France Telecom

La Poste

Salman Abou Hassan

Marie-Josephe Revillet

An electronic fingerprint sensor works by the detection of pressure, the ridge lines of the finger exerting a greater pressure than the valleys. The sensor has a matrix of pressure microsensors and electronic control and signal-processing circuits. It is made in an entirely monolithic form, according to techniques for the making of electronic circuits (deposition of thin layers, photo-etching, doping and thermal processing), both for the pressure detection part and for the signal-processing and control part. The matrix-type pressure sensor uses either piezoelectric resistors lying on an insulator layer stretched above a cavity or a variable capacitor or a microcontactor.

Monolithic sensor of fingerprints

The Manchester coder/decoder of the invention includes the following modules. A synchronization signal generation module (11), gives the clocks' start signal. A module (12) for the synchronization and generation of clocks generates the transmission/coding and decoding clocks and a low frequency clock. A decoding module (13) includes a flip-flop driven by the decoding clock. The decoding is a simple sampling of the input signal of the Manchester coded data which is to be decoded during the reception phase. A coding module (14) carries out an 'OR EXCLUSIVE' function between the input signal to be coded in Manchester code and the transmission clock.

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Caen, France

Salman Abou Hassan