- 學位論文
運用於4G LTE通訊系統之本地振盪源研製
Developing a Local Oscillator for 4G LTE Communication System
摘要
本論文針對4G LTE通訊系統設計一操作頻段於Band 2 (UL：1850 MHz - 1910 MHz)且應用於用戶端設備(User Equipment, UE)端的本地振盪源。利用安捷倫科技所研發的先進設計系統(Advanced Design System, ADS)模擬軟體工具來輔助設計並預測電路特性，壓控振盪器部分，本論文採用克拉普式振盪器架構，其中運用共射極雙極性電晶體結合串聯諧振電路作設計；分數式頻率合成器方面，則搭配三階被動式迴路濾波器進行設計模擬。本論文之電路模組設計採用德州儀器公司生產之LMX2485E頻率合成器晶片，電路架構內有運用差異積分調變器的技術與選用不同迴路頻寬的迴路濾波器，並透過軟體控制對晶片內部暫存器及各項參數進行設置，不過所設計的LMX2485E頻率合成器模組的電路有問題，因此藉由TI生產的LMX2531頻率合成器模組替代原設計之電路模組，在4G LTE通訊系統的載波中心頻率與頻率合成器之迴路頻寬為7.4 kHz時來量測相位雜訊、鎖定時間等特性，並於結論來針對欲符合4G LTE通訊系統規範的整體電路性能之量測結果作討論。
並列摘要
This paper presents a design of local oscillator, which is operated by User Equipment in a 4G LTE communication system operating Band 2(UL：1850 MHz - 1910 MHz). In order to design the local oscillator, the simulation tools of Advanced Design System, which was developed by Agilent Technologies Inc., was used to predict the characteristics of circuits. Meanwhile, The Clapp oscillator architecture(the combination of common emitter bipolar transistors and series resonant circuit), which was adopted by this paper, was based on voltage-controlled oscillator. About the fractional frequency synthesizer and combination with the third-order passive loop filter. In order to present a practical module of frequency synthesizer, the main chip of LMX2485E frequency synthesizer, the main circuit structure use the technology of delta-sigma modulator, which was developed by Texas Instruments Inc., was used to control the chip’s internal registers, different loop bandwidth’s loop filters and set the various parameters by the code loader. However, the LMX2485E frequency synthesizer module has some problem, therefore use the LMX2531 frequency synthesizer module which was developed by Texas Instruments Inc. to replace the original design of the circuit modules, and then fix the loop bandwidth to measure lock time, phase noise and other features., Finally, this paper analysis and discussion in 4G LTE communication system specification of the practical module’s performance measurement results.