Sdh Digital Cross-connect Matrix Of The Design Study

SDH Digital Cross Connect (SDXC) equipment, a highly intelligent transmission node equipment, is one of the most important network elements in SDH optical transport network. It provides great capabilities of multiplexing, connection layout, protection/recovery, realtime check and control and network management. Its appearance has brought the enormous flexibility , economy and intelligence to the transport network, and thus got the general attention of telecommunication industry and fast development. The cross connect matrix is the core module of SDXC equipment which can provide the function of non-blocking cross-connect. In order to implement the free cross connect among the tributaries at certain rank in N input signals, it adopts time slot interchange(TSI) technology to re-arrange the cross-connect paths according to the cross-connect figure that is reserved in advance or that get from dynamic calculation. At present, there are many companies at home which produce the large-scale SDH cross-connect chip, such as ZTE's ZXSM series chips, and so on. In order to meet the market requirement better and reduce the product cost, the author participates in the design of SDXC system for a company and takes charge the research and development of the cross connect matrix module in SDXC system. And this paper is about the design and realization of 4×4 cross-connect matrix.First, the theory foundation of SDH digital cross-connect matrix is dissertated. The superiority, basic principle of SDH and its equipments' logical composition are outlined. The basic concept and characteristic of SDXC and its equipment's types and functional requirements are introduced simply. Three kinds of exchange principle of cross-connect matrix are narrated in detail.Then, in this foundation, the two-stage structure design of 4×4 cross-connect matrix is introduced. The design scheme, functional configuration and circuit realization of the matrix are discussed mainly. This design takes the successful design of 2×2 cross-connect matrix as the foundation, adopts the technique of column exchange and is carried on according to the ASIC design route. At the same...