Non-contact IC card with phase variation detector
First Claim
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1. A batteryless non-contact IC card, using electromagnetic waves as a communication medium, comprising:
- an antenna resonance circuit for data transmission and reception;
phase variation detecting means for detecting presence of a phase variation in a voltage of said antenna resonance circuit from an amplitude variation of the received signal wherein said phase variation detection means detects the presence of a phase variation in the received signal when the received signal has an amplitude larger than ground and smaller than a threshold amplitude; and
demodulating means for demodulating data from the received signal in the phase variation detected by said phase variation detecting means.
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Abstract
A batteryless non-contact IC card, using electromagnetic waves as a communication medium, includes an antenna resonance circuit for data transmission and reception; a phase variation detector for detecting a phase variation of a voltage of the antenna resonance circuit due to a received signal, on the basis of an amplitude variation of the received signal; and a demodulator for demodulating data in accordance with the phase variation detected by the phase variation detector.
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2 Claims
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1. A batteryless non-contact IC card, using electromagnetic waves as a communication medium, comprising:
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an antenna resonance circuit for data transmission and reception; phase variation detecting means for detecting presence of a phase variation in a voltage of said antenna resonance circuit from an amplitude variation of the received signal wherein said phase variation detection means detects the presence of a phase variation in the received signal when the received signal has an amplitude larger than ground and smaller than a threshold amplitude; and demodulating means for demodulating data from the received signal in the phase variation detected by said phase variation detecting means. - View Dependent Claims (2)
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Specification