Abstract: A device for determining the concentration of a compound in an aqueous phase in a dynamic manner and while flowing, and a device (300) for determining the concentration of a compound in a gaseous phase and soluble in an aqueous phase. The device (200, 300) for determining the concentration of a compound in a gaseous phase includes elements (302) for transferring the compounds present in the gaseous phase to an aqueous phase then determining in a dynamic manner and while flowing, the concentration of the compounds in this aqueous phase by fluorescence spectroscopy. The devices (300) are robust, conveyable and less costly, and have greater temporal as well as spatial sensitivity than the devices of the state of the art.

Abstract: A method for digitally demodulating a complex modulation signal and allowing different parameters to be transmitted thereby. The input signal is baseband filtered and a complex demodulation is performed on the first subcarrier at a frequency Fp to obtain a correction signal, after squaring. The input signal is demodulated around a frequency exactly equal to twice the frequency of the first demodulation in order to obtain output signals which exhibit a frequency error with respect to 2Fp. This frequency error is corrected by multiplication with the previously derived frequency correction signal. The corrected signal is filtered at a frequency lower than 1 Hz, in order to obtain a signal giving the phase error at a frequency 0, that is to say that of the subcarrier at 2Fp. The signal makes it possible to correct the phase of signals which were previously frequency corrected in order to obtain two signals which are complementary to one another and transmitted by quadrature modulation around the frequency 2Fp.