基于DDS的2PSK調制

電子通信論文編號:TX201 附外文翻譯,原理圖及PCB,程序,論文字數:17313,頁數:26

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目    錄
引言………………………………………………………………………………1
1  緒論……………………………………………………………………………1 
2  設計要求……………………………………………………………………7
3  使用的器件及芯片介紹…………………………………………………8
4  方案設計……………………………………………………………………17
5  電路實現……………………………………………………………………19
6  電路制作和調試心得體會………………………………………………20
7 結論……………………………………………………………………………21
謝辭………………………………………………………………………………23
參考文獻…………………………………………………………………………24
附錄………………………………………………………………………………25

摘  要

二進制移相鍵控方式是受鍵控的載波相位按基帶脈沖而改變的一種數字調制方式。由于二進制移相鍵控系統在抗噪聲性能及信道通信頻帶利用率等方面比二進制FSK及OOK的優越，因而被廣泛應用于數字通信中。本課題就是采用了最流行的DDS技術來實現2PSK調制的。
DDS技術中，輸出信號波形的三個參數；頻率、相位和振幅A都可以用數據字來定義。的分辨率有相位累加器中比特數來確定，的分辨率由ROM中的比特數確定，而A的分辨率由DAC中的分辨率確定。因此，在DDS中可以完成數字調制和模擬調制。頻率調制可以用改變頻率控制字來實現，相位調制可以用改變瞬時相位來實現。本課題采用的芯片AD9856就是基于直接數字頻率合成技術，在單片機的控制下實現信號的2PSK調制。該芯片功能強大，具有多種調制功能，只需要使用外部控制器寫入對應的控制字，就能夠實現信號的2PSK調制。基帶信號可以由單片機產生的串行碼元控制DDS發生器的相位控制端來實現，而AD9856芯片內部集成的鎖相環可以產生載波，其頻率也是通過外部單片機的接口來設置。
關鍵字：直接數字頻率合成；2PSK調制；相位累加器；控制字；基帶信號；載波頻率

Abstract

2PSK modulate way to modulate the way signal carrier a kind of figure that phase place changes according to pulse of the baseband that key Control.. Because it is more superior than that of the binary scale FSK and OOK that the binary scale moves the looks key and accuses of the system in resisting noise performance and channel communication frequency band utilization ratio etc., widely used in digital communication. This subject is to adopt most popular DDS technology to realize 2PSK and modulate.
In DDS technology, output three parameters of the signal wave form ; Frequency , phase place and amplitude A can all be defined with the data word. There are the resolution ratio of frequencies bit is counted to confirm in accumulating device of phase place , the resolution ratio of the phase place is counts and confirms by bit in ROM, and the resolution ratio of amplitude A is confirmed by the resolution ratio in DAC. So, can finish figures to modulate and modulate with simulation in DDS. Modulating and can control words to realize with the frequency of changing in frequency, the phase place is modulated and can be realized by changing the instantaneous phase place. Chip AD9856 that this subject adopts is because of the directly digital frequency synthetic technology, realize under the control of the one-chip computer that 2PSK of the signal is modulated. This chip is powerful, have many kinds of modulation function , only need to use the outside controller to be written into the corresponding control word, can realize that 2PSK of the signal is modulated . Baseband signal can control by serial each that one-chip computer produce phase place , DDS of generator control and bring in realizing, and the phase locking ring of the integration can produce the signal carrier within AD9856 chip, its frequency is set up through the interface of the outside one-chip computer.
Key words: Digital frequency is synthetized directly； 2PSK is modulated； the accumulating device of phase place, control words； the signal of the baseband； the frequency of the signal carrier