| 摘要 |
An RFID transponder (1) comprises a demodulator (3) for demodulating received phase modulated carrier signals (CSQ), converting them down to a modulated baseband signal (MS) and filtering the converted signal. Sampling means (7) sample the filtered signal (FS) and store an actual sampling value (S(t0)) and a previous sampling value (S(t1)) of the filtered signal (FS). Subtracting means (8) calculate a difference (DS) between the actual sample value (S(t0)) and the previous sample value (S(t1)). Difference evaluation means (9) evaluate the difference (DS) according to the following criteria: a. if the difference is positive and outside of a predefined zero range (ZR) a first logical value is determined; b. if the difference is negative and outside of the zero range a second logical value is determined; c. if the difference is within the zero range the logical value of the latest evaluation is kept.
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