具二階三角積分調變技術之頻率調變射頻接收機

Abstract

近年來，隨著半導體製程的進步，近身通訊網路(WBAN 802.15.6)等短距離的無線通訊系統蓬勃發展。但是由於電池能量密度在近期並未有顯著的提升，尺寸上的限制，導致傳統的收發機架構無法直接應用在低功耗的攜帶式或植入式生醫設備。因此如何提升無線收發機的能量效率，是非常重要的議題。 本論文提出一個具高能量效率，操作在四億赫茲的無線射頻接收機。採用高斯頻率調變(GFSK)，頻率調變相對於其他調變方式具有較高的雜訊忍受能力。運作核心則是以鎖相迴路架構的特性解調輸入的頻率調變信號。此接收機架構是將射頻接收區塊及解調數位化區塊做結合，並利用連續時間三角積分技術取得較佳的信號雜訊比。因此，可簡化系統架構，進而降低成本及功耗。此接收機是使用台積電90奈米製程設計，消耗功率為3.32 毫瓦，當接收 2-Mbps 的訊號時，能源效益為1.66 nJ/bit，此接收器經由模擬得知其靈敏度為-76 dBm。

Recently, as the advancement of semiconductor, short range wireless applications like the wireless body area network (WBAN) experience a rapid growth. However, the improvement in battery energy density does not catch up with the semiconductor, traditional transceiver architecture cannot be implemented in low power portable or implantable bio-medical application. Therefore, there exists a critical issue of how to enhance the transceiver energy efficiency. In this work, a 400-MHz GFSK receiver is present. The GFSK signals store the input information in its frequency and are much more robust against channel noise. This work adopted a PLL-based architecture which can track the input frequency to demodulate GFSK signal. The proposed receiver combines RF receiving block with demodulation digitizing block. To get better SNDR, it also adopts the technique of continuous-time delta-sigma modulation. Therefore, it reduces the cost and power consumption by simplifying system architecture. The receiver is fabricated in TSMC 90-nm CMOS technology. It consumes 3.32 mW with 1.2-V supply. The simulated system sensitivity is -76 dBm. The energy efficiency is 1.66 nJ/bit with 2-Mbps input signal.