Abstract
The invention relates to a method for demodulating load-modified signals in a system and to a reading device (LES), which supplies a high-frequency carrier signal (ST) to a transmitting antenna (ANT). Passive transponders (TRA) located in the area of influence of the antenna (ANT) receive the signal and subject the received signal to a load modulation. The retroactive modulated HF signal is demodulated inside the reading device in order to evaluate the modulation signal. Auxiliary carriers (SH), which are shifted by a phase angle (f) and which are frequency-synchronous with the carrier signal (ST), are generated by means of an auxiliary signal transmitter (HSG), and carrier signals (ST) and auxiliary carriers (SH) are added in a summing circuit (SUM). Both the resulting sum signal (SR) as well as the carrier signal (ST) are subjected to an amplitude demodulation by means of a demodulator (DEI), and the demodulated signals (sI, sQ) are processed further for evaluation.
| Translated title of the contribution | METHOD FOR DEMODULATING AND READING DEVICE FOR EVALUATING LOAD-MODULATED SIGNALS |
|---|---|
| Original language | German |
| Patent number | WO2006105565 |
| IPC | H04L 27/ 233 A I |
| Priority date | 7/04/05 |
| Publication status | Published - 12 Oct 2006 |