2FSK数字调制通信系统的设计毕业论文.doc

2FSK数字调制通信系统的设计 华北科技学院毕业设计（论文） 第 PAGE 12 页 共 NUMPAGES 42 页 第 PAGE 11 页 共 NUMPAGES 42 页 2FSK数字调制通信系统的设计 摘要 调制解调器是通信系统中的关键设备，其性能的好坏直接关系到整个系统的性能。本次设计的FSK调制系统具有抗干扰、抗噪声、抗衰减性能较强、技术复杂程度比较低、成本低等诸多优点，因而广泛应用与实际电路中。在中低速数据传输通信系统中得到了较为广泛的应用。此外，许多集成芯片里也用到了FSK调制技术。 本次设计的FSK电路可广泛用于计算机网络、办公自动化、远程自控系统及移频通信中。现代通信系统要求通信距离远、通信容量大、传输质量好。作为其关键技术之一的调制解调技术一直是人们研究的一个重要方向。从最早的模拟调幅调频技术的日臻完善,到现在数字调制技术的广泛运用,使得信息的传输更为有效和可靠.。采用FSK调制方式的主要优点是：①无需载波恢复，大大降低了系统复杂度。②对幅度的非线性抗干扰能力强。因为FSK信号为恒包络信号，其信息完全包含在信号的过零点上，所以比起调幅信号，其对幅度非线性抗干扰能力要强。③调制解调易用软硬件实现，简单易懂。 关键字： VHDL语言；2FSK调制；2FSK解调；MFSK调制 2FSK Digital modems Communication System Design Summary? Modem is the key equipment of communications system; its performance will have a direct effect on the performance of the whole system. The design of the FSK modulation system has advantages such as anti-jamming, anti-noise, high-attenuation performance, relatively low technical complexity and low cost, thus widely applying in actual circuit. It has been more widely used in the low-speed data transmission communication system. In addition, many integrated chip also used the FSK modulation technique. The design of the FSK circuit can be widely used in computer networking, office automation, remote-controlled system and the frequency shift in communication. Modern communication systems require far distance communications, telecommunications capacity, and transmission quality. As one of the key technologies of its modem technology has always been an important researching direction of people. From the earliest AM FM analog technology improving, and now digital modulation of the extensive use of technology, making the transmission of information more effective and reliable. The main advantages of using FSK modulation are: ① without carrier recovery, significantly reducing system complexity. ② strong anti-interference capability on the rate of non-linear. Because the FSK signals are constant envelope signals, the information are totally included in the over 0.1 signal po