布朗亂數展頻時脈產生器

Abstract

本論文討論分為五個章節，其中所提的電路皆由TSMC 65nm CMOS 製程來實現，第一章為介紹，第二章為展頻時脈產生器的討論，第三章為電路設計，第四章為量測結果，第五章為總結。 第一章介紹了各種降低 EMI 的方法，其中最有效的方法為一種名叫展頻時脈產生器的技術。 第二章討論了不同展頻時脈調變的方法，以及優缺點，由於三角波調變容易造成頻譜兩側的能量延展不均勻，因此無法有效的降低 EMI。而使用真實亂數調變的方法雖然在模擬上能有效的降低 EMI，但是由於實際量測時，真實亂數調變會導致鎖相迴路的輸出頻率跳頻過快，而無法有效的降低 EMI。同時，使用真實亂數調變的電路過於複雜，因此很難實現於產品上。因此本論文提出了一種新式的調變技術 : 布朗亂數調變。此方法能有效消除真實亂數調變所帶來的跳頻過快的問題，且同時又能保有亂數調變所帶來的好處。同時，此亂數調變方法可以由全數位方式來實現，因此可以有效降低複雜度，進而達成產品化。 第三章討論了布朗展頻時脈產生器的細部電路。此電路由一個鎖相迴路，以及一個展頻時脈調變器所構成。本論文所使用的壓空震盪器為雙端環型震盪器。除頻器為多模除頻器。相位頻率偵測器為九個NAND式的相位頻率偵測器。低通濾波器為二階 RC 低通濾波器。並且使用一階 Σ-△ 調變器。 第四章為量測結果。其中，使用protel DXP 2004來設計PCB板的電路。同時也展示所使用的示波器，電源供應器，訊號產生器，以及頻譜分析儀。最後在量測結果上也展示了不同頻率下的鎖定功能。 第五章為總結，歸納了第一章到第四章的重點分析，以及未來的展望。

There are five chapters in this paper. We use the TSMC 65nm CMOS process to design our circuits. Chapter one is introduction. Chapter two is spread spectrum clock generator (SSCG). Chapter three is detail circuits. Chapter four is measurements. Chapter five is conclusion. Chapter one is the introduction of reduction of EMI. And the most useful method is spread spectrum clock generator. Chapter two is the introduction of the spread spectrum clock generator (SSCG). We analyze the advantages and the disadvantages of every different kinds of modulations. The triangular modulation cause the part of the power is too concentrated on both ends, so that EMI reduction is poor. And though the chaotic PAM modulation reduce EMI well in the simulations, but it is poor in the measurement. And the circuit of the chaotic PAM modulation is too complexity, so it is hard to use in the products. In this paper, we propose a new modulation : Brownian random spread spectrum clock generator. This modulation can solve the problem of the part of the power is too concentrated on both ends, and it has the advantage of the random modulation method too. The circuits of the Brownian random modulation is very easily to design because it is designed by all digital circuits. Therefore, it can be used in products. Chapter three is the design of the detail circuit of the Brownian random spread spectrum clock generator. There are a phase lock loop and a spread spectrum clock modulator in Brownian random spread spectrum clock generator. We use the ring voltage control oscillator, multi mode divider, nine NANDS phase frequency detector, second order RC low pass filter, and first order Σ-△ modulator. Chapter four is the measurements. We use protel DXP 2004 to design our PCB circuits. And we show the power supply, the signal generator, the Oscilloscope, and the spectrum analyzer. And we show the function of difference frequencies to lock. Chapter five is the conclusion of the chapter one to chapter four. And we discuss the future work that we can do on the next step.