基于DDS和DPLL的捷变信号源设计

【作者】 龙始华；

【导师】 赵建中；

【作者基本信息】 南京理工大学 ， 通信与信息系统， 2004， 硕士

【摘要】 直接数字频率合成器(DDS)是一种全数字化的频率合成器，由相位累加器、波形ROM、D／A转换器和低通滤波器构成，DDS技术具有频率分辨率高、频率切换速度快、频率切换时相位连续、输出相位噪声低和可以产生任意波形等优点。由于上述特点，DDS技术可被用于雷达、通信、电子对抗和仪器仪表等领域。 本文前三章主要介绍DDS，首先系统地论述了DDS的基本结构和工作原理，分析了DDS理想条件下的输出频谱特性。由于杂散性能较差是DDS应用受限的主要原因，本文从理论和实际应用两个方面着重分析了实际参数DDS的输出频谱特性。 受当前数字器件工作速度的限制，直接数字频率合成的工作频率还不能做的很高。后两章介绍了将直接数字频率合成技术与锁相环相结合构成的DDS和PLL组合式频率合成器，它同时兼顾高工作频率、高分辩率、高频率捷变速度，在许多电子系统具有很高的应用价值。本文分析了两种DDS和PLL组合式频率合成器方案，提出了一种基于DDS和DPLL的捷变信号源方案，给出了仿真结果，介绍了硬件设计过程。更多还原

【Abstract】 The Direct Digital Frequency Synthesizer is a kind of fully digitized frequency synthesizer, which consists of the phase accumulator, the sine look-up table, the digital to analog converter and the low band filter. It is of high frequency resolution, fast frequency switching speed, low phase noise, the ability to switch frequencies while maintaining constant phase, and the ability to producing arbitrary waveforms. Because of above features, DDS can be used in such fields as radar, communications, electronic warfare and electronic measurement instruments.The Chapter 2 and 3 emphasizes on DDS. First synthesizes the Direct Digital Frequency Synthesizer in mathematics. Analysis the spectrum characteristic of DDS output in ideal case. The bad spurious performance is the major problem that restricts the applications of DDS, so the theoretical and practical analysis attaches importance to the spectrum performance of DDS.For the speed limitation of digital hardware, the output frequency of DDS cannot get a high level yet. By combining the DDS and PLL technology, we can get high frequence, high frequency resolution and excellent frequency agility. Two methods of DDS hybrid PLL technology are discussed. In this dissertation, a new methods of DDS hybrid PLL technology are analyzed detailedly. The results of simulation and the measured by spectrum analyzer are given.更多还原