Patents Examined by David L. Stewart
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Patent number: 4276641Abstract: Methods and apparatus for converting time-division data signals received over an incoming trunk having v.sub.e channels into time-division data signals for transmission over an outgoing trunk having v.sub.s channels (where v.sub.s >v.sub.e).The device includes means for storing the data bits contained in each incoming frame; means for reading at an intermediate frequency f.sub.i, during read enable periods, the stored data bits corresponding to v.sub.e busy outgoing channels and for evenly distributing v.sub.s -v.sub.e free outgoing channels amongst the v.sub.e busy outgoing channels, during read inhibit periods; and means for transmitting at a frequency f.sub.s the data bits read at the intermediate frequency f.sub.i.This device may advantageously be used in PCM telephone exchanges.Type: GrantFiled: May 25, 1979Date of Patent: June 30, 1981Assignee: Le Material TelephoniqueInventors: Hieu K. Nguyen, Marc P. G. Dieudonne, Jean-Paul Lager
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Patent number: 4271500Abstract: A device for forming omitted samples by extrapolation in a transmitted signal having non-uniform, grouped samples representing a short-time stationary signal such as speech. The grouped samples are passed through a series of delay circuits. Fourier transformation of the samples is performed to form omitted samples which are inserted in the signal between the grouped samples. The Fourier transformation is used to select multiplication coefficients which are multiplied by the sample amplitudes, with the products of the multiplication being summed to form the omitted samples. In one embodiment the extrapolation is performed in both carry forward and carry back circuits.Type: GrantFiled: February 1, 1979Date of Patent: June 2, 1981Inventor: Tore Fjallbrant
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Patent number: 4271509Abstract: A digital transmission system is disclosed in which time slots in selected frames are reserved for supervisory signaling bits. These signaling bits can be used to represent a large number of supervisory states by assigning at least three bit patterns to each of two interleaved streams of supervisory bits. These bit patterns may include, for example, continuous ones, continuous zeros and alternating ones and zeros. A supervisory state encoder and decoder for these bit patterns are disclosed.Type: GrantFiled: July 13, 1979Date of Patent: June 2, 1981Assignee: Bell Telephone Laboratories, IncorporatedInventor: Stephen J. Brolin
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Patent number: 4271499Abstract: A linked compressor-expander (LINCOMPEX) circuit for use in telecommunications is implemented digitally. A speech compressor circuit in a modulator and a speech expander circuit in a demodulator controllably attenuate given syllables of a speech signal by values determined in response to binary input signals which collectively represent the amplitude of a given symbol of the speech signal. A control tone signal is generated by the modulator, and the demodulator is responsive to the control tone signal for operating the voltage attenuator circuit of the digital expander to thereby reconstruct the speech signal. Calibrate circuitry is provided for periodically detecting a test frequency of the control tone generator during a brief period prior to transmission of syllables of the speech signal. Also included is a data multiplexing circuit for transmitting and receiving data between speech syllables to optimize transmitter loading.Type: GrantFiled: July 12, 1978Date of Patent: June 2, 1981Assignee: H.F. Communications CorporationInventor: J. Howard Leveque
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Patent number: 4271505Abstract: A distributed, electronic process control system is disclosed having a plurality of remotely located stations interacting to control a complex industrial process. The stations communicate via a process communication link which supports secure, multi-master communication. The link provides a transparent medium of exchange for the secure transfer of process status and control information among the stations, such that each station may initiate and control system communication for a predetermined time period.Type: GrantFiled: July 2, 1979Date of Patent: June 2, 1981Assignee: The Foxboro CompanyInventors: Robert Menot, Robert E. Willard, Paul D. Griem, Guy E. Devine
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Patent number: 4270204Abstract: A multiplexer circuit is disclosed wherein a diode ring circuit is coupled to a pair of logical signal sources and a first winding of a transformer. A second winding of the transformer is coupled to a control signal source. One of the pair of logical signal sources is coupled to a center tap of the first winding selectively in accordance with the control signal.Type: GrantFiled: December 22, 1978Date of Patent: May 26, 1981Assignee: Raytheon CompanyInventor: Bruce E. Gordon
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Patent number: 4270203Abstract: A slip-free timing adjustment system adjusts channel timing for a multiplexed digital data stream. The data stream in each of c time division channels (10, 11) is modified preparatory to switching in a digital time-division circuit switch (14). The multiplexed digital data stream may arrive at the switch at a rate R0. The switch clock rate may be at a rate R1. Rates R0 and R1 are potentially different.Signal means (12, 13) provide for inserting a variable length timing code, one bit at a time, in each of the c channels in each multiplexed digital data stream. The multibit timing code is composed of successive variable length code words of length L and L+1 bits.Adjustment means (18, 42) receives the multiplexed data stream and adjusts individual channel rates in each of the c channels.Type: GrantFiled: November 13, 1978Date of Patent: May 26, 1981Assignee: Arthur A. Collins, Inc.Inventors: Arthur A. Collins, Jon W. Bayless, Sr., Robert D. Pedersen
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Patent number: 4270202Abstract: Circuitry for automatically and dynamically reconfiguring the channel or port configuration of a modem handling a plurality of ports. A standard signal such as DTR (data terminal ready) is used to provide a code to a master modem indicating the particular port configuration requested by cooperating apparatus. The requested configuration code is continuously compared to a code stored by a shift register controlling the actual modem port configuration. When the requested code changes, an indication of the code change is transmitted to a communicating slave modem and a control signal is sent, after a suitable delay, to the shift register to conform its contents to the newly requested configuration code. During the delay, the slave modem switches to the newly requested configuration. The circuitry follows a defined sequence of configuration switching, dropping channels successively and adding channels by passing through the state where all channels are active.Type: GrantFiled: February 1, 1979Date of Patent: May 26, 1981Assignee: Racal-Milgo, Inc.Inventors: Edward B. Stuttard, John E. Blackwell, Jessie Chao
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Patent number: 4268722Abstract: A telephone system for providing communications between mobile radiotelephones, portable radiotelephones and landline telephones includes a land-line telephone system including a land-line switching network for providing communication paths for land-line telephones and a mobile radiotelephone system for providing communications paths for mobile and portable radiotelephones. The mobile radiotelephone system includes a digital switching network, base stations, and PCM analog-to-digital (A/D) and digital-to-analog (D/A) converters interposed between the base stations and the digital switching network and between the land-line switching network and the digital switching network. Analog ports are interfaced by the PCM A/D and D/A converters to incoming and outgoing serial bit streams coded according to pulse-code-modulation (PCM) techniques standardized for telecommunications systems by the International Telegraph and Telephone Consultative Committee (CCITT).Type: GrantFiled: September 6, 1979Date of Patent: May 19, 1981Assignee: Motorola, Inc.Inventors: Richard I. Little, Barry D. Lubin, Stephen L. Spear
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Patent number: 4266292Abstract: An apparatus and method for testing for faults in an analog-to-digital (A/D) section and a digital-to-analog (D/A) section of a code converter in a digital time division, multiplex telecommunications system are disclosed. The A/D section is tested by connecting a digital test pattern via the switching network to the D/A section and monitoring for faults by comparing the resulting output to a reference value. The A/D section is tested by interconnecting the A/D section to be tested between a first previously tested D/A section and a second previously tested D/A section and then connecting the digital test pattern to the first D/A section while monitoring the output of the second D/A section for faults.Type: GrantFiled: November 20, 1978Date of Patent: May 5, 1981Assignee: Wescom Switching, Inc.Inventors: John F. Regan, Satyan G. Pitroda, Byung C. Min
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Patent number: 4262356Abstract: A method and a system are disclosed for synchronizing within a recurrent time frame the starting points of the transmissions from the various stations in a TDMA network wherein N stations distributed among M separate zones covered by M different down-link frequencies exchange pulse bursts through a satellite, each pulse burst being comprised of a preamble, a unique word, the transmitting station's address, and traffic data. The satellite includes a global beam antenna which covers all of the M zones and is adapted to receive M different up-link frequencies, means for converting these M up-link frequencies to M corresponding down-link frequencies, and M directional beam antennas covering the M zones, each of said M antennas being adapted to transmit the down-link frequency associated with the particular zone it covers. The bursts transmitted by the various stations are assigned a predetermined position within the frame.Type: GrantFiled: September 13, 1979Date of Patent: April 14, 1981Assignee: IBM CorporationInventors: Alex Lautier, Jean L. Monrolin
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Patent number: 4259738Abstract: A multiplexer system providing a transmission frame field containing information derived from the cumulative total of stuff bits used over a plurality of frames. The stuff bits which also have assigned positions in the transmission frame are generally used in asynchronous systems to compensate for the input data rate of a group not being a fixed submultiple of the transmission rate. The demultiplexer system uses the information derived from the cumulative total to improve the bit count integrity performance of data channeled out to a user device. Also, during transmission fade conditions, the demultiplexer uses information derived from the frequency of past stuff operations to maintain group bit count close to its expected value.Type: GrantFiled: May 18, 1979Date of Patent: March 31, 1981Assignee: Raytheon CompanyInventors: Nathan A. Liskov, David L. Hendry
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Patent number: 4258434Abstract: A bit-by-bit time-division digital switching network switches a plurality of incoming and outgoing isochronous digital data channels having rates which are different but sub-multiples of a given low rate. After phasing said incoming digital channels, bits having a predetermined binary state are detected. Previously stored address words of said outgoing digital channels to be switched to said incoming digital channels are read-out and correspond to switched incoming channels whose detected bits have said predetermined binary state. Then the read outgoing channel address words are multiplexed into a multiplex digital highway at high rate. In the transmission part of each outgoing digital channel address words of said outgoing digital channel are detected. A bit at said predetermined binary state or a bit in the other binary state is transmitted on the outgoing digital channel in response to the detection or failure of detect the address word of said outgoing digital channel.Type: GrantFiled: June 18, 1979Date of Patent: March 24, 1981Inventors: Albert Glowinski, Pierre M. Lucas
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Patent number: 4258435Abstract: Bandpass channel filters are connected to a uniform impedance manifold. Immittance compensation is provided in a way that preserves the canonic form of the network while at the same time serving to separate the filters (channels) along the manifold. The manifold forms a phase shifter between each channel which is sufficient to compensate for filter interactions to thereby permit the design of contiguous or non-contiguous channel multiplexers. Design procedures are described for both a frequency independent manifold and a frequency dependent manifold. One design is of a waveguide WR229 manifold triplexer employing 37 MHz bandwidth 6-cavity Chebyshev filters having ripple return loss of 26dB (VSWR=1.1) with center frequencies at 3720, 3800 and 3880 MHz.Type: GrantFiled: January 8, 1979Date of Patent: March 24, 1981Assignee: Microwave Development Labs. Inc.Inventors: Ralph Levy, John D. Rhodes
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Patent number: 4257120Abstract: An improved conference circuit for use in a Pulse Code Modulation telephone switching system wherein a number of channels are combined so that a number of subscribers may participate in a common telephone conversation. The conference circuit is provided with a multi-frame voice level summing arrangement whereby spurious channel switching caused by noise peaks is effectively eliminated.Type: GrantFiled: August 6, 1979Date of Patent: March 17, 1981Assignee: GTE Automatic Electric Laboratories IncorporatedInventors: Tim Funderburk, Donald W. McLaughlin
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Patent number: 4256925Abstract: In a time division multiple access communication system utilizing a satellite for communicating signals between a plurality of ground stations, at spaced times a reference ground station reallocates the total channel capacity of the system among the several ground stations to minimize system blocking and to thereby utilize the available system channel capacity more effectively. To increase the time between successive reallocations, channels are reallocated only when a ground station makes a channel capacity request that is greater than or equal to its corresponding present channel allocation. System blocking is minimized by using a table look-up scheme to generate excess capacity allocation factors for the stations and to thereby determine each station's proportionate share of excess system capacity. An appropriate portion of excess capacity is then added to each station's channel capacity request to provide a new channel allocation for each station.Type: GrantFiled: December 12, 1978Date of Patent: March 17, 1981Assignee: Satellite Business SystemsInventor: Burwell Goode
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Patent number: 4254495Abstract: A control system features built in test equipment for wiring harness interface testing, i.e., testing critical wires leading to the system from external signal sources, for reducing maintenance costs and for insuring critical wire validity of line replacement units.Type: GrantFiled: June 27, 1979Date of Patent: March 3, 1981Assignee: The Bendix CorporationInventor: Robert J. Bollard
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Patent number: 4253193Abstract: A tropospheric scatter radio communication system uses a multiple signal diversity system in order to improve reliability of reception. A dual time diversity is used in which adjacent bits in a digital word are interleaved with bits from adjacent digital words so that more than one bit from a particular digital word is unlikly to be adversely affected by short term fading.Type: GrantFiled: November 2, 1978Date of Patent: February 24, 1981Assignee: The Marconi Company LimitedInventors: Paul A. Kennard, Stewart J. R. Hartley
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Patent number: 4251880Abstract: There is disclosed a digital loop for interconnecting a number of data interchangers, each data interchanger connectable over a single high speed communication link to a remote station controller. The high speed link is arranged to bidirectionally transfer both bursty and continuous data to and from the data interchanger. A central controller is serially inserted in the digital loop and serves to assign time slots in a frame for information exchange between the various programmable data interchangers. Each frame contains a first field for data interchange between the data interchangers and the central controller; a second field having time slots assignable under control of the controller to a specific set of data interchangers for transferring information from the continuous data inputs; and a third field having time slots assignable under control of each data interchanger for transferring information from the bursty data input.Type: GrantFiled: July 31, 1979Date of Patent: February 17, 1981Assignee: Bell Telephone Laboratories, IncorporatedInventors: Charles R. Baugh, Robert M. Smith
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Patent number: 4249241Abstract: A serialization apparatus for a data processing system wherein access restrictions are automatically enforced: (1) in behalf of individual machine instructions in order to maintain object integrity; and (2) at each user's discretion in order to maintain synchronization among all concurrent users of any given object. Various types of restrictions can be enforced in behalf of both machine instructions and users, allowing concurrent access to objects at various levels where appropriate.Type: GrantFiled: October 23, 1978Date of Patent: February 3, 1981Assignee: International Business Machines CorporationInventors: Gary F. Aberle, Gerald J. Balm, Viktors Berstis, Leon E. Gregg, Kuang-Chi Hu, James G. Ranweiler, William C. Richardson, Terry L. Schardt, Charles T. Watson