高精度的信號源是各種測試和實驗過程中不可缺少的工具,在通信、雷達、測量、控制、教學等領域應用十分廣泛。傳統的頻率合成方法設計的信號源在功能、精度、成本等方面均存在缺陷和不足,不能滿足電子技術的發展要求,直接數字合成(Direct Digital Synthesis)DDS技術可以提供高性能、高頻高精度的信號源,方便地獲得分辨率高且相位連續的信號,基于FPGA的DDS技術提供了升級方便并且成本低廉的解決方案。
本文對DDS的基本原理和輸出頻譜特性進行理論分析,總結出雜散分布規律。同時以DDS的頻譜分析為基礎,給出了幾種改善雜散的方法。本文結合相關文獻資料采用傅立葉變換的方法對相位截斷時DDS雜散信號的頻譜特性進行了研究,得到了雜散分布的規律性結論,并應用在程序設計程中;DDS技術的實現依賴于高速、高性能的數字器件,本文將FPGA器件和DDS技術相結合,確定了FPGA器件的整體設計方案,詳細說明了各個模塊的功能和設計方法,并對其關鍵部分進行了優化設計,從而實現了波形發生器數字電路部分的功能。軟件部分采用模塊設計方法,十分方便調試。為了得到滿足設計要求的模擬波形,本文還設計了幅度調節、D/A轉換和低通濾波等外圍硬件電路。
實驗結果表明,本文設計的基于DDS技術的多波形信號源基本能夠滿足普通學生實驗室的要求。
·詳細說明:C++寫的DTMF算法,內含一個pcm數據文件,讀入文件并分析按鍵-c writes the DTMF algorithm, contains a pcm data file, the read-in document and the analysis pressed key。文件列表: DTMF ....\DTMF.cpp ....\DTMF.
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1.an fpga implementation of the image space reconstruction algorithm for hyperspectral imaging analysis\r\n2. fpga implemention of a median filter\r\n3. fpga implementation of digital filters\r\n4.hardware acceleration of edge detection algorithm on fpgas
Designers of signal receiver systems often need to performcascaded chain analysis of system performancefrom the antenna all the way to the ADC. Noise is a criticalparameter in the chain analysis because it limits theoverall sensitivity of the receiver. An application’s noiserequirement has a signifi cant infl uence on the systemtopology, since the choice of topology strives to optimizethe overall signal-to-noise ratio, dynamic range andseveral other parameters. One problem in noise calculationsis translating between the various units used by thecomponents in the chain: namely the RF, IF/baseband,and digital (ADC) sections of the circuit.
One of the strengths of Synplify is the Finite State Machine compiler. This is a powerfulfeature that not only has the ability to automatically detect state machines in the sourcecode, and implement them with either sequential, gray, or one-hot encoding. But alsoperform a reachability analysis to determine all the states that could possibly bereached, and optimize away all states and transition logic that can not be reached.Thus, producing a highly optimal final implementation of the state machine.