Abstract: A phase-shifted diffraction grating for devices such as semiconductor lasers is produced by forming a first diffraction grating pattern of a first material having a reference pitch on a substrate. The substrate is then coated with a second material on both the first material and an exposed portion of the substrate in a region where a second diffraction grating having a pitch which is the reverse of the reference pitch of the first diffraction grating pattern is to be formed. The first material is removed by lift off to obtain the second diffraction grating pattern on the second diffraction grating region. The substrate is etched using the first diffraction grating as an etching mask to form the first diffraction grating and then the substrate is etched with the second diffraction grating pattern as an etching mask to obtain a second diffraction grating continuous with the first diffraction grating.

Abstract: A peaking system for a compressed digital video signal includes a transform coder for converting 8.times.8 blocks of video pixels into corresponding groups of transform coefficients and supplying the coefficients to an image classifier where the coefficients are classified according to their perceptual nature or image types, e.g. edge, flat area, texture, etc. of the video represented thereby. Control signals for horizontal and vertical perceptual classifications are developed and applied to a peaking filter for selectively peaking the video signal in accordance with the horizontal and vertical control signals. A receiver operates to recover the selectively peaked compressed video signal. In another embodiment, the transmitter supplies the video signal with the developed control signals for use by a receiver in selectively peaking the recovered video signal in accordance with the control signals.

Abstract: An image processing apparatus extracts an edge or line portion of an image, judges grayness of the image, and processes the image according to outputs of the means used for the edge- or line-extraction and grayness-determination. The further processing may, for example, comprise undercolor removal and/or black-addition. Edge extraction can be performed by use of a Laplacian. The grayness can be judged by, for example, providing a colorlessness signal formed from two color component signals. Extraction of a line region, instead of Laplacian edge extraction, can be performed, for example, by use of an Hadamard transformation. Also, the invention more generally includes detecting grayness of an image, detecting other characteristics of the image, and judging additional characteristics of the image according to the first two determinations.

Abstract: An improved 120 Volt/40 Watt incandescent light bulb is adapted to be used in an ordinary Edison-type lamp socket and provides nearly twice the effective Lumen-output as that of an ordinary 120 Volt light bulb of same power rating and same life expectancy.The improved light bulb comprises an electronic inverter-type voltage conditioner that provides a voltage of about 15 Volt RMS magnitude to the filament of a small Tungsten-Halogen lamp. This voltage conditioner is comprised within the bottom part of the light bulb and the Tungsten-Halogen lamp is mounted right above the power conditioner--all within an outer envelope.The improved light bulb has shape and size substantially the same as that of an ordinary household 120 Volt/40 Watt light bulb.Means are provided by which the Lumen output can be manually adjusted over a wide range.In one version, the outer envelope is removable and the small Tungsten-Halogen lamp is replaceable.

Abstract: A temperature switch for HID lamp fixtures is provided to enable such lights to be operated at low temperatures on the order of minus forty degrees Celsius, or minus fifteen degrees Fahrenheit. In one embodiment, the switch is comprised of a thermistor circuit and a resistive photocell circuit. When the resistance of either the thermistor or the photocell exceeds the reference value, or when the combined resistance of thermistor and the photocell exceed that value, the HID lamp will be turned on. The lamp is thereby turned on when the ambient temperature becomes very cold, regardless of the amount of ambient light in order that the components of the light fixture may be heated internally for more reliable operation.

Abstract: A power supply for helix and collector electrodes of a traveling wave tube is driven by an AC power source having a frequency of at least 500 KHz. The helix supply includes plural, stacked voltage doubler AC to DC modules responsive to the 500 KHz source. The collector supply includes plural AC to DC modules, each having a diode full wave rectifier bridge, connected in stacked relation. Each of the modules includes a transformer with a ferrite, toroidal core dimensioned so that it is not driven into saturation by the 500 KHz source. Each module also includes inexpensive, signal switching diodes having a recovery time of approximately 4 nanoseconds. The ratio of the collector to helix DC voltages is maintained constant by threading a common lead through the apertures of the toroidal cores of the helix and collector modules. A separate common lead threaded through the apertures of the toroidal cores in the collector modules is connected directly to the 500 KHz power source.

Abstract: A lamp switching circuit and method for selectively energizing one or more lamps of a bank of lamps and thereafter energizing other of the lamps when power is interrupted and next applied. The lamp switching circuit and method is also effective in selectively and sequentially operating one or more ballasts in a group of ballasts which, in turn, operate one or more lamps in a circuit arrangement. The lamps with which the present invention is used are typically phosphor excitable lamps, such as flourescent lamps. In this way, power consumption is reduced, even through lumen output is correspondingly reduced. However, by selectively and sequentially energizing only certain of the lamps in a circuit arrangement, the overall life of the lamps is materially increased. Moreover, the lamps will operate with the same degree of efficiency as they would operate if all lamps connected to a ballast were operating.