基于FFT的兩種偽碼快速捕獲方案的研究與實現(xiàn)
Two Methods of Rapid Code Acquisition Based on FFT
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摘要: 該文提出兩種基于FFT的偽碼快速捕獲方案，一種是基于分?jǐn)?shù)倍采樣率轉(zhuǎn)換器的快捕方案；另一種是基于抽取器的快捕方案。兩種偽碼快捕電路均利用設(shè)計復(fù)用技術(shù)使硬件規(guī)模大幅減少；采用并行設(shè)計使系統(tǒng)的運(yùn)算速度大大提高；采用塊浮點算法以提高動態(tài)范圍和運(yùn)算精度。兩種快捕電路均由一塊FPGA實現(xiàn)。仿真和測試結(jié)果表明，基于分?jǐn)?shù)倍采樣率轉(zhuǎn)換器的快捕電路與基于抽取器的快捕電路相比，占用的硬件資源較大，但是捕獲精度更高。
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關(guān)鍵詞:
- 快速傅里葉變換; 偽碼快速捕獲; 現(xiàn)場可編程門陣列; 塊浮點算法
Abstract: Two methods of rapid code acquisition based on FFT are presented, one method is based on fractional multiple sampling rate convertor, and the other is based on decimation. To reduce hardware resource, two rapid code acquisition circuits utilizes duplicate design. Two designs applied parallel pipeline structure to improve the processing speed. Block floating-point arithmetic is used to enhance the dynamic range and computation accuracy. Two designs are implemented with a chip of FPGA respectively, simulation and measurement results show that the rapid code acquisition circuit based on fractional multiple sampling rate convertor costs more hardware resource, but can gain higher acquisition accuracy to be compared with the method based on decimation. -
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