Abstract: The invention is directed to an improved method for making a porcelain enamel tag or sign. The process involves forming a single white porcelain enamel base coat over a suitable metal backing, and firing to bond the porcelain enamel to the metal, resulting in the formation of a porcelain coated metal blank. The blank is then coated with a photographic emulsion which contains a colored frit. The emulsion coating is allowed to dry, and is then ready to receive a printed image. The desired image or graphic to be reproduced is formed on a light transmitting backing, which is made in the form of a print. The print is then affixed to the porcelain enamel blank which contains the emulsion overcoating. The blank containing the image on its surface is then exposed to a source of activating radiation. Following exposure, the image containing blank is developed in a warm aqueous solution, whereby the water serves to develop the emulsion mixture.

Abstract: A metal matrix composite comprises randomly-oriented inorganic oxide fibres of density below 3 g/ml embedded in a metal matrix material such as a light metal, for example aluminium or magnesium or an alloy thereof. In a particular embodiment the fibres are of density 1.8 to 2.5 g/ml and preferably are of mean diameter from 2 to 10 microns. The composite can be made by liquid infiltration of a fibre preform comprising the fibres bound together with an inorganic or an organic binder or by extrusion of a mixture of the fibres and a powdered metal matrix material.

Abstract: A phase locked loop with pre-set and squelch capability particularly adapted for burst type signals. In addition to the conventional phase detector, loop filter (LF) and voltage controlled oscillator (VCO) the loop includes a squelch switch connected between the phase detector and LF. A track and hold circuit is connected in series with another switch between output and input of the LF. Both switches and the track and hold circuit itself are controlled by the output of a level detector which indicates presence of an intermittent (i.e., bursty) carrier. The squelch switch is closed, connecting the phase detector to the LF, when the output of the level detector indicates the presence of a carrier burst. At the same time, the second switch is opened so that the LF is not affected by the output of the track and hold circuit. In addition, the track and hold circuit is enabled to track the error voltage output of the LF.

Abstract: A side lock detector to prevent side lock in coherent PSK demodulation. For demodulation purposes it is necessary to recreate the carrier at the receiver. This may be accomplished with a phase-locked loop. However, with plural phase PSK modulation the input signal to the phase-locked loop has energy at side bands spaced at modulation rate intervals from the desired lock frequency as well as at the desired lock frequency. To detect side band lock, a band pass filter monitors the phase detector output of the phase-locked loop. The center frequency of the filter is equal to the modulation rate and the filter band width is very narrow. Only during side lock will significant amounts of energy pass the filter. This energy may be detected by a simple diode detector or the like. A lock inhibit means is provided, responsive to the output of the detector, to drive the voltage controlled oscillator out of a side lock condition.