Legic Identsystems Ag

Legic Idenstsystems Ag

Peter Hausmann

Marcel Plüss

Peter Plüss

Matthias Schnaubelt

Marcel Plūss

Andreas Koch

Marcel Pluss

For detecting within a communication range of an antenna a contactless data storage device which is configured for inductive coupling with an electromagnetic field emitted by the antenna, a return signal is detected (S) at the antenna during emission of an electromagnetic field pulse. During amplitude build-up of carrier oscillation at the beginning of the electromagnetic field pulse, an evaluation signal is generated (S) based on the return signal, and the data storage device is detected (S) based on the evaluation signal. By detecting the presence of the data storage device based on an evaluation signal generated during amplitude build-up, the detection of the data storage device can be initiated before carrier oscillation of the electromagnetic field pulse is stable. Consequently, the width of the electromagnetic field pulse can be shortened and, therefore, energy consumption for detecting the presence of the data storage device can be reduced.

Detection of a contactless data storage device

In an apparatus for operating a read/writer, including an antenna and a read/write unit, for communication with an identification medium via a communication link, a read/writer supply and a read/writer have a breakable connection arranged between them. When there is a contactless (operative) interconnection between the external power supply and the read/writer, the connection between the read/writer supply and the read/writer is open and the read/writer can be operated with the identification medium.

Device and method for operating a read/write device

The invention relates to a method for recognizing identification media in the communication area of a write/read device functioning according to the principle of inductive coupling in the MHz range, wherein an antenna is used for transmitting and receiving HF signals, in addition to a circuit for transmitting HF signals with a standard transmitter power output and a logic circuit for evaluating communication between a write/read device and an identification medium. A short inquiry signal consisting of several fundamental components of the HF field and having a standard transmission power output is periodically transmitted via a transmission path and the antenna and a response signal is detected on the antenna. The response signal is compared to a reference signal and a communication signal is transmitted in order to recognize an identification medium in the event that the response signal is different from the reference signal. This enables energy-saving, reliable recognition of identification media occurring in the field of communications for subsequent communication with the write/read device, particularly with respect to battery-operated write/read devices.

Method for recognizing identification media

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Pfaffhausen, Switzerland

Peter Hausmann