傳統的頻率特性測試儀不僅價格昂貴，且得不到相頻特性，更不能保存頻率特性圖和打印頻率特性圖，也不能與計算機接口，給使用者帶來了諸多不便。而本文采用DDS技術作為掃頻信號源；同時采用了集成模擬芯片AD8302對幅度和相位進行檢測，用DSP芯片TMS320VC5409 和CPLD芯片EPM7128進行測量控制和數據處理，人機接口部分是利用單片機AT89C51實現，并配有打印機接口和串行通信接口。系統基本達到了全數字化，這有利于縮小儀器的體積，減輕重量，降低成本，并能較好的顯示幅頻特性和相頻特性曲線。

Abstract:

?Traditional tester for frequency characteristic not only had high price， but also couldn’t give phase frequency characteristic of the quizzed network， yet couldn’t save and print frequency characteristic and couldn’t connet with PC.These gave user a lot of discommodity. However， adoptting the DDS technology as a sweep frequency signal source， using the AD8302 of integrated simulation chip to test amplitude and phase and using the TMS320VC5409 of DSP chip and the EPM7128 of CPLD chip to control measuring and process data. The section of man-machine interface uses the AT89C51 of SCM to realize， and has the printer and serial communication of the interfaces. The system reaches a basic all-digital， which make for shrinking the size， reducing the weight and the cost of equipment， moreover can display the characteristic curve of amplitude and phase preferably.

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