Abstract: An automatic gain control circuit for an amplifier operating over a prescribed frequency range detects the output level of the amplifier; and couples a repeated predetermined waveform occurring at a rate greater than the reciprocal of twice the upper frequency of the prescribed frequency range to the output level signal. The waveform varying level signal is compared to a reference threshold to control the gain of the amplifier through a switched resistive elemement in the amplifier feedback path. The repeated waveform variations about the amplifier output level causes the value of the switched resistance to vary as a function of the output level. A low pass filter connected to the amplifier output removes switching transients resulting from the high frequency changes in the switched resistive element. The gains of a plurality of amplifiers may be determined by a common control for accurate tracking over a wide dynamic range.

Abstract: A high resolution image is decomposed into a low resolution replica and into corresponding supplemental information for facsimile transmission to a remote location. The low resolution replica is generated by replacing a super pixel (picture element) including a plurality of high resolution image pixels with a single low resolution pixel and corresponding supplemental information, if any is required. The pixels of the low resolution replica are chosen such that all supplemental information required to convert the low resolution replica back to the original high resolution image is located at the "edges " of the low resolution replica. Thus, if a low resolution pixel is at an edge in the low resolution pixel is at an edge in the low resolution replica, supplemental information is generated in accordance with prescribed criteria.

Abstract: A method and apparatus for processing calls to a directory number, shared by a multiple number of terminals, in which a switching system selects a preferred terminal for serving the call based on call answering activity. The switching system establishes a connection to the preferred terminal. This system connection is for use in answering the call at the preferred terminal. Although the system connection is established to the preferred terminal, all the terminals sharing the directory number are enabled to answer the call. The arrangement dynamically selects the preferred terminal rather than establishing an initial system connection to only a statically defined terminal.

Abstract: A connector body (26) which terminates at least one transmission medium includes on each side thereof a cantilevered arm (66) having a latching nub (70) projecting from a free end of the arm. A release cover (80) having a gripping portion (88) oriented toward a cable input end (32) of the connector body is mounted slidably on the connector body with the latching nubs of the arms each projecting through a window (90) in the cover. Conductors in the connector body are connected to conductors of another connector or of a device by inserting the connector body and release cover into a coupling (100) or into a receptacle. The latching nubs of the arms protrude into openings (106--106) provided in a housing (102) of the coupling to secure the connector body thereto. In order to withdraw the connector body from the coupling, a user moves the cover slidably along the connector body toward the cable input end.

Abstract: Group III-V compound MISFETs include a low-doped diffusion barrier layer disposed between a source/drain contact-facilitating layer and the channel layer.

Abstract: A multilayer ceramic package for optical devices is disclosed for use in both high and low bit rate applications. A side portion of the multilayer package is formed to provide a multilayer microwave input connection for a high bit rate signal. In an exemplary arrangement, an intermediate ceramic layer of the multilayer structure is defined with an appropriate thickness and metallized on areas of the top and bottom surfaces. This combination thus forms a multilayer microwave connection defined as a microstrip. Other multilayer configurations, for example, a stripline, may also be used. By utilizing a multilayer microwave connection in place of a conventional electrical connection, the impedance of the high frequency input source can be better matched to the optical device.

Abstract: A method for forming articles which include silica-containing glass bodies, as well as the resulting articles, are disclosed. In accordance with the method, silica-containing gel particles are fused to form a glass body. In contrast to previous such methods, these particles are formed by mechanically, substantially uniformly subdividing either a substantially cohesive gel body, or an ungelled or partially gelled sol capable of yielding a substantially cohesive gel body, to form substantially uniformly sized, wet gel particles. Significantly, only substantially cohesive gel bodies which are also substantially elastic are useful in the invention, i.e., mechanical subdivision of non-elastic gel bodies results in these bodies undergoing plastic flow to yield non-particulate, pasty masses.

Abstract: A memory matrix for storing control words for controlling a common control time division multiplexed (TDM) switch is formed by employing a plurality of shift registers connected in recirculating configuration. Synchronization of control word time slots in the memory matrix to system timing is realized by storing a timing marker which is advanced in identical manner as the control word time slots. If synchronization between the system timing and control word time slots is interrupted, it is restored by controllably inhibiting advancing of the control word time slots and the stored timing marker.

Abstract: A call coverage arrangement in which coverage personnel are informed of the switch-hook status of covered terminals by way of a single two-part indicator on the coverage terminal. The two-part indicator indicates switch-hook status for any one of a number of covered terminals. The first part of the indicator identifies the covered terminal and the second part defines the switch-hook status of the identified terminal. The arrangement is flexible in providing coverage for additional terminals and in providing coverage via forwarding from any termianl, since there is no need to assign and dedicate status indicators to particular terminals.

Abstract: A memory array included with logic circuitry on an integrated circuit is tested by a technique that reads and writes a specified sequence of test bits into a given memory word before progressing to the next word. A checkerboard pattern of 1's and 0's is written into the physical memory locations. This provides for an improved worst-case test while allowing case of implementation for the test circuitry. The test results from a comparator circuit may be compressed to provide one (or a few) test flags indicating whether the memory passed the test, requiring a minimal number of test pads or terminals for the chip.

Abstract: A high capacity metropolitan area network (MAN) is described. Data traffic from users is connected to data concentrators at the edge of the network, and is transmitted over fiber optic data links to a hub where the data is switched. The hub includes a plurality of data switching modules, each having a control means, and each connected to a distributed control space division switch. Advantageously, the data switching modules, whose inputs are connected to the concentrators, perform all checking and routing functions, while the 1024.times.1024 maximum size space division switch, whose outputs are connected to the concentrators, provides a large fan-out distribution network for reaching many concentrators from each data switching module.

Abstract: A high capacity metropolitan area network (MAN) is described. Data traffic from users is connected to data concentrators at the edge of the network, and is transmitted over fiber optic data links to a hub where the data is switched. The hub includes a plurality of data switching modules, each having a control means, and each connected to a distributed control space division switch. Advantageously, the data switching modules, whose inputs are connected to the concentrators, perform all checking and routing functions, while the 1024.times.1024 maximum size space division switch, whose outputs are connected to the concentrators, provides a large fan-out distribution network for reaching many concentrators from each data switching module.

Abstract: A controlled amount of flux is applied to a circuit board (10) by first directing liquid flux through a nozzle (54) containing means for disintegrating the flux into a very fine fog of tiny flux droplets (62). The fog of flux droplets is injected into a laminar gas stream (52), thereby creating a laminar flux stream which is directed at the circuit board to coat the board with flux. As the flux spray is being directed at the circuit board, the concentration of flux solids on the board is being regulated, typically by controlling the rate of flux pumped into the nozzle.

Abstract: A high capacity metropolitan area network (MAN) is described. Data traffic from users is connected to data concentrators at the edge of the network, and is transmitted over fiber optic data links to a hub where the data is switched. The hub includes a plurality of data switching modules, each having a control means, and each connected to a distributed control space division switch. Advantageously, the data switching modules, whose inputs are connected to the concentrators, perform all checking and routing functions, while the 1024.times.1024 maximum size space division switch, whose outputs are connected to the concentrators, provides a large fan-out distribution network for reaching many concentrators from each data switching module.

Abstract: A contention mechanism is disclosed for a communication network that provides perfect scheduling to avoid collisions between packets from a cluster of M circuit boards connected to a communications bus. The contention mechanism includes a 2-phase contention procedure comprising a first phase priority contention phase, where boards with a highest priority and a real data packet to transmit proceed into a second contention phase, where a pointer is used to declare one of the remaining priority phase circuit boards as the overall winner to transmit its packet during a subsequent packet period. When no circuit board has a packet to transmit, all M circuit boards are declared as winners of the first priority phase, and a board is declared the winner on a distributed basis to transmit a "dead-space" packet over the bus.

Abstract: When the disclosed frequency-hopping communication system is initially enabled, it detects another system operating within range by listening for a predefined radio frequency of a fixed duration. When that particular frequency is detected, the system knows that a master system is operating within range and is utilizing a first predetermined group of communication frequencies and, consequently, selects a second, third, etc. predetermined group of communication frequencies. If the particular radio frequency is not detected, the system becomes the master system, selects the first predetermined group of communication frequencies for intra-system communication and begins transmitting the predefined radio frequency to indicate its master status.

Abstract: An optical system is disclosed which includes at least a first source of electromagnetic radiation (signal beam radiation), a device for processing the signal beam radiation, and a detector for detecting the processed signal beam radiation. The processing device functions, for example, as an amplitude modulator, a demultiplexer, or a switch, and includes a material region exhibiting a nonlinear optical response at one or more resonant wavelengths of electromagnetic radiation, as well as at least a second source of electromagnetic radiation (control beam radiation) for selectively inducing the nonlinear optical response. Significantly, the wavelength, duration and intensity of the control beam radiation are chosen to induce a resonant, nonlinear optical response, essentially free of any relatively slow component, in said material region at repetition rates higher than about 1.25.times.10.sup.4 Hz, or higher than about 3.3.times.10.sup.10 Hz, or even as high, or higher, than about 2.5.times.10.sup.11 Hz.

Abstract: A high capacity metropolitan area network (MAN) is described. Data traffic from users is connected to data concentrators at the edge of the network, and is transmitted over fiber optic data links to a hub where the data is switched. The hub includes a plurality of data switching modules, each having a control means, and each connected to a distributed control space divisison switch. Advantageously, the data switching modules, whose inputs are connected to the concentrators, perform all checking and routing functions, while the 1024.times.1024 maximum size space division switch, whose outputs are connected to the concentrators, provides a large fan-out distribution network for reaching many concentrators from each data switching module.

Abstract: By adjusting the AC field conditions, i.e., by grounding the environment of a substrate being etched with a chlorine-containing plasma, a significant increase in etch selectivity is achieved. By applying a similar AC field adjustment to the reaction chamber surfaces, excellent etch uniformity is achieved in conjunction with excellent selectivity.

Abstract: Currently, metallic loops are tested for shorts, opens and grounds by applying a test signal (DC or 20 Hz) directly to the metallic looop. A test signal cannot be applied to any part of the network other than the metallic loop because it will be blocked by the A-to-D converters and the hybrid of the system before it can reach the metallic loop.In this invention, digital signal processing is used to test a metallic loop for shorts, opens, grounds and the presence of loading coils from a remote location. Direct metallic connection to the metallic loop is no longer necessary.Briefly, a test signal, in digital form, is fed into the network at some convenient location remote from the metallic loop that is to be tested. As the signal passes through the A-to-D converter from the digital section of the network to the analog metallic loop, it is converted by the A-to-D converter into an analog signal having a specific frequency and a predetermined amplitude.