Abstract: Provided is a power amplifier installed in wireless communication terminals and systems. According to one aspect of the present invention, a reconfigurable power amplifier capable of selecting a wide band frequency is provided. The reconfigurable power amplifier includes input transistors receiving a radio frequency (RF) signal and a reconfigurable adaptive power cell configured to select the wide band frequency by applying a common-gate bias voltage to a plurality of common-gate transistors with a plurality of separate common gates to amplify the RF signal.

Abstract: Exemplary embodiments of the present invention relate to an RF transmitter supporting carrier aggregation and envelope tracking and an RF transmitter according to an embodiment of the present invention comprises an RF path configured to convert a carrier aggregation signal in which a plurality of component carriers belonging to a baseband are aggregated into an RF signal; an ET path configured to generate an envelope signal by calculating magnitudes of the plurality of component carriers, respectively, and adding the calculated each magnitude of the component carriers; and an amplifier configured to power-amplify the converted RF signal according to a bias voltage corresponding to the generated envelope signal. According to exemplary embodiments of the present invention, power amplification efficiency and data transmission efficiency are improved by applying carrier aggregation and envelope tracking.

Abstract: The present invention relates to a single frequency synthesizer based FDD transceiver. A single frequency synthesizer generates and provides a carrier frequency so that frequency up-conversion and frequency down-conversion can be performed at the time of transmission and reception. Accordingly, the area, power consumption, and design complexity of the entire system can be reduced, and the performance of the system can be improved.

Abstract: A secret key generation apparatus and method are provided. The secret key generation apparatus includes at least one antenna, amplification/phase controllers, a transceiver, and a random signal controller. The antenna receives a wireless signal from a counterpart terminal that performs wireless communication. The amplification/phase controllers control the amplification gain and phase of the wireless signal that is received via at least one antenna. The transceiver measures the status of a wireless channel using the wireless signal having the controlled amplification gain and phase, determines parameters based on results of the measurement, and generates a secret key based on results of the determination. The random signal controller controls the amplification/phase controllers so that the amplification gain and phase are adjusted whenever the transceiver generates a secret key.

Abstract: An apparatus includes a user input unit, a display unit, a control unit, and a buffer unit. The display unit includes a speed setting menu. The control unit selects a mode from the speed setting menu in response to the selection signal of the user, and controls a compression ratio of a voice codec and a transfer rate of a modem corresponding to a transmission-side radio, and a reception rate of a modem and a restoration rate of a voice codec corresponding to a reception-side radio, based on the selected mode. The buffer unit performs a storage function if there is a difference between the compression ratio of the voice codec and the transfer rate of the modem or if there is a difference between the reception rate of the modem and the restoration rate of the voice codec.

Abstract: Disclosed is an interpolation filter based on time assignment algorithm. An interpolation filter comprises an enable signal generating part generating enable signals for operation of the interpolation filter, an input value generating part generating input values, a first calculating part generating a first output value based on a first enable signal and a first input value, a second calculating part generating a second output value based on a second enable signal and a second input value, and an output value selecting part selecting a final output value among the first output value and the second output value. Thus, continuity of output data can be guaranteed, and hardware can be shared by using time assignment algorithm so that a total size of the interpolation filter can be reduced.

Abstract: An information protection system includes a mobile terminal and an encryption module. The mobile terminal requests a key sequence by transmitting a message including a Personal Identification Number (PIN) number input by a user, and encrypts or decrypts one or more communication signals, including voice signals and data signals, based on the key sequence when the key sequence is received. The encryption module is connected to the mobile terminal. The encryption module encrypts a security key using the identifier and the PIN number of the mobile terminal, decrypts the encrypted security when requested by the mobile terminal, and transmits the key sequence generated based on the decrypted security key to the mobile terminal.

Abstract: A WCDMA 3G voice communication protection method and a terminal using the method are provided. The method is performed by a terminal operating in conjunction with an S-USIM for voice communication protection. When a calling terminal connects a voice communication channel to a called terminal, secure voice communication is prepared for by collecting information about relevant voice communication. At the calling terminal, synchronous data is set by exchanging the voice communication information with the called terminal, and a secure synchronization procedure is performed based on the set synchronous data. At each of S-USIMs that operate in conjunction with the calling and called terminals, a session key for secure voice communication is generated based on the synchronous data. Secure communication is performed by encrypting and transmitting voice-coded data to be transmitted based on the session key, and decrypting and reproducing received voice-coded data based on the session key.

Abstract: A digital RF converter, a digital RF modulator, and a transmitter are provided. The digital RF converter includes a delta-sigma modulated bits (DSMB) sub-block that generates a current magnitude corresponding to least-significant n bits among input signals at a first sampling speed, a least-significant bit (LSB) sub-block that generates a current magnitude corresponding to intermediate k bits among the input signals at a second sampling speed lower than the first sampling speed, and a most-significant bit (MSB) sub block that generates a current magnitude corresponding to most-significant m bits among the inputs signals at the second sampling speed.

Abstract: Provided is a digital analog converter that output currents having different magnitudes for a digital input value according to a mapping table. The digital analog converter includes: a plurality of current sources; and a calibration unit configured to sort index values for identifying the plurality of current sources according to current magnitudes of the current sources, couple each two current sources which are symmetrical left and right about the center of the sorted index values, and map the current source pairs into a mapping table.

Abstract: A secret key generation apparatus and method are provided. The secret key generation apparatus includes at least one antenna, amplification/phase controllers, a transceiver, and a random sign& controller. The antenna receives a wireless signal from a counterpart terminal that performs wireless communication. The amplification/phase controllers control the amplification gain and phase of the wireless signal that is received via at least one antenna. The transceiver measures the status of a wireless channel using the wireless signal having the controlled amplification gain and phase, determines parameters based on results of the measurement, and generates a secret key based on results of the determination. The random signal controller controls the amplification/phase controllers so that the amplification gain and phase are adjusted whenever the transceiver generates a secret key.

Abstract: A WCDMA 3G voice communication protection method and a terminal using the method are provided. The method is performed by a terminal operating in conjunction with an S-USIM for voice communication protection. When a calling terminal connects a voice communication channel to a called terminal, secure voice communication is prepared for by collecting information about relevant voice communication. At the calling terminal, synchronous data is set by exchanging the voice communication information with the called terminal, and a secure synchronization procedure is performed based on the set synchronous data. At each of S-USIMs that operate in conjunction with the calling and called terminals, a session key for secure voice communication is generated based on the synchronous data. Secure communication is performed by encrypting and transmitting voice-coded data to be transmitted based on the session key, and decrypting and reproducing received voice-coded data based on the session key.

Abstract: The present invention provides a signal input device of a digital-RF converter including: a phase-modulated signal input unit configured to input a phase-modulated carrier signal to an LO switch of a digital-RF converter; and a digital signal input unit configured to correct a digital signal to correspond to the phase-modulated carrier signal, and input the corrected digital signal to a data switch of the digital-RF converter.

Abstract: Disclosed is a programmable complex mixer. In accordance with the embodiments of the present invention, it is possible to control an output by programming paths and signs of internal signals in a complex mixer to reduce a processing bandwidth, power consumption, and a chip area in a transceiver, thereby improving performance of a transceiver.

Abstract: The present invention relates to a single frequency synthesizer based FDD transceiver. A single frequency synthesizer generates and provides a carrier frequency so that frequency up-conversion and frequency down-conversion can be performed at the time of transmission and reception. Accordingly, the area, power consumption, and design complexity of the entire system can be reduced, and the performance of the system can be improved.

Abstract: An information protection system includes a mobile terminal and an encryption module. The mobile terminal requests a key sequence by transmitting a message including a Personal Identification Number (PIN) number input by a user, and encrypts or decrypts one or more communication signals, including voice signals and data signals, based on the key sequence when the key sequence is received. The encryption module is connected to the mobile terminal. The encryption module encrypts a security key using the identifier and the PIN number of the mobile terminal, decrypts the encrypted security when requested by the mobile terminal, and transmits the key sequence generated based on the decrypted security key to the mobile terminal.

Abstract: An all digital phase-locked loop (ADPLL) includes: a phase counter accumulating a frequency setting word value and the phase of a digitally controlled oscillator (DCO) clock and detecting a fine phase difference between a reference clock and a retimed clock; a phase detector detecting a digital phase error value compensating for a phase difference between the frequency setting word value and the DCO clock according to the fine phase difference to detect a digital phase error value; a digital loop filter filtering the digital phase error value and controlling PLL operational characteristics; a lock detector generating a lock indication signal according an output of the digital loop filter; a digitally controlled oscillator varying the frequency of the DCO clock according to the output from the digital loop filter; and a retimed clock generator generating the retimed clock by retiming the DCO clock at a low frequency.

Abstract: A voice transmission apparatus is provided. The voice transmission apparatus includes a voice input unit, an Analog-to-Digital (AD) converter, a transmission synchronization unit, a channel status determination unit, and a transmission unit. The voice input unit receives an analog voice signal corresponding to a communication session. The AD converter converts the analog voice signal into a digital signal. The transmission synchronization unit generates a transmission target signal by respectively assigning a start identifier and an end identifier to the first frame and final frame of the digital signal corresponding to the communication session. The channel status determination unit determines the status of a channel. The transmission unit transmits the transmission target signal over the channel in such a way that the transmission rate of the transmission target signal is set on a communication session basis depending on the status of the channel.

Abstract: Provided are a digital radio frequency (RF) converter and an RF converting method thereof. The RF frequency converter includes first and second RF output terminals of a differential form outputting an RF signal; a differential switch selectively connecting first and second nodes into the first and second RF output terminals in response to an oscillating waveform; at least one digital delay device column outputting a plurality of unit bits by sequentially delaying an input bit corresponding to the digital input signal; a front-end processor summing an output of the at least one digital delay device column; a plurality of current sources; and a plurality of first switches corresponding to the plurality of current sources, respectively, and delivering currents of current sources whose number corresponds to the sum value of the front-end processor among the plurality of current sources, to one of the first and second nodes.

Abstract: Provided is a digital analog converter that output currents having different magnitudes for a digital input value according to a mapping table. The digital analog converter includes: a plurality of current sources; and a calibration unit configured to sort index values for identifying the plurality of current sources according to current magnitudes of the current sources, couple each two current sources which are symmetrical left and right about the center of the sorted index values, and map the current source pairs into a mapping table.