公开(公告)号：JP2001266102A

公开(公告)日：2001-09-28

申请号：JP2001026126

申请日：2001-02-01

Applicant: ST MICROELECTRONICS SA

Inventor： ROBERTS ANDREW J ,  SUBBIOTTO FREDERIC

IPC: G06K7/08 ,  G06K19/07 ,  H03D1/10 ,  H04B1/59 ,  H04B5/02 ,  H04L25/06 ,  H04L27/06 ,  H04L27/08

Abstract: PROBLEM TO BE SOLVED: To provide a demodulator for non-contact chip card, which is not affected by the level of a received signal. SOLUTION: A non-contact chip card where binary data is transmitted by a radio frequency includes a demodulator for binary data. The demodulator includes a circuit for detecting a transmitted signal, a rectifying circuit, a band pass filter, a comparator stage and a memory circuit. The band pass filter gives a low frequency signal used as a reference for two comparators and a high frequency signal supplied for comparison with the reference which changes with the low frequency signal. Consequently, demodulation is not affected by the average level of the received signal.

公开(公告)号：DE69834607T2

公开(公告)日：2007-05-03

申请号：DE69834607

申请日：1998-09-17

Applicant: ST MICROELECTRONICS SA

Inventor： ROBERTS ANDREW ,  SUBBIOTTO FREDERIC ,  DONAT NATHALIE

IPC: G06K19/07 ,  H04B1/59 ,  H04B5/02

Abstract: The detector (24) has a resonant detector circuit (10) formed from an antenna winding and parallel capacitor (C0). The resonant circuit drives a circuit (28 or 30) which detects presence of a radio signal, using the signal from the antenna winding (20). To confirm this detection, a detector (26) senses phase opposition between the voltages at opposite ends of the resonant circuit. Its output is applied to an AND gate along with the outputs from the two detector circuits.

公开(公告)号：DE69834607D1

公开(公告)日：2006-06-29

申请号：DE69834607

申请日：1998-09-17

Applicant: ST MICROELECTRONICS SA

Inventor： ROBERTS ANDREW ,  SUBBIOTTO FREDERIC ,  DONAT NATHALIE

IPC: G06K19/07 ,  H04B1/59 ,  H04B5/02

Abstract: The detector (24) has a resonant detector circuit (10) formed from an antenna winding and parallel capacitor (C0). The resonant circuit drives a circuit (28 or 30) which detects presence of a radio signal, using the signal from the antenna winding (20). To confirm this detection, a detector (26) senses phase opposition between the voltages at opposite ends of the resonant circuit. Its output is applied to an AND gate along with the outputs from the two detector circuits.