GMSK数字化调制的FPGA设计与实现

Design and Implementation of FPGA for Digital GMSK Modulation

针对GMSK调制的特点,提出了一种数字化的调制方法。使用matlab仿真工具对GMSK调制进行截断和量化,生成GMSK调制查找表,存入FPGA内部的存储器,通过查表实现GMSK调制的数字化,克服了传统GMSK模拟调制方法的相位不够准确,无法进行相干解调的缺点,提高系统设计的灵活性。最后分析了调制信号的频谱特性和接收端信号的基带波形,验证了GMSK数字化调制的正确性和可行性。

Aiming at the characteristics of GMSK modulation,a digital modulation of GMSK is presented.The modulation of GMSK is cut off and quantified by using matlab simulation tool in order to generate a modulation lookup which is stored in FPGA, and the digital modulation is achieved by using lookup. The digital modulation overcomes the shortcoming of analog modulation by which the coherent demodulation can＇t be implemented and the flexibility of system design can＇t be improved.By analyzing the spectral characteris- tic of GMSK modulation signal and the baseband waveform of receiving end signal, the validity and feasibility of digital GMSK modula- tion are proved.