Presents the development of modern signal processing techniques , a new implementation method which realizes quadrature coherent detection by direct sampling of if signal generated during the implementation of traditional quadrature coherent detection with analog elements in the form of two parallel baseband channels where in phase ( i ) and quadrature ( q ) components of ceived if singnal where , the imperfect matching of the separate channels due to the analog elements results in high phase and amplitude which meets the needs for high performance radar signal processing , the elementary principles and the implementation process for each method and concludes from simulation results to compare their features and application conditions that the new approach can satisfy of the requirements of high performance sp 針對近年來提出的通過直接中頻采樣來實現(xiàn)正交相干檢波的方法,分析了其基本實現(xiàn)原理,并用統(tǒng)一的觀點解釋了迄今為止國內(nèi)外基于此提出的各種實現(xiàn)方法;對每一實現(xiàn)方法的基本原理和實現(xiàn)過程都作了分析,并給出了計算機仿真結(jié)果;在此基礎上比較了各方法的性能指標及適應條件.理論分析和仿真結(jié)果證明,這一方法完全可以滿足高性能信號處理的要求