Wcdma Wireless Repeater Key Circuit Developed

The research of the third generation (3G) mobile communication has become more significant in mobile communication field. There are 3 kinds of standards in the world, which are WCDMA, CDMA2000, TD-SCDMA. Whatever which standard is applied, RF front-end technology is indispensable. Repeaters have already been widely used in 2G mobile communication system, which effectively enlarged the coverage area of mobile network and reduced the cost of building mobile network.The WCDMA repeaters should have high dynamic range, low noise, multi-chip transmission and linear modulation, which bring new challenges to the design of RF front-end. In this paper, the key techniques of the RF front-end in WCDMA selective band wireless repeater are discussed, and the final circuits are given. Through debugging and testing, the equipment researched achieved the related national standards.The paper is concentrated on:1. The system structure and theory in super-heterodyne receiver are discussed, the feasibility analysis is made.2. The design methods of those key circuits in the system are proposed, including LNA (Low Noise Amplifier), PLL (phase-locked loop), and PA (power amplifier). The analog pre-distortion technology is utilized to improve linearity.3. The testing methods of several main indexes in repeaters are introduced, the measure results are also brought out, which met the standards of 3GPP.