Transmission system for STM-1 signals of sync. digital hierarchy

摘要

The signals contain several sync. words, and in a transmitter the bit rate of the signal to be transmitted is adjusted to a reference bit rate by a stop stage, during which one or more bits are inserted into, or removed from one frame sync. words (A1,2). A receiver, accepting the STM-1 signal with changed bit rate, determines the spacing of the frame sync. words of successive frames in the STM-1 signal and inserts or removes a corresp. number of bits for recovery of the original length of the frame sync. words. The signal processing is controlled by the transmitter/receiver cooperation.