The invention proposes a data transmission process, from a first unit (1) situated at a predetermined depth of an oil well to a second unit (2) situated at the surface of this well, the process comprising a digital-analog conversion stage (8) of the data to obtain an analog signal forming support of the data, and an amplification stage (9) of this signal prior to its emission in a cable (11) connecting the two units, characterized in that at least two distinct scramblings (20, 21) of the data are completed, such that there is a first and a second set of scrambled data. After passage in a single complex inverse Fourier transform, that intended for emission is selected (26), whereof the dynamic in amplitude is the lowest. If the probability of saturating with a single set is 10−q, then due to this process the probability will be 10−2q.