STM-1 Introduction

The basic transmission module in SDH is STM-1, with a transmission rate of 155.52 Mbps.
　　SDH (Synchronous Digital Hierarchy) is a comprehensive information transmission network that integrates multiplexing, line transmission, and switching functions, operated by a unified network management system. It was proposed by Bell Communications Research Institute in the United States as Synchronous Optical Network (SONET).
　　Synchronization technology is a very important technology in digital communication systems. Generally, there are bit (symbol) synchronization, word (code group) synchronization, carrier synchronization, and frame synchronization. For network systems, there is also network synchronization. Modern SDH digital transmission networks are fully synchronized digital transmission networks. For data processing at the receiving end, frame synchronization information must first be extracted from the synchronous data stream. The performance of frame synchronization extraction directly affects the processing quality of the entire data and the performance of the entire system. FPGA technology can be used to achieve modularization, miniaturization, and chip-based implementation of synchronization systems, resulting in stable and reliable frame synchronizers.