溫度補償壓控石英振盪器之研究

Abstract

本論文在於使用金氧半製程研究溫度補償壓控石英振盪器。經由小信號與大信號解析克服石英晶體品質因素很高，起振時間相當長之缺點，達成低功率消耗且快速起振之石英振盪器，此外並利用改變可變電容等效電容值以改變振盪頻率進而實現壓控石英振盪器(VCXO)。並提出一新型的電路實現一具溫度補償功能之壓控石英振盪器，在-25℃~75℃內，頻率漂移在±1ppm以內。此晶片除石英晶體及一旁路電容外接之外，其餘均為積體化。最後並將VCXO應用於短距離通信之發射晶片，以達到FSK及FM的目的，其調變速率為20kbit/sec，頻偏為215kHz。

The purpose of this study is to develop a temperature compensated voltage controlled crystal oscillator (TCVCXO) using CMOS process. The optimum design for initial starting is got by small-signal approach, and the steady-state is performed by large-signal approach. A novel circuit with amplitude sensing is proposed to overcome the long start-up time and power consumption problem for the high Q crystal oscillator. An analog temperature compensated crystal oscillator is realized via a folded multiplier and adaptive bias, which covers from -25℃~75℃within ±1ppm. Finally a VCXO with FSK and FM functions is presented for the applications in short range wireless transmitter.