Patents Assigned to Ascom Tech AG
  • Patent number: 5375118
    Abstract: For transmitting digital data between any parties of an N-ISDN network, the latter is interlinked with an ATM network. Two network adaptors are connected in each case with one node of each of the networks over incoming and outgoing lines of the respective network norm. The network adaptors are constructed on the side of the N-ISDN network for receiving and sending out time-multiplexed octets and, on the side of the ATM network, for receiving and sending out cells, which serve as addressed carriers for octets and have the same destination direction. The network adaptors operate free of blockages and losses.
    Type: Grant
    Filed: August 17, 1993
    Date of Patent: December 20, 1994
    Assignee: Ascom Tech AG
    Inventors: Sathyanarayana Rao, Eberhard Schwerdtel
  • Patent number: 5319643
    Abstract: A method for shortening a distributed queue, the distributed queue being formed by the first node and the second node which communicate using packets transmitted and received over first and second buses, the first and second nodes having first and second distributed queue images, respectively, which form first and second portions of the distributed queue, respectively, the packets travelling over the first bus having a request mode and a non-request mode and the packets travelling over the second bus having an empty mode and a full mode, the first node creating packets in the empty mode in the non-request mode; the first node has an information queuing state which changes a first packet originally in the non-request mode into the request mode and transmits the first packet over the first bus and adds first information to be sent to the first distributed queue, the first node transmitting information stored in the first distributed queue when second packet in the empty mode and a third packet is the non-reques
    Type: Grant
    Filed: October 16, 1990
    Date of Patent: June 7, 1994
    Assignee: Ascom Tech AG
    Inventors: Sathyanarayana Rao, Reto Beeler, Martin Potts
  • Patent number: 5319486
    Abstract: The transmission equipment includes a plurality of subscriber nodes which are connected serially to an optical fiber. Every node comprises an access unit with at least one directional coupler, an address detection unit, a receiver, a synchronization unit, as well as a control unit with a switching transmitter. Addressed packets continuously reach the nodes and pass through the latter via the fiber in the form of modulated light. In a first switching position, the directional coupler branches off a part of the light power of the packets from the fiber, converts the light in the optoelectrical transducer into electrical signals and reads the respective packet address in the detection unit. If this packet address matches the address of the node the control unit switches the directional coupler into a second switching position. The coupler branches off another part of the light power of the packet in this second switching position and, in so doing, feeds the occurring electrical useful signals to the receiver.
    Type: Grant
    Filed: July 24, 1991
    Date of Patent: June 7, 1994
    Assignee: Ascom Tech AG
    Inventors: Paul Vogel, Thomas Martinson
  • Patent number: 5227907
    Abstract: Every subscriber node connected to an optical fiber comprises an access unit with a directional coupler which is controlled via an output amplifier, an optoelectric converter being connected subsequent to the directional coupler. Packets run on the fiber. The first bit of the packets indicates whether it is an empty packet (shown by "light" or "bright") or a data packet (shown by "no light" or "dark"). As soon as the node has prepared data for transmission in a buffer storage, a test is effected at each arriving packet as to whether or not it is an empty packet. For this purpose, the light of every first bit is guided to a L/I detector which carries out this test in a "flying" manner, while a no-light bit passes on to the outgoing fiber. If the L/I bit indicates a data packet, the control immediately switches the directional coupler to pass, so that the packet passes the node so as to be unchanged.
    Type: Grant
    Filed: June 15, 1990
    Date of Patent: July 13, 1993
    Assignee: Ascom Tech AG
    Inventors: Sathyanarayana Rao, Martin Potts, Reto Beeler
  • Patent number: 5220448
    Abstract: The bit and frame synchronization unit (51) serves for the synchronization of an access node to the bit stream running along an optical fiber.The unit (51) comprises an optical switching element (57) which can be controlled electrically and serves as a light switch. It further comprises a sequence generator (75) for electrically controlling the switching element (57), a clock generator (72), an optoelectrical transducer (60), an electrical integrator (63), a regulator and evaluator (66) and a control unit (69). In addition, there is a coarse regulator (48).An optical bit pattern (BM) occurs periodically at the input (53), an equivalent electrical comparison pattern (VM) assigned to the latter occurs at the control input (44). The level of the resultant electrical voltage pulse U at the output (64) of the integrator (63) is a measurement for the respective relative phase deviation during approximate synchronous running. There is a sharp pulse maximum during absolute synchronous running.
    Type: Grant
    Filed: December 2, 1991
    Date of Patent: June 15, 1993
    Assignee: Ascom Tech AG
    Inventors: Paul Vogel, Thomas Martinson
  • Patent number: 5214703
    Abstract: The device (12) comprises nine encryption stages (61.1, 61.2, 69), the first eight of which are constructed identically. It further comprises a key subblock generation unit (63), an input unit (21), and an output unit (79). It serves for the block-by-block encryption of a plaintext (X) proceeding from a message source (11) into a ciphertext (Y) to be delivered on a transmission line (13), wherein a secret key block (Z) is inputted beforehand via a secure channel 17. The encryption is effected in a step-by-step and parallel manner for four subblocks (X.sub.1 -X.sub.4 ; W.sub.11 -W.sub.14 ; W.sub.21 -W.sub.24 ; W.sub.81 -W.sub.84 ; Y.sub.1 -Y.sub.4). Every encryption stage (61.1, 61.2, 69) comprises four first inputs (25-28; 35-38), six and four second inputs (29, 30, 32, 33, 49, 52; 129, 130, 132, 133), respectively, and four outputs (75-78). A total of fifty-two key subblocks (Z.sub.1 -Z.sub.52) which are formed from the key block (Z) are connected to the second inputs.
    Type: Grant
    Filed: January 7, 1992
    Date of Patent: May 25, 1993
    Assignee: Ascom Tech AG
    Inventors: James L. Massey, Xuejia Lai
  • Patent number: 5181225
    Abstract: In a receiver (3 ) for a DSSS signal (DSSS=direct sequence spread spectrum), an inverse filter (12) is utilized in place of a matched filter for detecting the symbols (B.sub.m). The inverse filter (12) is distinguished in that it responds to the predetermined pulse sequence as such with a pure Kronecker delta sequence. Preferably, the DSSS signal is generated with a pulse sequence realizing a maximum process gain.
    Type: Grant
    Filed: November 21, 1991
    Date of Patent: January 19, 1993
    Assignee: Ascom Tech. AG.
    Inventors: Fredy D. Neeser, Markus D. Hufschmid, Jurg P. Ruprecht
  • Patent number: 5170412
    Abstract: In a multiple access method for the simultaneous exchange of several data streams ({B.sub.1,m }, {B.sub.2,m }, {B.sub.3,m }) among several participants of a transmission system, various data streams ({B.sub.1,m }, {B.sub.2,m }, {B.sub.3,m }) with the same spread sequence (s[.]) are expanded to a corresponding DSSS signal ({B.sub.1,m s[.]}, {B.sub.2,m s[.]}, {B.sub.3,m s[.]}. During transmission, the various DSSS signals ({B.sub.1,m s[.]}, {B.sub.2,m s[.]}, {B.sub.3,m s[.]}) are heterodyned to a single incoming signal. For detecting the various data streams in a receiver, the incoming signal is filtered in a filter that is inverse with respect to the joint spread sequence (s[.]). In order to permit reliable detection, heterodyning takes place in each case so that the spread sequence intervals pertaining to different data streams are chronologically shifted with respect to one another by a given minimum value (delta.sub.-- T).
    Type: Grant
    Filed: November 21, 1991
    Date of Patent: December 8, 1992
    Assignee: Ascom Tech AG.
    Inventor: James L. Massey