| 摘要 |
<p>The present invention is a data synchronizer and a data synchronization method for waveform-shaping an input signal which is a digital signal by data-synchronizing the input signal with a clock signal, wherein a period in which the input signal can be sampled from the count value of the clock signal counted by a counter and an out of synchronism detection period for monitoring whether the edge of the input signal exists in a counting possible period or a period in the vicinity of the counting possible period are formed, a sampling phase for the input signal is shifted when the edge signal is detected in the out of synchronism detection period. With this constitution, it is possible to maintain a data synchronization state after a certain period in an input signal reception initial period and to effectively remove jitter, glitch, noise and the like contained in the input signal. In addition, the present invention is a non-contact IC card receiving a modulation signal space-transmitted from a data transmitter, demodulating the reception signal and decoding the data and conducting a predetermined data processing, wherein data synchronization means for sampling the demodulation output with a clock signal obtained from the received modulation signal to thereby make data synchronization and determining that out of synchronism of data occurs when the edge of the demodulation output is in the sampling period to thereby change a sampling phase, is provided between an analog circuit system demodulating the received modulation signal and a digital signal processing system decoding the demodulated data signal. By so constructing the non-contact IC card, jitter, glitch, noise and the like contained in the output of the analog circuit system are not transmitted by the digital signal processing system, thereby making it possible to prevent a vicious circle caused by the multiplier effect of "external noise", "offset drift" and "power variation" which are problems for non-contact IC card communications. <IMAGE></p> |
