臺灣博碩士論文加值系統

本篇論文主要在於探討36.5 GHz微波輻射接收機的研製，包括射頻前端與類比數位轉換器的實現及量測，並以隨機過程模擬雜訊在經過類比數位轉換器與數位相關器後的結果，有助於了解解析度對於接收機的等效雜訊靈敏度的影響。射頻前端是採用超外插結構設計，將36.5 GHz的射頻訊號降頻至500 MHz的中頻訊號，並提出適當的中頻放大器增益大小，提供全刻度的類比數位轉換器輸入。
在類比數位轉換的實現方面，解析度6位元、取樣頻率1GSPS以及輸入頻寬1.4GHz的快閃式類比數位轉換器的使用，除了滿足本論文的輻射接收機設計需求，更可以提供未來進一步的用途，如直接數位化的處理等。在文中並研究兩種統計模組，針對高斯分佈下的窄頻雜訊擾動來分析，且由電腦程式提供說明，以了解等效雜訊靈敏度與解析度的關係。
從以上系統的實現、量測及模擬，提出了36.5GHz的數位微波總功率輻射接收機之原型機的架構，未來的目標朝著數位相關器的實現與全系統量測以驗證統計模組的結果。

In the thesis,the 36.5 GHz Microwave Total Power Digital Radiometer is designed,implemented and simulated. Include RF front end, analog to digital converter and digital correlator. The superheterodyne structure is applied on the design of receiver frond end. The 36.5 GHz RF signal is then downconverted to 500 MHz IF signal using a mixer-preamplifier. The gain of the IF amplifier are determined in the measurement to achieve the full-scale input of analog-to-digital converter.
The flash analog to digital converter digitizes full scale input into 6-bit digital words at an update rate of 1 Giga Sample Per Second (GSPS) . It not only results in the required sensitivity of the radiometer, it also makes the system possibly extended in the future using the direct-sampling approach. Two statistical model of noise signal in digital radiometer are also studied. The narrow band noise signal is modeled as a Gaussian random process. A computer program is developed to help understand the relationship between Noise-Equivalent sensitivity and quantization resolution.
Finally the prototype of 36.5 GHz Microwave Total Power Digital Radiometer is presented. Future works will involve realizing the digital correlator to verify the sensitivity predicted by statistical models.

第一章導論1
1.1研究目的1
1.2論文介紹1
第二章輻射計系統介紹3
2.1輻射計簡介3
2.2接收器原理4
2.2.1 雜訊功率及等效雜訊溫度4
2.2.3 靈敏度8
2.2.4 動態範圍9
2.3輻射計原理14
2.3.1 全功率輻射計（TPR）︰14
2.3.2 迪克輻射計（DR）︰16
2.3.3 雜訊注入輻射計（NIR）︰17
2.4全功率數位接收器（TPR）方塊圖19
第三章天線及射頻前端（RF Front End）的實現25
3.1天線25
3.2連接器28
3.3射頻放大器29
3.4射頻濾波器32
3.5降頻元件及其週邊元件33
3.6中頻帶帶通濾波器37
3.7輻射接收器的靈敏度與雜訊溫度40
3.8中頻放大器43
3.9各元件量測結果48
第四章類比數位轉換器的實現與靈敏度分析58
4.1轉換器原理58
4.1.1取樣與保持時間58
4.1.2總諧波失真60
4.1.3訊雜比60
4.1.4訊雜及失真比61
4.2類比數位轉換器的電路製作62
4.2.1SPT7610的功能介紹62
4.2.2驅動電路之設計與實現64
4.3類比數位轉換器測試68
4.4輻射接收器系統的數位分析69
4.5直流偏壓漂移之統計模組70
4.6有限取樣之統計模組78
第五章結論93
參考文獻95
附錄一 Matlab程式97
附錄二 廠商所附之元件規格111

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