Abstract: An electronic device for a local area network of electronic apparatuses is characterized by a timer operatively associated with each apparatus, each timer being retriggerably responsive to the occurrence of a periodic feature of a code to assert a line driver for the period of the timer. The period of the timer is greater than the period of the feature.

Abstract: A fault-tolerant fiber optic coupler/repeater for use in a terminal in a high speed digital, audio or video data transmission system has optical data input from one or a plurality of upstream terminals and sends optical data to one or a plurality of downstream terminals via fiber optic lines. The terminal includes one or more bypass lines and is connected to the bypass line of at least one upstream terminal. The terminal receives optical data signals from upstream terminals via a primary line and one or more bypass lines which bypass one or more of the upstream terminals. The terminals includes a logic device which analyzes the signals received by the terminal via the primary line and via the bypass line and analyzes or compares these signals to preset values. The logic device selects the signal having characteristics closest to the preset values and rejects the other signals.

Abstract: A system for data communication between ground stations using an orbiting satellite as a relay includes a technique for avoiding the loss of signals from the satellite during periods of heavy precipitation. Data is communicated from an orbiting satellite to a plurality of earth stations on a single transmission frequency. The data is communicated on two separate transmission channels on that one frequency by using orthogonal channels of a coherent phase quadrature transmission system. The overall data rate on one of the two transmission channels is much lower than the overall data rate on the other of the two channels. The data on the lower data rate channel is less likely to be affected by heavy precipitation occurring in the line of sight between the satellite and the ground station, and the lower data rate channel is thus used to communicate data to a ground station located in an area of heavy precipitation.

Abstract: In a communication system, the combined advantages of decision feedback equalization and delayed decoding are achieved in a receiver by interleaving the signal points at the transmitter, and deinterleaving them at the receiver so that sufficiently reliable delayed decoder decisions can be used in estimating the distortion component of the received signal presently being processed in the decision feedback circuit.

Abstract: A single transmission line bidirectional optical communication system comprising a directional coupler employing a polarizing beam splitter, an optical transmitting circuit for coding the data and converting the coded data into optical signals and outputting said signals, an optical receiving circuit employing a comparator having a function of automatically establishing a threshold for converting optical input signals into electrical signals and then decoding the data, a circuit for detecting the frequency differences between the sending signals and receiving signals, and a line diagnosing circuit.The polarizing beam splitter eliminates a near-end reflected beam, and the optical receiving circuit having a function of automatically establishing a threshold eliminates a remote-end reflected beam. The line diagnosing circuit diagnoses the line condition by comparing the sending frequency and receiving frequency.

Abstract: A digital wireless subscriber telephone unit for wireless connection with a base station. The subscriber unit has baseband processor which is coupled to storage means for the baseband functions. The baseband processor is direct access coupled to a modem processor whereby the two processors may communicate with each other. The modem processor generally acts as the master in the system, although lock-out means may be used in certain circumstances. The signal from the modem processor is converted to an analog signal, which is subjected to deglitching, and the deglitched signal is then upconverted and filtered to form an IF signal which is thereafter amplified. The amplified IF signal is combined with a signal generated by a synthesizer to provide an RF signal. On the basis of certain signals received from the base station, the baseband processor produces initiating signals which determine whether the subscriber unit will be in the transmit mode or the receive mode.

Abstract: A wavelength division multiplexing structure for establishing dedicated high bit rate point-to-point connections between network nodes is disclosed. The information transmitted out of any given network node is modulated on a plurality of wavelengths according to destination. These wavelengthds are multiplexed and transmitted to the network hub. At the hub, all the different wavelengths from all the nodes are demultiplexed, passively rearranged, multiplexed again and transmitted to the appropriate destinations. The information handling capacity of this structure exceeds 1 Terabit/second.

Abstract: Multiplexer-demultiplexer including:(a) a fiber-carrying element in which the entrance and exit fibers are embedded, with their ends in flush alignment in a plane surface of contact with the following element,(b) an element carrying the wavelength separation system, with a plane surface of contact with the fiber-carrying element and an opposite plane face of contact with the following element,(c) an intermediate element of the same index n as the element carrying the wavelength separation system, with a plane face of contact with the element carrying the wavelength separation system, and a spherical face of contact with the following element,(d) a mirror element with a spherical face of contact with the intermediate element and an opposite spherical face treated to form a concave spherical mirror towards the intermediate element.

Abstract: Optical-fiber transmission system with heterodyne coherent detection in which, at the transmitting side, the polarization of an optical carrier is modulated, and at the receiving side the beam resulting from a combination of the modulated beam and a beam emitted from a local oscillator is split into two orthogonally-polarized components. The two optical signals are detected and sent to an electronic mixer which receives the two components and carries out a synchronous demodulation eliminating the effects of the linewidth of the source and of the local oscillator.

Abstract: The industrial installation comprises an active zone (III) with which there are associated means for measurement and for command and a control position (I) separated from the active zone. Means for measurement, for control and for command (15) located in the active zone are supplied with luminous radiations, from the control position, through an optical fibre (8) joining the active zone to the control position. Radiation having a broad spectral band is emitted in the fiber (8) from the control position (I) and then divided in order to obtain unitary radiations for supplying each of the means (15). The invention applies to nuclear reactors.

Abstract: An apparatus for housing a plurality of remote control units wherein the units are consolidated at a common location and wherein the units are protected from damage which may be occasioned upon them. Each housing is defined by a wall having a window formed therein and a drawer for mounting a unit therewithin whereby an infrared emitter of a remote control unit is disposed so that it will project an infrared signal through the window. Further, the housings include hook and notch arrangements for mating the plurality of housings together whereby each transmission path from a remote control through the corresponding window to electronic equipment is rendered unobstructed.

Abstract: A communication network and method implementing a star-tree topology utilizes conventional hardward and the CSMA/CD protocol. The network comprises in one embodiment at least two sets of user devices, in turn comprised of at least two user devices, connected through optical connectors and intelligent hubs to one another. Within each set of devices, the devices themselves are connected together by optical connectors through an optical coupler and an intelligent hub.The method according to one embodiment involves the steps of assigning unique addresses to each hub and subhub in the network and of assigning a device address to each user device. The device address need only be different from the addresses of the other devices in the family. The messages are sent from any one station through a passive coupler to all the other stations connected thereto.

Abstract: The system is used for transmitting information wherein each possible message unit in a set, (e.g. the alpha-numeric symbol set) is defined by a specific interval (I=f.sub.s /f.sub.RR) and messages are transmitted by conversion to the interval code and for the sending of signals of any two frequencies (f.sub.s and F.sub.R) that are related by the specific intervals. The signals are received by a receiver which computes the interval, matches it with the pre-defined message unit interval and outputs that message unit. A sequence of message units may be sent using a reference frequency signal and a succession of specific signals each related to the reference frequency by the specific interval for that message unit. A computer program can be utilized for automatically encoding or decoding.

Abstract: In a Pulse Code Modulated (PCM) circuit chip, apparatus in the transmit path to compensate for an offset voltage signal from a band-pass filter includes an up-down counter which is actuated to provide a digital value equivalent to the offset signal and a digital to analog converter coupled to the counter to provide an analog signal representing the digital value in the counter. During an initialization phase, the counter is incremented until the digital value of the counter provides, by means of the digital to analog converter, an analog signal that compensates for the off-set signal. After the initialization phase when the band-pass filter's offset voltage is compensated, then other circuitry including an exclusive OR gate and an associated overflow counter are used to eneable or disable the up-down counter to insure that the PCM output signal is an accurate representation of the analog input signal.

Abstract: An SSB signal demodulator comprising an analog bandpass filter for band-limiting such signal, an analog-to-digital converter 20 for digitizing the band-limited signal, and a pair of quadrature related decimating filters (28, 29) for deriving quadrature related decimated signals therefrom which are applied to a Hilbert transform pair (30, 31). The upper or lower sideband signal is obtained by taking the sum or difference of the outputs of the Hilbert transform pair, and the resulting digital signal is reconverted to an analog signal. By using a decimation factor which is an odd numbered integer greater than 1, the periodic transfer function of the demodulator has alternate passbands and stopbands. This relaxes the performance requirements of the analog filter and of the Hilbert transform pair, and greatly enhances the adjacent channel selectivity of the demodulator.

Abstract: In optical demultiplex transmission equipment, light conductor fibers are used for decoupling individual diffracted light signals of different wave length from a multiplex signal. These fibers have their input end regions arranged close together side-by-side in the diffraction plane of a diffraction grating. The respective diffraction angles of the light signals impinging on the grating are adjusted, by variation of the wave length of the light signals, so that the diffracted light beams fall into the input ends of respective output light conductor fibers. However, only every nth light conductor fibre is used for decoupling the various light signals (in which respect n is a natural number greater than one) so there may be spacer fibers disposed between the light-receiving output fiber. In this way, no complex output fibre guide is required and changes in channel spacing are possible without any structural changes being required.

Abstract: A transmitter for multiplexing three optical channels at different wavelengths has (a) first, second and third laser diode means delivering linearly polarized optical beams at respective wavelengths .lambda.2, .lambda.3 and .lambda.4 which are mutually different; (b) an assembly located in the path of the light of wavelength .lambda.2 emitted by said first diode means and including a plate which is substantially quarter-wave for the wavelength (2 .lambda.2-.lambda.4), a filter having a band pass centered on wavelength .lambda.2, a plate quarter-wave which is substantially for wavelength .lambda.4 and a polarizer, the first diode means being oriented so that its beam is transmitted by the polarizer. A first light beam combiner directs light from said third diode means onto the polarizer along a direction of 90.degree. from the direction of the beam of wavelength .lambda.2 and with the same polarization direction, so that the beam of wavelength .lambda.4 is reflected towards said filter.

Abstract: In a communication system, a plurality of remote modems send streams of data to a local modem, each remote modem preceding its transmission with a unique preamble consisting of phase reversed signals. At the local modem a preamble decoder detects the phase reversals of received signals without requiring channel equalization and the local modem uses this information for system setup.

Abstract: An improved miniature hand-held low power transmitter utilizing a surface acoustic wave (SAW) resonator as the control element to establish the carrier frequency of the oscillator. The SAW resonator stabilizes the frequency of the transmitter to within 0.05% of the center frequency of the SAW resonator for the condition of the user's hand enclosing the transmitter. This stability allows the companion receiver to operate at a narrow bandwidth, 0.1% of the center frequency of the SAW resonator, thus reducing the spurious noise received by the receiver. The configuration of the transmitter allows schemes such as pulse position or pulse width modulation to be utilized to encode the transmitted information. The physical size of the SAW resonator allows the transmitter to be mounted within a housing small enough to be enclosed by the user's hand.

Abstract: The system of the present invention allows transmission of information and data across a gap, for example, from the steering wheel of an automobile to the steering column, without any physical connection between the information source and the information or data gathering circuit. Furthermore, the information source requires no power. The system of the present invention utilizes the principle that an oscillator circuit is loaded by an inductively coupled circuit tuned to oscillate at approximately the same frequency. Loading the oscillator circuit causes the oscillator L-C loop voltage amplitude to decrease.