This device (10) includes elements (12) for receiving an analogical signal including a data signal in a frequency channel, elements (18) for amplifying the received signal, elements (20) for filtering the amplified signal so as to cut out frequencies outside the frequency channel of the data signal, members (24) for converting the filtered analogical signal into a digital signal, elements (32) for measuring the power (Pwhole) of the whole received signal after amplification and before filtering, and members (26) for determining an amplification control signal for the received signal amplification as a function of the received signal measured power (Pwhole).