Abstract: An acoustic echo erasing apparatus which generates a pseudo-echo component from an audio reception signal (a vector x.sub.1) using an adaptive filter, and removes the pseudo-echo component from an audio transmission signal (a vector y). The apparatus extracts a feedback component depending only on the audio reception signal from the audio transmission signal, and passes the audio reception signal through the adaptive filter to generate the pseudo-echo component while setting a transfer characteristic of the adaptive filter in accordance with the feedback component.

Abstract: A device for plating two or more metal plates, strips, etc., by the absoron of laser energy. The device is fitted with beam-forming optics which form the laser radiation into a beam with a rectangular cross-section. The radiation source is a laser-diode array in which several laser diodes are disposed next to each other in the same plane to give bars which can be laid next to each other, as well as stacked one on top of each other, in any numbers. In order to homogenize the laser radiation produced by the array to give a rectangular cross-section, the device proposed is fitted with special optics such as a prism which converges in the shape of a wedge, a glass plate, with a rectangular cross-section, reflective boundary drives, etc. The rectangular cross-section beam heats the two surfaces of the metal plates being plated only locally, over limited areas and to small depths, to the plastic state.