论文部分内容阅读
目的:设计并实现一个单工无线通讯系统,实现单工语音和短信数据的传输业务。方法:以DDS(DirectDigital Frequency Synthesis)数字频率合成芯片AD9954,单片机MSP430F449和FPGA为控制核心,采用二次调频的方式实现短信信号和语音信号的调制和发送,通过收音芯片CXA1238S解调出信号。结果:本系统发射功率≤20mW,语音传输距离为25米。短信传输距离不小于15米,并可实现对八个从站的选台功能。结论:数字调制方式可以极大地提高信号传输的稳定性和可靠性。
Purpose: To design and implement a simplex wireless communication system to realize simplex voice and SMS data transmission services. Methods: Using DDS (Direct Digital Frequency Synthesis) digital synthesizer chip AD9954 and MSP430F449 and FPGA as the control core, the modulation and transmission of short message and voice signal were realized by the second frequency modulation. The signal was demodulated by the radio chip CXA1238S. Results: The system transmit power ≤ 20mW, voice transmission distance of 25 meters. SMS transmission distance of not less than 15 meters, and can achieve the function of eight slave station selection. Conclusion: Digital modulation can greatly improve the stability and reliability of signal transmission.