Abstract: This circuit arrangement includes an interpolation filter (3) which converts the incoming signal values (A) into interpolated signal values (B) of increased repetition frequency. The interpolated signal values (B) are reduced in word length by means of a quantizer (4a) and by quantization error feedback through an error filter (25). A D/A converter (6) consists of two or more nonweighted switching stages connected in parallel. The activated switching stages deliver currents which are added together at the output end. The D/A converter (6) is controlled by a control circuit (5) which processes the output signals (D) of the quantizer (4a). The activated switching stages are continuously interchanged on a cyclic basis, so that relative resistance tolerances in the circuit average out.

Abstract: If a three-phase current is generated by dc-to-ac conversion, a higher ac output voltage is achieved by connecting each of the three phases alternately to one of the two terminals of the dc voltage source during a sixth-period section, while the two other phases have a sinusoidal waveform, such that the difference voltages between all three phases are sinusoidal.

Abstract: A prismatic protective shield for each flash-lamp and reflector combination as arrays of parallel prisms in order to level the light distribution with a tendency to produce an intensity dip at the pattern center. Arrays of horizontal prisms occupy a central vertical stripe of the shield plane. Arrays of vertical prisms are at each side of the horizontal prisms.

Abstract: Method for applying protective sleeves to combustion-type photoflash lamps herein there is placed proximate a mold means a strip of organic plastic having a thickness of from about 0.3 to 0.8mm, a tough-plastic characteristic at a temperature of from about 160.degree. to 200.degree. C, a tough-elastic characteristic at a temperature of from about 90.degree. to 125.degree. C, and a freezing temperature of from about 65.degree. to 70.degree. C. The strip is heated to the tough-plastic temperature and drawn into the mold means to form a series of plastic cups which have a dimension slightly smaller than the lamps to be sleeved. When the temperature of the formed cups is in the tough-elastic range, they are expanded to be slightly larger than the lamps to be sleeved, and are then frozen. The lamps are then placed into the cups which are then heated to cause them to shrink-fit onto the lamps. The sleeved lamps are then severed from the residual plastic strip.

Abstract: The invention provides a system for developing sync pulses when PICOR is used on sound film systems. The sprocket holes in the feed track of the film are used in conjunction with a light source and a photocell to develop sync pulses which are required to synchronize a rotating electronic switch with periodic sequential information recorded on the sound track of the film.