Data transmission and reception system

摘要

A data transmission and reception system according to this invention comprises a transmitter for transmitting data by modulating transmit data and a receiver for receiving and demodulating a signal from the receiver, wherein the receiver includes a parallel resonator for receiving a PSK signal; a full rectification circuit for detecting output from the parallel resonator; a low pass filter for shaping the waveform of output from the full rectification circuit; and a comparator for converting output from the low pass filter into a binary-coded signal so that demodulated signals can be obtained from the output of the comparator. Therefore, PSK signals can be demodulated without a PLL or a tank circuit, the overall system consumes a smaller amount of power and is thin and reliable, the transmitter has an amplifier that can operate efficiently, particularly with a limited power supply as in IC cards or a single power supply used for portable terminals, and the receiver is reliable even with a simple circuit using a communication method that locally suppresses the amplitude at phase change points to remove an oscillation circuit in order to reduce the size and thickness of the device.