Title:
DEMODULATOR FOR NON-CONTACT CHIP CARD
Document Type and Number:
Japanese Patent JP3177502
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a demodulator for non-contact chip card.
SOLUTION: A non-contact chip card, to which binary data are transmitted at a radio frequency(RF), is provided with the demodulator for binary data. This demodulator is provided with a circuit for detecting transmitted signals, rectifier circuit 12, band pass filter 14, comparator stage 16 and memory circuit 18. The band pass filter 14 applies a low frequency signal to be used as a reference for two comparators and a high frequency signal to be used for comparison with a reference to change together with the low frequency signal. As a result, demodulation is not affected by the average level of received signals.
Inventors:
Andrew James Roberts
Frederick Subiot
Frederick Subiot
Application Number:
JP26935698A
Publication Date:
June 18, 2001
Filing Date:
September 24, 1998
Export Citation:
Assignee:
STMicroelectronics Society Anonymous
International Classes:
G06K7/08; G06K19/07; H03D1/10; H04B1/59; H04B5/02; H04L25/06; H04L27/06; H04L27/08; (IPC1-7): H04B5/02; G06K19/07; H04B1/59
Domestic Patent References:
| JP513863A | ||||
| JP5775050A |
Attorney, Agent or Firm:
Takashi Koshiba
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