Abstract: Provided is a multiband low noise amplifier including a first transistor, an input matching circuit, and a first capacitor. The first transistor includes a collector electrically connected to a first power supply, a grounded emitter, and a base connected to the other end of a first inductor having one end as an input end of the low noise amplifier. The input matching circuit is connected between the collector and the base of the first transistor. The first capacitor connected to the collector of the first transistior. The input matching circuit includes a varactor. The input matching circuit includes a second capacitor connected to the varactor. The input matching circuit includes a first resistor connected to the varactor. In the multiband low noise amplifier, a varactor having a variable capacitance is installed at an input end, thereby easily performing band switching through bias voltage control by a small amount and minimizing noises that may be caused by a control signal.

Abstract: An active inductor capable of tuning a self-resonant frequency, an inductance, a Q factor, and a peak Q frequency by applying a tunable feedback resistor to a cascode-grounded active inductor is disclosed. The tunable active inductor includes a first transistor having a source connected to a power supply voltage and a gate connected to first bias voltage; a second transistor having a drain connected to a drain of the first transistor and a gate connected to a second bias voltage; a third transistor having a drain connected to a source of the second transistor and a source connected to a ground voltage; a fourth transistor having a drain connected to a gate of the third transistor, a source connected to the ground voltage and a gate connected to a third bias voltage; a fifth transistor having a source connected to the drain of the fourth transistor and a drain connected to the power supply voltage.

Abstract: A method of channel coding a digital communication system and a device using the same is provided. The method includes quantizing analog data to digital data, the digital data corresponding to a predetermined number of digital codes; allocating channel codes to the digital codes, as a Hamming distance between a pair of channel codes corresponding to any pair of the digital codes is proportional to a difference between analog values of the pair of the digital codes; and channel coding the digital data by using the channel codes which are allocated to the digital codes to generate channel coded digital data. Accordingly, digital data, such as multimedia digital data without source coding and the like, of which information significance is different may be effectively transmitted and received.

Abstract: Disclosed is a mobile terminal with plural antennas. The mobile terminal with plural antennas, comprising a circuit board formed with a variety of elements, at least one first antenna formed on one surface of the circuit board to transmit and receive a radio signal for mobile communications, and at least one second antenna formed on the other surface of the circuit board to transmit and receive a radio signal for additional services. Accordingly, as the size of the mobile terminal does not necessarily increase to have plural antennas, the mobile terminal can be miniaturized.

Abstract: A mobile terminal is provided having an radio frequency identification (RFID) function and includes an antenna which transmits and receives a radio signal; a radio frequency identification matching circuit which changes an operating band of the antenna to a frequency band where an RFID radio signal is input and output; a communication module which processes a mobile communication radio signal transmitted and received via the antenna; and a switch which connects the antenna to either the communication module or the RFID matching circuit according to whether an RFID function is used or not. Accordingly, the compactness of the mobile terminal can be realized, and the RFID communication performance can be enhanced.

Abstract: A wireless communication system and a method for reducing a ranging time. The communication system includes a main synchronization block group which processes the transceived signal and determines whether the transceived signal is a signal desired by a transmitting device when a receiving device re-transmits the transceived signal to the transmitting device; a ranging block which measures a distance between the transmitting device and the receiving device using a ranging signal when the transceived signal is the desired signal of the transmitting device based on the determination of the main synchronization block group and when the transceived signal is the ranging signal; and a symbol synchronization block which detects a start point and an end point of a symbol forming the signal when the transceived signal from the receiving device is a data communication signal. Accordingly, the fast ranging is feasible and channel occupation time can be shortened.

Abstract: A PPB-CM communication system and method. The PPB-CM communication system includes a transmitter which splits a symbol period, which is a transmission unit of a communication signal, into at least a pair of parts, inserts a data signal into one of the parts, and transmits a communication signal having the data signal inserted; and a receiver which receives the communication signal from the transmitter and determines bit information of the symbol period according to which part of the symbol period has the data signal inserted, as determined by comparison of energy levels of the parts. Accordingly, a separate threshold is not required to determine the data bit of the symbol period. Thus, the communication signal can be accurately determined. Also, the communication system can be simply implemented without need of a delay line.

Abstract: A communication system which transmits and receives a communication signal having an intra-guard-interval (IGI) inserted is provided. The communication system includes a signal generator which is configured to generate a signal to carry data; and a signal output part which is configured to split a symbol period, which is a transmission unit of the communication signal into a plurality of sections, and to selectively insert the signal which is generated into the plurality of sections, and to output the communication signal.

Abstract: A communication system using a length shift keying (LSK) modulation method provides a transmitter having a carrier signal generator for generating carrier signals, and a modulator for modulating lengths of the carrier signals from the carrier signal generator according to combinations of data bits, and a receiver having an integrator for calculating an energy value by integrating the carrier signal that corresponds to a data bit combination, and a data judgment unit for judging the data bit combination by comparing the energy value with a predetermined threshold value. Power is maintained without changing the bandwidth of a communication signal when the communication signal is modulated.

Abstract: An adjustable chaotic signal generator using pulse modulation for UWB communications, and a chaotic signal generating method thereof are provided. The chaotic signal generator for UWB communications includes a plurality of pulse generators which generates pulses of different frequencies; at least one combiner which combines the pulses generated at the pulse generators; and a plurality of local oscillators which receives signals from the combiner, respectively, and generates a chaotic signal by increasing the received signals to different frequency bands. Accordingly, a plurality of users can conduct the radio communications in a specific wireless communication range at the same time by generating the chaotic signal that can be split to the multiple channels. Also, the chaotic signal generator is structured using devices integratable on an integrated circuit.

Abstract: A communication system includes a transmitter having a signal generator for generating a signal for transmitting data, a transmission delay unit for repeatedly delaying the signal from the signal generator for a predetermined delay time within a symbol period and generating corresponding delayed signals, and a selector for selectively providing one of the delayed signals from the transmission delay unit to an antenna; and a receiver having a reception delay unit for receiving the signal from the transmitter and delaying the signal as long as the delay time of the transmission delay unit, and a data judgment block for discriminating data bits of the signal from the transmitter by comparing the signal from the transmitter with the delayed signal from the reception delay unit. According to the communication system, the delay time can be accurately adjusted even if the delay line is shortened, and the data bits of the communication signal can be accurately judged in the receiver side.

Abstract: An antenna for a slide-type wireless terminal device includes a radiator formed in a first body, a ground surface formed on a second body, a power feeder connected to the ground surface in the second body, a first connection part connected to the radiator in the first body and operative to come in contact with the power feeder when the first body is slidably moved, and a short-circuit wire operative to come in contact with the radiator and the ground surface when the first body is slidably moved.

Abstract: A small broadband monopole antenna including a shorted patch and a probe with a strip line that are electromagnetically coupled with each other. The probe with a strip line has a length of about ?/4, where ? is a wavelength. The strip line may be one of a spiral type, a folded type and a helix type. A resonance frequency of the antenna can be adjusted by varying the inductance and the capacitance of the resonance circuits. In addition, a double-band antenna or a single-band antenna having a broad bandwidth can be designed in accordance with application purpose of the antenna.

Abstract: A subharmonic mixer, including an amplification unit for amplifying an input signal using at least one pair of amplification devices connected in parallel and a mixing unit for mixing the amplified signal with local oscillation signals from local oscillators is provided. The mixing unit performs switching over the amplification devices and at least four pairs of switching devices connected in parallel with each other, two pairs of switching devices being connected in parallel with each other and performing switching over one amplification device. The switching devices are supplied with local oscillation signals having different phases respectively, and two switching devices forming a pair are connected in parallel with each other and supplied with local oscillation signals having a 180° phase difference therebetween. Accordingly, the switching stage is formed with one stage, the operation is enabled with low-voltage power supplies, and noise performance, linearity, and gain are enhanced.

Abstract: In a non-volatile memory device having a relatively high operation performance and a method of manufacturing the same, a substrate may be prepared to include an active region on which a conductive structure is located and defined by a field region in which an isolation layer is formed. A tunnel oxide layer may be formed on the active region of the substrate. A floating gate pattern may be formed on the tunnel oxide layer, and may include a lower part having a first width that is formed on the tunnel oxide layer and an upper part having a second width that is formed on the lower part, where the second width is substantially smaller than the first width. A dielectric layer pattern may be formed on the floating gate pattern, and a control gate pattern may be formed on the dielectric layer pattern. Accordingly, the non-volatile memory device may have an improved efficiency in programming and erasing data.

Abstract: A diode circuit having a passive element property, and an impedance modulator and a direct current (DC) source that use the diode circuit are provided. The diode circuit includes a first diode that generates a predetermined DC and alternating currents (AC) when a radio frequency (RF) signal is applied; and a DC path that is connected in parallel to the first diode, forms a predetermined loop and circulates the DC current within the loop. The DC path includes an inductor or an LC parallel resonator. The DC path includes a second diode that is disposed in the opposite direction to the first diode and connected to the first diode in parallel. The present invention can relieve difficulty in designing an RF circuit.

Abstract: A transmitter and a signal amplifier are provided. The signal amplifier includes a digital-to-analog converter converting an input digital signal into an analog signal, a local oscillator signal generator outputting in-phase and quadrature-phase oscillator signals, a first mixer mixing the analog signal with the in-phase local oscillator signal to output an in-phase high frequency signal, a second mixer mixing the analog signal with the quadrature-phase local oscillator signal to output a quadrature-phase high frequency signal, a main amplifier amplifying the in-phase high frequency signal output from the first mixer, and an auxiliary amplifier amplifying the quadrature-phase high frequency signal output from the second mixer.

Abstract: A small broadband monopole antenna having a perpendicular ground plane with an electromagnetically coupled feed is provided. The small broadband monopole antenna may be realized as a small antenna having a size of 0.085?0×0.085?0×0.085?0 by positioning a folded strip line under a shorted square disc. A resonance of the shorted square disc may be coupled to a resonance of the square folded strip line so as to form a wide bandwidth of about 36.6% of a central frequency of 2.313 GHz based on a VSWR?2. Also, rectangular slits may be inserted into the perpendicular ground plane to improve a distortion of a radiation pattern that forms on the perpendicular ground plane so as to reduce a backward radiation by 3 dBi or more. The small broadband monopole antenna exhibits a forward radiation pattern similar to that of a general monopole antenna and has a gain of about 2.6 dBi within a bandwidth.

Abstract: An apparatus and method for self-calibrating mismatching orthogonal signals and non-linearity of a circuit occurring in a mobile transceiver. For this, in a mobile terminal, a transmitter is used as a signal generator and a receiver is used as a response characteristic measurer. A base band processor calibrates mismatching signals and non-linearity in a reception side and a transmission side, based on a test signal received via the transmitter and a test signal received via the receiver.

Abstract: Provided is an apparatus and a method of measuring a distance between devices using a low clock frequency signal. The apparatus includes clock frequency generators, counters, a controller and a calculator for determining the distance based on clock signal overlap. Radio waves are transmitted and a number of clocks of a clock signal having a clock frequency b are counted, and if the transmitted radio waves are received again, a number of clocks of a clock signal having a clock frequency a are counted. If the clock signals having the clock frequencies a and b overlap with each other, counting of the numbers of the clocks of the clock signals having the frequencies b and a stops, and the distance is measured using the count values of the clock signals having the clock frequencies a and b. As a result, number of clocks of clock signals having low clock frequencies with a uniform difference can be counted to precisely measure a distance.