Radio IC card system
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Jan 25, 2000
Grant Date -
N/A
app pub date -
Apr 10, 1997
filing date -
Apr 15, 1996
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
A radio IC card system includes an IC card and a toll collector. When an automobile with the IC card passes by a tollgate, the toll collector installed in the tollgate transmits a first radio signal which is spread modulated using a pseudorandom noise (PN) code from an antenna. The first radio signal is received by the antenna of the IC card and is transmitted to a surface acoustic wave (SAW) correlator. The SAW correlator extracts a PN code included in the received signal, and outputs a peak signal. An accumulation circuit accumulates the peak signal. A threshold discharger is activated to switch on a relay switch when the output voltage of the accumulation circuit exceeds a constant value. Thereby, the voltage of a battery is supplied to a data communication unit. Then, the identification code of the IC card and a record of tollgates by which the automobile has passed are transmitted via radio signal to the toll collector.
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Cited Art Landscape
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