Abstract: A laser materials processing system for computing a real time cooling rate experienced on a workpiece and responsively controlling the operation of a materials processing laser. An image of a point of laser beam-material interaction is transmitted via imaging optical fibers to ratio pyrometer apparatus which provides temperature proportional signals. The temperature signals are used to compute cooling rate.

Abstract: Configured for accelerated operation of processing elements in a SIMD parallel processing system is disclosed. The output of an exclusive-OR gate is coupled to one input of the element ALU while a first input of the gate is adapted to receive signals intended for the ALU input. Upon loading a `1` bit into a register coupled to a gate second input, signals applied to the gate first input are complemented and applied to the ALU input. As a result, different arithmetic and logic operations can be performed simultaneously by different elements in the processing system in response to a single series of instructions.

Abstract: A laser-materials processing system including means for determining an incident diameter of a laser beam at a point of laser beam-material interaction on a workpiece, is disclosed. A filtered image of the interaction point is transmitted, via an imaging fiber bundle, to a video camera. The analog video signal generated thereby is digitized and provided to a computer which evaluates the pixel magnitudes along a beam image diameter line to determine therefrom the incident laser beam diameter.

Abstract: A bus accessing method and apparatus for the practice thereof in a communication network is disclosed. The network comprises a transmit bus, a receive bus, a plurality of BIUs connected between the transmit and receive buses and a head-end for directing signals leaving the transmit bus onto the receive bus. Each information packet has two control bytes respectively following the start frame delimiter and preceding the end frame delimiter. Each BIU includes means for comparing the bits it receives with the bits as transmitted thereby, a bit mismatch indicating that a downstream BIU has been preempted. During packet transmission, upon detecting a bit mismatch, the transmitting BIU sets one or both control bytes to "1010" so that receiving BIUs in the network are apprised of the preemption. Subsequently, preempted BIUs transmit their packets in accordance with a predetermined protocol, each packet so transmitted having its control bytes set to "1010".

Abstract: An optical fiber holder includes a pair of flat, adjacent surfaces. Each of the surfaces includes a straight groove, the grooves opposing so as to form a passage shaped to engage an optical fiber in a snug fit. Means are provided for fastening the two surfaces together. The optical fiber holder is preferably constructed of material transparent to a laser beam at a predetermined wavelength, thereby making the optical fiber holder particularly adapted for use with a laser device generating such a laser beam.

Abstract: The present invention comprises a local area network wherein a network control center is provided to maintain a dynamic logical ring. In accordance with the method of the present invention, the local area network is provided with a transmission medium having first and second channels, wherein prospective entrants to the logical ring are solicited over the first channel and wherein information transfer among BIUs occurs over the second channel. The network control center is provided for continuously soliciting successors and resolving contentions over the first channel. Further, the network control center is adapted to add entering stations to the logical ring by receiving the token and transmitting next neighbor packets over the second channel. Additionally, the network control center may be adapted for monitoring communications over the second channel to determine when a station has received the token and failed and, thereafter, to reestablish the logical ring.

Abstract: Apparatus configured to minimize wavefront distortion of a coherent light beam is disclosed. The lasing medium of the laser apparatus has a hexagonal cross section and an internal surface with a circular cross section coaxial with a longitudinal axis of the lasing medium. The internal surface defines an interior space for receiving an optical pumping source. The external faces of the lasing medium are surrounded with a circumferential reflector and fluid coolant is flowed over the internal surface and external faces. The coherent light beam is passed through the lasing medium to follow a helical course totally internally reflecting off of the external faces.

Abstract: Method and apparatus for interconnecting the processing cells of a parallel processing machine configured in a two-dimensional rectangular array in which each cell includes a plurality of ports, each port having a unique port address, and a plurality of cells have similarly addressed ports. The cells are interconnected, via the cell ports, to form cell clusters having a central cell and eight neighboring cells such that a plurality of neighboring cells share a common connection to the central cell and further such that no two similarly addressed ports are coupled to one another. During a data transfer operation, in accordance with the single instruction multiple data (SIMD) format, each cell transmits data from one port and receives data from another port such that all cells transmit data from similarly addressed ports and receive data at similarly addressed ports to provide data transfer throughout the array in a uniform direction.

Abstract: A system for injecting successive beam pulses of a pulsed power laser into optical fibers, for transmission therethrough, is disclosed. The system comprises four lens, four fiber groups with the tips thereof respectively proximate the focal points of the lenses, two galvanometer driven mirrors for directing the laser beam through one of the lenses for focusing onto a selected fiber tip, and control means to drive the galvanometers to reorient the two mirrors between laser beam pulses into successive pairs of predetermined positions effective to inject the successive beam pulses into selected fibers. Failure to reorient the mirrors before the succeeding beam pulse arrives results in laser shutdown. Means are provided for detecting a malfunction of the mirrors, fracture of a lens or a missed fiber injection and, in either case, shutting down the laser.

Abstract: A method for operating a communication network bridge is disclosed. The bridge receives a message frame from a first network connected thereto and reads the source and destination addresses of the received frame. The bridge determines if the addresses are contained in a source address table maintained thereby and if both addresses are present, discards the frame. The bridge transmits the frame to a second network connected thereto if the source address is not in the table or if the source address but not the destination address is in the table.

Abstract: A bus accessing method and apparatus for the practice thereof, in a communication network, for transmitting information packets without the need for long communication periods following each transmission, is disclosed. The network comprises transmit and receive buses, a plurality of BIUs coupled between the buses, and a head-end for directing packets leaving the transmit bus onto the receive bus. Each packet has a preamble with a gap long enough to enable receiving BIUs to reset for receipt of a new packet. Each BIU in an active state with a packet to transmit measures a first time period so long as it detects no signals on the receive bus. The BIU transitions to a wait state upon completing the first time period measurement and initiates a second time period measurement. Upon completing the second time period measurement, the BIU transitions to a transmit state and initiates transmission of its packet, reverting to the active state upon completing transmission.

Abstract: A combination integrate and dump filter comprises an amplifier for performing both the integrate and level detecting functions. Selective circuit configuration (SCC) apparatus is provided and responsive to a first state of a baud signal for providing reactive feedback to the amplifier such that voltage is stored by the SCC apparatus, which stored voltage represents the time integral of the input signal. The SCC apparatus is further responsive to a second state of the baud signal for terminating the reactive feedback and for coupling the stored voltage to the amplifier input such that the stored voltage is amplified and, therefore, the amplifier output represents the cumulative polarity of the input signal over the integration interval.

Abstract: An optically pumped slab laser includes a solid-state lasing medium having a longitudinally extending lasing axis. A lamp is disposed proximate the lasing medium for emitting optical pumping radiation, and a reflector surrounds the lamp for directing the radiation at selected portions of the lasing medium. A fluid coolant is flowed across a major surface of the lasing medium to remove heat therefrom. The lasing medium exhibits a typical negative focal power lens effect distortion in portions proximate its lateral edges. The reflector is shaped to introduce a positive lens effect distortion, equal in magnitude to the negative lens effect distortion, to a central portion of the lasing medium between the lateral edge portions. External reflectors are positioned so as to direct a subsequently generated laser beam through alternate regions exhibiting the positive and negative focal power lens effect distortions, so that the beam subsequently exits the slab laser with no net distortion.

Abstract: A digital frequency locked loop is disclosed for use with programmable signal processing apparatus wherein frequency locking is desired from staggered data samples. Sampling means are provided for sampling an input signal, at instants determined by the sampling signal, to provide N data signals from M cycles of the input signal wherein each data signal represents the magnitude of the input signal at the sampling instant. Signal processing means are provided for performing a unique approximation to the optimal mean square estimation analysis to provide a frequency deviation signal which is proportional to the difference in frequency between the sampling and input signals. The frequency deviation signal is used to modulate the period of the sampling signal such that the frequency of the sampling signal is maintained in constant proportion to the frequency of the input signal.

Abstract: Method and apparatus are disclosed for providing a sampling signal having a frequency which is maintained in constant proportion to the frequency of an input signal. The input signal is sampled at instants determined by the sampling signal to provide a plurality of data signals associated with one cycle of the input signal. A signal processor is adapted to receive first and second pluralities of data signals associated with first and second cycles of the input signal and to perform two discrete Fourier analyses to provide two phasor signals representing two voltage phasors of respective fundamental frequencies of the discrete Fourier transforms. The phasor signals are used to generate a difference signal indicative of the angle between the two voltage phasors and, therefore, proportional to the difference between the sampling frequency and the input frequency.

Abstract: Apparatus for bridging between two local area networks is disclosed. The apparatus has two bridge sides each including means for receiving or transmitting a message frame, controller means for directing an incoming message frame into a memory means shared between the bridge sides or directing a frame out of the memory means for transmission, address reading means for reading an address portion of the incoming frame and processor means for determining frame transmissibility from the address portion as provided by the address reading means. The apparatus is configured such that the processor means determines incoming frame transmissibility substantially concurrent with the controller means directing the incoming frame into the memory means.

Abstract: A direction sensitive coupling unit, and method of operation, is disclosed for use in a communication medium to indicate the presence and source direction of transmissions. A directional coupler is provided for receiving information signals from first and second directions along the medium and for providing an attenuated information signal as its output wherein the attenuation to information signals received from the first direction is greater than the attenuation to signals received from the second direction. A voltage sensitive indicating circuit is coupled to the medium and is adapted to respond to the coupler output for providing a digital indication of the presence and source direction of transmissions on the medium.

Abstract: A token passing local area network LAN is disclosed wherein each bus interface unit BIU monitors the token rotation time to determine if this time exceeds a predetermined maximum and, if so, creates a second token to be passed through the LAN 180.degree. out of phase with the existing token. Further, each BIU monitors token acquisition time, i.e. the time the BIU has a token to the time that the BIU has another token whether or not they are the same token, to determine whether this token acquisition time is below a predetermined minimum value and, if so, a token is destroyed such that only one token is passed between BIUs.

Abstract: Apparatus and method for bus accessing, in a communication system, effective to minimize user to user delay variance is disclosed. The communication system comprises a transmit bus, a receive bus, a plurality of BIUs coupled between the buses, and a head-end coupled between the buses at one end for directing signals from the transmit bus onto the receive bus and further for intermittently alternately transmitting a left sweep or right sweep startup packet onto the receive bus. Upon receipt of the startup packet, each BIU having an information packet to transmit, transmits a beep signal and then subsequently receives its own beep as well as the beeps transmitted by other BIUs. Each BIU determines a transmission ranking for itself according to the number of beeps received before or after receiving its own beep depending on whether the startup packet was respectively a right sweep or left sweep type.

Abstract: The subject invention comprises method and apparatus for providing protection against an open transmit cable, an open receive cable and/or a failed BIU in a local area network. Each BIU of the network is adapted to monitor tansmissions received from its predecessor to determine whether the primary transmit channel coupling it to its predecessor is open circuited and, if so, to reestablish communications between it and its predecessor over an auxiliary transmit channel. Further, each BIU is adapted to monitor transmissions received over the primary receive channel of the network to determine whether the channel is idle and, if so, to begin receiving message signals over an auxiliary receive channel. Lastly, a network control center is provided to monitor the transmit medium to determine whether a BIU is "babbling", i.e., transmitting signals for longer than is permitted by the network protocol and, if so, to identify the babbling BIU and, thereafter, remove the babbling BIU from the network.