The Research Of RF Circuit And BaseBand Module On The Basis Of The Wireless Communication System

No wonder, we are living at Information Age. Information-based technology has become the main theme of our life. Normally, there are two approaches for us to receive valuable information -wired or wireless information transformation system. However, in a lot of cases, we prefer wireless technology to the wired. Why? Because it is low-cost, it is easy to carry, and it saves you the time-consuming of setting up the cables. Followings are the major areas wireless often wins: Communication with hand-held equipment; Remote control; Remote inspection; Small wireless network; Industrial data collection system.The purpose of the thesis is to research the base theory of the wireless communication system, comprehend the working principle and key technology of RF circuit and baseband module in this system, master the developing conditions and using prospect, and design the VCO and QPSK of baseband signals in the RF transmit-receive circuit system. The research method of this thesis apply theory to practice, and use the practice return to verify the theory, that is to apply the base theory of wireless communication to direct the hardware design of VCO and QPSK modem, and to test and verify the theory foundation according to the optimization and emulation.At first, the thesis introduces the conception of wirelesscommunication system, including the RF communication circuit and baseband module. Then concerns the composing of RF transmit-receive circuit and the performance requiring of each module in detail, includingthe LNA,PA,MIXER, OSCILLATOR. In order to further investigate thefunction and design method of each module, the thesis probe into the design of VCO. Put forward the design scheme of VCO working on 1.8GHz-2GHz and 800 MHz -900MHz, through analyzing the originaloscillatory, equilibrium and stable condition, analyzed the performancerequiring with ADS software. Second, it introduces some knowledge about modem in baseband module, and concerns the modulation and demodulation process of QPSK signal in detail. Take the theory analyzing as a basis and combine the advantage of DSP to design the completely digital QPSK modem. At last build the remote environmental control system, compiled the data of transmit-receive program which combined the hardware and software in order to prove the working characteristic of wireless communication system go step further ,and reflect the key thought of the wireless communication system.