本論文以軟體定義無線電平台實現即時頻譜分析儀，此平台使用 Zedboard SDR 軟體定義無線電開發套件，在硬體方面它是由ZedBoard zynq-7000 （FPGA Board）與 Analog Devices AD9361（RF Board）結合而成，透過筆電以Matlab程式進行即時頻譜分析。論文首先簡介頻譜分析的重要性、頻譜分析儀的架構以及掃頻式頻譜分析儀的缺點，從而導入即時頻譜分析的必要性。接著簡介即時頻譜分析儀的硬體架構以及離散傅立葉轉換的相關概念，以正交（I/Q）取樣點的離散傅立葉轉換的數學模型分析建立基本觀念，並以此為基礎說明I/Q不平衡、直流偏移（DC OFFSET）、無衍生信號的動態範圍（Spurious Free Dynamic Range,SFDR）、解析度頻寬（Resolution Bandwidth，RBW）等。後續陳述即時頻譜分析儀之設計，詳細解說 zynq-7000與AD9361的特性，以及與其相關的數值運算觀念，如 Fixed Point、Floating Point 和 CORDIC。最後為即時頻譜分析儀的實現與實例運算，此為前者的設計結果的應用，以三個不同信號為例驗證本研究的可用性與探討設計的優缺點。;This thesis implements a real-time spectrum analyzer with a software-defined radio platform. This platform uses the Zedboard SDR software-defined radio development kit. In terms of hardware, it is a combination of ZedBoard zynq-7000 (FPGA Board) and Analog Devices AD9361 (RF Board). performing real-time spectrum analysis with Matlab program through laptop. The thesis firstly introduces the importance of spectrum analysis, the structure of spectrum analyzer and the shortcomings of swept analyzer, so as to introduce the necessity of real-time spectrum analysis. Then it introduces the hardware structure of the real-time spectrum analyzer and the related concepts of discrete Fourier transform, establishing the basic concept based on the mathematical model analysis of discrete Fourier transform of quadrature (I/Q) sampling Points. The concepts I/Q imbalance, DC offset, spurious free dynamic range (SFDR), and resolution Bandwidth (RBW) and introduced. The design of the real-time spectrum analyzer is described in the follow-up, and the characteristics of the zynq-7000 and AD9361, as well as the related numerical operation concepts, such as Fixed Point, Floating Point and CORDIC, are explained in detail. Finally, the realization and practical operation of the real-time spectrum analyzer, These are the application of the design results of the former, taking three different signals as examples to verify the usability of this study and discuss the advantages and disadvantages of the design.
