Abstract:
본 발명은 송신 누설 신호를 상쇄하기 위한 RFID 읽기 장치에 관한 것이다. 본 발명은 상기 송신 누설 신호의 크기와 위상을 계산하고, 그 결과를 저장하고 있는 디지털부; 및 상기 디지털부의 제어에 응답하여, 상기 송신 누설 신호를 상쇄하기 위한 누설 상쇄 신호를 발생하는 누설 상쇄 회로를 포함한다. 본 발명에 의하면, 송신 전력의 손실 없이 송신 누설 전류를 상쇄할 수 있다. 그리고 본 발명은 디지털부의 제어에 의해 송신 누설 전류를 상쇄하기 때문에 전력 소비를 줄일 수 있다.
Abstract:
A method for controlling a resonance frequency of a near field communications (NFC) device that includes a resonance unit to transmit and receive data through electromagnetic waves and an NFC chip comprises the following steps: detecting whether an NFC card or NFC reader exists around the NFC device; setting a resonance frequency of the resonance unit as a first optimal frequency based on the magnitude of a voltage generated from the resonance unit while a carrier wave is radiated to the NFC card through the resonance unit when the NFC card is detected; and setting a resonance frequency of the resonance unit as a second optimal frequency based on at least one of the magnitude of a voltage generated from the resonance unit in response to an electromagnetic wave received from the NFC reader and the magnitude of an inner current generated from the NFC chip in response to the electromagnetic wave received from the NFC reader when the NFC reader is detected. The method can independently set a resonance frequency as an optimal frequency with respect to each of a reader mode and a card mode.
Abstract:
A near field communications (NFC) antenna matching network system connected to an NFC transceiver is provided. The NFC antenna matching network system comprises a source coil connected between a first terminal and a second terminal of the NFC transceiver; and a resonant coil physically separated from the source coil.
Abstract:
The present invention discloses a clock generator and a clock generating method. The clock generator according to the present invention includes a reference clock generating part receiving a carrier signal, a multiplexer receiving an output signal of a phase locking loopand an output signal of the reference clock generating part, the phase locking loopreceiving its output signal and an output signal of the multiplexer, and a pause detecting part receiving the carrier signal and outputting a section detection signal to the multiplexer. According to the invention, even in a pause section of the carrier signal, a clock signal without a distortion can be generated by using the phase locking loop (PLL) and the multiplexer (MUX). [Reference numerals] (110) Reference clock generating part;(132) Phase detection part;(134) Charge pump part;(136) Loop filter part;(140) Pause detecting part;(150) Selection signal generating part;(410) Clock selection signal generating part;(AA) Carrier signal
Abstract:
PURPOSE: An RFID tag and a signal receiving method thereof are provided to improve signal receiving performance by preventing the lowering of signal receiving performance due to the change of the size of the received signals. CONSTITUTION: A voltage signal generator(101) creates first and second voltage signals from received signals. An inverter(130) inverts the second voltage signals and obtains data pulse. A buffer(140) buffers data pulses and restores received data. The inverter comprises a current source and PMOS(Positive Metal Oxide Semiconductor) transistor. The PMOS transistor comprises a source connected to the first voltage signal, a gate connected to the second voltage signal, and a drain connected to the current source.
Abstract:
An RFID communication method is provided to prevent signal interference between portable terminals when the portable terminals having a mobile RFID function access one tag. A portable terminal requests channel allocation for RFID(Radio Frequency ID) communication to a base station(310). A channel is allocated to the portable terminal from a base station(312). The portable terminal communicates with an RFID tag by using the allocated channel. The base station allocates one or more channels during each operation time.
Abstract:
A radio frequency identification reader and their wireless frequency transmission method for efficiently utilizing the frequency are provided to prevent the deterioration of a reader by communication interference due to changing transmission environment according to use area of the reader. An RFID(Radio Frequency Identification) reader selects a part of all of a plurality of channels(S135,S155). The radio frequency identification reader measures the selected channel each radio frequency power(S130). According to the measurement result, the radio frequency identification reader determines the transmission environment of the radio frequency(S170,S180). The transmission environment of the radio frequency is the multiple reader environment or the congestion reader environment.
Abstract:
An RFID reader for offsetting transmission leakage signals is provided to reduce the whole power consumption by cancelling the transmission leakage current by the control of a digital unit. An RFID reader comprises a digital unit(370) which calculates the amplitude and phase of a transmission leakage signal, and stores the calculated result, and a leakage offsetting circuit(330) which generates a leakage offset signal in response to the control of the digital unit, wherein the leakage offset signal has the same amplitude as that of the transmission leakage signal and has a phase reverse to that of the transmission leakage signal. The leakage offsetting circuit receives a local oscillation signal from a frequency synthesizer(350), and then generates the leakage offset signal.