KR102083096B1 - EMP filter with adjustable characteristic frequencies - Google Patents

Abstract

The present invention relates to a shielding filter which effectively prevents electromagnetic interference and, particularly, to a technology which can arbitrarily set a cutoff frequency in a field in accordance with transmission characteristics in the shielding filter that counteracts an electromagnetic pulse (EMP) and a transient electromagnetic pulse (TEMPEST). The shielding filter not only can be easily matched to the transmission characteristics in field construction after the shielding filter is manufactured, but also can be manually or automatically reset in accordance with changed transmission characteristics without replacing the shielding filter even when a change in the cutoff frequency is required in accordance with uses of lines or electronic equipment during use.

Description

EMP filter with adjustable characteristic frequencies

The present invention relates to a shielding filter that effectively prevents electromagnetic interference. In particular, the present invention is an advanced shielding filter technology optimized for high-frequency electromagnetic wave pulse prevention (EMP) and electromagnetic wave interception prevention (TEMPEST) construction.

In the field of electromagnetic interference, EMI, EMS and EMC are important variables.

Electromagnetic Interference (EMI) refers to a phenomenon in which electromagnetic waves incidentally generated from electronic equipment affect the operation of its own or other devices, and EMS (Electromagnetic Susceptibility) indicates that even if a certain degree of electromagnetic interference (EMI) occurs, The immunity to which an equipment can operate normally or to be protected from electromagnetic interference. Electromagnetic compatibility (EMC) is a term encompassing both and refers to electromagnetic compatibility.

Furthermore, by receiving a nuclear explosion in high altitude, the EMP (Electromagnetic Pulse), which disables the electronic equipment of the enemy country such as a computer by the strong electromagnetic waves from it, and receiving the noise generated from the electronic equipment of the enemy country, deciphering the signal component contained in the noise, the information of the other party TEMPEST is a technology that utilizes or exploits electromagnetic phenomena.

For civil purposes, EMI, EMS and EMC are the major considerations, while in the military, EMP and TEMPEST are the major considerations.

In particular, the military or important administrative agencies seal the entire communication room with metallic materials to protect important electronic equipment from the EMP. For this purpose, the doors to which humans enter and exit are based on the length, bending, and mechanical automatic In the process of opening and closing the door, the shielding filter is installed at the inlet and outlet of the power line and the inlet and outlet of the communication line. Waveguide theory is applied to the optical cable in the communication line, but UTP cable, which is a solid line, is inevitably connected as a so-called signal line filter combining L (coil) and C (capacitor). In the present invention, a combination of L and C is used to define a shielding filter to connect a solid twisted wire (UTP) to the shielding chamber and the outside, so that the detailed description and claims will be described.

If UTP solid line is connected to inside and outside of shield room without shielding filter, EMP, which is the electromagnetic interference signal, will flow into the room when EMP occurs. If the inlet is blocked without shielding filter, communication inside and outside of shielding room will be cut off. will be. Therefore, the shielding filter performs a function of mutually transmitting only a communication signal while preventing the EMP, which uses a selective open feature that blocks only this frequency since the EMP typically includes a frequency component of about 30 MHz to 1 GHz.

However, since EMP is generated even below 30MHz, the shielding filter for EMP aims at the EMS function to open only the desired frequency and cut off the remaining frequencies. For reference, the shielding filter formula applied by the US Department of Defense is 20logf-60dB, and the proper insertion loss is 60dB to 100dB. Recently, about 40dB is considered for civilian use, but the role of the shielding filter may be considered from 20dB.

The waveguide theory is that even if the shape of the through hole is physically formed, if the pipe is formed to be 6 times longer than the diameter of the through hole, EMP does not flow through the pipe.

EMP can be used as an EMI function for TEMPEST, in contrast, the shielding filter of the present invention can be commonly applied for EMP and TEMPEST.

Typically, the shielding filter is manufactured by setting the cutoff frequency at about 1.5 times the highest frequency, which is intended to satisfy only necessary transmission characteristics and to seal the remaining frequency bands. Unnecessarily widening the signal passing range of the shielding filter increases the likelihood of penetration of the EMP, so setting the cutoff frequency requires careful consideration. Here, the cutoff frequency may be determined by referring to, for example, a frequency characteristic in which the frequency characteristic of the shielding filter is 3 dB lower than a value for the reference frequency. Here, setting the cutoff frequency at about 1.5 times the maximum frequency is an example of a kind, and the present invention is not limited thereto.

The transmission frequency characteristics of the communication line (UTP cable) are based on the connection of the terminal, general telephone (3,4kHz, 64kbps), multifunction telephone (1,152kHz, 144kbps), ISDN telephone (128kbps), IP telephone (1 ~ 100Mbps). It is different from each other, and it is a line for voice signal such as microphone (20Hz ~ 20kHz), audio mixer (20Hz ~ 20kHz), speaker (20Hz ~ 20kHz), or different through RS-485 (10kHz). It is desirable to be set to have various passband characteristics. This passband characteristic is determined at the time of manufacturing the shielding filter mainly taking into consideration the construction site situation and the frequency characteristic of the signal line.

However, sometimes, a shielding filter with a characteristic of a general telephone (3,400 Hz) is ordered and delivered where a multi-function telephone (1,152KHz) should be installed, resulting in a problem of insufficient protection from EMP or signal transmission characteristics due to frequency characteristics. No action can be taken on site unless the filter is replaced. In particular, the replacement of a new filter has to be designed and manufactured at the factory again. Since this technology is a pure analog technology that requires reassembly of each component, unlike general digital technology, it takes a long time to correct it. Inevitably, large disruptions in construction, such as delays in construction period, will be inevitable.

Since the shielding filter is completely sealed in the metallic container, if the manufactured shielding filter is dismantled and remanufactured, the constants of L and C, which are the internal materials of the filter, are changed due to the temperature variation during the disassembly and assembly process. Replacement of the filter means substantially remanufactured after disposal.

In order to prevent this problem, if all the shielding filters are set to the highest frequency band (for example, multi-function phone frequency), the use of ordinary telephones leads to a problem of increasing the possibility of EMP penetration as it is extended to unnecessary bandwidth.

Therefore, there is a need to study a shielding filter having a new structure that can be arbitrarily changed in the cutoff frequency even in the construction site or the maintenance site even after installation in the field.

KR 10-1417473 B

The first object of the present invention is to dynamically match the transmission characteristics of the shielding filter with the frequency passing characteristics of the shielding filter by randomly changing the cutoff frequency at the time of construction after the shielding filter is manufactured.

The second object of the present invention is to prevent phenomena in which the use of electronic equipment is limited according to the characteristics of the shielding filter, and furthermore, thoroughly match the characteristics of the shielding filter with the signal characteristics to thoroughly respond to the response of EMP and TEMPEST. It's in the ship.

A third object of the present invention is to disclose a shielding filter technology for automatically adjusting band characteristics by detecting attenuation of a signal passing through the shielding filter.

To achieve the above technical problem

A network array unit including a plurality of time constant networks in which the range can be adjusted while restricting a signal passing through the first terminal and the second terminal to a predetermined frequency band through a combination of L and C in the shielding filter;

A network switching unit configured to set the plurality of time constant networks outside the shielding filter;

The first terminal and the second terminal is connected between the electronic equipment in the shielded room and the line outside the shielded room to operate the shielding filter, but adjust the pass frequency characteristics between the first terminal and the second terminal through the network switching unit. It is characterized by the configuration.

In addition, the cut-off frequency variable shielding filter according to the first embodiment of the present invention:

Inside the shielding filter, the signal passing through the first terminal and the second terminal is limited to a predetermined frequency band range through a combination of variable L and C, but a trimming structure in which the frequency band range can be adjusted to constitute a plurality of time constant networks. A network array unit;

A network trimming unit including a through knob to trim the network array unit in the shielding filter;

The first terminal and the second terminal are connected between the electronic equipment to be protected in the shielded room and a line outside the shielded room to operate the shielding filter, and adjust a pass frequency characteristic between the first terminal and the second terminal through the network streaming unit. It is characterized by a configuration that allows.

In the configuration of each embodiment, the network switching unit or the network trimming unit includes a configuration in which a relay is controlled by a switch set by a user, or a configuration in which a microprocessor senses and automatically controls an input / output terminal of a shielding filter as a sensing unit. Or a configuration achieved through a material change such as a mechanical switch, an electronic switch, or a magnetic field change.

According to the present invention, in particular, even after the shielding filter is manufactured in the shielding filter corresponding to the EMP and TEMPEST, the characteristics of the electronic equipment and the shielding filter can be easily matched according to the site situation, Even when the cutoff frequency is required according to the application, it can be easily reset to the changed transmission characteristics without replacing the shielding filter.

Furthermore, according to the present invention, a shielding filter for automatically setting and controlling a cutoff frequency by detecting a transmission state of normalized data is disclosed, and through this, it provides an effect of precisely controlling the cutoff frequency to minimize attenuation of a signal.

BRIEF DESCRIPTION OF THE DRAWINGS The figure explaining the structural principle of EMP shielding and the site | part in which a through filter is installed.
Fig. 2 is a diagram explaining an external circuit and an internal circuit structure of a through filter.
Figure 3 is a structural diagram and block diagram showing a through filter and the internal circuit of the present invention.
4 is a block diagram showing the configuration of the signal characteristics and the control unit of FIG.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that the present invention has been described as one part of all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

1 is a view explaining the structural principle of the EMP shielding and the site where the through filter is installed.

According to (a) of FIG. 1, the interior of the EMP protection target is a ceiling (1), a wall (2), and a floor (3), and the enclosed space in which the entire three-dimensional indoor area is welded with metal.

Figure 1 (b) shows the principle that the shielding filter 20 is inserted through the wall surface (2). Reference numeral 21 denotes an outward direction, and 22 denotes an inner direction, and is divided between the brackets 2a as an interface. In other words, (22) is the interior of the enclosed space surrounded by metal, and (21) means the outdoor located outside.

FIG. 2 is a view for explaining the external shape and the internal circuit structure of the shielding filter 20 penetrating the wall 2. As shown in FIG.

According to this, in the case of the signal line filter, the inside constitutes a network in which the inductors 22a-1, 22b-1 and 22a-2, 22b-2 and the capacitor 23 are combined, and this network transmits as shown in FIG. Characteristics. That is, the frequency characteristic of the shielding filter is manufactured by any one of a high pass filter (HPF), a low pass filter (LPF), a band pass filter (BPF), and a band eliminate filter (BEF). Each term is a well-known or well-known technical term in the information and communication field, and thus a detailed description thereof will be omitted.

However, as can be seen in Figure 2, the prior art is not provided with a means for changing it once produced. There is therefore a number of problems raised in the background, since the filter is made from a pure analog perspective and is made of a metallic container that is externally sealed from radio waves and magnetic waves to prevent the penetration of EMP.

3A and 3B are structural diagrams and block diagrams illustrating a through filter and an internal circuit of the present invention, and FIG. 4 is a block diagram illustrating signal characteristics of FIG. 3.

That is, the first embodiment of the present invention,

The first terminal 21 and the second terminal through the combination of the fixed inductors 22a-1, 22b-1, 22a-2 and 22b-2 and the capacitors 23a, 23b, 23c and 23d in the shielding filter 20. A network array unit 200 including a plurality of time constant networks in which the signal passing through the terminal 22 is limited to a predetermined frequency band range and the frequency band range can be adjusted;

A network switching unit 24 formed of a through-operation type switch to operate the network array unit in the shielding filter 20;

The shielding filter is operated by connecting the first terminal 21 and the second terminal 22 between the electronic device to be protected in the shielding chamber 2 and the line outside the shielding chamber, and operate the shielding filter through the network switching unit. This is a shielding filter with adjustable cut-off frequency setting that allows adjustment of the pass-frequency characteristics between two terminals.

Looking at the network switching section 24, the switches switch the connection between the plurality of inductors 22a-1, 22b-1, 22a-2, 22b-2 and the capacitors 23a, 23b, 23c, 23d. According to the switching, the time constant of the network switching unit 24 may vary. That is, the capacitance is variable so that the time constant can be adjusted. Here, a plurality of switches may be connected between a node between upper inductors 22b-1 and 22a-1 and a node between lower inductors 22b-2 and 22a-2.

3A and 3C are structural diagrams and block diagrams showing a through filter and an internal circuit of the present invention. Based on the second embodiment of the present invention,

Through the shielding filter 20, the first terminal 21 and the second terminal 22 pass through the combination of the variable inductors 25a-1, 25b-1, 25a-2, 25b-2 and the capacitor 23. A network in which a plurality of time constant networks are formed as inductors 25a-1, 25b-1, 25a-2, and 25b-2 of trimming structure in which the frequency band range can be adjusted while limiting a signal to a predetermined frequency band range. Array unit 200;

A network trimming part 25 including a through knob 24a, 24d to trim the network array part in the shielding filter 20;

The shielding filter is operated by connecting the first terminal 21 and the second terminal 22 between the electronic device to be protected in the shielding chamber 2 and the line outside the shielding chamber, and operate the shielding filter through the network streaming unit. This is a shielding filter with adjustable cut-off frequency setting that allows adjustment of the pass-frequency characteristics between two terminals.

In addition, in the configuration of the first embodiment

The network switching unit configured to adjust and set a pass frequency characteristic between the first terminal and the second terminal may include a configuration controlled by a relay contact.

That is, the network switching unit may be configured such that a relay contact is controlled by a switch set by a user, and the connection point of the inductor L and the capacitor C is linked to the relay contact. According to this, there is an effect of separating the control mechanism unit and the L / C network further away from the electromagnetic wave path.

In addition, the network switching unit may be configured to automatically set the plurality of time constant networks to an insertion loss range according to a passing frequency by connecting a band filter or the like to the network array unit so as to sense a signal passing through the shielding filter. Can be. By this structure, the shielding filter can be the most preferable configuration which sets the pass frequency band by itself rather than an operation by manpower. In the sensing of the bandwidth, the bandwidth of the set range may be maintained by transmitting a wideband signal including a required frequency and then detecting the bandwidth with a spectrum analyzer. Sensing may also be achieved with bandwidth sensing means capable of sensing the upper or lower frequency band. At this time, the bandwidth can usually be based on around -3dB point.

That is, the network switching unit controls the relay contact by detecting and analyzing the attenuation degree of the signal passing through the inside of FIG. 4 to control the relay contact. In order to achieve this, the shielding filter periodically transmits a signal of a promised band, and the microprocessor attenuates the frequency band by measuring the signal flatness of the band by a header or sweep search included in the signal band. By analyzing the degree of control, the set frequency of the shielding filter can be automatically set and controlled with the minimum attenuation.

The network switching unit may be achieved through a mechanical switch, an electronic switch, or a material change.

In the above configuration, the network trimming unit 25 may be externally set to a screw position by a driver or the like from the outside, or may be applied to the automatic control configuration of the microprocessor as described above via a posting means such as a motor. To this end, the through knob includes a configuration for manipulating a coil or a capacitor embedded in a shield tube made of metal. The penetrating knob includes a means corresponding to a metal shield between the internal element and the external control unit, or includes a through hole rather than the diameter of the through hole. Physical waveguide configurations of lengths of six times or more can be employed.

As mentioned earlier, EMP protection using waveguides is negligible for EMPs that penetrate into the interior if the length of the through hole (ie, the length of the waveguide) is six times longer than the diameter of the through hole, even if the through hole is physically open. The theory is that it is attenuated to a degree.

In each of the above configurations,

The signal passing through the first terminal and the second terminal includes a noisy signal scattered over a wide range, and limiting to a predetermined frequency band range means a band limitation that passes only a signal having a desired frequency range among the pass signals.

A plurality of time constant networks in which the frequency band range can be adjusted means a configuration in which the pass constant is changed by changing the time constant when the parameters of L and C are different.

The shielded room is a term that includes a room surrounded by metal or the like in order to prevent the inflow of radio waves or magnetic waves.

The electronic device to be protected is a term that includes a communication device for protection and a communication device for non-protection, and means a conference device such as an audio image or general information communication device.

In the present invention, the trimming refers to an adjustment to change from tight coupling to small coupling in order to change the induct value in the inductance composed of a ferrite core or the like. Execution adjustment can be accomplished manually with screws or automatically with a motor.

FIG. 3 (b) shows the configuration of the network switching unit 24 having different time constants by combining and changing a single inductance L and a plurality of capacitors C as necessary, and FIG. 3 (c). ) Shows the configuration of the network trimming unit 25 configured to combine the coil having a variable inductance and a single capacitor so that the time constant changes according to the inductance value which is changed as necessary, and thus the pass frequency of the shielding filter is adjusted.

In (b), it is advantageous to gradually switch the relay, and (c) is advantageous in linearly changing or changing the bandwidth such as adjusting the ferrite core by using a motor. Can be.

In this case, the sensing may be achieved through a spectrum analyzer, for example, or may be configured to measure the required bandwidth based on the value of the voltage induced in the pickup link coil installed at each upper limit of each frequency.

Each of the components disclosed in the above embodiments may be implemented in various embodiments within the scope of not exceeding the technical spirit of the present invention, and the technical spirit of the present invention is defined by the following claims.

The above-described embodiments of the present invention are disclosed for the purpose of illustration, and those skilled in the art having ordinary knowledge of the present invention may make various modifications, changes, and additions within the spirit and scope of the present invention. Should be considered to be within the scope of the following claims.

Interior Ceiling (1), Wall (2), and Floor (3)
Exterior of shielded filter (20)
Inductance L (22a-1, 22b-1 and 22a-2, 22b-2)
Capacitor C (23, 23a, 23b, 23c, 23d)
Outer side first terminal 21
Inner side second terminal (22)
L and C of network array part (22a-1, 22b-a, 22a-2, 22b-2, 23a, 23b, 23c, 23d)
Male positions 24a, 24b, 24c and 24d of the network switching unit
Network array unit 200 for determining the filter band frequency
Shielded Room (2)
Adjustable Variable Inductance (25a-1, 25b-1, 25a-2, 25b-2)
Knob (24, 25) with adjustable outside

Claims (6)

A network array unit configured to limit a signal passing through the first terminal and the second terminal to a preset frequency band range through a combination of fixed inductors and capacitors; And
A network switching unit having switches for switching a connection between the inductors and the capacitors and adjusting a time constant of the network array unit through switching of the switches,
The time constant is adjusted according to the switching of the switches to change the frequency characteristics of the signal passing through the first terminal and the second terminal,
Sensing the band of the signal and further comprising a sensing unit connected to the network array unit,
And a microprocessor connected to the sensing unit analyzing the attenuation in the band of the signal to automatically set and control the network switching unit. A network array unit configured to limit a signal passing through the first terminal and the second terminal to a preset frequency band range through a combination of a variable inductor and a capacitor; And
Including a network trimming unit having a through knob to be able to vary the inductance of the inductor of the network array unit by trimming,
According to trimming of the network array unit, a frequency characteristic of a signal passing through the first terminal and the second terminal may vary.
Sensing the band of the signal and further comprising a sensing unit connected to the network array unit,
And a microprocessor connected to the sensing unit analyzing the attenuation in the band of the signal to automatically set and control the network trimming unit. The method of claim 1, wherein the first and second terminals are connected between the electronic device to be protected in the shielded room and a line outside the shielded room to operate the shielding filter. Shielded filter. The method of claim 1,
The relay contact is controlled on-off by the switch,
The cutoff frequency setting adjustable shield filter, characterized in that the connection point of the inductor and the capacitor is interlocked with the relay contact. delete The method of claim 1,
The network switching unit cut-off frequency setting adjustable shielding filter, characterized in that it comprises a configuration to achieve through the mechanical switch, electronic switch or L / C variable capacity.

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