Abstract: A wavelength division multiplexing or demultiplexing optical coupler of the diffraction grating type includes a pure fused silica optical element having a convex spherical surface on one end and a diffraction grating on a portion of its other end. The remaining portion of its other end receives a multiple fiber array for transmitting and receiving the light to be multiplexed or demultiplexed.

Abstract: A transmission chip for a telephone subscriber's instrument can be used in a variety of modes, some of which involve use with other chips. Depending on which mode is in force, different amplifiers are used. Thus for plain ordinary telephone (POT) service, amplifiers 30,35 and 43 are used, for loudspeaking mode amplifiers 30, 35 and 43 are used, for handsfree use amplifiers 35, 43 and 46 are used, while for VF "dialling" amplifier 46 is used. To save power, the control block (42) detects the mode in which the set is operating and, via a control bus, operates electronic switches to disable the amplifiers not needed.

Abstract: A TACAN beacon is disclosed in which the pulse-modulated carrier signal generated in a transmitter is applied to the elements of a circular antenna array through controllable phase shifters that generate 15-Hz and 135-Hz sidebands through, switches, and through a Butler matrix. A switching facility generates two states. In the first state, the phase shifters are controlled to generate the upper and lower 15-Hz sidebands and the upper 135-Hz sideband, respectively. In the second state, they are controlled to form the respective opposite sidebands.The Butler matrix generates, radio-frequency phase-rotation fields at the antenna. In the two states, the ordinal numbers of the radio-frequency phase-rotation fields differ in their signs. The absolute value of the largest ordinal number is smaller than or equal to six, and the sum of the absolute values of the ordinal numbers for the carrier signal and the upper or lower 135-Hz sideband is equal to 9.

Abstract: The digital tie line provides a high speed pulse code modulation (PCM) digital path between private branch exchange (PBX) systems. The invention has a capability of providing a plurality of simultaneous two-way channels. By providing for twice the number of available channels in each PBX system, PBX systems may be interconnected by using one digital tie line per system, resulting in a non-blocking traffic situation between systems. High speed digital data may be directly passed via assigned channels between systems. The digital tie line provides a connection between the internal system parallel PCM bus and an externally located serial bus. A multiple PBX network can be interconnected by multiple external buses by employing a single digital tie line in each PBX system, per external bus. A modular time slot interchanger (MTSI) is used to direct signals between the system PCM bus and the external bus.

Abstract: This invention is a technique for providing isolation between the two channels of a handsfree telephone subset without resorting to gain switching or gain variations in the transmission path. The invention involves separating the frequency spectrum into two portions and allowing the stronger signal to capture a major portion of that available spectrum. Switched capacitor filters are used to control the degree of frequency bandwidth allocated to each channel while the filters are clocked from a common source assuring no possibility of overlap in the frequency spectrum. The affect of varying the bandwidth is much less noticeable than varying the amplitude and, therefore, creates much less user irritation.

Abstract: The invention concerns a centrifugal pump for pumping heavily polluted liquids. The impeller is provided with an inlet having cutting means cooperating with an inlet opening of the pump housing, which cutting means cut elongated bodies, such as rags before they get into the pump housing.

Abstract: There is disclosed a multiple processor system which employs dynamically programmable processing elements (DDPE) utilized as slave devices and under the control of a master processor. A plurality of DPPE's have input/output data lines connected to a digital signal processing (DSP) bus. Communication between the DPPE's is afforded via the (DSP) bus from a master processor which interfaces with the bus via a dual port memory designated as a global memory. Each DPPE is connected together via another bidirectional serial bus so that the individual DPPE's can communicate one with the other in regard to processing and exchanging of arithmetic data. The digital signal processing bus allows the master processor to interface with the DPPE devices for control of input/output and control functions. In this manner, the master processor interfaces directly with a codec and has outputs which allow the transmission of plaintext or ciphertext data which data is formed by arithmetic operations performed by the slave DPPE's.

Abstract: Two electrical-to-acoustical transducers (W1, W2) are attached to two contiguous sides of a cube (B) made of optically transparent material. The propagation directions of the two waves delivered by the transducers intersect inside the cube. The frequency of the light beam striking the device is shifted by f.sub.1 -f.sub.2, where f.sub.1 and f.sub.2 are the frequencies of the drive signals for the two transducers. The deflection of the light beam in the two propagation directions of the sound waves is proportional to the frequencies of the drive signals.

Abstract: An arrangement for the remote actuation of a controlled device, e.g. a hydraulic valve, in situations with stringent safety requirements, uses optical power. The optical power, e.g. from a high-power laser, is conveyed via an optical fibre (1) to the controlled device. Here it falls on a heat-absorbent surface (2), as a result of which a volatile fluid (e.g. freon) is evaporated. This via a bellows (4) drives an output rod (5), which operates the controlled device.Alternatives include a bimetallic strip, a thermostat-type capsule, and a memory metal strip, as the heat responsive device.

Abstract: An arrangement for introducing an auxiliary gaseous medium into the interior of an exhaust tube that is joined to a downstream end of a substrate tube from which a primary gaseous medium carrying glass soot particles during a chemical vapor deposition phase of an optical preform fabrication process emerges into the exhaust tube comprises a gas injection tube which is partly received in the exhaust tube with radial spacing therefrom except at a contact zone and having a free end disposed at the region of joinder of the exhaust tube with the substrate tube. The auxiliary gaseous medium flows through the gas injection tube into the joinder region for mixing thereat with the emerging flow of the primary gaseous medium. Relative circumferential movement is effected between the contact zone and at least the exhaust tube to release any soot present at the contact zone for entrainment in the mixed flow through the spacing and out of the exhaust tube.

Abstract: The invention relates to a method of transferring information between microcomputers in a decentralized process control system, particularly for telephone systems. To prevent contention for possession of the information transfer bus without the need for central equipment, a simple bus system consisting of a multiwire data bus and two single-wire control buses is proposed. Bus mastership is passed on after transmission, with the address of the next transmitter being determined by each microcomputer itself and forming part of each message. Bus mastership is determined by communication of the previous transmitter and by calculations performed by the microcomputer itself.

Abstract: The invention relates to a supply circuit for a variable load, particularly for a line circuit in telephone systems.Conventional supply circuits, in which each of the two supply-current branches to the line wires contains the collector-emitter path of a transistor in series with an emitter resistor, offer a high AC resistance to voice-frequency voltages and longitudinal noise voltages, so that the bridging loss of the line remains small. To achieve a low AC resistance of the supply circuit to the longitudinal noise voltages, special measures in the control circuits of the transistors, particularly the use of a nonlinear element in the form of a CRD current-limiting diode in parallel with the controlled current path of each of the transistors, are proposed. These measures greatly reduce the amplitude of the longitudinal noise voltages at the inputs of subsequent circuits, which are thus protected.

Abstract: An arrangement for collapsing tubular formations into optical preforms includes a control arrangement which controls the pressure build-up at the downstream end of the tubular formation during all of but the last one of the collapsing increments to control the flow of a gaseous medium through the interior of the tubular formation from an upstream end to and beyond the downstream end of the tubular formation. The magnitude of the back-up pressure is controlled by a set point controller in dependence on the actual value of the back-up pressure, the set point controller being operative for counteracting any deviation from the desired pressure. The set point controller controls the flow-through cross-section of a control valve that admits a pressurized inert gas to a region situated downstream of the downstream end of the tubular formation and also downstream of the point at which the pressure build-up is being measured.

Abstract: There is disclosed an automatic phasing network which network receives a data signal and synchronous timing signals. Initially, these signals are in an arbitrary but fixed phase relationship to one another. The circuit establishes a fixed phase relationship between the data and timing signals with a large degree of resistance of phase jitter. In order to accomplish these results, the circuit operates to select the edge of the clock signals which is farthest from given data transitions and uses this edge to produce a data signal which is synchronized to the timing signal. The circuit provides an accurate phase relationship between the data and timing signals for various out-of-phase conditions as where the data transitions lag the rising edge of the clock by angles which vary between -45 degrees to +315 degrees.

Abstract: To permit address-free fault location on digital communication paths with several intermediate repeaters, one or more identification signals must be recognized in the intermediate repeaters with sufficient certainty. The identification signals are digital signals with periodically recurring sections which are marked with a string of successive like bits (e.g., 0 bits) and have different durations for a first identification signal and a second identification signal.The circuit contains a time discriminator (1) which responds when a string of successively received like bits is characteristic of a section of an identification signal. It then provides a pulse equal in length to this section to a frequency discriminator (2) which responds when such pulses recur at a frequency characteristic of an identification signal. The frequency discriminator thus delivers an output voltage whose amplitude is typical of one identification signal or the other because of the different pulse durations.

Abstract: A ring generator capable of supplying a plurality of predeterminedly selected distinct voltages each having a predetermined high amplitude and a predetermined frequency to a telephone line comprises a programmable computer having a low amplitude version of the plurality of voltages stored therein in digital form, the computer being responsive to predetermined control signals to select a desired one of the low amplitude version of the plurality of voltages stored therein, a first circuit arrangement coupled to the computer to convert the select one of the low amplitude version of the plurality of voltages to an analog version thereof and to increase the analog version to the predetermined high amplitude prior to coupling to the telephone line and a second circuit arrangement coupled to the first circuit arrangement, the telephone line and the computer to monitor the selected one of the plurality of voltage coupled from the first circuit to the telephone line to detect the operating condition of the ring genera

Abstract: A telecontrol system is disclosed whose substations contain a control unit and plug-in interface modules for entering messages or measured values and delivering commands. Both the control unit and the interface modules are equipped with microcomputers and connected via suitable interfaces to a common serial data bus. Because of the presence of the serial data bus, the parallel buses of the microcomputers need not leave the individual modules, which reduces the susceptibility to interference on the buses. In addition, the serial data bus makes it possible to use any form of protection coding, so that individual modules can even be located away from the substation. Each interface module consists of an invariant portion, which is of the same design in all modules, and a problem-adapted portion, whose design depends on the task to be performed.

Abstract: In a stripe-geometry multimode laser having a current-flow-determining stripe, only the flow of electric current is confined to a narrow area, while the heat can flow off through a large area. A window for the flow of electric current is formed by a narrow epitaxial semiconductor stripe which, because of its high doping level and of additionally diffused charge carriers, is highly conductively connected to both the underlying semiconductor and the overlying metal, while next to the stripe, electric conductivity from the semiconductor to the metal is very poor. The thermal conductivity, however, is approximately the same over the entire area.

Abstract: A valve actuator is described which employs a hollow housing fabricated from a stamped metal. Located within the housing is a rotatable spindle which spindle is associated with a traveling nut which nut travels along the spindle as the spindle is rotated. The traveling nut has pivotally secured thereto a pivot nut which pivot nut rides in a slot formed in the top portion of a pivot arm. The pivot arm is associated with an aperture to accommodate a valve shaft and pivotally moves when the spindle is rotated due to the movement of the traveling nut along the spindle. The rotation of the pivot arm rotates the valve shaft to thereby open or close an associated valve in a given number of turns as required by the particular system characteristics. Associated with the pivot arm is a switch activator which activator will operate an electrical switch for a given movement of the pivot arm during valve operation.