The Research And Design Of Digital Intermediate Frequency Module Of TD-SCDMA Repeater

Along with fast development of information technical, the communicate ability of small quantity has already can't satisfied the business requirement of people .The narrow band digital communication system is developing gradually to the wideband third generation mobile communication system. TD-SCDMA is one of air interface technical criterion of the third generation mobile communication system released by ITU, first brought forward by China. Now, the TD-SCDMA industry has already had the international competition ability, our country is also pushing the development of the TD-SCDMA industry strongly.TD-SCDMA repeater will be an important part of the mobile communication system.Not only increase the network covery ability, extend the base station, it also increase the telephone traffic load of the idle base station and optimize the net work. Repeater can be flexible placed in the signal blind area like underground and emporium. Adopt base station as principle, repeater as makeup is very meaningful. Because of the influence of the TDD, TD-SCDMA repeater needs to study relevant correspondence standard. Date transmit by wireless frame ,the frame is divised to different time slot,up-line and down line time slot can be flexible distributed. So , for TD-SCDMA repeater,first need find the switching point of the up-line and down line time slot, then amplify the up-line and down line signal power respectively. To find the switching point of the up-line and down line time slot, need to transform the RF signal to base band. Directly RF sample is difficult now, this system use Digital Intermediate Frequency technology,change the RF signal to IF signal,,then do IF sampling and DDC process,output the I/Q signal . In this paper, attention is concentrated on the Digital Intermediate Frequency module.This paper first introduce the research background and significance of TD-SCDMA repeater,TD-SCDMA mobile communication standard and physical layer configuration,digital intermediate frequency technology. Then analyze the system design of TD-SCDMA wireless repeater and research the design method of the Digital Intermediate Frequency module based on the TD-SCDMA wireless repeater. Design and emulate the DDC module in the environment of Quartus II. In the last, design the configuration of synchronization switch control module of the repeater based on the AD6654.