Abstract: Method for removing air wave noise from shallow water controlled source electromagnetic survey data, using only the measured data and conductivity values for sea water (140) and air. The method is a calculation performed numerically on CSEM data and resulting in an estimate of those data that would have been acquired had the water layer extended infinitely upward from the seafloor. No properties of the sub-sea sediments are used. Synthetic electromagnetic field data are generated for (a) an all water model (141) and (b) an air-water model (146-147) of the survey region. These simulated results are then used to calculate (148-150) electromagnetic field values corresponding to a water-sediment model with water replacing the air half space, which represent measured data adjusted to remove air wave noise.

Abstract: The invention concerns a sensor comprising two electrodes (1, 3a) separated by a dielectric material (2). One electrode (3a) being produced by using a non-porous metal sheet, the other electrode (1) being advantageously made of a non-metallic porous material made conductive and the dielectric material being advantageously in the form of a multilayer polymer film (2). The resulting sensor can be adjusted to the desired value by a particular capacitor by reducing the useful surface of the porous electrode (1). The reduction step carried out by simply scraping or eroding the material constituting the porous electrode (1).

Abstract: A method for creating signal unidirectionality in electronic circuits is disclosed. This invention describes a method for achieving unidirectionality in an electronic circuit with an input side having a signal source and an output side with a load comprising detecting the current passing through the load on the output side, bypassing a portion of the current passing through the load on the output side, and feeding the bypassed portion of the current on the output side to the input side to achieve unidirectionality. Specifically, unidirectionality in an electronic circuit is accomplished by applying feedback such that the impedance looking into the input of the amplifier is increased. These methods are particularly applicable to negative resistance amplifier circuits.