Abstract: Particles of electroluminescent phosphor having a moisture proof coating are re-coated by treating the phosphor in a fluidized bed with a mixture of water vapor and an organotrichlorosilane compound for approximately thirty minutes. The resultant siloxane coating further improves the moisture resistance of the phosphor.

Abstract: EL panels are made with PVDF/HFP copolymer resin binder, in substantially an uncrosslinked form, with DMAC solvent and/or other higher boiling point solvents/latent solvents/extenders. The resin binder is characterized by a melt viscosity of 1.0-8.5 kP using an industry standard test (ASTM D3835).

Abstract: Voice activity is detected by comparing a signal with two thresholds and producing data representing the energy of the signal. The data, in binary form, is compared with thresholds to determine voice activity. In accordance with another aspect of the invention, the thresholds are adjusted based upon statistical information. In accordance with another aspect of the invention, the data can be weighted to provide an indication of the quasi-RMS energy of an input signal. In accordance with another aspect of the invention, voice activity detectors, individually weighted, are provided at each input and each output of a telephone for reliably controlling echo cancelling circuitry within the telephone.

Abstract: A fire resistant air transfer grille or damper (10), suitable for use as a ventilating means in fire resistant doors, walls and ventilation ducts, includes an outer frame (12) and a plurality of slats (14). Each of the slats (14) is provided with an intumescent core and is positioned in one of a number of predetermined positions within the outer frame (12). The predetermined positions are determined by a number of recesses (26) provided in the outer frame (12). The outer frame (12) may be formed as two separate frame components (16, 18), and is preferably made from steel. The slats (14) are preferably formed from aluminium with an intumescent material provided within the aluminium slat (14) to provide an intumescent core. Each of the slats (14) also preferably includes an elongate channel member (30, 32) along each of two of its side edges, wherein the elongate channel members (30, 32) of each of the slats (14) engage within the recesses (26) in the outer frame (12).

Abstract: Light scattering particles are added to the ink used for printing the cascading layer. The particles and cascading material are then printed in the same layer. Light entering the cascading layer is scattered, re-entering the cascading material thereby increasing the effectiveness of the cascading material and enabling one to use less material. Because less cascading material is used, the cost of the EL lamp is reduced and cascading efficiency is increased. The light scattering particles and the cascading material are in an overprint or are in the phosphor layer.

Abstract: An input signal is applied to a notch filter having a transfer function that is the inverse of the expected noise signal. The filtered signal is coupled to a first amplifier and the input signal is coupled to a second amplifier. The outputs of the amplifiers are summed. The gains of the amplifiers are oppositely adjusted in response to the magnitude of the input signal. At low amplitude, the filtered signal is amplified more than the unfiltered signal. At high amplitude, the unfiltered signal is amplified more than the filtered signal.

Abstract: Amplitude is corrected by subtracting a component signal from a composite signal to produce a remainder signal, correlating the remainder signal with the component signal to produce a product signal, averaging the product signal, and adjusting the magnitude of the component signal in accordance with the averaged product signal to minimize the product signal. The amplitude of the component signal is adjusted in a programmable gain amplifier controlled by an up-down counter. The up-down counter is part of a digital control loop including a pseudo-multiplier for multiplying the remainder signal with the component signal. The output of the multiplier controls the direction of the count, which is generally continuous except that it cannot roll over or roll under. The remainder signal is the received signal with the echo removed.

Abstract: At least one layer of cascading material overlying an EL lamp converts the light emitted by the EL lamp into infrared light. The EL lamp is supported within in a container transparent to at least infrared light, along with at least one battery and an inverter to provide power for the lamp in portable applications. The lamp is rolled to form a cylinder and fits within the inside diameter of the container. The lamp can be turned on or off by means of a switch interrupting current from a battery or to the lamp.

Abstract: A complementary comb filter includes a plurality of band pass filters and a plurality of notch filters, wherein the notch filters have the same center frequencies as the band pass filters or the same center frequencies as the dead bands defined by the band pass filters. Phase distortion by the notch filters occurs primarily in the notch, thereby eliminating distortion of the signal.

Abstract: An inverter for driving an EL lamp is tapped to provide voltage or current for driving one or more EL lamps and an LCD. In accordance with one aspect of the invention, one side of the pump inductor is tapped for a voltage that drives the LCD.

Abstract: An inverter for driving an EL lamp is tapped to provide voltage or current for driving one or more EL lamps, LEDs, and an LCD. In accordance with one aspect of the invention, one side of the pump inductor is tapped for a voltage that drives one or more LEDs and the LCD. In accordance with another aspect of the invention, the LEDs are in series with a storage capacitor and are driven by the current pulses to the storage capacitor.

Abstract: A scooter lift includes a post and boom made from a single piece of curved pipe. The boom further includes an arm that is rotationally adjustable about the pipe to provide small, incremental changes in elevation. Incremental rotational adjustment is achieved by a plate attached to the pipe and having a first set of holes that align with second set holes in the angular portion. The holes are drilled in a pattern that provides a vernier-like adjustment of position. The post is mounted on a base such that at least some of the post overlies a point outside the footprint of the base.

Abstract: Brightness is improved, without decreasing lamp life, by driving an EL lamp at higher voltage and less current, by increasing phosphor loading, by low loss dielectric, and by depositing the phosphor layer in two passes.

Abstract: A band pass filter includes a pair of filters having different center frequencies and a difference amplifier coupled to the outputs of the filters. The filters preferably have response curves that intersect at −3 dB. The separation of the center frequencies determines, in part, the ripple in the response curve of the band pass filter.

Abstract: An SMR repeater is made agile by adding a microprocessor controlled frequency selection circuit to enable the repeater to operate on any one of several available frequencies in a band. For dispatch service, the output of the repeater is switched to a power amplifier feeding an omni-directional antenna. The repeater scans several frequencies sequentially. If a signal is detected, scanning is halted to provide repeater service, after which scanning is resumed. The frequency agile repeater is coupled to an antenna system having a narrow beam which can be steered electronically. A control computer scans the azimuth of the beam. The computer divides a service area into a plurality of cells extending radially from the antenna system and assigns channels as needed to service a subscriber. More than one cell can be on the same frequency without interference.

Abstract: A driver for an EL lamp includes a voltage boost circuit and an H-bridge output having an AC diagonal and a DC diagonal. An EL lamp is coupled across the AC diagonal. A current path is coupled in series with the DC diagonal and limits current through the EL lamp. The current path is either internal or external to the semiconductor device implementing the driver.

Abstract: EL panels are made with PVDF/HFP copolymer resin binder, in substantially an un-crosslinked form, with DMAC solvent and/or other higher boiling point solvents/latent solvents/extenders. The resin binder is characterized by a melt viscosity of 1.0-8.5 kP using an industry standard test (ASTM D3835).

Abstract: Gas discharge lamps having filaments at each end thereof are operated in groups according to the power applied to separate line inputs to the ballast. The filaments of the lamps in a first group are powered by a first inverter that provides lamp current to a second group. The filaments of the lamps in the second group are powered by a second inverter that provides lamp current to the first group of lamps. Thus, even if an inverter is turned off, the lamps powered by that inverter are in a pre-heated state for instant starting. Power is coupled to the filaments by a network that is relatively insensitive to changes in frequency.

Abstract: An electroluminescent lamp includes two electrodes and at least three connectors, a first connector coupled to a first electrode and a second connector and a third connector coupled to the second electrode. A first electric current flows through the lamp between the first connector and the second connector, causing the lamp to emit light. A second electric current flows through the second electrode between the second connector and the third connector, whereby the second electrode increases in temperature in response to the second electric current. When backlighting a liquid crystal display, the second electrode provides heat to warm the display for proper operation. Either electrode can be used as a heater.