摘 要随着通信技术、航空航天技术、电子科学技术的迅速进展，数字通信技术的进展速度呈现出爆发式增长。如何提高数字通信技术中更好地过滤噪声成为数字对讲机进展的重要环节，而基于 DCR 标准的 4FSK 基带信号处理技术则应运而生，成为了一个热门的讨论领域。本文以数字对讲机为基础，讨论并设计数字对讲机中的滤波器系统，即基带信号处理系统的。通过针对日本的数字对讲机标准 DCR，讨论了 4FSK 调制解调系统中基带信号处理的几项关键技术。本文设计主要包括均方根余弦滚降滤波器、Isinc 滤波器和帧同步检测器的设计方法，给出了相应的仿真结果，分析了整个系统的误码率，仿真结果表明系统误码率接近理论值，可以满足 DCR 标准的要求。关键词：DCR；4FSK；成形滤波器；匹配滤波器；Isinc 滤波器；帧同步检测器AbstractWith fast development of communication technology, aeronautical and space technologies,electronic science and technology ,the digital communication technology has explosive growth of development speed.How to improve filter out the noise better in digital communication technology become an important part of the digital interphone development, and based on DCR standard of 4FSK baseband signal processing technology arises at the historic moment, has become a hot area of research.In this paper, based on the digital interphone, research and design digital filter of intercom system, namely the baseband signal processing system.through the several key technologies of baseband signal processing are studied in 4FSK modulation and demodulation module based on the Japanese DCR standard．The work includes the design methods of square-root raised cosine FIR filter,inversed sinc(Isinc)filter and frame sync detector.The corresponding simulation results are given and the bit error rate(BER)of the entire system modules is analyzed.The simulation results show that the bit error rate of the system is close to the theoretical value,and able to meet the dema...
