| 摘要 |
The invention concerns a device for demodulating a modulated signal resulting from an amplitude modulation of a sinusoidal signal of frequency fo by a signal of frequency fm according to an unknown modulation rate, comprising a transistor (10) whereof the gate is connected to said modulated signal (Et) so as to obtain in the transistor (10) output a derived signal (St) equal to a power N of the modulated signal, N being an integer greater than 1, and a filter for selecting the frequency component fm in the transistor output signal. Said device can be used to demodulate an amplitude-modulated signal received by a scanner of a system identifying contactless portable objects.
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