Method for synchronizing the pulse frames in time multiplex data transmission via communication satellites

• US 4,004,225 A
• Filed: 05/20/1975
• Issued: 01/18/1977
• Est. Priority Date: 05/21/1974
• Status: Expired due to Term

• Current Assignee: Licentia Patent-Verwaltungs-GmbH (AB Electrolux)
• Original Assignee: Licentia Patent-Verwaltungs-GmbH (AB Electrolux)
• Inventors: Ganssmantel, Horst
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Ng, Jin F.
• Application Number:
  US05/579,254
• Time in Patent Office: 609 Days
• Field of Search: 325/2, 325/4, 325/58, 179/15 BS, 179/15 BA, 178/69.5 R
• US Class Current: 370/324
• CPC Class Codes: H04B 7/2128 Changing of the reference station

Abstract

A data transmission system for the transmission of time multiplex data between a plurality of stations via the transponder of a communications satellite wherein each pulse frame includes a code sequence (SRUW) periodically transmitted by a reference station and which can be used for synchronization by the other stations, and pulse bundles transmitted by a pedetermined sequence by the other station. A plurality of the stations are utilizable as reference stations but only one is active. Each of the stations which can be used as a reference station periodically transmits its own code sequence at the beginning of successive pulse frames, with the reference stations being synchronized with the coded sequence from the active reference station and the other stations being synchronized with the coded sequence of any of the reference stations. Upon a malfunction in the system so that the coded sequence from the active reference station cannot be received by the other reference stations, the one of the reference stations which is active is changed.

Claims

1. A method for synchronizing the pulse frames occurring during the transmission of time multiplex pulse coded data between the stations of a multi-station communication system via the transponder of a communications satellite in which each pulse frame includes a code sequence (SRUW) periodically transmitted by one of the stations which functions as a reference station and pulse bursts transmitted in a prescribed sequence by the other stations of the system, and wherein a plurality of the stations of the system, which plurality is less than the total number of stations of said system, are utilizable as active reference stations with only one station of said system being an active reference station at any time, comprising:

causing all of said stations utilizable as reference stations to periodically transmit their own code sequences (SRUW) at the beginning of successive pulse frames;

synchronizing the coded sequence from each of said stations utilizable as reference stations with the coded sequence of the presently active reference station;

synchronizing the time of transmission of the pulse bursts of the other stations of said system with the code sequence of any one of said stations utilizable as a reference station; and

in the event of malfunction whereby the coded sequence from the presently active reference station is not received by the stations utilizable as a reference station, changing the one of said stations utilizable as a reference station which operates as the active reference station.

2. A method as defined in claim 1 wherein each of said stations utilizable as a reference station includes a clock pulse generaor and a phase synchronization loop responsive to the received coded sequence from the active reference station for controlling the clock pulse generator;

and wherein said step of changing includes interrupting the phase synchronization loop of the station which is to be made the active reference station.