【作者】 何璞；

【导师】 张平；

【作者基本信息】 西安电子科技大学 ， 信号与信息处理， 2004， 硕士

【摘要】 随着微电子技术、数字信号处理技术和计算机技术的发展，频谱分析技术正在进行深刻的变革。数字化﹑软件化是频谱分析的发展趋势。 数字中频处理过程就是将数字化处理向射频输入前端靠近，直接将射频模拟信号变换成数字中频信号，再经过数字下变频、数字滤波等处理，最终转换成数字基带信号的过程,这时候再对基带信号进行谱分析，这种频谱分析具有测量速度快和实时性强的优点。 本文提出了基于中频数字化技术的频谱分析的整个架构，它包括模数转换、抽取滤波、中频处理、频谱分析四大模块。在模数转换模块里比较了奈奎斯特（Nyquist）采样、正交采样、带通采样和 Sigma Delta(∑ -?)采样等方法的优缺点。在抽取滤波模块里主要介绍了整数倍抽取技术及其多相滤波结构。在中频处理模块介绍了直接采样进行正交相干检波的各种方法和数字下变频技术，并给出了数字下变频中 CIC 滤波器，半带滤波器，FIR 滤波器的设计方法，在 Matlab 上进行了仿真。在频谱分析模块里介绍了一种适合于硬件处理的基 2FFT 算法和频谱分析中的细化技术，加窗技术，最终在 TMS320C6000（6711 芯片）的开发平台上实现了 FFT 的频谱分析，实验结果良好。更多还原

【Abstract】 With the development of the technologies of micro-electronics,digital signalprocessing and computer, the technique of frequency spectrum analysis has hadprofound changes. To make it digital and be realized by softwares is a trend forspectrum analysis. Digital IF processing is the process that RF analog signal is changed into digitalsignal,then become to base band signal through DDC and digital filters.there havespecrum analysis on base band signal.This method of spectrum analysis is used rapidlyand efficiently. The whole structure of the spectrum analysis based on the digital IF is presented inthis paper,including four parts of ADC, multi-rate signal processing ,digital IFprocessing and frequency spectrum analysis .The part of ADC discusses the advantages anddisadvantages of several technologies of sampling such as Nyquist sampling,perpendicular sampling,band-pass sampling and Sigma Delta sampling.In the part ofmulti-rate signal processing,there intrduced decimation with integral factors and thesructure of multiphase filtering. The technologies of quadrature coherent detection of IFsampling and digital down conversion are presented in the three part of digital IFprocessing. The designs and simulations of CIC filters, HB filters, FIR filters of thestructure is also given. The algorithms of radix-2 FFT,the digital frequency conversionand multiplying window are proposed in the last part of frequency spectrum analysis.Finally the FFT spectrum analysis is realized on the DSK of TMS320C6000(6711)，the experimental results are good.更多还原