Patent ID: 7575165

Claim:
Remote transmission device comprising a fixed station and a portable object provided with an antenna inductively coupled to the fixed station, the portable object comprising a variable load impedance connected to terminals of the antenna, and a regulation loop regulating the voltage at terminals of the variable load impedance comprising rectifier means for rectifying the voltage at the terminals of the antenna and control means designed to modify the variable load impedance according to the output voltage of the rectifier means, object characterized in that, the fixed station emitting an alternating magnetic field modulated in amplitude on 2 N levels by data to be transmitted, encoded on N bits, the portable object comprises demodulation means comprising an n-bit analog-to-digital converter, clocked at an oversampling frequency much higher than the frequency of the data and connected between the rectifier means and the control means, and digital processing means connected to the output of the converter.