Appeal No. 95-0868
Application 07/987,552
DECISION ON APPEAL
This is a decision on appeal under 35 U.S.C. § 134 from the
final rejection of claims 5 and 6, all the claims pending in
the application. Claims 1-4 and 7 have been cancelled.
The invention is directed to a non-contact IC card. Prior art non-contact IC cards have a receiver
with a single threshold level. The signal is detected by comparing the level of the received signal with the
threshold level. As illustrated in appellant's figure 4, if the receiver has an excessively high threshold value
V it cannot detect the data D and D , as shown by an output waveform S . If the receiver has anH 11 12 H
excessively low threshold value V there is the danger of detecting not only the true data D and D butL 11 12
also noise N and N , as shown by an output waveform S . Even if the threshold level is properly set,11 12 L
if the IC card is used in a different environment the threshold level may need to be reset. The invention
allows a threshold level to be easily set in correspondence with the strength of the received signal.
The invention uses at least three receivers each with different signal detection threshold levels as
shown in figure 2 (showing four receivers). Undisclosed structure determines which receivers accurately
detect the data. In figure 2, receivers 10 and 10 , which output the signals S and S , accurately detect2 3 2 3
the data. Since the current consumed by a receiver having a high threshold level is large, the CPU selects
from the receivers that have accurately detected the data the receiver having the lowest signal detection
threshold. This minimizes current consumption.
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Last modified: November 3, 2007