Abstract: A power supply for an EL lamp includes a boost circuit and four semiconductor switches connected as a bridge having an AC diagonal and a DC diagonal having one end grounded. The voltage boost circuit is coupled across the DC diagonal and an electroluminescent lamp is coupled across the AC diagonal of the bridge. The two semiconductor switches coupled to ground are SCRs.

Abstract: A microprocessor controlled ballast includes a single front end and a plurality of inverters separately controlled by a single microprocessor. Lamps are operated in groups according to separate line inputs to the ballast. Total power is reduced to fifty percent or less if a line input is off.

Abstract: A high resolution delay line includes a coarse delay having a minimum period of delay and a fine delay having a total delay, wherein the total delay is equal to or greater than half the minimum period. Each delay can be implemented in analog or digital form and the delay line can be implemented with one portion in analog form and the remainder in digital form. The digital delay can provide a delay upward of 1,500 milliseconds. The fine delay provides a resolution of ten microseconds or less. An unknown delay is measured by coupling a signal into two channels, wherein the first channel includes the unknown delay and the second channel includes the coarse delay and the fine delay. The output signals from the channels are correlated while adjusting the coarse delay for maximum correlation and then adjusting the fine delay for maximum correlation.

Abstract: A microprocessor controlled ballast includes a single front end and a plurality of inverters separately controlled by a single microprocessor. Lamps are operated in groups according to separate line inputs to the ballast.

Abstract: A constriction in the exhaust side of a discharge chamber containing oxygen isolates the oxygen supply from the rest of the system. A constriction of equal size or larger is used in the supply of another gas, thereby enabling mixtures of oxygen and other gases to be used in a downstream plasma system. In one embodiment of the invention, the gases are dissociated separately and then combined in a mixing chamber. In another embodiment, oxygen is dissociated and then a lighter gas is added and the mixture is dissociated. In a preferred embodiment of the invention, the lighter gas is selected from the group consisting of water vapor and nitrogen.

Abstract: An electronic ballast includes a zener diode in series with the bulk capacitor of the ballast to provide a charging voltage for a small capacitor that powers a power factor correction circuit within the ballast. A SCR in parallel with the zener diode shuts off the zener diode after the power factor correction circuit begins operation.

Abstract: An EL lamp is powered by bursts of high frequency signal repeated at low frequency, i.e. having a low duty cycle envelope, in order to shift the color of light emitted by the phosphor in the lamp without degrading the life of the lamp. The bursts include one or more consecutive cycles of a high frequency signal or several closely spaced cycles of a high frequency signal.

Abstract: The signal in each channel of a stereo is modulated at an inaudible frequency by a replica of the original signal. The modulated signal is broadcast into a room by a loudspeaker and is picked up by a microphone. The microphone is coupled to the stereo, which includes a demodulator for separating the replica from the signal as received at the microphone. By comparing the replica with the demodulated signal, data is extracted to compensate for the acoustic characteristics of the loudspeaker and the room in which the loudspeaker is located.

Abstract: An inductive boost circuit is added in parallel with an inverter to increase current to an EL lamp. The inverter and the boost circuit each include a switching transistor. The switching transistor in the inductive boost circuit may be matched to the switching transistor in the inverter and may be driven synchronously with the switching transistor in the inverter.

Abstract: An insulating enclosure for an electronic ballast has at least one major surface and a thermally conductive heat spreader at the major surface. The heat spreader is thermally coupled to at least one of the electronic components within the ballast and has an area greater than the area of the component as measured parallel with the major surface. The electronic components are thermally coupled to the heat spreader by a thermally conductive, deformable means such as caulk or by domes or dimples in the heat spreader that accommodate the variations in height among the electronic components. An electrically insulating layer can be located between the heat spreader and some of the components to prevent the heat spreader from electrically shorting the components.

Abstract: A computer is programmed to implement an incentive compensation plan by obtaining existing data on employees and business activities, evaluating the profitability of the activities, and indicating what amounts should be paid to existing employees based upon criteria defined by management in accordance with existing business conditions.

Abstract: An EL lamp is driven by a power supply including a voltage boost circuit and a low power inverter. The boost circuit includes a level shifting capacitor to provide voltage doubling. The inverter includes an inductor and at least one transistor connected in series between the output of the boost circuit and ground.

Abstract: A repeater system includes a plurality of repeaters, a low level combining circuit, and a tower unit for attachment to an antenna tower. The tower unit includes a linear amplifier, duplexer, filter, and low noise amplifier. The repeaters do not have final amplifiers. Instead, the low level combining circuit couples the signals from each repeater to the tower unit. The output from the linear amplifier in the tower unit is coupled to an antenna over a relatively short cable.

Abstract: An ballast includes a variable frequency boost circuit and a driven half-bridge inverter having a series resonant, direct coupled, parallel output. A control circuit includes a variable frequency driver section, a multivibrator section, and a sensing section. The variable frequency driver changes frequency smoothly, i.e. without discontinuities. The multivibrator section acts as a switch that is enabled or disabled by the sensing section for controlling the frequency of the inverter. Lamp current is required for continued operation of the control circuit. The multivibrator section controls starting by causing the inverter to produce an output signal having a trapezoidal envelope. In the event of an arc, the control circuit quenches the arc and the multivibrator periodically pulses the lamp to attempt to re-start the lamp.

Abstract: An instant start ballast includes a variable frequency boost circuit and a driven half-bridge inverter having a series resonant, direct coupled, parallel output. A control circuit includes a variable frequency driver section, a multivibrator section, and a sensing section. The variable frequency driver changes frequency smoothly, i.e. without discontinuities. The multivibrator section acts as a switch that is enabled or disabled by the sensing section for controlling the frequency of the inverter. Lamp current is required for continued operation of the control circuit. The multivibrator section controls starting by causing the inverter to produce an output signal having a trapezoidal envelope. In the event of an arc, the control circuit quenches the arc and the multivibrator periodically pulses the lamp to attempt to re-start the lamp.

Abstract: An electronic ballast for a gas discharge lamp includes an AC to DC converter for changing alternating current at power line voltage to direct current and an inverter powered by the converter and having a series resonant, direct coupled output coupled to the lamp. The inverter includes an AC switch having a diode bridge defining an AC diagonal and a DC diagonal and a transistor connected across the DC diagonal. The primary winding of a filament transformer is connected across the AC diagonal of the bridge and the transistor is coupled to the microprocessor for controlling current through the primary winding. The microprocessor is programmed to close the AC switch while the lamp is starting and to open the switch after the lamp is started, thereby cutting off the filaments from a source of power and reducing the power consumed by the ballast during normal operation. A resistor in series with the transistor is used to detect filament resistance and provide an indication of lamp type.

Abstract: A microprocessor controlled, electronic ballast operates a lamp at nominal settings and shifts the operation of the ballast away from nominal settings to reduce interference. The shift is randomized by a test--flip--?shift! routine that prevents all ballasts from attempting the same correction at the same time. On DC input voltage, the frequency of the boost controller is varied to reduce EMI. The ballast operates in bands according to the input voltage. Some bands correspond to full brightness, some to a fixed amount of dimming, and some to a variable amount of dimming. In the event of an abrupt change in load, the microprocessor changes the frequency of the inverter, thereby reducing output power and gradually unloading the boost circuit and maintaining power to the microprocessor.

Abstract: A data processing system includes a backplane and a plurality of logic boards connected to the backplane by a plurality of connectors. A set of common points is electrically coupled to the connectors by individual conductive traces between each common point and the corresponding pins of the connectors. The inductance of longer traces is reduced by merging traces near a central portion of the backplane to form a conductive region that extends to at least one connector on either side of the common points, thereby electrically shortening the longer traces. The inductance is further reduced by widening the longer traces. Longer traces are wider than shorter traces to reduce the differences in the LC products associated with each trace and, therefore, the differences in delay among the traces.

Abstract: An electronic ballast includes an AC to DC converter for power factor correction, a bulk capacitor for storing energy from the converter, and a microprocessor controlled, half-bridge inverter including a series resonant, direct coupled output. Input ports of the microprocessor are coupled to several locations within the ballast to monitor the operation of the ballast or the operation of a gas discharge lamp coupled to the ballast. An analog voltage limiter overrides the microprocessor to limit output voltage under fault conditions. A storage capacitor, connected in series with the bulk capacitor, stores energy at low voltage for powering the microprocessor. The microprocessor is programmed to provide lamp protection features, lumen maintenance, and a warm-up period for a lamp. The microprocessor is also programmed to meet the operating requirements of world markets and of different lamp types.

Abstract: An employee eligible to participate in a pension plan is loaned up to the full employee contribution to the plan, thereby encouraging participation in the pension plan. This "Participation Loan" includes periodic payments to the employee until employment ceases, the employee retires, or the loan terminates. Data on the Loan, the pension plan assets, the employer, and the employee is kept by the lender. The employee must provide current information to the lender to prevent termination of the loan, at which point the loaned amount, plus interest, is due. Failure to provide current information causes an alarm that can lead to termination of the Loan. At termination, the loaned amount, plus interest, is preferably re-paid in a single payment. The Participation Loan can be secured or unsecured. The secured variant can use traditional assets for collateral or an existing balance in the defined contribution pension.