Abstract: A horn that radiates a radioelectric wave coming from an input waveguide, comprises a grating placed over the aperture of the horn. The waveguide comprises a horn-shaped segment, an entrance, an aperture, and a grating placed next to the aperture. It makes it possible for at least one linearly polarised electromagnetic wave to propagate between the entrance and the aperture along a first axis. The grating comprises a frame and a set of plates extending longitudinally and continuously from a first short side of the frame to a second short side of the frame, so as to form a linear polarising filter for any electromagnetic wave the electric field of which is not polarised along a second axis orthogonal to the first axis. The grating of the waveguide comprises corrugations to reinforce the filtering of the electromagnetic wave the electric field of which is not polarised along the second axis.

Abstract: A system for the processing of signals collected by an eddy current absolute point transducer moving along an inner surface of a conductive material tube and supplying a representative signal concerning the state of the inner surface. The system incorporates a stage for scanning the surface in accordance with a given order or sequence of elementary measurement zones and recording the sampled values of the signal supplied by the transducer for each of the elementary zones, which makes it possible to obtain a three-dimensional image representative of the surface. The system also constructs a background noise surface on the complete image, subtracts the background noise surface from the image and detects a defect or fault on the surface. Such an invention may find particular application to the inspection of steam generator tubes.