Abstract: The device comprises an elongated acoustic wave translating isotropic body and a pair of transducers applied over one of the two parallel end faces thereof. Said transducers are arranged with relatively crossed axes of linear transversal polarization. The other end face of the isotrope body is intended to be applied to a sample or a structure made of an acoustically active substance presenting anisotropy, either intrinsic or induced, with respect to acoustical polarization. The length of the isotropic body is such that when the transducers are both simultaneously driven by pulsed high frequency voltages which are modulated in respective phase quadrature by a low frequency oscillation, the two transversal acoustic waves propagated through the body vectorially combine so that the opposite end face of the body is the subject of a constant amplitude acoustic wave which rotates at the speed of the pulsation of the low frequency.

Abstract: A telephone private switching equipment of the space-division operated type comprises a matrix of electronic switch cross-points each made of a single controllable two-state member connected across a conversation conductor of a row and a conversation conductor of a column of the matrix and having a trigger terminal connected through unidirectional members to both a cross-point activation conductor of this row and a cross-point activation conductor of this column, each row and each column comprising only these two conductors. Each column of the matrix is controlled from a cross-point selection control unit capable of applying trigger pulses to the cross-point activation conductor of the column and service voltages and currents to the conversation conductor of the column.