Abstract: A method is provided for transmitting signals on a multi-conductor cable (12) formed from a plurality of conductors (1-7) surrounded by an armor (10), the plurality of conductors having a central conductor (7) surrounded by a first peripheral layer of conductors (1-6) with an even number of conductors symmetrically arranged around the central conductor. The two following transmission modes are carried out simultaneously: a common mode (TX1) that uses the central conductor (7) with a return on the armor (10), for transmitting a first signal (s1); and a differential mode (TX2) between a first path comprising all odd rank conductors (1,3,5) of the peripheral layer and a second path comprising all even rank conductors (2,4,6) of the peripheral layer, for transmitting a second signal (s2).

Abstract: A system and method for adjusting a clock signal of a seismic data acquisition system. The system includes a data acquisition device having an oscillator that generates a clock signal; a clock adjustment module that receives a time reference signal and the clock signal and outputs an adjusted clock signal; and an analog-to-digital convertor configured to transform analog data into digital data having a sampling rate (FDATA). A sampling frequency (fADC) of the analog-to-digital convertor is selected to be at least twice the sampling rate (FDATA).

Abstract: A system and method for adjusting a clock signal of a seismic data acquisition system. The system includes a data acquisition device having an oscillator that generates a clock signal; a clock adjustment module that receives a time reference signal and the clock signal and outputs an adjusted clock signal; and an analog-to-digital convertor configured to transform analog data into digital data having a sampling rate (FDATA). A sampling frequency (fADC) of the analog-to-digital convertor is selected to be at least twice the sampling rate (FDATA).

Abstract: A method is provided for transmitting signals on a multi-conductor cable (12) formed from a plurality of conductors (1-7) surrounded by an armor (10), the plurality of conductors having a central conductor (7) surrounded by a first peripheral layer of conductors (1-6) with an even number of conductors symmetrically arranged around the central conductor. The two following transmission modes are carried out simultaneously: a common mode (TX1) that uses the central conductor (7) with a return on the armor (10), for transmitting a first signal (s1); and a differential mode (TX2) between a first path comprising all odd rank conductors (1,3,5) of the peripheral layer and a second path comprising all even rank conductors (2,4,6) of the peripheral layer, for transmitting a second signal (s2).

Abstract: 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.

Abstract: 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, characterised 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.