Abstract:
An electromagnetic transponder intended to draw the power necessary to its operation of from a field radiated by a terminal of transmission of a carrier at a first supply frequency and to back-modulate the received signal at the rate of a sub-carrier at a second frequency lower than the first one, and comprising means capable of demodulating and decoding signals modulated by said sub-carrier, as well as a system of communication between such transponders.
Abstract:
A demodulator for an amplitude modulated alternating signal includes a peak detection circuit for extracting the reference modulating signal from the amplitude modulated alternating signal, and a first translation circuit for offsetting the level of the reference modulating signal by a value equal to the DC component to obtain an offset reference modulated signal. A comparison threshold generator circuit generates a comparison threshold to locate the start and the end of the modulation, and a comparator circuit compares the offset reference modulating signal with the comparison threshold for providing signals that cross the comparison threshold. An unregulated supply circuit provides a supply voltage to the different circuits.