基于数字频率合成技术的雷达数字接收机设计

摘要

AFC(Automatic Frequency Control)is realized with technology of DDS (Direct Digital Synthesis)and hith accuracy frequency measurement,quadrature double channel receiver is made up of circuits of IF quadrature sampling directly coherent sampling clock realized with DDs. By doing so, the effect of all kinds of unstable factors such as frequency shift and the limits placed by analogy circuit is diminished effectively, even eliminated. Meanwhile, the performance of the receiver is imporved greatly, for example, the limits on I on an average. Additionally, some practical problems in realizing are discussed.%采用DDS与高精度测频技术相结合完成AFC,采用由DDS实现的相参采样时钟电路和中频正交直接采样电路构成正交双通道接收机.由此,有效地消除或减少了频率漂移等各种不稳定因素和模拟实现时各种因素对系统性能的影响,提高了传统接收机对系统的整机性能,如系统改善因子和SCV的限定值.