the optimal filtering effect is achieved.

Although illustrative embodiments of the present invention have been described above to facilitate the understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the embodiments, and various changes may be made apparent to those skilled in the art as long as they are within the spirit and scope of the present invention as defined and defined by the appended claims, and all matters of the invention which utilize the inventive concepts are protected.

Claims (1)

1. An information leakage prevention filter, comprising: a three-stage filter circuit;

the three-stage filter circuit is positioned in a closed rectangular shell with a cover plate, the cover plate is packaged by screws, three independent cavities are isolated in the rectangular shell by using shielding plates, each stage of filter circuit is positioned in the three cavities respectively, the cavities are isolated by using the shielding plates, common-mode capacitors CF1 and CF2 are arranged on the shielding plate between the two front cavities, common-mode capacitors CF3 and CF4 are arranged on the shielding plate between the two rear cavities, and the three-stage filter circuit is connected by the common-mode capacitors on the shielding plates; the left end of the rectangular shell is provided with an adapter which is used as the input end of the filter, the right end of the rectangular shell is provided with an output hole, an insulating medium is arranged on the output hole, the output end of the three-stage filter circuit is connected with an output lead, and the lead passes through the insulating medium and then is output;

the first stage filter circuit comprises a filter capacitor C1, a common-mode inductor L1, common-mode capacitors CF1 and CF 2;

an input power supply is connected to the filter through the adapter and then connected in series with the common-mode inductor L1, wherein the anode input end of the common-mode inductor L1 is connected with the anode of the input power supply, and the cathode input end of the common-mode inductor L1 is connected with the cathode of the input power supply; common-mode capacitors CF1 and CF2 are connected in series and then connected in parallel with the output end of the common-mode inductor L1, and the common end of the common-mode capacitors CF1 and CF2 is grounded;

the second stage of filter circuit comprises a filter capacitor C2, a common-mode inductor L2 and common-mode capacitors CF3 and CF 4;

the common-mode inductor L2 is connected in series after the common-mode inductor L1, and the filter capacitor C2 is connected in parallel at the input end of the common-mode inductor L2; common-mode capacitors CF3 and CF4 are connected in series and then connected in parallel with the output end of the common-mode inductor L2, and the common end of the common-mode capacitors CF3 and CF4 is grounded;

the third stage of filter circuit comprises a filter capacitor C3 and a common mode inductor L3;

the common-mode inductor L3 is connected in series behind the common-mode inductor L2, a filter capacitor C3 is connected in parallel with the input end of the common-mode inductor L3, and the positive output end and the negative output end of the common-mode inductor L3 are connected through a shielding wire and serve as the final output end of the filter;

after input signals are input from the input port, the input signals are filtered step by step through the three-stage filter circuit, shielded and attenuated interference signals step by step in the totally closed cavity, and finally output from the output port.

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