Abstract: A system and method for controlling an electron beam in accordance with the present invention includes an electron gun, a cathode ray tube with a faceplate, a deflection drive, a pair of positioning electrodes, an electron beam controller, and a pair of capacitors. The electron gun generates an electron beam in the cathode ray tube which is deflected in a desired direction towards and between at least one pair of positioning electrodes formed on the inner surface of the faceplate. Each of the positioning electrodes generates a position signal which is capacitively coupled by the capacitors to the electron beam controller. The electron beam controller adjusts the deflection of the electron beam in response to the position signals. The capacitors comprise a pair of first and second capacitor plates which are separated by the cathode ray tube. The first capacitor plates are disposed on opposing sides of an inner surface of the cathode ray tube adjacent to the faceplate.

Abstract: A device, utilized for the separation or combination of two signals of different wavelengths, of the type in which the waveguides comprise straight interaction segments (1.sub.1, 2.sub.1 ; 1.sub.in, 2.sub.in) parallel and close to one another and to curved approach segments with inflection points (1.sub.2, 2.sub.2, 1.sub.3, 2.sub.3 ; 1.sub.2n, 2.sub.2n, 1.sub.3n, 2.sub.3n), connected to the ends of the straight segments, and, for certain ones, to inputs/outputs (4,5,6) of the device. In accordance with the invention, the approach segments situated on at least the same side of the straight segments are free of any inflection point, the coupling of the straight segments being optionally modified to compensate for the variation of the coupling between the waveguides along said approach segments due to the omission of the inflection points.