BINARY CIRCUIT IN READER/WRITER FOR IC CARD

摘要

PROBLEM TO BE SOLVED: To provide a binary circuit that converts a reception signal from an IC card accurately into a digital signal regardless of fluctuation in the received signal level. SOLUTION: An automatic threshold circuit that changes automatically a reference level in response to fluctuation in a level of an input signal to a comparator 4 is provided to a noninverting input terminal of the comparator 4. The threshold circuit compares the input signal level with the reference level at a leading point of time and a trailing point of time of the input signal to allow the comparator 4 to convert the input signal (analog signal) into a digital signal.