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公开(公告)号：DE19938998A1
公开(公告)日：2001-03-08
申请号：DE19938998
申请日：1999-08-17
Applicant: INFINEON TECHNOLOGIES AG
Inventor： SCHRAUD GERHARD , REINER ROBERT , EICHNER DIERK , GUENGERICH VOLKER
Abstract: The invention relates to a method for discriminating two modulated signals having the same or almost the same amplitude swing and the same or different carrier frequency. In order to reliably discriminate both modulated frequencies from one another, digital filtering, for example, using a digital filter (DF), is carried out before or after demodulation. The invention can be used advantageously in contactless chip cards. If several chip cards according to the invention are inserted into a read/write device, each chip card can determine using the disclosed method whether the signals received were transmitted by the read/write device or by another chip card since the read/write device transmits in a modulation different from that of the chip cards. Nevertheless, the signals transmitted by the read/write device and the chip card have almost the same or even the same amplitude swing.
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公开(公告)号：ES2216588T3
公开(公告)日：2004-10-16
申请号：ES99955954
申请日：1999-11-03
Applicant: INFINEON TECHNOLOGIES AG
Inventor： NEBEL GERHARD , GINGERICH VOLKER , BLUM ANDREAS , WEDER UWE , EICHNER DIERK , REINER ROBERT
Abstract: A method for demodulating a voltage which has been ASK modulated by changing the amplitude between a low level and a high level, in particular for use during contactless data transmission from a card reader/writer to a smart card, is described. The method is distinguished, in that, in an initialization phase, a first mean value is produced from the high voltage level and a stored partial voltage derived therefrom in order to detect a change to a low voltage level. The change to the low voltage level represents a start value and is detected by a subsequent comparison of the modulated voltage with the first mean value. In a subsequent demodulation phase, a second mean value is produced from the detected low voltage level and the high voltage level in order to demodulate the modulated voltage by comparing the modulated voltage with the second mean value.
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Patent Agency Ranking
公开(公告)号：DE19938998B4
公开(公告)日：2008-01-17
申请号：DE19938998
申请日：1999-08-17
Applicant: INFINEON TECHNOLOGIES AG
Inventor： SCHRAUD GERHARD , REINER ROBERT , EICHNER DIERK , GUENGERICH VOLKER
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公开(公告)号：DE59908482D1
公开(公告)日：2004-03-11
申请号：DE59908482
申请日：1999-11-03
Applicant: INFINEON TECHNOLOGIES AG
Inventor： NEBEL GERHARD , GUENGERICH VOLKER , BLUM ANDREAS , WEDER UWE , EICHNER DIERK , REINER ROBERT , SCHRAUD GERHARD
Abstract: A method for demodulating a voltage which has been ASK modulated by changing the amplitude between a low level and a high level, in particular for use during contactless data transmission from a card reader/writer to a smart card, is described. The method is distinguished, in that, in an initialization phase, a first mean value is produced from the high voltage level and a stored partial voltage derived therefrom in order to detect a change to a low voltage level. The change to the low voltage level represents a start value and is detected by a subsequent comparison of the modulated voltage with the first mean value. In a subsequent demodulation phase, a second mean value is produced from the detected low voltage level and the high voltage level in order to demodulate the modulated voltage by comparing the modulated voltage with the second mean value.
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公开(公告)号：AT396458T
公开(公告)日：2008-06-15
申请号：AT00106222
申请日：2000-03-22
Applicant: INFINEON TECHNOLOGIES AG
Inventor： REINER ROBERT , MELCHIOR MARC , GAUL LORENZ , SCHRAUD GERHARD , EICHNER DIERK , NEBEL GERHARD , KARGL WALTER , MELCHER GEBHARD
IPC: G06K19/07
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公开(公告)号：AT259128T
公开(公告)日：2004-02-15
申请号：AT99955954
申请日：1999-11-03
Applicant: INFINEON TECHNOLOGIES AG
Inventor： NEBEL GERHARD , GUENGERICH VOLKER , BLUM ANDREAS , WEDER UWE , EICHNER DIERK , REINER ROBERT , SCHRAUD GERHARD
Abstract: A method for demodulating a voltage which has been ASK modulated by changing the amplitude between a low level and a high level, in particular for use during contactless data transmission from a card reader/writer to a smart card, is described. The method is distinguished, in that, in an initialization phase, a first mean value is produced from the high voltage level and a stored partial voltage derived therefrom in order to detect a change to a low voltage level. The change to the low voltage level represents a start value and is detected by a subsequent comparison of the modulated voltage with the first mean value. In a subsequent demodulation phase, a second mean value is produced from the detected low voltage level and the high voltage level in order to demodulate the modulated voltage by comparing the modulated voltage with the second mean value.
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公开(公告)号：BR9915115A
公开(公告)日：2001-07-31
申请号：BR9915115
申请日：1999-11-03
Applicant: INFINEON TECHNOLOGIES AG
Inventor： NEBEL GERHARD , GUENGERICH VOLKER , BLUM ANDREAS , WEDER UWE , EICHNER DIERK , REINER ROBERT , SCHRAUD GERHARD
Abstract: A method for demodulating a voltage which has been ASK modulated by changing the amplitude between a low level and a high level, in particular for use during contactless data transmission from a card reader/writer to a smart card, is described. The method is distinguished, in that, in an initialization phase, a first mean value is produced from the high voltage level and a stored partial voltage derived therefrom in order to detect a change to a low voltage level. The change to the low voltage level represents a start value and is detected by a subsequent comparison of the modulated voltage with the first mean value. In a subsequent demodulation phase, a second mean value is produced from the detected low voltage level and the high voltage level in order to demodulate the modulated voltage by comparing the modulated voltage with the second mean value.
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