Abstract: A coupling clamp-type pulse injection apparatus, which can couple a high-voltage wideband pulse having a peak voltage of several tens of kV and having a rising time of several hundreds of ps or less to a cable without causing dielectric breakdown and a 50 ohm impedance mismatch, is provided. The pulse injection apparatus includes an input connector, an output connector, and a main body including an inner plate connected at a first end thereof to the input connector and at a second end thereof to the output connector, and a coupling plate connected to the inner plate and configured to fix a cable to the inner plate and to couple a high-power electromagnetic pulse input through the input connector to the cable.

Abstract: An antenna line protection device includes a pair of coaxial connectors and a streamer discharge module. The pair of coaxial connectors are disposed on both side ends of the antenna line protection device. The streamer discharge module is coupled between the coaxial connectors so that, when a pulse signal is input via the coaxial connectors, the streamer discharge module induces an electric field and thus establishes a discharge current channel, thereby suppressing an excessive input pulse.

Abstract: A stacked diode limiter, which can suppress and eliminate a malicious high-power electromagnetic pulse signal and an Intentional Electromagnetic Interference (IEMI) signal that are input to the antenna line of a wireless system and that include a communication service frequency component having a power of several kW or more, includes a stacked diode unit including one or more diode stack parts formed on a center electrode of a coaxial line formed between an input connector and an output connector, each diode stack part being configured such that a plurality of diodes are arranged in series and stacked on top of one another, and an impedance matching unit for configuring dielectrics between the connectors and the coaxial line as heterogeneous dielectrics and matching impedances between the connectors and the coaxial line.

Abstract: A vent structure for electromagnetic shielding includes: a conductive shielding case having a vent formed therein: a conductive shielding duct installed on the shielding case so as to cover the vent, including a space formed perpendicular to the direction of motion of air discharged from the vent to vent the air and a discharge port connected from the space to the outside to discharge the air introduced into the space to the outside, and shielding electromagnetic waves; and an EMI (Electro Magnetic Interference) gasket installed at a bonding surface between the shielding case and the shielding duct, and electrically connecting the shielding case and the shielding duct.

Abstract: An antenna line protection device includes a pair of coaxial connectors and a streamer discharge module. The pair of coaxial connectors are disposed on both side ends of the antenna line protection device. The streamer discharge module is coupled between the coaxial connectors so that, when a pulse signal is input via the coaxial connectors, the streamer discharge module induces an electric field and thus establishes a discharge current channel, thereby suppressing an excessive input pulse.

Abstract: A coupling clamp-type pulse injection apparatus, which can couple a high-voltage wideband pulse having a peak voltage of several tens of kV and having a rising time of several hundreds of ps or less to a cable without causing dielectric breakdown and a 50 ohm impedance mismatch, is provided. The pulse injection apparatus includes an input connector, an output connector, and a main body including an inner plate connected at a first end thereof to the input connector and at a second end thereof to the output connector, and a coupling plate connected to the inner plate and configured to fix a cable to the inner plate and to couple a high-power electromagnetic pulse input through the input connector to the cable.

Abstract: The coaxial cable includes a central conductor, a cable dielectric formed along the outer circumferential surface of the central conductor, and a protruding central conductor configured to protrude from one side of the central conductor and be exposed from the cable dielectric. The diameter of the central conductor is equal to the outer diameter of an end of a transition electrode formed on one side of a connector inner electrode. The connector includes a connector inner electrode configured to be selectively coupled to and separated from a coaxial cable having a central conductor, and provided with a transition electrode on one side thereof, and a connector dielectric formed along the outer circumferential surface of the connector inner electrode. The outer diameter of an end of the transition electrode is equal to the diameter of the central conductor of the coaxial cable.

Abstract: A stacked diode limiter, which can suppress and eliminate a malicious high-power electromagnetic pulse signal and an Intentional Electromagnetic Interference (IEMI) signal that are input to the antenna line of a wireless system and that include a communication service frequency component having a power of several kW or more, includes a stacked diode unit including one or more diode stack parts formed on a center electrode of a coaxial line formed between an input connector and an output connector, each diode stack part being configured such that a plurality of diodes are arranged in series and stacked on top of one another, and an impedance matching unit for configuring dielectrics between the connectors and the coaxial line as heterogeneous dielectrics and matching impedances between the connectors and the coaxial line.

Abstract: A waveguide feedthrough for broadband electromagnetic wave attenuation is provided in an electromagnetic wave shielding structure, in which data processing and communication devices are installed, so that a plurality of optical cables or the like which are connected to data processing and communication devices are led into the electromagnetic wave shielding structure through the waveguide feedthrough. Thereby, broadband electromagnetic waves generated from external other devices can be prevented from entering the electromagnetic wave shielding structure. For this, the waveguide feedthrough includes a waveguide feedthrough body which is made of conductive material and has a through hole therein, and an electromagnetic wave absorber which is provided on an inner side surface of the through hole.

Abstract: An apparatus for preventing leakage of a weak signal from a speaker is provided. The apparatus passes a normal speaker drive signal coming through speaker signal lines and blocks a weak signal generated by the sounds around the speaker, thereby preventing wiretapping the speaker.

Abstract: A surge protection apparatus is provided. The surge protection apparatus includes a non-linear element unit, a signal generation unit, and a switching element unit. The non-linear element unit enables an electrical surge to pass therethrough by rapidly decreasing resistance of the non-linear element unit when the difference in voltage between two ends of the non-linear element unit is equal to or greater than a predetermined value. The signal generation unit generates a control signal in response to current which passes through the non-linear element unit. The switching element unit switches the status thereof in response to the control signal.

Abstract: A vent structure for electromagnetic shielding includes: a conductive shielding case having a vent formed therein: a conductive shielding duct installed on the shielding case so as to cover the vent, including a space formed perpendicular to the direction of motion of air discharged from the vent to vent the air and a discharge port connected from the space to the outside to discharge the air introduced into the space to the outside, and shielding electromagnetic waves; and an EMI (Electro Magnetic Interference) gasket installed at a bonding surface between the shielding case and the shielding duct, and electrically connecting the shielding case and the shielding duct.

Abstract: A surge protection apparatus is provided. The surge protection apparatus includes a non-linear element unit, a signal generation unit, and a switching element unit. The non-linear element unit enables an electrical surge to pass therethrough by rapidly decreasing resistance of the non-linear element unit when the difference in voltage between two ends of the non-linear element unit is equal to or greater than a predetermined value. The signal generation unit generates a control signal in response to current which passes through the non-linear element unit. The switching element unit switches the status thereof in response to the control signal.

Abstract: Provided is a device for preventing eavesdropping through a speaker. More particularly, a device for preventing eavesdropping by transmitting a jamming signal through a speaker common signal line is provided, the device including: a jamming signal generator for generating a jamming signal comprising a noise signal; an amplifier for amplifying the jamming signal; and a transformer for receiving the amplified jamming signal from the amplifier and outputting the amplified jamming signal to a speaker common signal line. The device may transmit a jamming signal in an audible frequency band to the speaker common signal line, thereby rendering conversations unrecognizable to eavesdroppers when an electrical signal induced from a speaker is detected through the speaker common signal line.

Abstract: An apparatus for preventing leakage of a weak signal from a speaker is provided. The apparatus passes a normal speaker drive signal coming through speaker signal lines and blocks a weak signal generated by the sounds around the speaker, thereby preventing wiretapping the speaker.

Abstract: Various methods, systems, and apparatuses in which a wavelength-division-multiplexing passive-optical-network includes a first broadband light source and a second broadband light source. The first broadband light source supplies an optical signal containing a first band of wavelengths to a first plurality of optical transmitters. The second broadband light source supplies an optical signal containing a second band of wavelengths to a second plurality of optical transmitters. A fiber is used for bi-directional transmission of optical signals in at least two different wavelength bands.

Abstract: Provided is an apparatus for preventing eavesdropping using a piezoelectric film. The apparatus includes a vibrator including the piezoelectric film, conductive layers connected to top and bottom surfaces of the piezoelectric film, and electrodes connected to the conductive layers, and a noise signal generator electrically connected to the vibrator to generate and transmit an electrical noise signal to the vibrator. The vibrator generates vibration in a solid body in close contact with itself in response to the electrical noise signal.

Abstract: An optical transmitter has a resonance wavelength characteristic that varies with the refractive index of the optical transmitter. The optical transmitter receives a narrow band injected wavelength signal from an incoherent light source. The controller substantially matches a resonant wavelength of the optical transmitter to the wavelength of the injected wavelength signal by changing the refractive index of the optical transmitter to substantially match the resonant wavelength of the optical transmitter and the wavelength of the injected wavelength signal. A detector measures a parameter of the optical transmitter to provide a feedback signal to a controller to determine when the resonant wavelength of the optical transmitter and the wavelength of the injected wavelength signal are substantially matched.

Abstract: Provided is a device for preventing eavesdropping through a speaker. More particularly, a device for preventing eavesdropping by transmitting a jamming signal through a speaker common signal line is provided, the device including: a jamming signal generator for generating a jamming signal comprising a noise signal; an amplifier for amplifying the jamming signal; and a transformer for receiving the amplified jamming signal from the amplifier and outputting the amplified jamming signal to a speaker common signal line. The device may transmit a jamming signal in an audible frequency band to the speaker common signal line, thereby rendering conversations unrecognizable to eavesdroppers when an electrical signal induced from a speaker is detected through the speaker common signal line.

Abstract: Various methods, systems, and apparatuses is described in which a passive-opticalnetwork includes a first multiplexer/demultiplexer, a second multiplexer/demultiplexer, a wavelength tracking component, and a transmission wavelength controller. The first multiplexer/demultiplexer is located in a first location. The second multiplexer/demultiplexer is located in a second location remote from the first location. The wavelength tracking component determines the difference between the transmission band of wavelengths of the first multiplexer/demultiplexer and the second multiplexer/demultiplexer to provide a control signal to match the transmission band of wavelengths of the first multiplexer/demultiplexer and the second multiplexer/demultiplexer. The transmission wavelength controller alters an operating parameter of the first multiplexer/demultiplexer based on the control signal to control the transmission band of wavelengths of the first multiplexer/demultiplexer.