Abstract: A laser system employing one or more mirror sets having substantially astigmatism-free focusing power sufficient to maintain a desired laser beam diameter, for example, to compensate for thermally-induced distributed lensing. In one class of preferred embodiments, the invention is a high power gas laser system having a folded optical cavity with a periodic intracavity refocusing means to compensate for distributed negative thermal lensing in the hot plasma that comprises the active medium, and thus maintain a substantially constant beam diameter throughout the optical cavity. The periodic intracavity refocusing means preferably includes a corner mirror set (including at least one curved mirror and at least one other mirror) at each corner of the folded optical cavity. In one preferred embodiment, each corner mirror set is a mirror pair including a spherical mirror and cylindrical mirror.

Abstract: A microwave transceiver comprising a Gunn diode microwave radiation source, a Schottky-barrier diode mixer, a closed rectangular waveguide cavity, a coaxial-waveguide joint, and a monopole antenna providing a microwave radiation dispersion/collection pattern occupying a spatial region elevated from and extending radially outward and 360.degree. in azimuth with respect to said antenna, said spatial region having a substantially spatulate radial cross-section.

Abstract: An adaptive gate charge circuit for switching a power FET on in response to a control signal. The adaptive gate charge circuit includes driving circuitry that responds to assertion of a control signal by providing a charging current from a charge pump reservoir capacitor to the gate of the power FET for an initial time period sufficient to switch the power FET on. After the initial time period, holding circuitry provides holding current from the charge pump to the power FET gate to compensate for charge leakage. Current limiting circuitry connected to the holding circuitry limits current drain from the charge pump after the initial time period to the holding current required to compensate for charge leakage plus a minimum additional current.

Abstract: An illuminated sign system which uses a flexible fabric face material has an improved system for tensioning the material. A tensioning bar is used which extends the full length of the sign face and holds the fabric material along one edge and uses the sign frame as a fulcrum along the other edge to draw the material tight. The sign system also includes a flexible hinge which acts as a seal to restrict the accumulation of water.

Abstract: The thread guide box (1) of a flat-bed knitting machine is slidingly mounted on a sliding rail (2) extending along the needle beds. The box is driven in both directions of motion of the lock carriage, together with the latter, by a driving pin (4) arranged on the lock carriage. To ensure uniform, constant braking of the thread guide box (1), at least one permanent magnet (6) is mounted on the latter in the region of the sliding rail (2) and has a fixed air gap (7) for the magnetically conducting sliding rail (2).

Abstract: An adaptive gate discharge circuit for discharging the gate of a power FET transistor. The adaptive gate discharge circuit includes discharge driver circuitry which responds to the control signal by discharging the power FET gate from the initial "on" potential of the power FET to below a selected potential at which the power FET is turned off. During gate discharge, but prior to the potential of the power FET gate dropping below the selected potential, adaptive bias circuitry continues to operate to provide biasing current both to the discharge driver circuitry as well as to any other circuitry it may be biasing. However, when the potential of the power FET gate drops below the selected potential, low current biasing circuitry reduces the operating voltage of the adaptive biasing circuitry thereby turning off the adaptive biasing circuitry and any other circuitry it may be biasing.

Abstract: A 360.degree. pattern field of view optical system for passive infrared detection device is disclosed. The optical system uses a combination of a fresnel lens and a fresnel prism to gather infrared radiation, focus the radiation, and refract radiation onto a focal point. Each of the combination of fresnel lens and prism is positioned substantially circumferentially about a central location to gather the infrared radiation from a 360.degree. field of view and for focusing radiation gathered onto the central location. At the central location, a sensor is located. The sensor converts the focused infrared radiation into an electrical signal.

Abstract: A digital controlled clock provides ultra fine resolution for a sampling clock signal for recovering data from a received signal, the phase jump of the sampling clock signal being determined the number of stages in a multiphase clock generator that generates a number of equally-spaced phase clock outputs based on a reference clock signal. Phase selection is performed through a very low overhead phase commutator in response to phase advance/retard inputs. A clock deglitcher matched to the stages of the ring oscillator eliminates spikes generated when the phase commutator switches.

Abstract: A fiber optic probe sensor for accurate measurement of displacement of a target over very small distances is disclosed. The probe sensor is comprised of plurality of light emitting fibers exclusively occupying a central region and connected to a light source for illuminating the target; a first and second plurality of light receiving fibers arrayed in two concentric regions exterior to and at two different distances from the central region, and means for measuring reflected light received from the target and for generating an output proportional to the light received and independent of target reflectivity or light source variation.

Abstract: A current limiting circuit (200, 300, 400) for instantaneously limiting the peak current of a fast high side power switch (212) or power FET has a reference switch (213) or FET, a first comparator (218), a current source I.sub.CL, control circuitry (209), and a clamping circuit (238). The reference FET (213) is smaller than the power FET (212). The first comparator compares the voltage drop across the power FET (212) and compares it with the voltage drop across the reference FET (213) and produces a signal COMPOUT which initiates the turn-off of the power FET (212) if the voltage drop across the power FET (212), caused by a load current flowing through it, is greater than or equal to the reference FET voltage drop induced by I.sub.CL. The clamp circuit (238), having diodes (D.sub.1, D.sub.2) and a tracking current source I'.sub.CL, disconnects the FETS (212, 213) from the comparator (218) when they are OFF.

Abstract: In the present application, a disc storage apparatus is disclosed. The disc drive is of the type that has a transducer head assembly connected to a pivoting assembly at one end thereof. The other end of the pivoting assembly is pivotally movable about a pivot axis. A voice coil motor is used to actuate the pivoting assembly to move the transducer heads over the surface of the data discs. The pivoting assembly further has a support member connecting the transducer assembly to the pivot axis. The support member has an arcuate region substantially at the location of the voice coil motor which is near the center of percussion. The arcuate region is arched in a direction to the plurality of discs and provides greater mechanical stability, thereby resulting in greater frequency response.

Abstract: Preamble smoothing for information character transmissions in a data transmission network is accomplished as follows. First, the smoothing filter identifies the start of a new preamble. If the start of a new preamble is identified and a previously received preamble has been extended, then the preamble is contacted by deleting an IDLE byte or, if the frame received prior to the initial IDLE byte was a frame fragment, then the information character preceding the initial IDLE byte is deleted. Following the contraction of the preamble, a determination is made as to whether next received byte is an IDLE byte. If it is not, then the preamble is extended by inserting an IDLE byte and the smoothing filter begins searching for the start of a new preamble. If it is, then a counter is incremented. If the counter has not yet reached its preset threshold, then the next byte is checked to determine whether it is an IDLE byte. If it is, then the counter is again incremented.

Abstract: An improved design for an optical encoder with a compensation feedback signal for compensating for effects of time and temperature on the photoemission characteristics of the encoder's light source. By using a current mirror, the photodiodes which normally provide only the data signal now provide both the data signal and the compensation feedback signal, thereby eliminating the need for a separate, dedicated photodiode for the compensation feedback signal. This results in eliminating the necessity of matching the electrical operating characteristics of the data photodiodes to those of a compensation feedback photodiode. This further results in eliminating the large die area required for including a compensation feedback photodiode in an integrated circuit design.

Abstract: The subject invention integrates a two-channel defibrillator with a programmable stimulator to provide a means for assessing lethal ventricular tachyarrhythmias and determining defibrillation thresholds during implantable defibrillator procedures. The subject apparatus includes a number of features to aid doctors as well as improve patient care at substantially decreased patient risk. These features include an automatic charging circuit, as well as dual channel high voltage capacitor circuits to reduce the time in which a rescue shock can be delivered to a patient after an initial test defibrillation shock. Parameter storage is provided to allow the unit to be preprogrammed prior to the initiation of an electrophysiologic procedure. A microprocessor controlled display system provides the physician with information parameters regarding defibrillation shocks. This displayed information includes the energy delivered and the resistance in the patient.

Abstract: An improved insert anchor assembly which provides a lifting clevis is disclosed. A novel void former comprising a body and plug to completely surround the lifting clevis is also disclosed. An improved hoisting attachment capable of complimentable receipt within the recess created by the void former is further provided.

Abstract: A first-in, first-out (FIFO) memory configuration comprising a fully addressable memory (e.g. random access memory), a write pointer, a read pointer, and a third, "commit" pointer serving as a boundary between first and second subsets of data stored within the FIFO. During data reception, a comparator circuit compares a predetermined subset of imcoming data with a predefined reference data set for determining whether the incoming data should be stored or aborted. This determination establishes the appropriate memory address value for positioning the commit pointer. The first subset of data behind the commit pointer may selectively be stored, while the second subset of data ahead of the commit pointer may selectively be aborted. During data transmission, a status register monitors the readiness of the data medium onto which the data is to be transmitted. If and/or when the data medium is ready to accept data, the commit pointer may be selectively positioned to demarcate data committed for transmission.

Abstract: The present invention improves the accuracy of waveshape measurements and transducers. Specifically, it is a method and apparatus which calibrates a system, which comprises transducers, amplifiers, filters and analog-to-digital converters, by digitally removing phase and amplitude errors over a frequency spectrum.