Abstract: The present invention relates to switching wide band electric transmission signals. It provides a switching matrix which includes inlet/outlets one of which sets forms the columns while the other set forms the rows of the matrix and switching points disposed at the intersections of the conductors. The wiring of the matrix includes plane supports equal in number to that of its rows and of its columns, each row conductor or column conductor being wired on a distinct support, the supports being assembled in two stacks disposed perpendicularly to each other, one stack being constituted by the wiring supports of the column conductors while the other is constituted by the wiring supports of the row conductors. The figure shows a set of two stacks 204, 205, of four supports in individual screen boxes which form a switching matrix with four rows and four columns. Such a matrix is used advantageously for switching telecommunication signals.

Abstract: Low-level, wide-band signals e.g. for use in telephone transmission are switched in a matrix device. The overall matrix is subdivided into elementary matrices of smaller size and each inlet of the overall matrix is provided with a selector for selecting the appropriate elementary matrix which contains the desired cross-point. This subdivision is performed as is conventional to reduce interference and attenuation from echos generated in the unused portions of the matrix, but it has the drawback of increasing the complexity of switch control, two selectors and one cross-point needing activation in the place of a single cross-point. The present invention provides selectors which are sensitive to the conductive state of the cross-points to which they are directly connected to repeat the conductive condition to their respective inlet of the overall matrix, thereby simplifying switching control without sacrificing transmission characteristics.

Abstract: The invention concerns a level regulator for a frequency division multiplex group, having a variable gain network controlled basically by the observing of the amplitude of a pilot wave contained in the multiplex group, comprising a digital filter preceded by a sampling device and an analog-digital converter for extracting the pilot wave from the multiplex group downstream from the variable gain network, a calculation circuit connected to the digital filter for determining a number which is a function of the level, over a predetermined interval of time, of the pilot wave at the output of the filter, and a digital comparison element which compares that number with a reference value with a view to generating a control signal for the said network. In a particular embodiment of the invention, the multiplex group is transposed towards the low frequencies before being digitally processed.