Abstract: Device for mixing at least two chemically reactive plastics components under pressure, having a mixing chamber, into which the plastics components are injected in each case by way of a component-feeding opening, wherein a reversible control piston is provided for opening and closing the component-feeding openings and for discharging plastics mixture remaining within the mixing chamber, wherein the control piston is connected to an electric drive. Alternatively, in the case of a transfer mixing head, the cleaning piston may be coupled to an electric drive. A method for operating such a mixing head is also disclosed.

Abstract: Methods in an optical receiver, for decoding a received M-level pulse-amplitude-modulated, PAM-M, optical signal. An example method comprises, for a first interval, decoding (510) the received PAM-M optical signal using a standard PAM-M decoder with M-1 thresholds, using first sampling times, to obtain a first set of decoded bits, and decoding (520) the received PAM-M optical signal using a duobinary decoder with 2M-2 thresholds, at second sampling times offset from the first sampling times, to obtain second set of decoded bits. The method further comprises calculating (530) first and second error metrics corresponding to the first and second sets of decoded bits, respectively, and selecting (540) the standard PAM-M decoder or the duobinary decoder for subsequent decoding of the received PAM-M optical signal, based on the first and second error metrics.