Patent ID: 6421431
Filing Date: 2002-07-16
Classification: G06F,G06K

Abstract:
A method of transmitting a binary data sequence in voice form from a piezoelectric transducer, the method comprising:defining a sinewave signal from a stream of pulses each having a logic â€œ0â€  or a logic â€œ1â€  state; generating a sampling frequency that differs depending on the logic state of the bit of the sequence that is to be transmitted; reading the stream of logic pulses at the sampling frequency corresponding to the logic state of the bit to be transmitted so as to obtain an intermediate logic signal; applying the intermediate logic signal alternately to one and then to the other of two input terminals of a piezoelectric transducer, at a voice frequency that differs depending on the logic state of the bit to be transmitted, so as to obtain a logic excitation signal made up of a positive half-cycle and of a negative half-cycle; reconstituting an acoustic signal having a sinusoidal waveform from the logic excitation signal by making use of the capacitive portion of the impedance of the piezoelectric transducer, in particular in the vicinity of its resonant frequency; and causing the transducer to emit the acoustic signal of sinusoidal waveform at the voice frequency which corresponds to the logic state of the bit to be transmitted.