Study Of The Related Techniques On Building Integrated Timing System

Timing & Synchronization is a key technology in digital communication network. Building Integrated Timing System (BITS in short) equipment is the most common synchronization supply equipment in digital synchronization network, which also is the key equipment supplying telecommunication network signal. All kinds of new services, such as GSM, CDMA, the video service and the introduction of the 7th signaling and the building of SDH transportation network lodge higher request on the short-term stability and the other capability. Therefore, It is necessary to mount timing system alone in synchronization network node and the place where there are more telecommunication equipments and the important hinge, which supplies the primary synchronization signal conformed to the standard. BITS supplies the synchronous timing signal to these equipments inside the telecommunicationt building, such as DPS, ATM, NO.7, DXC, TM & ADM in SDH, DON and IN etc. The related techniques are involved in the content of synchronization network , timing distribution, the timing signal transportations x impairments etc.The second chapter tells the structure and the function of the Building Integrated Timing System. The third chapter summarizes the digital synchronization network techniques, which emphasizes the basic concept of synchronization networks analyzes the necessity of building the synchronization network and introduces all kinds of synchronization methods. The fourth chapter represents the transportation of the synchronization signal. The fifth chapter represents the messages sustained by BITS equipments. The sixth chapter, the seventh chapter are emphasis of the article. We build up mathematics module by timing signal, analyze the theory of timing internal noise and timing signal damage produced by phase transient change in principle and try to find better method to control frequency drift.Finally,the article introduces the BITS equipment (Clockstar) that the author participates in tapping in WRI(Fiberhome under WRI), which applies the DDS technique and Different Frequency Multiplication technique to the equipment and analyzes the circuit diagram tapped by the author himself. The test shows that the various features of the BITS completely accord with the standard that the ITU-T Recommendation.The concept of "timing" in the article is not the clock in our ordinary living, but syntheses which is made up of some frequency source in the signal generator (such as Cs atom frequency standard, Rb clock & high accuracy quartz crystal oscillator) whichproduces the primary frequency, the matching input interface and the matching output interface and controlling circuit etc. For example, BITS is a kind of timing equipment, which is used to control the timing of some functions. The signal provided by the equipment is called primary signal, timing signal and synchronization signal.