The portable object is equipped with an antenna inductively coupled to a fixed station of a remote transmission device. The portable object comprises a variable load impedance and a rectifier connected in parallel to the terminals of the antenna, a regulation loop of the voltage at the terminals of the load impedance, connected between the output of the rectifier and a control terminal of the load impedance. The regulation loop comprises, in series, means for determining a difference between a setpoint voltage and the output voltage of the rectifier, a one-bit analog-to-digital converter, and command means of integrator type. The command means comprise a gain control input connected to an output of the gain control means receiving on input signals representative of the difference. Demodulation means are connected to the output of the converter.