Duplex transmission in an electromagnetic transponder system
AssigneeSTMicroelectronics S.r.l.
InventorsLuc Wuidart, Michel Bardouillet, Jean-Pierre Enguent
Life of this patent
Estimating the term…
Abstract
A method of transmission between two elements chosen from a terminal and a transponder, each element including an oscillating circuit, a modulator and a demodulator, including simultaneously performing a transmission in amplitude modulation of a signal transmitted from a first to a second element and a transmission of a signal from the second to the first element adapted to being submitted to a phase demodulation in the latter, and wherein the amplitude modulation rate is smaller than 100%.
Claims7
A method of transmission between a terminal and a transponder, each including an oscillating circuit, a modulation means and a demodulation means, the method including steps of simultaneously performing an amplitude-modulated transmission of a signal transmitted from the terminal to the transponder and a transmission of a signal from the transponder to the terminal adapted to being submitted to a phase demodulation in the terminal, and wherein an amplitude modulation ratio is smaller than 100%, the method further comprising regulating a signal phase in the oscillating circuit of the terminal with respect to a reference value, a response time of phase regulation being shorter than an amplitude modulation period and longer than a period of a signal that will have to undergo a phase demodulation.
A terminal for implementing a method of transmission between the terminal and a transponder, each including an oscillating circuit, a modulation means and a demodulation means, the method including steps of simultaneously performing an amplitude-modulated transmission of a signal transmitted from the terminal to the transponder and a transmission of a signal from the transponder to the terminal adapted to being submitted to a phase demodulation in the terminal, and wherein an amplitude modulation ratio is smaller than 100%, the terminal including:
- means for comparing transmitted and received signals clipped by respective clipping means;
- and
- means for regulating a signal phase in the oscillating circuit of the terminal with respect to a reference value, a response time of phase regulation being shorter than an amplitude modulation period and longer than a period of a signal that will have to undergo a phase demodulation.
A transponder for implementing a method of transmission between a terminal and the transponder, each including an oscillating circuit, a modulation means and a demodulation means, the method including steps of simultaneously performing an amplitude-modulated transmission of a signal transmitted from the terminal to the transponder and a transmission of a signal from the transponder to the terminal adapted to being submitted to a phase demodulation in the terminal, and wherein an amplitude modulation ratio is smaller than 100%, the transponder including an amplitude demodulation means sized according to attenuation introduced by a back modulation means.
A transponder for implementing a method of transmission between a terminal and the transponder, each including an oscillating circuit, a modulation means and a demodulation means, the method including steps of simultaneously performing an amplitude-modulated transmission of a signal transmitted from the terminal to the transponder and a transmission of a signal from the transponder to the terminal adapted to being submitted to a phase demodulation in the terminal, and wherein an amplitude modulation ratio is smaller than 100%, the transponder including an amplitude demodulation means, a result of which is only taken into account during one state out of two of an output signal of a back modulation means.
Dependencies are inferred from the claim text.