低頻標準時間碼廣播系統為我國試圖發展之目標，除了具有自動時間校準功能外，未來也將發展民生資訊的廣播以及天災預警的功能，因此對於國家安全而言非常重要。

在這個低頻標準時間碼廣播系統當中，民眾可藉由一個具有接收機裝置的電波鐘錶進行解碼對時；其中，前端接收機的優劣極為關鍵，將直接影響訊號接收品質。本篇論文的主題在於設計此一應用在低頻無線時頻傳播系統的接收機晶片，目的是接收基地台發射出的訊號，進一步做放大、濾波及解調等處理，將訊號還原至數位位元編碼，以利後續的微處理器將資訊解讀出來。

本篇論文所設計的接收機系統具有下列特點：此系統乃奠基於自動增益控制放大器迴路，先將天線接收的訊號振幅調整至某適當的輸出振幅，再進行解調。為了使接收機具有較好的靈敏度，於輸入端採用BJT元件，以克服低頻雜訊的干擾。為使系統同時具有振幅調控以及訊號解調的功能，須在電路中加入適當的控制開關。為避免電源開啟後，系統被鎖定在非正常操作下的穩定狀態，因此加入預充電路，使接收機開機後能夠進行正常解調。設計待機模式切換機制，在訊號接收完畢後，將接收機切換至待機模式下，以節省功率消耗。

本接收機晶片設計先後採用TSMC 0.35um SiGe BiCMOS製程以及 TSMC 0.18um CMOS製程加以實現，前者已於實驗室以及中華電信研究所完成特性量測，晶片實體面積為1300μm×908μm。本篇論文實現了一功能完整的前端接收機晶片，工作在0.343mW的低功率消耗之下，並可成功完成訊號接收及解調工作。

Low frequency (LF) broadcast system is not only an essential platform for the operation of radio watches but also a potential system for various applications such as disaster warning. The front-end IC of the LF receivers is a key component.

A low-power, low-noise receiver with complete function and realized in SiGe BiCMOS technology for low frequency (77.5 kHz) time signal broadcast system is presented in this work.

For the use at LF, flicker noise usually dominates the system noise floor. The receiver designed in this work uses SiGe HBT to reduce flicker noise. The receiver incorporates a variable gain amplifier (VGA) to adjust the signal amplitude, and the demodulation function is built in the automatic gain control (AGC) system. Under 3.3 V power supply, the receiver only consumes 0.343 mW when working. Stand-by mode has been implemented to save even more energy. The chip occupies an area of 1300 μm x 908 μm.

Another design in CMOS technology is also proposed to enhance the function of receiver. The frequency band of this version is expanded to accommodate multi-frequencies (40 kHz, 60 kHz, and 68.5 kHz). In this design, not only the crystal select circuit was inserted, but also the system of AGC was altered to break through the limitation of the VGA gain range. The chip area of the latter receiver is 1867 μm x 1899 μm.

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