摘要:
An RFID tag (1) includes an antenna coil (111) configured to transmit and receive a signal through near field communication, a signal processing circuit (121) configured to process the signal transmitted and received by the antenna coil (111), a capacitive element (112) arranged in series between the antenna coil (111) and the signal processing circuit (121), and a control unit (122) configured to control the capacity value of the capacitive element (112). The control unit (122) changes the capacity value of the capacitive element (112) according to whether a voltage is applied from an external power supply.
摘要:
In a polar modulation system, there is disclosed a polar-modulation transmission device, which can be dispensed with an isolator thereby to suppress a circuit scale and the heat loss of a power amplifier. In this device, a current detecting unit (130) detects a current value (Icc) to flow from a power source voltage transforming unit (120) to a power amplifier (180), and a power control unit (140) inputs a power control signal (S30) and outputs a control signal (S31) to a power applying unit (150) on the basis of the current value (Icc). The power applying unit (150) multiplies a baseband amplitude modulation signal (S11) by the control signal (S31) thereby to produce an amplitude modulation signal (S13). A regulator (160) feeds a power source voltage (S22), which is changed from a power source voltage (S21) by the amplitude modulation signal (S13), to a power amplifier (180). This power amplifier (180) amplifies the power of a phase modulation high-frequency signal (S14) by using the power source voltage (S22) as a power source, thereby to acquire an RF transmission signal (S15).
摘要:
A radio frequency identification (RFID) device (10) includes: a contact interface (2) for wired communication with a host; a contactless interface (1) for contactless communication with a reader/writer; a command processing unit (4) that obtains a command from the reader/writer in the contactless communication and process the command, the command instructing a data access; and (3) a memory that holds data. The command processing unit (4) determines a communication mode, and (i) executes the data access instructed in the command between the reader/writer and the memory (3), when the communication mode is determined as a first communication mode, and (ii) executes the data access instructed in the command between the reader/writer and the host (20), when the communication mode is determined as a second communication mode.