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    FREQUENCY AGILE TDMA COMMUNICATIONS SYSTEM
    71.
    发明专利
    FREQUENCY AGILE TDMA COMMUNICATIONS SYSTEM 未知

    公开(公告)号：CA2068430C

    公开(公告)日：1996-06-11

    申请号：CA2068430

    申请日：1991-09-25

    Applicant: MOTOROLA INC

    Inventor： FREEBURG THOMAS A ,  GERHARDT WILLY ,  LEY JOHN

    IPC: H04J3/00 ,  H04B7/26 ,  H04J3/16 ,  H04J4/00 ,  H04J3/02

    Abstract: An intelligent communications node (20) is capable of dynamically selecting frequency and time slot assignments for communications with remote communication devices (22, 24, 26) having different communication protocols including different available frequencies and time slots in a TDMA system. A frequency agile transmitter (62) and receiver (32) combined with an adaptable time slot selector (38, 60) enables communications with remote devices utilizing different protocols. The time and frequency management capabilities of the node (20) makes greater spectral efficiencies possible.

    72.
    发明专利
    未知

    公开(公告)号：DE68924187D1

    公开(公告)日：1995-10-19

    申请号：DE68924187

    申请日：1989-01-30

    Applicant: MOTOROLA INC

    Inventor： FREEBURG THOMAS A ,  DAUTEL DONALD F

    IPC: H04W76/04 ,  H04W88/02 ,  H04W88/16 ,  H04W92/02 ,  H04Q7/22 ,  H04B7/26

    Abstract: A unique cellular data telephone system includes a cellular telephone system (CTS 150), a cellular data switch (CDS 170), and a telephone central office (130) for providing both voice and data telephone services to portable and mobile cellular data telephones (CDTs 102, 122) located anywhere in a large geographical area. Each of the CDTs (102, 122) includes a data control unit (DCU 106), a cellular modem (162) and a cellular telephone (108) and associated antenna (110), and connects to a data terminal (104, 124) with keyboard and display. DCU (106) includes memory (302) for storing a CDS telephone number and CDT telephone number, microcomputer (304) with internal memory for controlling data communications between cellular modem (162) and data terminal (104), a duel tone multifrequency ("DTMF") encode (306) for encoding telephone numbers and control signals, a DTMF decoder (314) for decoding DTMF telephone digits and/or DTMF control tones, a buffer (312) for storing transmit data from data terminal (104), and analog switches (308, 310) for coupling DTMF encoder (306) and buffer (312) to the transmit data Td signal to cellular modem (162). If data transmit (104) is inactive for a predetermined time interval, DCU (106) automatically disconnects the cellular telephone call while maintaining the landline telephone call to a data host (140, 141). Once data is transmitted again by data terminal (104), DCU (106) automatically places another cellular telephone call and is reconnected to the landline telephone call.

    74.
    发明专利
    未知

    公开(公告)号：MX169671B

    公开(公告)日：1993-07-16

    申请号：MX2478991

    申请日：1991-03-05

    Applicant: MOTOROLA INC

    Inventor： FREEBURG THOMAS A ,  WHITE RICHARD E

    IPC: H04L9/24 ,  H04L9/18 ,  H04L9/00

    Abstract: An encryption circuit that operates with substantially zero delay. Using programmable keys and polynomials, the encryption algorithm can be constantly changed to thwart any unintended receiving parties from decoding the data. A key (101) and a polynomial (102) are loaded into registers. The key is then loaded into a shift register and shifted through XOR gates (106) at a programmable rate. The other input of the XOR gates come from the result of ANDing (103) a disable signal, the polynomial register (102), and the last stage of the shift register (104). Eight bits of the shift register outputs are XOR'ed with the input data to be encrypted. The output of these XOR gates (105) is the encrypted data.

    METHOD OF DETECTING ERRORS AND A DETECTOR FOR MAKING THE SAME
    77.
    发明专利
    METHOD OF DETECTING ERRORS AND A DETECTOR FOR MAKING THE SAME 未知

    公开(公告)号：CS268090A3

    公开(公告)日：1992-11-18

    申请号：CS268090

    申请日：1990-05-30

    Applicant: MOTOROLA INC

    Inventor： FREEBURG THOMAS A

    IPC: H04L1/00 ,  H04L1/02 ,  H04L1/20 ,  H04M7/02

    Abstract: There is provided a scheme for bit error rate detection. It is characterised by: detecting the bit value present in a received multi-level signal (102), more narrowly detecting the bit value present in that received multi-level signal (104), comparing the results of narrow detection with the results detected otherwise to identify errors in detection (203, 206, 207 and 209), and accumulating detected symbol errors over unit time. Bit error rate detection can be used for antenna selection-selecting one of a plurality of diversity antennas when the error rate exceeds (213) a certain error threshold.

    79.
    发明专利
    未知

    公开(公告)号：BR9007841A

    公开(公告)日：1992-09-08

    申请号：BR9007841

    申请日：1990-11-27

    Applicant: MOTOROLA INC

    Inventor： BERKEN JAMES J ,  FREEBURG THOMAS A ,  OGASAWARA ROY T ,  WHITE RICHARD E ,  MITZLAFF JAMES E ,  BEDLEK GREGORY J

    IPC: H04B7/24 ,  H04J3/00 ,  H04J3/16 ,  H04L12/28 ,  H04L12/56 ,  H04B1/38 ,  H04J3/24

    Abstract: A wireless in-building telecommunications system for voice and data communications is disclosed having at least one node (101) arranged for linking to the PSTN (151) and at least one digital information source (153, 155, 157, 159) multiplicity of user modules (103) (UM's) linked to the node via a shared RF communications path (107). Each UM is coupled to a voice telephone instrument (127) and to one or more data terminals (165). The UM's communicate with the node by exchanging fast packets via the common RF path (107). The node also includes a fast-packet-switched mechanism controlled by a bandwidth allocating scheme to prevent collisions of packets as they are transmitted between the various units (101, 103) (nodes and/or user modules) that may be accessing the RF path (107). Also disclosed is a method for allocating the required bandwidth to each of the users of the common communications path in a wireless in-building telephone system. The invention provides for the combination of both voice and data in a single switch using a common packet structure. It allows for the dynamic allocation of bandwidth based on system loading. This includes not only bandwidth within the voice or data areas of the frame, but also between the voice and data portions. It also synchronizes the transfer of the data and the allocation of bus bandwidth.

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