The invention concerns a radio-frequency transponder (12) for contact-free
identification with a reader (10), comprising: an antenna (24), an
analog circuit (25) including a capacitor (32) an AC-DC converter
(34), a modulator (40) and a demodulator (38), a logic control
circuit (26), a storage unit (27). Said transponder (12) is
designed such that: the antenna (24) and the capacitor (32) form
together a resonant circuit, the clock extractor (36) processes the first
signal (Tx) to extract therefrom a clock signal addressed to said modulator (38)
as long as the voltage of said signal (Tx) exceeds a first threshold value, the
converter (34) transforms the first signal (Tx) into a rectified signal,
to power the transponder (12). The performances of the transponder, and
more particularly energy recuperation and data transmission rate, are improved
by the fact that the analog circuit comprises two clock extractors, one of low
level type (35), the other of the high level type (36).
