乒乓环在跳频频踪中的应用

快速跳频锁相环技术已经广泛应用于短波、超短波、卫星通信以及雷达等军用领域。从频域上来看，跳频信号的频谱是一个在很宽频带上以不等间隔随机跳变的。与定频通信相比，跳频通信比较隐蔽也难以被截获。同时，跳频通信也具有良好的抗干扰能力，即使有部分频点被干扰，仍能在其他未被干扰的频点上进行正常的通信。文中主要介绍了下列四种跳频方式：1、直接混频法；2、高速单锁相环；3、DDS＋PLL快速跳频法；4、乒乓环交替输出法。

Design of Frequency Hopping Phase Locked Loop

Fast frequency hopping phase locked loop technique has been widely used in UHF satellite communications and radar and military field. From the frequency domain, the frequency hopping signal spectrum is a range in a broadband bring to interval random jump. Compared with the fixed frequency communication, frequency hopping communication is hidden and difficult to be intercepted. At the same time, the frequency hopping communication also has a good anti--jamming ability, even if is interference with some frequency points, still can be in other undisturbed frequency point for regular communication. This paper mainly introduces the following four kinds of frequency hopping mode. 1, direct mixing method 2, high speed single phase locked loop; 3,DDS＋PLL for fast frequency hopping method; 4, table tennis loop alternating output method.