Research And Development On Multifunctional Modulator In RF Wireless Communication System

Communication is the tremendous power that drives the civilization, advancement and development of society. Communication has a lot of kinds such as wire communication, wireless communication, microwave communication, optical-network communication.Today,the challenge of tele-communication markets is very austerity,but the wireless communication still keep the high increase. In the field of today's wireless communication, a new trend is the technology of direct RF modulation. The multifunctional quadrature modulator can be used in all kinds of wireless communication system such as cellular communication system, W-CDMA/CDMA/GSM/PCS/ISM transceivers,Fixed Broadband Access Systems LMDS/MMDS,Wireless LAN,Digital TV/CATV modulators,Single Sideband Upconverter. Comparing with other wireless transmitter,it is small and low-cost ,and its circuit design is simple.Besides,it has broad operating frequency,excellent amplitude balance and low phase error,so the futher for its application is bright. The following is my work for the project: (1) Introducing the general situation and develop trend of wireless communication.including the primary technology protocol of 3G-WCDMA ,CDMA2000 ,TDSCDMA and wireless broadband access techonology-WLAN, MMDS,LMDS. (2) Researching the common and important modulation and demodulation technologies of wireless communication,mainly including QPSK and QAM. (3) Analyzing the basic theory and development of PLL,and studying the design theory and impedance match problem of experimental circuit board. (4) Describing the development of FPGA/CPLD and the coding theory and build of PN,and introducing producing the baseband information sequence of modulation by CPLD. (5) Presenting the whole design scheme of the quadrature modulator. Using the AD8345 of ADI which is a quadrature modulator, the AD8132 of ADI and AD9761 which can supply differential drive singal of baseband, the ADF4113 of ADI and MAX2623 of MAXIM which supply the carrier signal,ETC1-1-13 that supply the differential drive singal of carrier and the MAX7000 to build the baseband singal and control information. (6) Developing the experimental hardware circuit board, and the software emulational and testing results are given.