Group frame synchronization system
AssigneeNippon Electric Co., Ltd.
InventorYukio Takimoto
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Abstract
A group frame synchronization system establishes the frame synchronization to a plurality of time-division multiplexed digital signals by the use of a common synchronization code pattern. The common synchronization code pattern and mutually time-shifted codes of identical pattern are respectively inserted at the transmitting end into vacant time slots of the respective digital signals. At the receiving end, the group frame synchronization signals are extracted and fed to an exclusive OR circuit whose output signal is applied to the group frame synchronization circuit.
Claims6
A group frame synchronization system for establishing the frame synchronization in common to a plurality of time-division multiplexed digital signals of a common bit rate to be transmitted through a common carrier wave, comprising:
- means at the transmitting end for inserting identical but time-shifted group frame synchronization pseudo-random sequence code patterns respectively into said digital signals, said time-shifting being by an interval equal to an integral multiple of the clock pulse period corresponding to said common bit rate;
- and at the receiving end, means for extracting said synchronization pseudo-random sequence code patterns from said digital signals derived from the transmitted carrier wave, gate means for obtaining the exclusive -OR function of said synchronization pseudo-random sequence code patterns supplied from said extraction means, and means for establishing the group frame synchronization among said digital signals in response to the output signal of said gate means.
Dependencies are inferred from the claim text.