Abstract: A ballast arrangement is disclosed for use in powering fluorescent and other gas discharge lamps. The ballast arrangement controls the arc voltage provide by an arc voltage oscillator independent of the filament voltage provided by a filament voltage oscillator. In this manner, safe maintenance condition during fault and interrupt condition are obtained. The full arc voltage is only applied to the lamp when the lamp filaments are warm or after a time period during which they are warmed. The filament pre-warming time reduces sputtering when an excitation or arc voltage in subsequently applied to induce lamp arcing.

Abstract: A fighting fixture disclosed is designed for installation in a cove of a public transit vehicle providing ready access to a space behind it, without requiring a variety of specially designed fixtures for special access requirements. The fixture comprises a pair of battens extending generally vertically to support the fixture, a longitudinally extending card panel supported in movable relationship by the battens and having a groove adapted to mount an advertisement card, a socket connected to each of the battens cooperating to mount a fluorescent lamp, and a bezel supported by the battens and supporting a lens covering the mounted lamp. Access to the space is obtained by releasing a lower edge of the card panel and rotating it about pivot pins to an open position. Similarly, the bezel is pivoted to provide access to the mounted lamp. An advertisement car card placed on the card panel is retained at a lower edge by the card panel throughout the pivotal displacement of the panel.

Abstract: A train communication and control system is described having the cars of the train connected by a two-wire train line running continuously from car to car. Each car has a transmitting circuit and a receiving circuit connected across the line. Any car may be selected to be a master unit. The selection of one car as a master unit disconnects the power sources of all other cars from the train line, leaving the master unit power source as the sole power source for the line. The master unit or any other car unit communicates with each other car by causing a high voltage ("mark" state or logic one) or a low voltage ("space" state or logic zero) to be on the train line. Each non-master car can receive a communication from a transmitting circuit, or can transmit to another car by applying a low impedance across the train line to change from a "mark" state to a "space" state. The power source consists of a voltage regulator with precision constant current limit.

Abstract: A lighting fixture disclosed is designed for installation in a cove of a public transit vehicle providing ready access to a space behind it, without requiring a variety of specially designed fixtures for special access requirements. The fixture comprises a pair of battens extending generally vertically to support the fixture, a longitudinally extending card panel supported in movable relationship by the battens and having a groove adapted to mount an advertisement card, a socket connected to each of the battens cooperating to mount a fluorescent lamp, and a bezel supported by the battens and supporting a lens covering the mounted lamp. Access to the space is obtained by releasing a lower edge of the card panel and rotating it about pivot pins to an open position. Similarly, the bezel is pivoted to provide access to the mounted lamp. An advertisement car card placed on the card panel is retained at a lower edge by the card panel throughout the pivotal displacement of the panel.

Abstract: An orientable passenger reading light is provided for vehicles having a two-part removable bezel arrangement. The lower part of the bezel is freely rotatable to disguise the method of relamping by requiring correct manipulation of the upper bezel part to allow release and removal of the bezel arrangement. A continuously adjustable ball and socket arrangement permits varying the orientation of the light over a wide range such as a 25 degree spherical zone. A simplified locking mechanism may be engaged in any position without tools, to prevent adjustment by passengers. When the locking mechanism is disengaged, enough friction is provided to maintain the orientation despite environment vibration.

Abstract: A ballast arrangement is disclosed for use in powering fluorescent and other gas discharge lamps. The ballast arrangement provides both full current and low current outputs for multiple sets of lamps so that dual lamps can be powered simultaneously, at the same or different output levels.

Abstract: A digital multiplier accumulator for performing the sum of products operation on two or more signal groups is described. The signal groups may be digitally coded and weighted. The multiplier accumulator will multiply selected signals from each signal group. Additionally, the multiplier accumulator can multiply the product of the signals by a scale factor. All of the products can then be summed to provide an analog output which represents the accumulated products of the digital inputs, scaled by the appropriate scale factor. The entire operation may be performed within a single logic element delay, since all the multiplication circuits operate in parallel and the summing is performed simultaneous to the multiplication. The digital multiplication is implemented with standard digital logic, while the analog multiplication and accumulation is implemented with a resistor array.

Abstract: A thermal printhead spring mount is provided, wherein a spring engages a printhead carrier at two points along the width of the carrier, the points being equidistant from the center of the carrier. A cam engages the center of the spring and selectively biases the spring against the carrier. The spring transfers equal force to the two points, creating a balanced carrier. By releasing cam force from the spring, through simple rotation, tension is relieved in the spring.

Abstract: A data acquisition system employs data conversion circuitry well suited to large multisensor systems such as computerized tomography systems utilizing X-ray detectors. The data conversion system consists of a number of detectors or similar signal sources and a corresponding number of data registers and accumulation registers. Each data register contains a previous sample output of a signal source. Differential data conversion is employed such that the difference between the previous output and the current signal source output is added to the data register in order to update it to the current signal source output. Each signal source is repeatedly sampled and the samples accumulated in an accumulation register. The data conversion system thus provides increased system linearity, accuracy, and dynamic range, and yields improved measurement simultaneity of a large number of signal sources. These factors combine to result in substantial improvement in image resolution after suitable processing by a computer.

Abstract: A fluorescent lamp socket disclosed is designed for use in environments subject to substantial vibration or shock. A fluorescent lamp is supported by its ferrule or end cap to firmly couple the lamp to the socket. The socket is provided with a retainer element for ready insertion or removal of the lamp. While the lamp is being inserted into the socket, the retainer element engages an edge of the lamp ferrule which impinges on a camming surface of the retainer element and forces the retainer element into a cavity of the socket body. At the same time, contact pins of the lamp are received in slots formed in the socket body having contacts disposed therein. The lamp contact pins cause the contacts to bow, thereby forming a reliable pressure contact between them. As the lamp ferrule continues to be inserted, the lamp ferrule will pass beyond the retainer element and the retainer element will be freed to be urged by a spring toward an extended position.

Abstract: An arrangement and method for providing an elongated light source, such as for illuminating a sign or the interior of a mass transit vehicle or other display, which includes emitting light from a light source into an elongated tubular member having a portion lined with a high reflectance film formed with longitudinal prismatic lenses, the tubular member having a light-transmissive opening along its length, with a diffusing medium substantially diametrically opposite such opening, and optionally a reflector or a second light source at one end of the tubular member. The emitted light propagates in the inner tubular member by reflecting from the high reflectance lining and the reflector to impinge on the diffusing medium and thereby transmit light outwardly through the light-transmissive opening so as to project light against a sign or advertising card or like object. Several units may be placed end-to-end to provide a longer illuminating arrangement.

Abstract: An apparatus for diffusing light and for directing circulation of air. A support (3), a grill panel (2) and a socket (12) are mounted together to form the apparatus. The support (30) is mounted to a base (64, 68). A nozzle (94) within the base (64, 68) creates a venturi effect by providing an emerging airstream which causes air to flow upward through the grill panel and then out to mix with the emerging air-stream. The grill panel (2) is cleaned of particulate matter because of the flow of the air through the grill panel. The emerging airstream travels in the same direction that it travelled when passing from the inlet to the outlet of the nozzle.

Abstract: Pulse fingers are disposed on a heat-generating material which fingers are pulsed to change the resistance of portions of the heat-generating material. By such change in the resistance of the heat-generating material, electrical current diffusion is prevented and heat diffusion is permitted between the changed resistance portion of the heat-generating material, thereby providing high resolution character printing and so-called "continuous" graphics printing.

Abstract: A train communication and control system is described having the cars of the train connected by a two-wire train line running continuously from car to car. Any car may be selected to be a master unit. The selection of one car as a master unit disconnects the power sources of all other cars from the train line, leaving the master unit power source as the sole power source for the line. The master unit communicates with each other car by causing a high voltage ("mark" state or logic one) or a low voltage ("space" state or logic zero) to be on the train line. Each non-master car can receive a communication from the master unit, or can transmit to another car by applying a low impendance across the train line to change from a "mark" state to a "space" state. The power source consists of a voltage regulator with precision constant current limit.

Abstract: A fixture for a fluorescent lamp includes a diffuser panel. The diffuser panel has a frame and longitudinal elements supported by the frame and spaced apart from one another. At least some of the elements are constructed of a material to allow diffusion of impinging light. Preferred materials are translucent or transparent, such as glass or plastic. The diffuser panel also functions as an air diffuser. Provision of a nozzle in the base of the fixture allows air to flow through the panel by a sucking effect created by high velocity forced air flowing through the nozzle. This results in fixture cleaning and temperature equalization. The fixture is particularly adapted to be mounted in a moving vehicle. For this purpose, the panel is designed to be tamper-resistant and to provide easy maintenance. The diffuser panel, when a latch is opened, may be lowered by rotation to provide access to the lamp and ballast.

Abstract: A fixture for a fluorescent lamp includes a diffuser panel. The diffuser panel has a frame and longitudinal elements supported by the frame and spaced apart from one another. At least some of the elements are constructed of a material to allow diffusion of impinging light. Preferred materials are translucent or transparent, such as glass or plastic. The diffuser panel also functions as an air diffuser. Provision of a nozzle in the base of the fixture allows air to flow through the panel by a sucking effect created by high velocity forced air flowing through the nozzle. This results in fixture cleaning and temperature equalization. The fixture is particularly adapted to be mounted in a moving vehicle. For this purpose, the panel is designed to be tamper-resistant and to provide easy maintenance. The diffuser panel, when a latch is opened, may be lowered by rotation to provide access to the lamp and ballast.

Abstract: A portable incandescent light assembly having a selectably interposable filter is disclosed. The light assembly is particularly applicable to night vision situations for airplane pilots. The light assembly comprises a housing in which a light source and a filter for filtering out infra-red light are located. The light assembly further comprises a mechanism for rotating the filter within the housing between a filtering position in which the filter is disposed across a light output axis and a non-filtering position in which the filter is disposed parallel to the light output axis.

Abstract: An arrangement and method for providing an elongated light source, such as for illuminating a sign or the like or, for other display, which includes emitting light from an exterior light source into an inner tube having a portion lined with a high reflectance film of prismatic lenses, the tube having a light-transition opening along its length, with a diffusing medium substantially diametrically opposite such opening, and optionally a reflector at one end of the inner tube. The inner tube is concentrically surrounded by an outer tube having light-transmissive portions of different colors. The outer tube is rotatable relative to the inner tube. The emitted light propagates in the inner tube by reflecting from the high reflectance lining and the reflector to impinge on the diffusing medium and thereby transmit light outwardly through the light-transmissive opening and thereafter through a selected one of the colored portions so as to project colored light against a sign or like object.

Abstract: A field telephone system having a widely dispersed set of telephone lines including a page line pair and a party line pair, audio processing equipment including telephone handsets, handset amplifiers, receiver amplifiers and paging speaker amplifiers is designed to have improved voice transmission by provision of a narrow band FM carrier system. The FM carrier system includes a device for generating a carrier frequency signal, a modulator for modulating the carrier frequency with an audio signal derived from one of the handsets at a transmitting station and circuitry for transmitting the modulated signal over a line pair to a receiving station. The receiving station includes circuitry responsive to the transmitted signal and the carrier frequency signal for extracting the audio component of the transmitted signal and for processing the extracted audio signal and for providing the processed audio signal to a handset at the receiving station.