Patents Examined by Robert L. Griffin
  • Patent number: 4928316
    Abstract: A communications systems is characterized by a pulse-shaping technique for producing shaped, stabilized, ultra-short (picosecond to femtosecond) pulses containing encoded information. Pulse shaping is accomplished by temporally stretching and chirping an ultra-short pulse from a pulse generator, modulating the pulse in real time and temporally compressing the pulse in a manner so as to cancel the original chirp.
    Type: Grant
    Filed: February 4, 1988
    Date of Patent: May 22, 1990
    Assignee: Bell Communications Research, Inc.
    Inventors: Jonathan P. Heritage, Andrew M. Weiner
  • Patent number: 4926499
    Abstract: A simplified carrier phase control apparatus used in a modem for demodulating a quadrature amplitude modulated data signal, to correct phase jitters of a carrier signal due to a 50 Hz or a 60 Hz frequency of the commercial power supply, and its harmonic wave frequency components. The carrier phase control apparatus has a predictive filter for predicting a carrier phase jitter, the predictive filter composed of band-pass filters with center frequencies of 50 Hz and 60 Hz, and a circuit where the output signals of the band-pass filters are multiplied by the coefficients and added linearly.
    Type: Grant
    Filed: November 18, 1987
    Date of Patent: May 15, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Naoya Kobayashi, Makoto Ohnishi, Yoshiro Kokuryo
  • Patent number: 4926412
    Abstract: A wavelength division multiplexer/demultiplexer having optical path lengths between a fiber array and a Fourier transform lens, and between a dispersion grating and the lens equal to the focal length of the lens. The optical path lengths reduce losses due to angular acceptance mismatch in the multiplexer. Close orientation of the fiber array about the optical axis and the use of a holographic dispersion grating reduces other losses in the system. Multi-exposure holographic dispersion gratings enable the multiplexer/demultiplexer for extremely broad-band simultaneous transmission and reflection operation. Individual Bragg plane sets recorded in the grating are dedicated to and operate efficiently on discrete wavelength ranges.
    Type: Grant
    Filed: February 22, 1988
    Date of Patent: May 15, 1990
    Assignee: Physical Optics Corporation
    Inventors: Tomasz P. Jannson, Joanna L. Jannson, Peter C. Yeung
  • Patent number: 4926494
    Abstract: A method and system for transferring information between a moving vehicle and a stationary information location having a vehicle detector system with a loop antenna by using the loop antenna as either the receiving antenna for signals transmitted from a moving vehicle or as the transmitting antenna for signals generated by a transmitter located at the vehicle detector site for transfer to a receiver mounted on a moving vehicle. The information is encoded on a carrier having a frequency outside the normal frequency range of the vehicle detector system, preferably by interrupted carrier pattern processing.
    Type: Grant
    Filed: December 28, 1987
    Date of Patent: May 15, 1990
    Inventor: Thomas Potter
  • Patent number: 4926442
    Abstract: An improved CMOS signal magnitude detector (SMD) for accurately quantifying the peak-to-peak magnitude of a received signal is disclosed. The SMD includes a precision gain amplifier, positive and negative peak detectors and a switched capacitive amplifier. The recited components are coupled to form a combination circuit arrangement which receives a differential signal and outputs a single ended signal which is compared with a reference signal to provide a control signal when the differential signal is of a sufficient peak to peak voltage magnitude. The control signal may be used to gate the differential signal and generate an output signal representative of received data.
    Type: Grant
    Filed: June 17, 1988
    Date of Patent: May 15, 1990
    Assignee: International Business Machines Corporation
    Inventors: Eugene R. Bukowski, Charles R. Hoffman
  • Patent number: 4924479
    Abstract: A communication control system arranged between a plurality of terminal apparatuses and a host processing unit in order to transmit and receive signals based on an NRZI coding system between them by way of a half duplex communication system, a "0" bit detecting circuit for detecting the "0" bit of a one-bit length is provided in the communication control system and the sending and receiving modes are automatically switched in accordance with the output of this detecting circuit.
    Type: Grant
    Filed: August 10, 1987
    Date of Patent: May 8, 1990
    Assignee: Hitachi, Ltd.
    Inventors: Hideki Iwao, Michio Kato, Shuichi Yamano
  • Patent number: 4922153
    Abstract: A method of, and a device for, reducing the magnetic stray field generated in the vicinity of the faceplate of a cathode ray tube by the deflection current in the deflection coils of the tube. A current loop (4) is arranged at a distance from the deflection coils and is supplied with current having a time function substantially coinciding with the time function of the deflection current. The stray field is thereby neutralized to a large extent in a region extending beyond the position of the current conductor (4) in a direction away from the faceplate.
    Type: Grant
    Filed: September 7, 1988
    Date of Patent: May 1, 1990
    Assignee: U.S. Philips Corporation
    Inventor: Bruno Kevius
  • Patent number: 4921468
    Abstract: An optical communication system suited for transmitting optical signals to a moving station located on a vehicle comprises a transmitting station to send out coded optical pulse signals through space and a receiving station to receive the pulse signals. The transmitting station comprises a data input device, a signal encoder to convert the data into coded signals, an optical pulse signal generator to deliver the coded optical pulse signals, and a transmitting path setter to set a space path for transmitting the optical pulse signals. The receiving station comprises a receiving device for receiving the optical pulse signals transmitted from the transmitting station, a signal decoder to decode the optical pulse signals into coded signals, and a data display to represent the data in visible form based on the coded signals. The transmitting device may provided with an external light shade for preventing the receiving surface of the receiving device from external lights.
    Type: Grant
    Filed: March 21, 1988
    Date of Patent: May 1, 1990
    Assignee: Aisin Seiki Kabushiki Kaisha
    Inventor: Naomasa Miwa
  • Patent number: 4922480
    Abstract: A technique for increasing the number of manufactured laser transmitters which meet a predetermined wavelength specification is disclosed. Semiconductor lasers which exhibit a relationship between operating temperature and wavelength can be tuned by adjusting the operating temperature to ensure that the transmitter's operating wavelength will fall within the system-specified limits.
    Type: Grant
    Filed: December 2, 1987
    Date of Patent: May 1, 1990
    Assignee: American Telephone and Telegraph Company
    Inventor: Fridolin L. Bosch
  • Patent number: 4922507
    Abstract: A technique for designing trellis codes to minimize bit error performance for a fading channel. The invention provides a criteria which may be used in the design of such codes which is significantly different from that used for average white Gaussian noise channels. The method of multiple trellis coded modulation of the present invention comprises the steps of: (a) coding b bits of input data into s intermediate outputs; (b) grouping said s intermediate outputs into k groups of s.sub.i intermediate outputs each where the summation of all s.sub.i,s is equal to s and k is equal to at least 2; (c) mapping each of said k groups of intermediate outputs into one of a plurality of symbols in accordance with a plurality of modulation schemes, one for each group such that the first group is mapped in accordance with a first modulation scheme and the second group is mapped in accordance with a second modulation scheme; and (d) outputting each of said symbols to provide k output symbols for each b bits of input data.
    Type: Grant
    Filed: December 1, 1987
    Date of Patent: May 1, 1990
    Assignee: California Institute of Technology
    Inventors: Marvin K. Simon, Dariush Divsalar
  • Patent number: 4922490
    Abstract: A communication station capable of transmitting audible speech represented by speech signals received on the line during the on-hook state. A calling party name may be spoken at the station without requiring the call to be answered. The station is also usable, while on-hook, for receiving voice messages, e.g., emergency warnings, transmitted from a central office or customer premises switch.
    Type: Grant
    Filed: August 8, 1988
    Date of Patent: May 1, 1990
    Assignee: American Telephone and Telegraph Company
    Inventor: James R. Blakley
  • Patent number: 4922509
    Abstract: The invention relates to a method of implementing programmable tuned filters, in particular for telegraph signal receivers, and also to tuned filters obtained by the method. A resonator (16) organized around a multipath filter and controlled by a first clock signal is associated with a comb filter (17) organized around a delay line (21) and controlled by a second clock signal, in order to constitute a tuned filter which is programmed by the clock signals. The invention is applicable to making programmable tuned filters and banks of such filters, in particular for remote protection equipment in grids for transporting electrical power.
    Type: Grant
    Filed: June 27, 1988
    Date of Patent: May 1, 1990
    Assignee: CGEE Alsthom
    Inventors: Alain Tresset, Francois Fontenelle, Gerard Javard
  • Patent number: 4920547
    Abstract: A stuff synchronization circuit includes a memory, a phase comparison D flip-flop, a stuff judgment flip-flop, and a control section including selectors and an encoder. In the memory, writing and reading are performed at different timings. The phase comparison D flip-flop detects a phase difference between a write timing for a specific bit included in data input to the memory and a read timing for the specific bit. The stuff judgment D flip-flop judges an insertion timing of stuff pulses on the basis of the detected phase difference. The control section keeps a time interval between a time at which the phase difference is detected by the phase comparison D flip-flop and a time at which the insertion timing of stuff pulses is judged by the stuff judgment D flip-flop constant.
    Type: Grant
    Filed: December 1, 1987
    Date of Patent: April 24, 1990
    Assignee: NEC Corporation
    Inventor: Kurenai Murakami
  • Patent number: 4920530
    Abstract: An adaptive time-discrete filter having an impulse response h(i) with i=0,1,2, . . . for forming a cancelling signal from synchronous data symbols (for example to cancel echoes or lagging intersymbol interference) comprises a transversal filter section (12) having adjustable coefficients C.sub.i with i=0,1,2, . . . , N-1 for realizing the first N values h(i) of the impulse response as well as a recursive filter section (12') for realizing the values h(i) with i=N,N+1, . . . . The recursive filter section (12') receives the input signal delayed over N-1 discrete time intervals from the adaptive filter as an input signal x(n) and forms an output signal y(n) according to the relationship:y(n)=C.sub.B [C.sub.A .times.(n-1)+y(n-1)]where C.sub.A is equal to the last adjustable coefficient C.sub.N-1 of the transversal filter section (12) and C.sub.B is a predetermined fixed coefficient.
    Type: Grant
    Filed: December 15, 1987
    Date of Patent: April 24, 1990
    Assignee: AT&T and Philips Telecommunications B.V.
    Inventors: Kornelis J. Wouda, Simon J. M. Tol
  • Patent number: 4918688
    Abstract: A method and apparatus for automatically and dynamically providing wiring connections at a central location coupled via ordinary phone lines to a plurality of work stations including a master work station. A central hub couples to a plurality of two wire telephone lines, each of which is coupled to an individual work station. The hub includes circuitry for monitoring transmissions to determine which of the work stations is the master. A receiver coupled to the master work station is coupled to transmitters to each of the other work stations. Receivers coupled to the remaining work stations are in turn coupled to a transmitter to the master work station.
    Type: Grant
    Filed: October 31, 1986
    Date of Patent: April 17, 1990
    Assignees: Convergent Technologies, Inc., David Systems, Inc.
    Inventors: Jeffrey J. Krause, George W. Harris, Jr., Richard A. Lagueux, Jr., Luca Kafiero, Maurilio T. DeNicolo, Mario Mazzolo
  • Patent number: 4918747
    Abstract: The invention relates to a method for compensating, in a coherent optical communication system with heterodyne detection, at the receiving side phase noise of the transmitting and of the local laser. Characteristic of the present method is that the phase-noise compensation takes place in the LF domain. The two MF heterodyne signals (Imf and Pmf) are first demodulated into LF signals (in which there is still noise), which are subsequently subtracted from one another, due to which the respective noise components cancel out each other. Preferably a local laser signal which is, qua frequency, between the two other HF signals is chosen. This offers the advantage that the two MF heterodyne signals can be modulated by one and the same demodulator; because for the compensation of phase noise the demodulated MF signals (Iif respectively Pif) which are, qua phase noise, in opposite phase with regard to each other are then added to one another.
    Type: Grant
    Filed: December 23, 1988
    Date of Patent: April 17, 1990
    Assignee: Staat Der Nederlanden
    Inventor: Johan P. Bekooij
  • Patent number: 4918708
    Abstract: Provided is an apparatus for analysing digital radio transmissions which can provide an output indicating the condition of a digital transmission link. The apparatus operates by sampling received radio signals to produce for each sampling instant a signal or signals representative of the modulation state of the transmission at the sampling instant. The apparatus includes a processor which can receive and measure a given number of such signals. The processing means is arranged to process the signals according to one or more stored routines and generate one or more parameters which indicate the condition of the transmission. The apparatus includes means for representing the samples by digitally encoded numbers and the processing means arranges those samples into one of a plurality of groups according to the value of the number. The number of groups correspond to the number of modulation states. This technique allows the apparatus to carry out accurate analysis of the transmission.
    Type: Grant
    Filed: March 17, 1987
    Date of Patent: April 17, 1990
    Assignee: Hewlett-Packard Company
    Inventors: John R. Pottinger, Murdo J. McKissock
  • Patent number: 4918440
    Abstract: Programmable logic cells, and arrays of those cells, having certain characteristics, including: (1) the ability to program each cell to act either as a logic element or as a logical identity element(s) between one or more inputs and one or more outputs; (2) the ability to rotate circuits by 90.degree. and to reflect circuits about horizontal and vertical axes; (3) an integrated logic and communication structure which emphasizes strictly local communications; (4) a minimal complexity of logic functions available at the cell level, making available a very fine-grained logic structure; and (5) suitability for implementation of both synchronous and asynchronous logic, including speed-independent circuits. Cells are arranged in a grid, with each cell communicating with its north, east, west and south neighbors. The cells are programmable to several states.
    Type: Grant
    Filed: November 7, 1986
    Date of Patent: April 17, 1990
    Inventor: Frederick C. Furtek
  • Patent number: 4918748
    Abstract: The tuner section of a communications receiver 10 includes a gallium arsenide voltage controlled oscillator 48 for upconverting the received signal in mixer 18. Phase noise and post tuning drift associated with oscillator 48 is impressed onto the signal supplied by a second oscillator network 46. Thus, the outputs of mixers 18 and 78 both contain noise and post tuning drift associated with the gallium arsenide oscillator 48. Mixer 28 is used to substract the noise and drift component on line 30 from that on line 32 to thereby provide an output 14 which is substantially free of the noise and drift associated with the efficient, but noisy gallium arsenide VCO 48.
    Type: Grant
    Filed: November 9, 1987
    Date of Patent: April 17, 1990
    Assignee: Hughes Aircraft Company
    Inventors: Iradj Shahriary, Kevin M. McNab
  • Patent number: 4918745
    Abstract: A method and system is described for electrically stimulating the auditory nerve with multiple channels of audio information. Audio information is transmitted from an external microphone to a speech processor through a single transcutaneous path to an implanted receiving device. Power is transmitted through a second transcutaneous path to power the implanted device.
    Type: Grant
    Filed: October 9, 1987
    Date of Patent: April 17, 1990
    Assignee: Storz Instrument Company
    Inventor: Steve Hutchison