Patents Examined by Leslie Van Beek
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Patent number: 4868897Abstract: An optical network, particularly fashioned as a homodyne or heterodyne receiver wherein a local oscillator (2) of an optical homodyne or heterodyne receiver comprising an optical wave guide network (1) is isolated from generally anisotropic reflections from the network (1) in order to preserve the stability and tunability of the oscillator (2) and a polarization filter (10), a polarization converter (11) and a phase shifter (12) are successively arranged in the direction of the outgoing optical wave in the beam path of the wave emitted by the oscillator (2) and reflected by the network (1) for optical homodyne or heterodyne reception.Type: GrantFiled: December 28, 1987Date of Patent: September 19, 1989Assignee: Siemens AktiengesellschaftInventor: Clemens von Helmolt
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Patent number: 4868809Abstract: An optical communications system comprises a pluarality of optical transmitters coupled by a common channel or bus to an optical receiver. The optical transmitters are operated using time division multiplexing (TDM), each TDM period being word or message length. The optical transmitters each comprise a least one current source to drive the light source, for example a laser, in response to the data signal, to vary its output power about a steady level which is the average of the maximum and minimum values. Therefore each current source may be controlled as to increase its output gradually (preferably sinusoidally) to reach the aforesaid mean level at the beginning of a TDM period and to decrease it in the converse way after the period ends. Such an arrangement avoids the need for guard time before and after the TDM time period, thereby increasing channel efficiency, and improves receiver sensitivity by reducing quantum shot noise due to steady light from inactive transmitters.Type: GrantFiled: January 2, 1989Date of Patent: September 19, 1989Assignee: Northern Telecom LimitedInventor: David A. Kahn
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Patent number: 4868894Abstract: A system for the transmission of signals along an optical carrier employs a technique to extend the effective frequency range of modulation beyond that of which a semiconductor laser is capable by combination of signals at the source to form a composite difference signal and recombination at the receiver to restore the original signal.Type: GrantFiled: December 9, 1987Date of Patent: September 19, 1989Assignee: United TechnologiesInventors: Meyer Gilden, Louis B. Allen, Jr.
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Patent number: 4868895Abstract: An optical device compensator obtains from an input modulating signal an additive component and a multiplicative component. The additive and multiplicative components are combined with the input modulating signal to produce a compensated modulating signal which is applied to a driver for modulating an optical device.Type: GrantFiled: March 14, 1989Date of Patent: September 19, 1989Assignee: The Grass Valley Group, Inc.Inventors: David L. Hershberger, Gordon E. Ransom
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Patent number: 4864648Abstract: A method of transmitting at least two measured values by means of light pulses which are passed by an optical transmitter through an optical transmission path to an optical receiver and whose relative separation in time is proportional to the measured value. The energy consumption for the optical transmission of the measured values is reduced by transmitting needle pulses cyclically, one after another in the same order of succession, in that per measured value an optical measuring pulse is transmitted, whose separation in time from the optical measuring pulse associated with a preceding measured value is proportional the magnitude of the measured value, and in that for each group of measured values an optical identification pulse is transmitted, whose distance in time from a preceding measuring pulse is smaller than the smallest possible distance in time between two successive optical measuring pulses.Type: GrantFiled: February 2, 1987Date of Patent: September 5, 1989Assignee: U.S. Philips CorporationInventors: Jurgen Kordts, Reiner U. Orlowski, Ingobert H. Gorlt, Gerhard Martens
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Patent number: 4864647Abstract: One or more infrared receiver units communicate by radio to an infrared transmitter unit in order to extend the operational range of an infrared remote control device that normally operates an electrical or electromechanical apparatus. The receiver converts the infrared radiation pattern produced by the infrared remote control device into a radio signal at a suitable frequency. The transmitter, located adjacent the apparatus, converts the radio signal back into the original infrared siganl used to operate the apparatus.Type: GrantFiled: December 18, 1987Date of Patent: September 5, 1989Assignee: Modcom CorporationInventor: Christopher C. Harrington
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Patent number: 4864651Abstract: A light signal receiver comprises a plurality of photo-sensors, a detector for detecting signal levels of light signals sensed by the photo-sensors, a selector for selecting those photo-sensors which result in a proper output signal, and output means for combining the signals sensed by the selected photo-sensors to produce the output signal.Type: GrantFiled: October 17, 1986Date of Patent: September 5, 1989Assignee: Canon Kabushiki KaishaInventors: Satoshi Ogiwara, Izumi Ichikawa, Haruo Imano, Genmei Miura
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Patent number: 4864649Abstract: A driver circuit for driving a light emitting element with a signal generated by superimposing an analog sub-information signal over the pulse string of a digital main signal. The driver circuit includes an input interception detector for detecting any interception of the digital main signal, and a gain-controlled amplifier for increasing the gain of the analog sub-information signal when the digital signal is intercepted.Type: GrantFiled: August 26, 1987Date of Patent: September 5, 1989Assignee: NEC CorporationInventors: Tsutomu Tajima, Toru Hamanaka
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Patent number: 4864650Abstract: An expansion network for increasing the number of subscriber terminations at a passive optical bus system comprising optical mixers is disclosed. The mixers are arranged in groups and the optical transmitters individually provided per subscriber are connected to the light receivers likewise individually provided per subscriber, being connected thereto in the manner of a mesh network via respectively only one of the mixers so that the attenuation of only one mixer is inserted into the optical path.Type: GrantFiled: September 10, 1986Date of Patent: September 5, 1989Assignee: Siemens AktiengesellschaftInventors: Hans Thinschmidt, Rudolf Mittelmann
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Patent number: 4856095Abstract: A field-effect transistor performs four functions, namely signal demodulation, generation of a local oscillator signal, generation of harmonics of this local oscillator signal through frequency multiplication, and mixing of the demodulated signal with either the local oscillator signal or one of its harmonics to produce a signal at a lower intermediate frequency; the field-effect transistor being the key element in a demodulator-downconversion circuit.Type: GrantFiled: May 28, 1987Date of Patent: August 8, 1989Assignee: The United States of America as represented by the Secretary of the NavyInventor: Christen Rauscher
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Patent number: 4856094Abstract: An arrangement for polarization control for an optical heterodyne or homodyne receiver wherein the state of polarization of the optical signal of the local oscillator of a heterodyne or homodyne receiver and the optical signal supplied to the receiver can be transformed so that both signals can be adjusted to the same identical state of polarization. A phase modulator PM1 and a following polarization converter PK1 are arranged onto an optical waveguide WL1 which receives at an input e.sub.1 an optical wave from a subscriber and another polarization converter PK2 and a following phase modulator PM2 are arranged onto another optical waveguide WL2 which has an input e.sub.2 for coupling in the local oscillator signal. The arrangement can be controlled such that the signals fed in have the same state of polarization at the output for superposition and IF generation.Type: GrantFiled: September 11, 1987Date of Patent: August 8, 1989Assignee: Siemens AktiengesellschaftInventors: Helmut Heidrich, Detlef Hoffmann, Hans-Peter Nolting
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Patent number: 4852079Abstract: An optical spectral analyzer (10) for receiving an input beam (30) through a multi-mode optic fiber (28). The input or beam (30) has a predetermined spectral band width. The random individual spectral components of the beam (30) are dispersed by a grating (40) to generate a spectrum (42, 42' . . . 42.sup.N). A detector (52) senses the magnitude of the elements in a reflected focused spectrum (50, 50' . . . 50.sup.N) to recover the information placed on the optic fiber (28) at a remote location by a spectrum encoding device.Type: GrantFiled: November 23, 1987Date of Patent: July 25, 1989Assignee: Allied-Signal Inc.Inventors: Terrance R. Kinney, Stephen M. Emo, Richard N. Poorman
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Patent number: 4850042Abstract: A dual media network interface module includes an electrical network interface and an optical network interface each having a transmit port to which signals to be transmitted on the associated network are applied and a receiver port at which signals received on the network are generated. The receiver port of each interface is connected to the transmitter port of the other interface so that signals received on either network are retransmitted on the other network. Blocking circuits block the receiver signal of a LAN which is transmitting during the transmitting interval plus an interval which exceed the worst case propagation time for the associated network to prevent endless repetition of a signal.Type: GrantFiled: April 14, 1987Date of Patent: July 18, 1989Assignee: Westinghouse Electric Corp.Inventors: Carlo F. Petronio, James C. Belz
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Patent number: 4850046Abstract: An infrared transmitter of coded message is provided having a fixed code and large number of combinations particularly but not solely for use in the automobile industry.The transmitter comprises a series programmable electronic memory (1), the content of which is addressed by a pulse transmitter (2), an oscillator or timer, the content of the memory (1) being supplied to a pulse generator (3) supplying an amplifier (4), the output of which is transmitted to a transmitter diode (5), the content of the memory (1) being supplied, in addition, to an end of message blocking device (6) controlling the reading pulse transmitter (2).Type: GrantFiled: October 29, 1987Date of Patent: July 18, 1989Assignee: NeimanInventor: Patrick Philippe
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Patent number: 4849960Abstract: An optical transmission system comprises a plurality of transducers located at intervals along a continuous optical fibre data transmission path. Data signals are derived from respective transmitters associated with the transducers and are applied to the transducers to produce mechanical stressing or deformation of the data transmission path optical fibre for imparting corresponding modulation of the polarization state of light being propagated along the optical fibre. A receiver connected to the far end of the transmission path includes means for determining the exact state of polarization of the received light and for extracting the modulation information and hence transmitted data therefrom.Type: GrantFiled: January 22, 1987Date of Patent: July 18, 1989Assignee: Plessey Overseas LimitedInventors: John P. Dakin, Christopher A. Wade, David J. Pratt
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Patent number: 4850047Abstract: An optical bus type communication system comprises a bus type transmission line consisting of an optical fiber, a light source provided at the one end of the bus type transmission line for sending an optical signal having a constant level to the bus type transmission line, a plurality of optical switches mounted on the bus type transmission line, and a plurality of terminal interfaces. Each terminal interface sends data by switching the corresponding optical switch so that the optical signals on the transmission line are modulated with the data.Type: GrantFiled: August 19, 1987Date of Patent: July 18, 1989Assignee: Fujitsu LimitedInventors: Kazuo Iguchi, Tetsuo Soejima, Shigeo Amemiya, Hiroaki Komine
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Patent number: 4845702Abstract: An optical switching system, wherein the input channels carrying packetized data are switched one-by-one at high bit rate to output channels through an optical switching network. The packets of a generic input channel are time compressed, converted into optical signals and, at suitable instants, sent to an optical switching network to be switched to the desired output channel, they are then reconverted into electrical signals and expanded to their original duration. A centralized processor controls the channel switching through the switching network by means of a driving circuit.Type: GrantFiled: February 23, 1988Date of Patent: July 4, 1989Assignee: CSELT - Centro Studi e Laboratori Telecomunicazioni SpAInventor: Flavio Melindo
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Patent number: 4839894Abstract: A multiplexer/demultiplexer for combining/separating a large number of contiguous frequency channels in microwave bands while incurring low insertion loss. The invention, in a demultiplexer mode, includes a power divider, to form a multiplicity of samples of an input signal; delay lines to non-dispersively differentially delay the samples in accordance with a first arithmetic progression; phase shifters to add fixed phase shifts to samples in accordance with a second arithmetic progression; and a Butler matrix to coherently combine the samples selectively at different output ports for different input signal frequencies. In a multiplexer mode, input signals are applied to the Butler matrix. The Butler matrix, phase shifters, delay lines, and power divider perform in reverse of the demultiplexer mode (the power divider thus performing as a power combiner). The present invention minimizes insertion loss by eliminating any requirement for resonators and any means for isolating resonators.Type: GrantFiled: September 22, 1986Date of Patent: June 13, 1989Assignee: Eaton CorporationInventors: Ronald M. Rudish, Scott F. Hall
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Patent number: 4839884Abstract: An external-cavity laser includes low-level, broad spectrum light sources and plural light amplifiers. The external cavity includes a common partially reflecting mirror, and a common diffraction grating which couples the mirror to the light amplifiers. The feedback light is at a different wavelength for each amplifier, so that lasing takes place at plural wavelengths. The output light, while deriving from plural light amplifiers, occurs as a single light beam comprised of plural wavelengths.Type: GrantFiled: March 4, 1988Date of Patent: June 13, 1989Assignee: General Electric CompanyInventor: Robert P. Schloss
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Patent number: 4837855Abstract: An optical space switch is formed in such a manner that switch elements having two inputs and two outputs are arranged in an n.times.n matrix form and optical signals from n input highways are switched to n output highways. The switch elements are connected in such a manner that the optical signals are always passed through the same number of switch elements, from the input highways to the output highways.Type: GrantFiled: August 18, 1987Date of Patent: June 6, 1989Assignee: Fujitsu LimitedInventors: Kazuo Hajikano, Toshio Shimoe, Jyoei Kamoi, Ippei Sawaki, Koso Murakami