Secondly , basing on single channel if sr receiver mathematic model , this thesis has designed if sr receiver subsystem and brought forward its design project and system circuit principle diagram , and explained the system working principle . furthermore , this thesis introduces the working principles and respective applications of wideband high - speed adc ad6640 , ddc ad6620 and high - speed dsp tms320c6713 according with the if sr receiver subsystem high - speed analog digital conversion department , digital down conversion department and high speed digital signal processing department . thirdly , the thesis emphatically demonstrates the software realization department of the if sr receiver subsystem , which including ad6620 ' s inner parameter software setup , tms320c6713 data transmission and processing and the quadrant demodulation algorithm program realization 其次，基于单通道中频软件无线电接收机数学模型，本文设计了中频( if ， intermediatefrequency )软件无线电接收机子系统，给出了中频软件无线电接收机子系统的设计方案和系统电路原理图，说明了系统工作原理，并分别对应系统中的高速模数转换部分、数字下变频部分、基带数字硕士学位论文软件无线电理论研究及中频软件无线电接收机子系统设计信号处理部分，介绍了高速adcad664o ，数字下变频器( ddc ， digitaldownconverter ) ad6620 ，高速数字信号处理器( dsp ， digitalsignalproeessor ) tms320c6713的工作原理，以及它们在中频软件无线电接收机子系统中的应用。
To utilize the advantages of dsp chips , the system should be computing sources economical . according to digital signal processing theory , the poly - phase fir can help reduce the workloads of the ddc / duc . therefore , adding the complex carrier mixers , the channelization system ( a method of using a single wideband facility to transmit many relatively narrow - bandwidth signals . by subdividing the frequency spectrum used in the wideband channel ) can be formed utilizing the characters of fft 为了使开发出的软件可以适用于高速dsp器件开发，节省系统资源，课题首先从数字信号处理的理论进行分析，得出可以利用抽样率转换的数字滤波器的特点，即多相滤波实现数字上下变频计算负担的减小，之后进一步将多相滤波器与频谱搬移部分结合，通过公式的推导，得出可利用快速傅立叶变换的特点实现多路信号的信道化发射和接收的处理模型。
