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公开(公告)号：US3571736A
公开(公告)日：1971-03-23
申请号：US3571736D
申请日：1969-01-14
Applicant: IBM
Inventor： WEST LYNN P
CPC classification number: H03D3/04
Abstract: The subject disclosure relates to a frequency demodulator. The demodulator produces two pulse trains from the transitions which are square wave trains with one train being inverted with respect to the other. These transitions define ''''transition periods.'''' During During the first transition period, a capacitor is discharged so that at the end of that period, it provides a signal that is a function of the time width of the first odd transition period of the first train of square waves. During the second even transition period, another capacitor is discharged so that at the end of this period the capacitor provides a signal which is a function of the time length of the second transition period. Thus, the two trains provide alternately a voltage level that is a function of alternate transition periods. These signals are then added to produce a quantitized version of the frequency modulation.
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公开(公告)号：US3466392A
公开(公告)日：1969-09-09
申请号：US3466392D
申请日：1966-03-03
Applicant: IBM
Inventor： CALFEE RICHARD W , HOPNER EMIL , MEYER ORMAN F , WEST LYNN P
CPC classification number: H04L27/10 , H03C1/545 , H04B14/006
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公开(公告)号：US3571710A
公开(公告)日：1971-03-23
申请号：US3571710D
申请日：1969-01-14
Applicant: IBM
Inventor： WEST LYNN P
CPC classification number: H04L5/06
Abstract: A communication system which transmits binary data by a frequency shift keyer to a plurality of receiving stations while the receiving stations are on a common channel with the transmitter. Each receiving station utilizes an FM demodulator wherein normally the output voltage is directly proportional to the frequency received by the demodulator. In each receiving station, a maximum and a minumum output voltage for the demodulator is established. Between each of these voltage levels, information can be received; whereas, outside the voltage level, there are no transitions but a constant signal output. Thus, by adjusting different level ranges for each receiver, the transmitter can transmit to one desired station without effecting or passing information to the other stations.
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公开(公告)号：BR8703890A
公开(公告)日：1988-03-29
申请号：BR8703890
申请日：1987-07-27
Applicant: IBM
Inventor： PEARCE HAROLD B , WEST LYNN P
Abstract: A method and apparatus are described for phase and frequency locking a reference oscillator to an incoming modulated signal. The method and apparatus enable the carrier recovery of the incoming modulated signal. Phase and frequency locking devices are connected in feedback loops (20, 30) with a coherent detector (10) that determine the amount of phase and frequency error between the reference oscillator of the coherent detector and the incoming modulated signal. The feedback loops correct such frequency and phase error so as to enable the reference oscillator to be in phase and frequency step with the modulated signal.
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Patent Agency Ranking
公开(公告)号：CA1141493A
公开(公告)日：1983-02-15
申请号：CA331678
申请日：1979-07-12
Applicant: IBM
Inventor： ALVAREZ JOSEPH A III , GOBIOFF BRUCE D , WEST LYNN P
Abstract: ADAPTIVE ERROR ENCODING IN MULTIPLE ACCESS SYSTEMS In a time division multiple access (TDMA) system, for "multi-path" data communication via satellite repeater, the form of transmitted data is varied adaptively to maintain error-free transmission under varying noise conditions. Adjustments are made on a path selective and channel selective basis to protect only the most vulnerable data in specific transmission paths experiencing noise deterioration. Accordingly any multi-channel burst may contain channels of data in both protected and unprotected forms. A predetermined portion of each channel containing data in unprotected format is used explicitly to designate the destination of the accompanying data and implicitly to distinguish the data format as unprotected. In protected format data including error protective coding is transmitted in two contiguous channels along with information in the first channel explicitly distinguishing the protected format This format-distinguishing information occupies the space allotted in the unprotected format for designating the data destination. The destination of protectively encoded data is explicitly designated in a separate predetermined space in the associated double-channel slot. MA9-77-019
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公开(公告)号：CA1000382A
公开(公告)日：1976-11-23
申请号：CA178372
申请日：1973-08-08
Applicant: IBM
Inventor： HAAS LEE C , LARSEN LARRY D , WEST LYNN P
IPC: H04L12/403
Abstract: A polling scheme is disclosed in which a plurality of remote terminals or stations sharing a single communication channel are polled by a central station at a high speed to solicit responses therefrom. The central station can effectively handle responses from only one remote station at a time and, since a plurality of stations are polled, the possibility of contention between more than one remote station trying to respond during the same time period exists. If contention does occur, a second poll of possible contenders is conducted at a slow rate of speed to resolve the contention.
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公开(公告)号：FR2296983A1
公开(公告)日：1976-07-30
申请号：FR7540400
申请日：1975-12-29
Applicant: IBM
Inventor： WEST LYNN P , MARKEY HAROLD G , BLASBALG HERMAN
Abstract: The digital circuit comprises any number 1 to k of similar switching modules connected to one of the 1 to k groups of subscriber and trunk lines and channels. Exchange of buffered signals between subscriber lines and trunk channels is carried out by the modules under central control. Each subscriber line in all 1 to k groups can be connected with any trunk channel in any group, and also all subscriber lines and all trunk channels can be connected with each other. Memory units are included for information bit storage (AZS) and remote group storage (FGM), the latter being connected to the system by duplex remote terminal connections. The signalling incorporates techniques for time assignment speech interpolation (TASF) and voice activity compression (VAC).
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公开(公告)号：FR2296970A1
公开(公告)日：1976-07-30
申请号：FR7540396
申请日：1975-12-29
Applicant: IBM
Inventor： FLEMMING DONALD C , MARKEY HAROLD G , METZ RALPH J , WEST LYNN P
IPC: H04J3/00 , H04B7/15 , H04B7/185 , H04B7/212 , H04J3/24 , H04M3/00 , H04Q11/00 , H04Q11/04 , H04L5/26
Abstract: Modular digital exchanges linked by earth satellite provide coordinated time division switching and time compressed communication services relative to externally attached telephone and data (user) trunks. Branch exchange modules (NCU's) perform call switching, buffer storage, time compression and activity selective channel assignment handling between individual external user trunks and multi-bit channels of external time division highways (digital links). The latter are linked pyramidally to time division multiple access nodes of the satellite through Network (Nodal) Access Unit modules (NAU's) which perform further time compression handling and adaptive assignment of satellite channels based upon nodal distribution of demand. The NCU modules also provide "local" switching between user trunks and "tandem" linkage directly between NCU's (without NAU and satellite handling). The modules have individual common control processors which inter-communicate via reserved signaling channels on the digital links and satellite. The modularity is in increments suitable for adaptive deployment of connection equipment relative to satellite access nodes (e.g. to adapt to shifts in user populations and/or plant facilities).
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公开(公告)号：CA1293060C
公开(公告)日：1991-12-10
申请号：CA520181
申请日：1986-10-09
Applicant: IBM
Inventor： EINKAUF MARK A , WEST LYNN P
Abstract: AT9-85-015 METHOD AND APPARATUS FOR VOICE DETECTION HAVING ADAPTIVE SENSITIVITY This invention enables voice energy to be distinguished from energy due to other sources such as telephone call progress signals. A portion of the audio spectrum is divided into a high and into a low frequency band and the energy content of these bands is examined. The audio energy of a signal is passed through a set of filters and compared. A frequency boundary crossing of an input signal subsequent to filtering is used to signify the receipt of a voice signal. By operating in this manner, voice, whose predominant frequency switches in a random fashion from being greater than to less than a cutoff frequency, can be distinguished from other signals either below or above the cutoff frequencies of the filters. The detection of voice energy is not begun until a predetermined threshold of energy has been received for a specified period of time. This specified period of time need not be continuous after a ringback signal is received. Subsequent to the receipt of a ringback signal the voice detection mechanism will proceed as long as the total time above the threshold exceeds the specified time.
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