本文首先對掃頻信號測試系統中的重要模塊：掃頻信號源進行了深入的研究與分析，
詳細推導了掃頻電路測試原理與理論依據。在對比了多種信號產生方法的優缺點后，提出
了基于直接數字合成的掃頻測試電路具體實現方案，重點探討了直接數據合成芯片與控制
單片機之間的通信方法和實現電路。最后對實現的掃頻信號源中的合成信號質量進行分
析，給出了實際電路與理想狀態下的信號圖。
關鍵詞: 掃頻信號；測試系統；DDS；電路；質量分析；
Abstract: At first this paper has deeply researched and analyzed the important module Frequencies-Scanning signal source in the Frequencies-Scanning signal Measurement system,
in detail inferred the test principle and the theory basis of Frequencies-Scanning circuit. After
contrasted several kinds of signals generate ways, has proposed the concrete realization plan of
the Frequencies-Scanning Measurement Circuit Based on DDS. has discussed the means of
communication between the DDS chip and the microcontroller chip, besides that the realization
electric circuit has been given. At last, has analyzed the synthesis signals quality generated form
the frequencies-scanning signal source. has produced the actual electric circuit and the perfect
condition signal chart.
Keyword: frequencies-scanning signal; measurement system; DDS ;circuit; quality analysis