基带数字信号源是合成孔径雷达 (SAR)系统中的关键设备 ,开发基带数字信号源对于满足SAR向多分辨率、多模式的发展具有重要的意义。随着SAR信号处理的完全数字化 ,基带数字信号源已经替代以往使用的声表面波器件 (SAW ) ,成为SAR数字线性调频产生单元的一部分 ,能够为雷达提供所需发射的各种波形信号。同时 ,面对复杂的SAR系统 ,如何测试和验证SAR设备的功能是开发人员所必须面对的重要环节。高速数字信号源的研制 ,对测试雷达视频信号处理设备有着十分重要的意义。该文首先简要介绍了数字信号源在SAR中的作用 ,然后 ,从理论上详细分析了基带数字线性调频信号的产生原理和设计过程 ;讨论并提出了数字信号源作为雷达视频信号处理测试设备的作用 ;给出了按照上述两种功能研制的高速基带数字信号源的性能、组成及其设计方案。

Base-band digital signal generator is an essential device in Synthetic Aperture Radar (SAR). It plays an important role in satisfying the development of multi-resolution and multi-mode of SAR system. With the digitization of SAR signal processing, base-band digital signal generator has substituted for SAW devices, and functioned as a part of the digital linear frequency modulator (chirp), which generates various sending signals for the radar. Facing more and more complicated SAR systems, in the meanwhile, developers must deal with testing and validation problems of the system. So it's necessary to develop a device that can help developers to validate the functions of SAR sub-assemblies, and digital signal generator just functions as a test device for the base-band signal processing devices of the radar. The author first introduces the functions of high-speed digital signal generator developed for SAR system, then analyses the principle and design process of linear frequency modulation signals, and discusses on the test function of the signal generator. The performance, composition and design scheme of a high-speed base-band digital signal generator is presented according to the above two functions.