Abstract: A power converter circuit requiting the periodic reset of a core of the power transformer includes a control circuit operative to alter a response of the converters voltage regulation feedback control to limit and/or control the power switch duty cycle to regulate a voltage of the reset capacitor whenever the reset capacitor sustains a voltage above a preset threshold.

Abstract: A half bridge power converter utilizes two oppositely phased power switches operated with unequal duty cycles. A magnetic arrangement with two inductance values having a ratio equal to the ratio of the unequal duty cycles is included in the converter to compensate for the unequal duty cycles.

Abstract: Magnetic components are fabricated as monolithic structures using multilayer co-fired ceramic tape techniques. Fabrication of these magnetic components involves constructing multiple layers of a magnetic material and an insulating non-magnetic mataerial to form a monolithic structure with well defined magnetic and insulating non-magnetic regions. Windings are formed using screen printed conductors connected through the multilayer structure by conducting vias.

Abstract: A method for enabling the service of mobilies by a microcell, in a two tier cellular system, involves identifying a microcell coverage area and offsetting microcell signal strength for a time sufficient to allow a fast moving vehicle, desiring service and having entered the microcell serving area, to exit the microcell coverage area before the call is set up or handed off forcing the controlling macrocell to handle the call setup or hand-off. Hence, only the mobile radiotelephones of stationary and relatively slow moving vehicles are served by the microcell. There is a substantially offset-coverage overlap period between the locations where a mobile may be found during the offset interval or duration of the apparent reduced signal strength of the microcell and the microcell coverage area. Calls that could be serviced by the microcell are instead serviced by the macrocell because the mobile radiotelephone responds to the strongest signal. This loss in capacity is solved by reducing the offset-coverage overlap.

Abstract: Phototools are located for processing both sides of printed circuit board panels by an apparatus and process that utilizes a work station with two alignment fixtures each including panel center registration PCR alignment mechanism to locate phototools and panels. Processing steps utilize the alignment fixtures to locate phototools on both sides of a panel. Each of the two phototools is initially positioned on its alignment fixture by the PCR alignment mechanism and secured to its alignment fixture by means of a vacuum supplied by a vacuum chuck which is operative as the top surface of the alignment fixture. The panel is then placed on top of the first phototool and aligned to the first phototool in the first alignment fixture using the PCR alignment mechanism. This first phototool is then affixed to the first side of the panel.

Abstract: A reduced-voltage/zero-current transition (RV/ZC-T) PWM converter includes an added active resonant network shunting the active power switch to reduce the switching losses in both the active power and and passive rectifier switches. The active power switch turns-on under reduced-voltage while the rectifier diode turns-off under zero-current. A soft current turn-off of the rectifier makes this converter suitable for high voltage applications where the reverse recovery losses of the diode can be considerable. An auxiliary switch included in the resonant network also operates with zero-current- switching.

Abstract: A drive arrangement and operative scheme for the power switching transistors of a half-bridge power drives the two power switching transistors with unequal duty cycles having conducting durations such that the sum of the conduction intervals substantially equals the combined switching period of the two power switching transistors. The conducting intervals are separated by very short dead time intervals controlled by the differing turn-on and turn-off times of the two power switching transistors. The short interval between alternate conductions of the two power switching transistors is sufficient to allow zero voltage turn on of the power switching transistors but short enough to minimize power loss and conducted noise.

Abstract: Therefore a method and apparatus for controlling a linear amplifier processing a plurality of carrier signals of a multi channel carrier system alters the phases of one or more sources of the multi-channel signals in response to a detected peak envelope power or of a peak to average power ratio at regular scheduled intervals. This reduces the peak envelope power to average envelope power ratio and enables the reduction in the power rating required by the amplifiers handling the multi-channel signal.

Abstract: A synchronous rectifier for use with a clamped-mode power converter uses in one embodiment a hybrid rectifier with a MOSFET rectifying device active in one first cyclic interval of the conduction/nonconduction sequence of the power switch and a second rectifying device embodied in one illustrative embodiment as a low voltage bipolar diode rectifying device active during an alternative interval to the first conduction/nonconduction interval. The gate drive to the MOSFET device is continuous at a constant level for substantially all of the second interval which enhances efficiency of the rectifier. The bipolar rectifier device may also be embodied as a MOSFET device. The subject rectifier may be used in both forward and flyback power converters.

Abstract: In plural channel amplifier systems processing many phase locked signals of different frequencies as a combined signal, these signals may drift into a phase convergence causing a peak power occurrence in the amplifier which greatly exceeds the rated capacity of the amplifier system. Therefore, in accord with the invention, a dynamic adjustment system is provided to minimize the peak power to which the amplifier is subjected by adjusting the relative phase relationships of the many signals. The dynamic adjustment system includes a peak power detector, a hard wired logic decision circuit and a timing control to control phase shift adjustment steps.

Abstract: Remote downloading of number assignment module designation parameters into a read-only memory circuit of a wireless telephone subscriber set (e.g., mobile, cordless, etc.) can be achieved by incorporating a tone signals receiver into the set and by bridging the receiver onto a wireless voice communication channel established between the subscriber's set and a service representative. The service representative can remotely enter subscriber-specific programming information and wireless service authorization data into the subscriber's telephone set for storage therein thereby quickly, reliably and cost-effectively providing authorized service to a new subscriber, or to an existing subscriber who requests a service change.

Abstract: Downloading of number assignment module designation parameters into a memory circuit of a mobile data telephone set utilizes the built-in voice band modem of the set so that service authorization codes and activation can be entered remotely into the subscriber's set thereby initiating cellular service or changing the type of service provided. As described, a cellular mobile subscriber first calls a remote cellular service provider center to establish a voice communication channel between the set and the center. Next, the modem of the set is selectively bridged onto the voice communication channel to achieve data transfer between a source of data located at the remote center and the subscriber's modem. The foregoing enables the remote programming of subscriber's authorization and information into the memory circuit of the mobile data telephone set.

Abstract: A converter operating in a resonant mode of operation is used as an off-line switching power supply operating with a high power density. A drive arrangement and operative scheme for driving the power switching transistors limits the dissipation losses within the power switching transistors. Drive circuitry drives two power switching transistors with unequal duty cycles having conducting durations such that the sum of the conduction intervals substantially equals the combined switching period of the two power switching transistors. These conducting intervals are separated by very short dead time intervals controlled by the differing turn-on and turn-off times of the two power switching transistors. The short interval between alternate conductions of the two power switching transistors is sufficient in duration to allow zero voltage turn on of the power switching transistors but short enough in duration to minimize power loss and conducted noise.

Abstract: A drive arrangement and operative scheme for the power switching transistors of a half-bridge power drives the two power switching transistors with unequal duty cycles having conducting durations such that the sum of the conduction intervals substantially equals the combined switching period of the two power switching transistors. The conducting intervals are separated by very short dead time intervals controlled by the differing turn-on and turn-off times of the two power switching transistors. The short interval between alternate conductions of the two power switching transistors is sufficient to allow zero voltage turn on of the power switching transistors but short enough to minimize power loss and conducted noise.Special biasing is provided to prevent drive signal application to power switches prior to attainment of a minimum voltage across the switch.Circuitry is provided for cancellation of output ripple currents at selected operating points of the power converter.

Abstract: Holdover circuitry for an off line switcher, including a DC-to-DC converter, maximizes holdover time, during source voltage failures, by commutating a precharged holdover capacitor to the input of a power factor correcting preregulator. This limits the size of the holdover capacitor required without any loss in holdover time. Reduction in the size of the required holdover capacitor required for a desired holdover time improves volumetric efficiency of the off line switcher. This arrangement further improves efficiency of the DC-to-DC converter and decreases stress on its components by narrowing the input voltage range requirement.

Abstract: A pressure relief valve, according to the invention, is mounted on a vent orifice providing a gas passageway from an interior plenum of a battery or a cell thereof to the ambient atmosphere. The valve fits on the vent orifice and opens to release gas at a high threshold battery gas pressure and reseals the vent orifice when the internal pressure of the battery drops to a low threshold.

Abstract: A mobile data telephone capable of transmitting and/or receiving voice and/or data signals over cellular communication channels or other air interfaces comprises a radio transceiver and a data modem in the same physical package. The transceiver and the modem have their respective controllers coupled so that they are effectively linked to achieve control of data transfer therebetween. In response to communication channel conditions in the air interface, the data flow between the modem and an audio processor of the transceiver can be selectively altered yielding high performance and high quality data transfer rates in the presence of severe channel impairments.

Abstract: A signal delay assembly for a high power linear amplifier, using feedforward circuitry to reduce distortion, comprises an interdigital delay line unit with included directional couplers. The structure of the interdigital delay line is substantially in a parallelepiped housing. A co-axial connector constructed as an integral part of the delay unit is used for signal connection to the amplifier.

Abstract: A battery charger control includes a thermal sensor attached to the battery being charged. If the temperature readings indicate a thermal runaway condition the charging current output is adjusted in accord with the temperature reading by means of voltage injeciton into an output sense lead of the charging circuitry as a means of achieving a control that prevents thermal runaway of the battery while still permitting continuous charging of the battery.