Abstract: A switching circuit of the type including a plurality of differential amplifiers on an IC chip and having a linear operating range about a bias point, having an operational amplifier connected as a comparator and coupled to an input thereof to receive a modulating signal, one input of the comparator being connected to the bias point so that the output thereof applied to the switching circuit varies about the bias point within the linear range of the switching circuit, and means coupling the signal to be modulated to a second input of the switching circuit so that the signal is bi-phase modulated by the modulating signal with substantial carrier suppression and significantly reduced harmonics.

Abstract: A method is herein disclosed by which a polymerizable monomer or a mixture thereof can be economically and efficiently converted to polymeric substances with a high yield catalyst in a vapor phase polymerization process using a stirred-bed, quench-cooled, horizontaL reactor together with essentially total reactor off-gas recycle and melt finishing. The method is further characterized by being essentially isobaric at least up to the polymer finishing steps.

Abstract: Apparatus for the vapor phase polymerization of at least one polymerizable monomer comprising: (a) a horizontal reactor of substantially circular cross-section containing a centrally-located drive shaft extending longitudinally through said reactor to which are attached a plurality of adjacently located paddles, which paddles cause essentially no forward or backward movement of the particulate matter contained in said reactor and extend transversely within and to a short distance from the internal surfaces of said reactor, said reactor being divided into two or more individually gas-composition-controllable and polymerization-temperature-controllable polymerization compartments, by one or more dividing structures so constructed to control gas intermixing and movement of said particulate matter between said compartments; (b) driving means for said drive shaft; (c) one or more reactor off-gas outlets in each of said compartments spaced along the topward part of said reactor; (d) one or more vapor recycle inlets