Abstract: A contactless chip card, receiving binary data transmitted by radio frequency, includes a demodulator for the binary data. The demodulator includes a circuit for the detection of the transmitted signals, a rectifier circuit, a bandpass filter, two comparators and a memory circuit. The bandpass filter provides a low-frequency signal used as a reference for the two comparators and a high-frequency signal that is compared with the references varying with the low frequency signal. As a result, the demodulation is independent of the mean level of the received signal.
Type:
Grant
Filed:
September 18, 1998
Date of Patent:
February 29, 2000
Assignee:
STMicroelectronics S.A.
Inventors:
Andrews James Roberts, Frederic Subbiotto