具注入式鎖定技術之差動相位調變射頻接收機

Abstract

近身通訊網路(BAN)與多通道的神經記錄器等短距離的無線通訊系統，在近年來蓬勃發展。由於電力上的限制，如何提升無線收發機的能量效率，是非常重要的議題。在傳統以混波器為主的收發機架構中，功率消耗受限於頻率合成器與混波器。可能在新應用的發展上受到限制。 在傳輸器方面，近年來以相位選擇器為主的高效能傳輸器已被提出。可達到20 Mbps 左右的資料傳輸速率。然而，高效能的相位調變無線接收機，仍還未發表。 本論文將描述一個具高能量效率，操作在四億赫茲，採用差動式相位調變(DPSK)的無線接收機。接收機的核心是利用注入式鎖定振盪器的動態特性，來完成將相位資訊轉換為振幅資訊。因此，不需要閉迴路系統來完成相位同步，可大幅簡化系統架構，進而降低成本及功耗。另外提出了一自動的增益調整機制，來控制注入振盪器的電流。此接收機是使用台積電0.18微米製程設計，消耗功率為1.77 毫瓦、接收器的靈敏度為-63 dBm，當接收10 Mbps的訊號時，能源效益為 177 pJ/bit。

In short range wireless communication like multichannel neural recoding system and body area network (BAN), energy efficiency is critical under stringent power budget. Conventional mixer-based architecture suffers from power hungry mixers and frequency synthesizer may be a poor choose for this application. MUX-based PSK transmitter has been proposed to increase energy efficiency by achieving much higher data rate up to 20 Mbps. However, PSK receiver with high data rate and good energy efficiency has not been published yet. In this work, an energy-efficient 400-MHz DPSK receiver is implemented. The proposed DPSK receiver adopts injection locking technique to perform amplitude-to-phase conversion. This technique can demodulate the PSK modulated signal with envelope detector. The proposed receiver demodulates DPSK signal without using Costas loop and mixers, which leads to reduced power consumption and cost. An automatic gain control loop is also proposed to regulate the injection power by controlling the injection current to the DCO. The receiver is fabricated in TSMC 0.18-μm CMOS technology. It consumes 1.77 mW with 0.9-V supply. The system sensitivity is -63 dBm. The energy efficiency is 177 pJ/bit with 10-Mbps input signal.