Abstract: An acoustical transmitting system and method for producing a narrow beam of acoustic energy over a broadband operating frequency range utilizes a parabolic reflector dish, a horn-loaded compression driver for directing acoustic energy toward the dish's reflecting surface, and a low frequency driver mounted behind a central aperture in the dish for producing acoustic energy that combines and interacts with the reflected acoustic energy produced by the horn-loaded compression driver. An input signal processing circuit is provided to condition the audio signal to the horn-loaded compression driver and the low frequency driver to achieve on-axis gain and off-axis cancellations at low frequencies. The addition of the low frequency driver to the reflector dish system effectively extends the ability of the system to produce and transmit acoustic energy in a narrow distribution pattern at frequencies below 1000 Hz using a four foot diameter dish.

Abstract: A method and correction circuit for improving and controlling the listening window and response of a two-way loudspeaker system utilizing a horn-loaded high frequency driver. The correction circuit includes adjustable active all-pass and band-pass filters, in a specific arrangement, coupled with conventional cross-over filters to achieve a maximally flat amplitude and phase response acoustically throughout a preferred listening window. A spectrum analyzer measures the near-field responses of the individual and combined transducers while adjustments are made. A phase shifting circuit is included in the low frequency channel which results in improved near-field to far-field response consistency and significantly improves the subjective characteristics of the high frequency horn.

Abstract: A bass reflex loud speaker system for use in high power applications which includes an enclosure with at least two, and preferably three, cone drivers mounted in front of separate and acoustically isolated bass reflex chambers. Each bass reflex chamber is tuned to a separate octave such that the bass reflex modules formed by each bass reflex chamber and its associate cone driver produces a complex acoustical signal comprised of different frequency components in the low frequency range at high sound pressure levels, but with minimum driver cone excursion and distortion.

Abstract: A seat cushion having means for attaching to a conventional stadium seat is disclosed. The seat cushion includes means for connecting the cushion to a stadium seat. In the preferred embodiment, the connecting means are two straps having a grommet hole therein. A screw or bolt means attaches through the grommet means to the stadium seat. Preferably, the seat cushion is attached to the front of the stadium seat. When in use, the seat cushion lays atop a metal seat. When not in use, the seat cushion can pivot about the attaching connection means and hang off the surface of the metal seat. This allows the cushion to be somewhat shielded from environmental elements when not in use.

Abstract: A Self Calibrating Color Printer. The present invention enables color printers to accurately reproduce color images despite variations in ink, paper or the printing system. The calibrated printer includes a movable optical sensor assembly which first calibrates itself by measuring an included known color gamut located within the movement range of the sensor assembly. Once calibrated, the sensor assembly measures a color print test pattern newly printed by a movable color print head of the printer. An analog-to-digital converter transforms electrical signals from the sensor assembly to sensor values in digital form, enabling a printer control processor to process the measured data, thereby producing two look-up tables stored in memory: first, a color correction look-up table which adjusts image color values to account for the ink/paper variations, and second, an error diffusion look-up table which spreads color value errors at a given pixel to its neighbors.

Abstract: A circuit for improving the transient behavior of a two-way loudspeaker system includes a crossover circuit with high selectivity, amplitude and phase correction circuitry for separately correcting the amplitude and phase responses of the high and low frequency drivers in their mounting environment, and correction circuitry for correcting the composite amplitude and phase response of the overall loudspeaker system after insertion of the crossover. A further phase offset technique and circuit provides for introducing frequency dependent phase shift in the loudspeaker system's high or low frequency channels for offsetting the phase responses of the high and low frequency drivers within the crossover frequency range. According to the phase offset technique of the invention, phase shift is added, preferably in the high frequency channel, until composite amplitude response curves observed on-axis and at different vertical angles off-axis are forced to be consistent.

Abstract: A digital bypass unit for a PBX or ACD telephone system having T1 spans provides the capability to place and answer calls on a digital T1 span in the event of a system failure or power failure. The bypass unit permits the bypass of the failed system, connecting T1 channels directly to digital telephone sets, and is automatically activated in the event of power or system failure. Queueing and distribution of incoming calls are both provided when the system is in the bypass mode.

Abstract: A circuit for improving the transient behavior of a two-way loudspeaker system includes a crossover circuit with high selectivity, amplitude and phase correction circuitry for separately correcting the amplitude and phase responses of the high and low frequency drivers in their mounting environment, and correction circuitry for correcting the composite amplitude and phase response of the overall loudspeaker system after insertion of the crossover. A further phase offset technique and circuit provides for introducing frequency dependent phase shift in the loudspeaker system's high or low frequency channels for offsetting the phase responses of the high and low frequency drivers within the crossover frequency range. According to the phase offset technique of the invention, phase shift is added, preferably in the high frequency channel, until composite amplitude response curves observed on-axis and at different vertical angles off-axis are forced to be consistent.

Abstract: Disclosed is an ink-jet composition including an organic carrier that is solid at 25.degree. C. and liquid at the operating temperature of an ink-jet nozzle and a driver having a critical pressure greater than 10 atmospheres, the carrier and driver being miscible in liquid phase. The ink-jet composition is characterized by a viscosity of less than 15 centipoise at 90.degree. C. and a surface tension of between about 20 to about 25 dynes per centimeter at 90.degree. C. The ink-jet compositions disclosed herein are particularly useful in thermal ink-jet printing using thermally induced vapor bubbles to eject ink droplets from the printer and onto a substrate.

Abstract: An ink jet ink including a waxy carrier that is solid at 25.degree. C. and liquid at the operating temperature of an ink jet nozzle and a driver having a critical pressure greater than 10 atmospheres, the carrier and driver being miscible in liquid phase.

Abstract: An ink jet ink including a waxy carrier that is solid at 25.degree. C. and liquid at the operating temperature of an ink jet nozzle and a driver having a critical pressure greater than 10 atmospheres, the carrier and driver being miscible in liquid phase.

Abstract: A digital bypass unit for a PBX or ACD telephone system having T1 spans provides the capability to place and answer calls on a digital T1 span in the event of a system failure or power failure. The bypass unit permits the bypass of the failed system, connecting T1 channels directly to digital telephone sets, and is automatically activated in the event of power or system failure. Queueing and distribution of incoming calls are both provided when the system is in the bypass mode.

Abstract: An ohmically isolating input circuit accepts a three pin connector of a cable from a signal source output for virtually all three pin connector standards, and will output a signal of the same voltage regardless of which of the three pin connector standards are used. In one embodiment of the invention, the input circuit includes a center tapped transformer having its tap primary winding side connected to the circuits three input terminals and having its secondary winding side connected directly into the input of an operational amplifier which forces the transformer to operate as a current transformer with virtually no voltage drop across its secondary or primary windings. The output of the operational amplifier, which serves as the output of the input circuit, is fed back to the inverting input of the operational amplifier to provide a high gain negative feedback circuit which converts signal currents from the transformer secondary winding to an output voltage signal.

Abstract: An ohmically isolated input circuit accepts a three pin connector of a cable from a signal source output for virtually all three pin connector standards, and will output a signal of the same voltage gain regardless of which of the three pin connector standards are used. The input circuit includes two magnetically isolated, serially connected transformers and three input terminals connected to the transformer's serially connected primary windings so that the input signal to any two of the three terminals is transformer coupled without change in gain to the circuit output through one or the other or both of the transformers depending on which two input terminals are selected. By using current transformers rather than voltage transformers the transformers run at very low signal levels thereby permitting the use of inexpensive and lightweight transformers without the introduction of distortion.

Abstract: A circuit and method are provided to compensate for the non-linear delay characteristics of a digital audio system introduced by the systems anti-aliasing filter. The circuit and method provide for introducing time delay to the digital system at the low and mid range frequencies, and adding decreasing amounts of time delay at the high frequency ranges to produce an overall composite time delay for the digital system which is relatively constant over its operating frequency range. The delay equalizer used to achieve such delay compensation is made up of active delay equalizer sections which are non-interactive, and which are independently tunable in terms of each sections center frequency and Q. An active delay equalizer section with a second order bandpass transfer functions has been devised to achieve this capability. It is comprised of an operational amplifier having input resistance and feedback resistance connected to its inverting input and a twin-T network connected in its non-inverting input.

Abstract: An optical fiber cable unit in which an elongated optical fiber is telescoped into an outer jacket such that an annular space is defined between the fiber and the jacket. The space is filled with a polyorganosiloxane "grease" having extremely good thixotropic properties which cause the material to establish a gas-tight seal between the fiber and the jacket while allowing the fiber to float freely within the jacket to avoid elongation of the fiber when tension is applied to the cable.

Abstract: The capability of varying sizes of a dot in a printer is fully exploited to provide a gray scale image of superior quality. Errors in gray level are used to modulate the sizes of the dots in producing the image.