Abstract: An analog-to-digital converter 2 for video signals has a sensitivity (reference) input 4 controlled by a controller 10 in response to the converter's digital output so as to maintain the grey level with a predetermined range. Preferably the controller employs an irregular subsampling of the digital values, and responds differently to extreme and mid-range samples. A scale factor may be forwarded to a digital-to-analog converter for reconversion.

Abstract: The present invention relates to hardenable mixtures containing:(i) a polyglycidyl ether or ester based on an aliphatic, cycloaliphatic or aromatic alcohol or a corresponding carboxylic acid and(ii) a hardener obtainable by reaction of:(A) a mixture of 2-4 mol of a monohydric, aliphatic alcohol and 1 mol of phosphorus pentoxide in an inert organic solvent, or of 2 mol of a dialkyl phosphate or of 2 mol of phosphoric acid, if appropriate in combination with 1-2 mol of a monohydric, aliphatic alcohol, with(B) 0.5-1.5 mol of a diglycidyl ether based on a cycloaliphatic or aromatic diol,with the proviso that the said diglycidyl ether used for the preparation of the hardener has an average molecular weight (number-average) of not more than 2,500 and the said hardener is essentially free from 1,2-epoxide groups.The hardenably mixtures are suitable in particular for the production of coatings.

Abstract: The invention relates to oligomeric and polymeric esters of difunctional polyphenylene ethers and phosphinic acids, phosphonic acids and phosphoric acid and to their use as a flame-retarding mixing component for other plastics.