Study On Digital Up-Conversion Scheme Based On FPGA In Millimeter Wave Communication System

This thesis introduces some modulation manners and up-conversion schemes, comparing their performance and characteristics. Finally the paper selects DQPSK modulation. Based on the analysis of digital up-conversion theory , a scheme to realize baseband digital signal modulation and up-conversion is put forward. The system is designed with Field Programmable Gate Array(FPGA) and Quadrature Digital Up-converter AD9857.The hardware system is mainly composed of AD9857 from AD company and EP1C6Q240C8 from Altera company. The processing of digital interpolation, digital filter and quadrature digital mix are all finished by AD9857. This scheme uses FPGA to process baseband digital signal and controls AD9857 in real-time. Baseband digital signal processing includes serial-parallel conversion and differential coding. Control processing includes serial interface communication and parallel interface communication between FPGA and AD9857. The software simulation is carried out with QUATUS II software and hardware description language VHDL. The whole system realizes DQPSK up-conversion with 70MHz carrier frequency and satisfies the requirements. The system is of simple structure, flexible control, high frequency resolution and fast frequency switching speed.