Design Of Wideband Vector Signal Transmitter

Vector signal transmitter is the basis of wireless communication system.With the continuous evolution of wireless communication technology,there are more and more kinds of wireless communication systems.The performance of vector signal transmitter has a great influence on wireless communication system.In this thesis,a broadband vector signal transmitter working from 1.5 MHz to 3000 MHz is designed.The main work is as follows:1.According to the structure and characteristics of many kinds of vector signal transmitters,the design scheme of broadband vector signal transmitter is determined.The transmitter adopts the structure of direct frequency conversion combined with heterodyne,and has the advantages of simple structure,low power consumption,small size and easy realization.2.A scheme for calibrating and optimizing carrier leakage and sideband suppression is proposed,and physical verification is completed.Through reasonable frequency planning,filter banks and final amplifier design,the stray outside the transmitting frequency point is effectively suppressed.3.The broadband vector signal transmitter is realized.The vector signal transmitter consists of hardware module and software.The software part includes the upper computer software and the bottom driver software,and the hardware part includes all of RF modules in the transmitter system.The performance of transmitter,such as gain,noise and spurious,is simulated and validated.The chip selection,evaluation and layout design of the final transmitter are also completed.Finally,the physical object of the vector signal transmitter is made,and the debugging and performance test of the transmitter are completed.The test results show that the broadband vector signal transmitter can achieve 0 dBm RF power output in the whole frequency range,and the spurious is restrained below-40 dBc.Under the conditions of output QPSK and 16-QAM modulation signals,the EVM of the whole transmitter is less than 2%.The size of transmitter is 2 cm*6.5 cm*14 cm,and the power consumption is less than 4 W.The test result meets the expected requirements.This broadband vector signal transmitter has excellent performance,small size and low power consumption.It can be directly applied to wireless application systems in common application scenarios.