【摘要】 在数字通信中,传输速率和传输可靠性是两个重要指标,也是互相制约的指标,他们遵循通信原理的重要基本理论——奈奎斯特(Nyquist)准则。在很多教科书上,对于该准则的证明比较繁琐,在教学中造成困难。用简单的方法改变了该准则的传统证明,先证明一个命题,进一步分析了克服码元串扰的一般条件,并从这一点出发,提出对实际滤波器的要求,提出数字通信中的滤波器的具体设计方法,也就是互补对称的滚降方法,可以消除码间串扰,提高通信系统的可靠性。最后,对“Nyquist”准则作了通俗的描述。更多还原

【Abstract】 The important performance of digital communication system are the transmission speed and the reliability of system, which are restricted by each other. They obey an important basic theory of communication principle-Nyquist rule. In this article, Nyquist rule is proved using a simple method which is different from the traditional one that result in obstacle in teaching. Firstly a proposition is proved, then the general conditions of overcoming interference between codes are analyzed. Based on this point, the requirement of practical filter and the specific design method (rolling-decrease method in complementary symmetry way) for filter in digital communication system are presented. In this way, the interference between codes can be avoided and the reliability of communication system be improved. At last, Nyquist rule is described in popular words.更多还原