Patent application number | Description | Published |
20080298228 | Transmitting/Receiving Apparatus of Wideband Wireless Channel Apparatus Using Multiple Carriers - The present invention relates to transmitting/receiving apparatuses of a wideband radio channel measuring device using a multi-carrier. The wideband radio channel measuring device using the multi-carrier may measure radio channel characteristics at a frequency domain. Since the radio channel is measured at the frequency domain by the wideband radio channel measuring device using the multi-carrier, the channel characteristics may be simultaneously measured while maintaining a maximum Doppler measurement frequency at a predetermined level regardless of increase of the number of transmitting and receiving antennas, in an MIMO configuration. | 12-04-2008 |
20090117867 | SCALABLE BANDWIDTH SYSTEM AND METHOD OF CONTROLLING TUNABLE FILTER - The present invention relates to a scalable bandwidth system and a method of controlling a tunable filter. In the present invention, the scalable bandwidth system inputs, as a control signal of a tunable filter, a voltage corresponding to a section in which the capacitance according to an applied voltage is not practically changed for characteristics of varactor diodes, and inputs each control bit of the control signal to each varactor diode of the tunable filter to adjust the capacitance of each of the varactor diodes, and consequently adjusts the capacitance of the tunable filter by adding the capacitance of the varactor diodes. | 05-07-2009 |
20090140813 | RECEIVED SIGNAL GAIN CONTROL METHOD AND RADIO FREQUENCY SIGNAL RECEIVING APPARATUS - A radio signal receiving apparatus receiving a radio signal over a radio channel generates a first amplified signal by amplifying the radio signal with a first gain, and determines the first gain by measuring the strength of the first amplified signal. In addition, the radio signal receiving apparatus generates a down-converted signal by frequency down-converting the first amplified signal, and generates a second amplified signal by amplifying the down-converted signal with a second gain. In addition, the radio signal receiving apparatus determines the second gain by measuring the strength of the second amplified signal. | 06-04-2009 |
20090140821 | APPARATUS AND METHOD FOR COMPENSATING CARRIER FEEDTHROUGH IN QUADRATURE MODULATION SYSTEM - The present invention relates to an apparatus and a method for compensating carrier feedthrough in a quadrature modulation system. In order to suppress the carrier feedthrough, and minimize and compensate the carrier feedthrough, differences of baseband differential input DC voltages in an in-phase as well as a quadrature-phase are simultaneously adjusted to 0 or a certain slight voltage difference by a simple analog circuit. Therefore, it is possible to suppress carrier feedthrough using a simple analog type apparatus for compensating carrier feedthrough, and simply achieve an apparatus for carrier feedthrough using a variety of quadrature modulators. | 06-04-2009 |
20090154617 | AUTOMATIC GAIN CONTROL DEVICE, SIGNAL RECEIVING APPARATUS, AND SIGNAL RECEIVING METHOD - A signal receiving apparatus according to an embodiment of the present invention includes: an amplifier that controls a gain according to a gain control signal and amplifies a received signal to generate an amplified signal; an analog-to-digital (A/D) converter that converts the amplified signal into a digital signal; a Fourier transform unit that performs Fourier transform of the digital signal to a frequency domain signal to generate a Fourier transform signal; a demodulator that demodulates the Fourier transform signal to generate a demodulated signal; and an automatic gain control unit that divides the Fourier transform signal into a noise period and a symbol period, calculates the signal level of the noise period based on the signal level of the symbol period, and generates the gain control signal according to the signal levels of the symbol period and the noise period. Accordingly, when a non-cyclic burst signal is received, the non-cyclic burst signal is divided into a signal presence period and a signal absence period, and the gain is only controlled by using the signal presence period. Therefore, accuracy of the signal level can be secured, and the signal level of the symbol can be calculated in the frequency domain, thereby reducing complexity. | 06-18-2009 |
20100118744 | WIRELESS TRANSCEIVER SYSTEM FOR SUPPORTING DUAL MODE - The present invention relates to a wireless transceiver system for supporting a dual mode, and more particularly to a wireless transceiver system for supporting a dual mode that simultaneously supports the Frequency Division Duplex (FDD) method and the Time Division Duplex (TDD) method in a certain frequency band. The present system supports the FDD system conducting transmission and reception simultaneously by using different frequency bands for transmission and reception as well as the TDD system temporally alternating transmission and reception by using the common frequency band among an upper frequency band and a lower frequency band used in the FDD system as well as another frequency band adjacent thereto, thereby selectively supporting both of the two communication systems in a wireless transceiver system. Therefore, efficient use of various wireless communication standards and the limited frequency resource is provided, and on this basis, an efficient application of all wireless transceiver systems adopting the TDD system and the FDD system as well as the mobile communication base station and the terminal is provided. | 05-13-2010 |
20100135421 | APPARATUS AND METHOD FOR REDUCING PEAK TO AVERAGE POWER RATION IN ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEM - An apparatus for reducing PAPR (Peack to Average Power Ratio) in an OFDM (Orthogonal Frequency Division Multiplexing) system includes: an IFFT (Inverse Fast Fourier Transform) unit for performing an IFFT on an input data stream modulated using a specific constellation to generate time-domain signals; a time-domain clipping unit for performing a time-domain clipping on the time-domain signals at a clipping level determined by characteristics of the time-domain signals; an FFT (Fast Fourier Transform) unit for performing an FFT on the clipped time-domain signals to generate frequency-domain signals; and a frequency-domain clipping unit for performing a frequency-domain clipping on the frequency-domain signals. The time-domain clipping reduces in the OFDM system, and the frequency-domain clipping reduces distortions generated by the time-domain clipping. | 06-03-2010 |
20100146021 | MODULAR-3 CALCULATION APPARATUS AND METHOD - A modular-3 calculation method for binary number includes: determining whether two 1s consecutive from MSB exist in a binary number, when a target value for modular-3 calculation is inputted, and generating a first binary number by substituting the two 1s with 0 whenever the consecutive two 1s exist; performing a modular-3 calculation on the first binary number; and determining the result of the modular-3 calculation. | 06-10-2010 |
20110059707 | BIAS MODULATION APPARATUS, AND APPARATUS AND METHOD FOR TRANSMITTING SIGNAL FOR WIDEBAND MOBILE COMMUNICATION USING THE SAME - In a wideband mobile communication system, a signal transmitting apparatus separates an envelope curve signal which is size information and a phase signal which is phase information from a signal to transmit, and compares the envelope curve signal with a predetermined voltage. The signal transmitting apparatus performs active bias control that amplifies and outputs an envelope curve signal according to different driving voltages based on a comparison result, and supplies a bias voltage to a power amplifier that amplifies a phase signal based on the amplified signal. | 03-10-2011 |
20110063026 | PRE-DISTORTION APPARATUS OF POWER AMPLIFIER AND METHOD THEREOF - A pre-distortion apparatus of a power amplifier includes: a pre-distortion unit configured to generate a pre-distorted signal of an input signal by calculating a magnitude of the input signal and outputting a complex correction coefficient corresponding to the calculated magnitude of the input signal, and provide the generated pre-distorted signal as an input of the power amplifier; and a complex correct coefficient update unit configured to generate an error signal by comparing an output signal of the power amplifier with the input signal and updating the complex correction coefficient to minimize a magnitude of the generated error signal, wherein the pre-distortion unit provides a constant bias value corresponding to the magnitude of the input signal as a bias of the power amplifier while updating the complex correction coefficient. | 03-17-2011 |
20110063030 | CMOS VARIABLE GAIN AMPLIFIER - A complementary metal-oxide semiconductor (CMOS) variable gain amplifier includes: a cascode amplifier including a common source field effect transistor and a common gate field effect transistor in a cascode structure; a first current generation unit connected in parallel to a drain of the common gate field effect transistor and configured to vary transconductance of the cascode amplifier; a second current generation unit connected to a common source of the cascode amplifier and configured to control a bias current of the cascode amplifier; a current control unit configured to generate a current control signal for the first and second current generation units; and a load stage connected in series to a drain of the cascode amplifier and configured to output an output current, which is varied by the overall transconductance of the cascode amplifier, as a differential output voltage. | 03-17-2011 |
20110063035 | CONTROLLED-GAIN WIDEBAND FEEDBACK LOW NOISE AMPLIFIER - Provided is controlled-gain wideband feedback low-noise amplifier. The controlled-gain wideband feedback low-noise amplifier includes: a feedback amplifier configured to isolate an input signal and an output signal obtained by amplifying the input signal, feed back the output signal to the input signal to amplify wideband input signals, resonate a low-frequency band signal among the wideband input signals to amplify the low-frequency band signal among the wideband input signals, and be switched in accordance with a control signal to control an amplification gain of the low-frequency band signal among the wideband input signals; and a cascode amplifier configured to amplify a high-frequency band signal among the wideband signals inputted from the feedback amplifier, and be switched in accordance with a control signal to control an amplification gain of the high-frequency band signal among the wideband signals. | 03-17-2011 |
20110128079 | MULTI-BAND POWER AMPLIFIER WITH HIGH-FREQUENCY TRANSFORMER - A multi-band power amplifier in a wireless communication system includes: a plurality of matching circuits connected in parallel to an output stage of the power amplifier and corresponding to a plurality of different operation frequencies, respectively; and a plurality of high-frequency amplifiers connected to the plurality of matching circuits, respectively. The plurality of high-frequency amplifiers are selectively operated depending on the operation frequencies. Each of the high-frequency amplifiers may include a plurality of stages. Each of the matching circuits may include a high-frequency transformer. | 06-02-2011 |
20110140746 | DUAL-BAND WIDEBAND LOCAL OSCILLATION SIGNAL GENERATOR - A dual-band wideband local oscillation signal generator includes an oscillation unit, a division unit, a poly phase filter (PPF), a switch unit, and a single side band (SSB) mixer. The oscillation unit is configured to generate a positive in-phase (IP) signal, a negative in-phase (IN) signal, a negative quadrature-phase (QN) signal, and a positive quadrature-phase (QP) signal. The division unit is configured to divide frequencies of the IP signal and the IN signal and generate an RF signal. The PPF is configured to receive the IP signal and the IN signals inputted to the division unit, and generate an LO IP signal, an LO IN signal, an LO QP signal, and an LO QN signal. The switch unit is configured to receive the generated LO signals and select a high band frequency signal or a low band frequency signal. | 06-16-2011 |
20110150139 | CALIBRATION METHOD FOR Tx/Rx PATH CHARACTERISTIC OF CHANNEL SOUNDER - The method includes performing a wired back-to-back test by forming M wired paths connecting one of the N transmission antennas with the M reception antennas through M cables, separating i | 06-23-2011 |
20110151775 | REPEATING APPARATUS AND METHOD IN WIRELESS COMMUNICATION SYSTEM - A repeating apparatus in a wireless communication system includes: a signal detection unit configured to receive a signal from a base station or a mobile station and detect strength of the signal; a control unit configured to compare the signal strength detected by the signal detection unit with signal strength predetermined by the system and provide comparison information; and an output signal control unit configured to receive the comparison information from the control unit and adjust and amplify gain of a signal transmitted to the base station or the mobile station. | 06-23-2011 |
20110237210 | APPARATUS AND METHOD FOR CONTROLLING GAIN OF POLAR TRANSMITTER - Disclosed is an apparatus for transmitting complex signals in a wireless communication system. The present invention, there is provided a method for controlling gain according to a magnitude change of output signals in a polar transmitter including an amplification unit having two or more amplification degrees, the method includes processes to control an output level of a modulated signal when a output-required power of transmission signals are less than a predetermined threshold value, and to perform a basic amplification through the amplification unit; to amplify the amplification unit at a first amplification level when the output-required power of the transmission signals is equal to or greater than a predetermined first threshold value and is less than a predetermined second threshold value; and to amplify the amplification unit at a second amplification level when the output-required power of the transmission signal is equal to or greater than the second threshold value. | 09-29-2011 |
20110312370 | METHOD AND APPARATUS FOR SUPPORTING DISCONTINUOUS OPERATION OF BASE STATION IN WIRELESS COMMUNICATION SYSTEM AND CONTROL SYSTEM THEREOF - An operation control method in a base station of a wireless communication system includes: checking whether or not an allowed mobile station exists in coverage of the base station and overall coverage of base stations adjacent to the base station; and controlling the base station to perform transmission/reception at a predetermined period through a first discontinuous operation, when the allowed mobile station does not exist in the coverage of the base station and the overall coverage of the adjacent base stations. | 12-22-2011 |
20120154040 | PREDISTORTER FOR COMPENSATING FOR NONLINEAR DISTORTION AND METHOD THEREOF - The predistorter may include: a predistortion filter predistorting an input signal to provide an output signal; a predistortion output estimation unit estimating the characteristics of a nonlinear device based on a signal processed by the nonlinear device and the output signal, and calculating a desired output signal of the predistortion filter by using the estimated characteristics of the nonlinear device; and an adaptive algorithm driving unit comparing the output signal with the desired output signal to output an error as a comparison result, calculating a filter coefficient according to which the calculated error is minimized, and providing the calculated filter coefficient to the predistortion filter in order to update a filter coefficient of the predistortion filter. | 06-21-2012 |
20120182836 | COMMUNICATION SYSTEM USING ULTRASONIC WAVES - Disclosed is a technology for performing a communication using an ultrasonic wave in an environment where an electromagnetic shielding is so severe that a wireless communication using an electromagnetic is difficult. In the environment where the electromagnetic shielding is severe, an ultrasonic terminal according to the present invention may transmit the ultrasonic wave using a solid structure as a medium, and an ultrasonic base station may receive the ultrasonic wave using the solid structure as the medium. | 07-19-2012 |
20130163690 | METHOD FOR TRANSMITTING SIGNAL OF ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING TYPE, AND APPARATUS APPLIED TO THE SAME - The method for transmitting a signal of an orthogonal frequency division multiplexing type according to an exemplary embodiment of the present invention has a configuration allowing a radio unit (RU) to perform a component adding a compression component and a decompression component before/after a serial interface interlocking between a digital unit (DU) and the radio unit (RU) and a component inserting a cyclic prefix (CP) into a signal so as to secure orthogonality of an orthogonal frequency division multiplexing (OFDM) signal, in a structure in which a base station is physically divided into the DU and the RU. | 06-27-2013 |
20130251055 | APPARATUS AND METHOD FOR CONTROLLING DISTORTION SIGNAL AND SYSTEM BY USING THE SAME - Disclosed are a signal distortion component adjusting apparatus and method capable of adjusting error vector magnitude of subcarriers of a predetermined position by adjusting a signal distortion component occurring while decreasing a peak to average power ratio (PAPR) in a communication system of an orthogonal frequency division multiplexing (OFDM) technology or an orthogonal frequency division multiple access (OFDMA) scheme, and a system using the same. The present invention includes a signal distortion component adjusting unit to add an additional signal distortion component Pe((n+N/2) % N) to a signal distortion component e(n) that is obtained by subtracting a threshold Th value, set to decrease peak power, from an absolute value of a time domain signal x(n) of an input signal, and to thereby adjust the signal distortion component. The present invention may transmit a highly reliable signal by adjusting error vector magnitude of subcarrier of a frequency domain. | 09-26-2013 |
20140064355 | DELTA-SIGMA MODULATOR AND TRANSMITTER INCLUDING THE SAME - A delta-sigma modulator and a transmitter apparatus including the same are disclosed. The delta-sigma modulator includes a first integrator, a second integrator, a first comparator configured to compare an output signal of the second integrator and a reference signal, and output a first comparison signal, a second comparator configured to compare the output signal of the second integrator and the reference signal, and output a second comparison signal, a first DAC configured to output the first signal corresponding to the first comparison signal and the second comparison signal, a second DAC configured to output the second signal corresponding to the first comparison signal and the second comparison signal, a delayer configured to generate a delayed signal that delays the first comparison signal and the second comparison signal by a predetermined time, and an output DAC configured to generate an output signal having a multi-level corresponding to the delayed signal. | 03-06-2014 |
20140085016 | LOCK DETECTER AND CLOCK GENERATOR HAVING THE SAME - A lock detector and a clock generator including the same are disclosed. A lock detector includes a counter unit which counts a non-matching section of a first signal and a second signal to provide a count value, the first signal and the second signal being comparison result signals obtained by comparing a phase of a reference signal with a phase of a comparison signal, and a lock detection unit which outputs a lock detection signal based on a result of comparing the count value with the reference value. Accordingly, a lock state of the phase-locked loop can be detected rapidly and exactly. | 03-27-2014 |
20140118045 | APPARATUS FOR CONTROLLING DUTY RATIO OF SIGNAL - Disclosed is an apparatus for controlling a duty ratio of a signal that includes a clock control unit configured to generate a plurality of control signals based on an input signal, a half-cycle generation unit configured to generate a multiplied signal by use of the input signal and a delay signal that is obtained by delaying the input signal based on a delay control voltage, and divide the multiplied signal to generate a first division signal and a second division signal that are in inverse relation to each other, a comparator unit configured to compare a pulse width of the first division signal with a pulse width of the second division signal based on the control signal provided by the clock control unit, and output a delay control signal corresponding to a result of the comparison, and a control voltage generation unit configured to output a delay control voltage. | 05-01-2014 |
20140159700 | BANDGAP REFERENCE VOLTAGE GENERATOR - Disclosed is a bandgap reference voltage generator insensitive to changes of process, voltage, and temperature. A bandgap reference voltage generator may detect current having characteristic of CTAT and current having characteristic of PTAT which flow in a current compensation part included in an amplification part, and provide body voltage to one of two input transistors included in the amplification part in response to ratio of the two currents when the ratio is different from the preconfigured reference value. Thus, characteristics according to changes of parameters of elements and change of offset of the amplification part due to changes of PVT may be enhanced, and a characteristic of power supply rejection ratio (PSRR) may be enhanced. | 06-12-2014 |