應用於感測結點與生醫系統之低功率收發機

A Low Power Transceiver for Wireless Sensor Nodes and Biomedical Systems

蔡林憬(Lin-Ching Tsai)

指導教授 ： 呂學士

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.10823

摘要

近年來，隨著生活的進步，人口結構逐漸老化，老人照護逐漸成為一個重要的議題。對於醫療資源的需求日益增加，但老年人求醫過程的不便在於需定時到醫院進行追蹤與檢查，其所耗費的不只是檯面上所看到的時間與金錢，暴露於醫療場所更增加了感染其他傳染病危害的風險。
　　隨著無線通訊以及網路的迅速發展，利用無線通訊達到無線監測和記錄來獲得病人及時的生理參數。不僅對病人和家屬可減少不必要的痛苦和經濟開銷，也減輕醫療人員的工作負擔。藉由長期的監控也會及早發現一些病徵，例如心律不整…等。生理無線監控設備必須要有輕便可攜、無線傳送資料之特點故有以下幾個特點，低成本、低功率消耗及可短距離無線傳輸。為了達到上述目標，本篇論文提出可利用於生醫頻段之低功率無線收發機之架構，為了將來可以與其他後端架構整合而實現在標準之0.18 微米CMOS 製程。
　　首先介紹如何用低功率喚醒接收機來解調OOK訊號。藉由比載頻低很多的頻率做為系統的操作頻率。除去較為耗電的電路，例如低雜訊放大器。利用以上的方式減少接收機的功率消耗。本系統先利用一個混頻器將射頻訊號降到中頻訊號其後透過單端轉雙端的放大器與四級雙端放大器來放大訊號，並利用封包偵測器將訊號擷取出來。其後用比較器來比較電壓大小以解調OOK訊號。
　　接著介紹超級再生接收機並將其整合於智慧型牙套系統。首先利用低雜訊放大器將訊號放大並進入其後的數位控制震盪器，當訊號出現時會讓數位控制震盪器提早起振，後端的電路藉由區分起振時間的快慢就可解調出OOK訊號。
　　接著介紹兩個發送機分別是LC-tank 電壓控制發送機跟環形震盪器。 LC-tank 發送機可以利用OOK或FSK的模式進行傳輸.。環形震盪器發送機主要是利用OOK模式進行傳輸。
　　最後我們將超級再生OOK收發機整合進智慧型牙套晶片中，此電路可在非常低功耗的狀態下利用OOK或FSK模式進行傳輸。藉由其低功耗的特性，讓整體系統能用於長期身理監控。

關鍵字

低功耗 ； 開/關鍵控 ； 喚醒接收機 ； 超級再生接收機 ； 匹配電路

並列摘要

In recent years, with the advance of medical, the importance of low-cost, accessible and flexible health care has increased dramatically. The need for remote medical resources is growing every day. The inconvenient is that elders need to regularly receive medical treatment to the hospital for tracking and checking. It takes not only time and money, but also increasing the risk of getting infection with bacteria.
　　With the fast progress of wireless communication and internet, the homecare technology achieves health monitoring and remote medical diagnosis to acquire the timely physiological parameter of patients by wireless communication have third benefits. First, it prevents the users from tiring and lengthy traffic, as patients don't have to leave their homes for the service. Furthermore, homecare technology reduces unnecessary pain and financial cost but also dampen the work burden of medical staff. Secondly, real time renewal and supervision of patients' medical data can be performed remotely to help doctor find some symptoms of disease in time, such as cardiac dysrhythmia. Thirdly, a patient's quality of life can remain unaffected if the sensors and remote medical systems can be made light, portable, highly-integrated and capable of wireless communication. For these and other reasons, the Medical Implant Communication Service (MICS) has been developed and operates in a dedicated frequency band between 402 and 405 MHz. The characteristic of wireless health monitoring devices are short distance communication, low power consumption, and low cost. To achieve above requirement. The thesis proposes low power wake-up receiver and super-regenerative receiver.
　　Firstly, we introduce the wake-up architecture. The receivers is implemented in producing TSMC 0.18um COMS process. By using frequency which is much lower than carrier frequency as operating frequency and removing the power hungry circuit, such as LNA, we decline the power consumption of receiver. The Mixer and five stages differential amplifier are used to amplify the signal. And the envelope detector circuit sample the voltage from OOK signal. By comparator we separate signal “1” from “0”.
　　Secondly, we introduce the super-regenerative receiver and integrate the receiver into Smart Oral Appliance. The receivers are both implemented in producing UMC 0.18um COMS process. By careful design, the LNA can send ISM band signal to DCO. And the DCO will oscillate earlier when signal is “1” and vice versa. The backside circuit will define signal “1” or “0” by oscillation time of DCO.
　　Thirdly, we introduce two transmitter LC tank voltage control oscillator and ring oscillator, respectively. The receivers is implemented in producing UMC 0.18um COMS process and TSMC 0.35um COMS respectively. The LC-tank voltage-controlled transmitter can communicate in OOK or FSK mode. The other transmitter is voltage control ring oscillator transmitter, which communicates in OOK mode. Finally, we integrate the super-regenerative receiver into smart oral appliance. The receiver can communicate in OOK or FSK mode. The low power consumption of receiver make whole system achieve long-term health monitor.

並列關鍵字

Low power consumption ； OOK ； Wake-up Receiver ； Super-Regenerative OOK transceiver ； Matching Network

參考文獻

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