Abstract: A laser system utilizing a Stimulated Brillouin Scattering SBS cell to produce optical phase conjugate retroreflection for nonmonochromatic light from a laser system.

Abstract: A back lighted transflective liquid crystal display with improved contrast ratio has a light mask positioned between the transflective element and the source of back lighting. The mask has light transmitting sections which are aligned with and have the same configuration as the indicia-forming electrodes in the cell. The mask has opaque or light blocking sections that are aligned with the background portion of the cell. In the transmissive mode light impinges on the cell only in the area of the indicia-forming electrodes, thereby enhancing the contrast ratio between the indicia and background portions of the cell.

Abstract: A phase angle balancing circuit for a variable speed constant frequency (VSCF) power system is disclosed. Multiphase electric power signals from cycloconverters are summed to produce continuously and automatically the zero sequence voltage of the multiphase electric power signals. The zero sequence voltage signal is provided to each of the modulator stages associated with the cycloconverters to effect phase angle correction of the phase relationships between the multiphase electric power signals. A bandpass filter, having a passband center frequency centered on the preselected frequency of the multiphase electric power signals, is added to the phase angle balancing circuit of the present invention to make the zero sequence voltage corrective means stable as a well damped negative feedback system. The bandpass filter also eliminates undesirable frequency harmonics and "hash" on the signal having the zero sequence voltage caused by undesired frequency components in the multiphase electric power signal system.