Abstract: An extrinsic optical fiber device for measuring a physical parameter, includes: a light source, of central wavelength ?, an optical fiber projecting, a unit for detecting an interferometric signal, the interferometric signal including the information about the physical parameter to be determined, elements for modulating a signal emitted by the light source, elements for calculating the physical parameter on the basis of the interferometric signal measured by the detection unit. The modulated signal from the light source includes an alternating component including a double frequency modulation generated by the modulation elements. The main application of this device is the measurement of the displacement of a target.

Abstract: An extrinsic optical fiber device (1) for measuring a physical parameter, includes: a light source (10), of central wavelength ?, an optical fiber projecting (13), a unit (15) for detecting an interferometric signal, the interferometric signal including the information about the physical parameter to be determined, elements (17) for modulating a signal emitted by the light source, elements (18) for calculating the physical parameter on the basis of the interferometric signal measured by the detection unit (15). The modulated signal from the light source (10) includes an alternating component including a double frequency modulation generated by the modulation elements. The main application of this device is the measurement of the displacement of a target (2).

Abstract: The device comprises a variable-characteristic nonlinear four-terminal network having one input for receiving a video signal V.sub.e and eight inputs for controlling transfer parameters. Statistical analysis of the amplitude of the signal V.sub.e permits acquisition of the luminance distribution function of said signal. On the basis of this distribution function, computing means determine the values of the transfer parameters to be applied to the control inputs of the four-terminal network in order to deliver at the output of the network a video signal V.sub.s which extends over the entire luminance scale and has the desired distribution for satisfying optimum conditions of vision.

Abstract: A method and apparatus for positioning an object in space in such a manner as to permit duplication of the positioning in a precise position wherein three characteristic points on the object wherein the coordinates of the points are determined and are electrically synthesized for generation of a signal for reproducing the points on the coordinates, and utilizing a television camera and monitor forming an image of the object on the screen and causing the points of the object to coincide with the reference points by means of a photosensitive sensor in such a manner that the characteristic points on the body are displaced so as to coincide with the synthesized points on the television screen.