本論文提出一創新植入式無線生醫遙測系統架構，此系統可分為三個部份：植入在體內的感測端、身體上的中繼站及體外的接收器。感測端主要是將量測訊號轉換成數位訊號後再調變到醫用植入通訊頻帶，藉由人體傳送到身體上的中繼站，中繼站會將收到的訊號升頻到2.4GHz的ISM頻帶，利用空氣傳輸到體外的接收機做資料的分析或是監測。模擬結果可知此系統可提供16個頻寬為150kHz或是40個頻寬為40kHz的數位訊號在體內傳輸；而在體外可提供16個不同的個體在同一個環境下傳輸。未來相信可利用此系統可設計出完整的病患監控系統。
根據所提出的系統，在本論文中分別設計專屬晶片包含可切換解析度之三角積分類比數位轉換器及射頻2.4GHz發射與接收機。可切換解析度之三角積分轉換器是以2-2階的多級串接架構為主，可依據不同狀況架構切換於二階與四階之間。晶片量測結果在1kHz訊號頻寬下，二階架構訊號雜訊比可達到65B(相當於10位元解析度)，四階架構訊號雜訊比可達到84dB(相當於14位元解晰度)，其消耗功率分別為48μW與152μW。2.4GHz發射與接收機主要採用兩階段射頻發射機及超外差接收機。在傳輸40kHz，傳輸距離為20公尺下，所量測的位元錯誤率小於0.001%，此時發射機功率消耗為20mW，接收機功率消耗為68mW。
為了印證所設計晶片的實用性，分別利用所設計的調變器晶片及射頻晶片實現生醫訊號擷取系統與多頻道無線監控系統來做實際的應用。實驗結果證實相較於傳統的擷取方式，所設計的生醫訊號擷取系統在擷取心電圖可減少30%功率消耗，在擷取腦波圖可減少15%功率消耗。多頻道無線監控系統可與不同感測器整合，此系統經實驗證實可同時傳輸心電圖、PH值、鈣離子值、鉀離子值、氨離子值與鈉離子值。由此可知所提出的架構是可行的。

This paper presents the novel biotelemetry architecture for implantable applications. The proposed architecture is composed of three parts: implanted sensor node, the terminal chip on body and the receiver out-off body. The sensor node is used to convert the biomedical signal from analog to digital and modulate it to Medical Implant Communication Systems (MICS) band for transmission to terminal chip in body. The received signal in terminal chip is up-converted to ISM band 2.4GHz and transmitted to the receiver by air for monitoring or analysis. From the simulation result, this system can provide 16 channels with 150 kHz bandwidth or 40 channels with 40 kHz bandwidth for transmission in the body; out of the body, it can provide 16 different individual applied in the same environment. It can be expected that the proposed architecture will be adopted to design a complete patient’s monitoring system.
According to the specifications of proposed architecture, the exclusive chip including the variable-resolution sigma-delta modulator (SDM) and 2.4GHz radio frequency (RF) transmitter, receiver are designed in this paper. The architecture of variable-resolution SDM is based on 2-2 multi-stage noise shaped SDM. The proposed modulator is switched between second-order single-loop modulator and forth-order cascaded second stage noise shaped modulator to reach different resolution requirement. Experimental results of the proposed variable-resolution SDM confirm the expected specifications switched from 65dB signal-to-noise distortion (corresponding to 10-bit) to 84dB (corresponding to 14-bit) with 1k Hz bandwidth and power consumption range from 48μW to 152μW. The architectures of RF chips are Two-Step transmitter and Super Heterodyne receiver. The measurement results shows in 20 meters transmission distance, it can reach 0.001% bit error rate and the power consumption of transmitter and receiver are 20mW and 68mW.
For the verification of the chips functions, the power-efficient biomedical acquisition system implemented by proposed modulator and the multi-channel wireless monitoring system are designed in this paper. Compared with traditional methods, the measurement results show the power-efficient biomedical acquisition system can save 30% power consumption in electrocardiogram (ECG) acquisition and 15% in electroencephalogram (EEG) acquisition. The multi-channel wireless monitoring system could be integrated with different kinds of sensors. The ECG and ion concentration of acidity, calcium, sodium, ammonia, potassium have been successively simultaneously transmitted by proposed system for monitoring applications. Thus it could be seen the proposed architecture is feasible.

[1] G. J, Pottie, and W. J. Kaiser, “Wireless Integrated Network Sensors,” Commun. ACM, pp. 51-58, May 2000.
[2] http://ewh.ieee.org/soc/cas/tbcas/
[3] M. Sawan. Y. Hu, and J. Coulombe, “Wireless smart implants dedicated to multichannel monitoring and microstimulation” IEEE Circuit and System Magazine,” vol. 5, no.1, pp. 21-39, 2005
[4] L. Wang, E. A. Johannessen, P. A. Hammond, L. Cui, S. W. J. Reid, J. M. Cooper, and D. R. S. Cumming, “ A Programmable Microsystem Using System-on-Chip for Real-time Biotelemetry,” IEEE Trans. Biomed. Eng., vol. 52, no. 7, pp. 1251-1260, July. 2005.
[5] P. Mohseni, and K. Najafi, “A 1.48-mW Low-Phase-Noise Analog Frequency Modulator for Wireless Biotelemetry,” IEEE Trans. Biomed. Eng., vol. 52, no. 5, pp. 938-943, May. 2005.
[6] S. Boyer, M. Sawan, M. Abdel-Gawad, S. Robin, and M. M. Elhilali, “Implantable Selective Stimulator to Improve Bladder Voiding: Design and Chronic Experiments in Dogs,” IEEE Trans. Rehab. Eng. vol. 8, no. 4, pp. 464-470, Dec. 2000.
[7] P. Mohseni, K. Nagarajan, B. Ziaie, K. Najafi, and S. B. Crary, “ An Ultralight Biotelemetry Backpack for Recording EMG Signals in Moths,” IEEE Trans. Biomed. Eng., vol. 48, no. 6, pp. 734-1260, July. 2005.
[8] K. S. Shanmugam, Digital and Analog Communication Systems, 1st ed. New York: Wiley, 1979.
[9] W. Liu, K. Vichienchom, M. Clements, S. C. DeMarco, C. Hughes, E. McGucken, M. S. Humayun, E. De Juan, J. D. Weiland, and R. Greenberg, “A neuro-stimulus chip with telemetry unit for retinal prosthetic device,” IEEE J. Solid-State Circuits, vol. 35, no. 10, pp. 1487–1497, Oct. 2000.
[10] G. Gunnar, E. Bruun, and H. Morten, “A chip for an implantable neural stimulator,” J. Analog Integr. Circuits Signal Process., vol. 22, pp. 81–89, 1999.
[11] B. Smith, Z. Tang, M. W. Johnson, S. Pourmehdi, M. M. Gazdik, J. R. Buckett, and P. H. Peckham, “An externally powered, multichannel, implantable stimulator-telemeter for control of paralyzed muscle,” IEEE Trans. Biomed. Eng., vol. 45, no. 4, pp. 463–475, Apr. 1998.
[12] T. Akin, K. Najafi, and R. M. Bradley, “A wireless implantable multichannel digital neural recording system for a micromachined sieve electrode,” IEEEJ. Solid-State Circuits, vol. 33, no. 1, pp. 109–118, Jan. 1998.
[13] M. Ghovanloo and K. Najafi, “A high data transfer rate frequency shift keying demodulator chip for the wireless biomedical implants,” in Proc. IEEE 45th Midwest Symp. Circuits Systems, vol. 3, pp. 433–436, Aug. 2002.
[14] S.-Y. Lee, and S.-C. Lee, “An Implantable Wireless Bidirectional Communication Microstimulator for Neuromuscular Stimulation,” IEEE Trans. Circuits Syst.I, vol. 52, no. 12, pp. 2526-2538, Dec. 2005.
[15] R. Morais, A. Valente, J.C. Almeida, A. M. Silva, S. Soares, M.J.C.S. Reis, R. Valentim, J. Azevedo, “Concept study of an implantable microsystem for electrical resistance and temperature measurements in dairy cows, suitable for estrus detection,” Sensors and Actuators A 132, pp. 354-361, 2006.
[16] Q. Tang, N. Tummala, S. Gupta, L. Schwiebert, “Communication scheduling to minimize thermal effects of implanted biosensor networks in homogeneous tissue,” IEEE Trans. Biomed. Eng. vol.52, no.7, pp. 1285–1294, 2005.
[17] E. Jovanov, A. Milenkovic, C. Otto, P. de Groen, “A wireless body area network of intelligent motion sensors for computer assisted physical rehabilitation,” J. Neuroeng. Rehabil, vol.2, no.1, Jun. 2005.
[18] K. Akingbehin, A. Akingbehin, “Alternatives for short range low power wireless communications, in: Software Engineering, Artificial Intelligence, Networking and Parallel/Distributed Computing, “2005 and First ACIS International Workshop on Self-Assembling Wireless Networks. Proceedings of the Sixth International Conference on SNPD/SAWN 2005, pp. 320–321, 2005.
[19] D. Rollins, C. Killingsworth, G.Walcott, R. Justice, R. Ideker,W. Smith, “A telemetry system for the study of spontaneous cardiac arrhythmias,” IEEE Trans. Biomed. Eng., vol. 47, no. 7, pp.887-892, 2000.
[20] K. Uemura, T. Kawada, M. Sugimachi, C. Zheng, K. Kashihara, T. Sato, K. Sunagawa, “A self-calibrating telemetry system for measurement of ventricular pressure–volume relations in conscious, freely moving rats,” Am. J. Physiol. Heart Circ. Physiol., vol.287, H2906–H2913, Jun. 2004.
[21] J. G. Webster, Medical Instrumentation Application and Design. New York: Wiley, 1998.
[22] Shyh-Chyang Lee, “ Design of implantable wireless bidirectional SOC for biomedical applications,” 國立中正大學電機工程研究所博士論文, 民國九十五年十月
[23] H. Y. Yang and R. Sarpeshkar, “A Bio-Inspired Ultra-Energy-Efficient Analog-to-Digital Converter for Biomedical Applications”, IEEE Trans. Circuits Sys, vol.53, no.11, pp. 2349-2356, Nov. 2006.
[24] Honglei Wu, Yong Ping Xu, “A 1V 2.3μW Biomedical Signal Acquisition IC”, Proc. ISSCC, Feb, 2006.
[25] A. Gerosa, and A. Neviani, “A 1.8μW sigma-delta modulator for 8-bit digitization of cardiac signals in implantable pacemakers operating down to 1.8 V”, IEEE Trans. Circuits Syst.Ⅱ: Briefs, vol. 52, no. 2, pp.71-76, Feb. 2005.
[26] Y. Perelman, and R. Ginosar, “A low-light-level sensor for medical diagnostic applications”, IEEE Journal of Solid-State circuits, vol. 36, no. 10, pp.1553-1558, Oct. 2001.
[27] E Kyriacou, S Pavlopoulos, A Berler, M Neophytou, A Bourka, A Georgoulas, A Anagnostaki, D Karayiannis, C Schizas, C Pattichis, A Andreou, D Koutsouris, “Multi-purpose HealthCare Telemedicine Systems with mobile communication link support,” BioMedical Engineering OnLine 2003, 2:7.
[28] P. Mohseni and K. Najafi, “A wireless FM multi-channel microsystem for biomedical neural recording application,” in Proc. Mixed-Signal Design, Southwest Symp., Feb. 2003, pp. 217-222.
[29] D. De Rossi, F. Carpi, F. Lorussi, A. Mazzoldi, R. Paradiso, E.P. Scilingo, A. Tognetti, “Electroactive fabrics and wearable biomonitoring devices,” AUTEX Res. J., vol. 3, pp. 180–185, 2003.
[30] M. Catrysse, R. Puers, C. Hertleer, L. Van Langenhove, H. Van Egmond, D. Matthys, “Towards the integration of textile sensors in a wireless monitoring suit,” Sens. Actuators A, vol. 114 pp. 302–311, 2004.
[31] J. Coosemans, B. Hermans, R. Puers, “Integrating wireless ECG monitoring in textiles,” Sens. Actuators A, vol. 130-131 pp. 48-53, 2006.
[32] M. Catrysse, B. Hermans, R. Puers, “An inductive power system with integrated bi-directional data-transmission,” Sens. Actuators A, vol. 115, pp.221-229, 2004.
[33] J. Coosemans, R. Puers, “An autonomous bladder pressure monitoring system, Sens. Actuators A,” vol. 123-124, pp. 155-161, 2005.
[34] K. V. Schuylenbergh, R. Puers, “Self-tuning inductive powering for implantable telemetric monitoring systems,” Sens. Actuator A, vol. 52, pp.1-7, 1996.
[35] S. Takeuchi and I. Shimoyama, “A radio-telemetry system with a sharp memory alloy microelectrode for neural recording of feely moving insects,” IEEE Trans. Biomed. Eng., vol. 5, no. 1 pp. 133-137, Jan. 2004.
[36] J. Ottenbacher, S. R¨omer, C. Kunze, U. Großmann, W. Stork, “Integration of a bluetooth based ECG system into clothing, in: Proceedings of the Eighth IEEE International Symposium on Wearable Computers,” (ISWC’04), Arlington, VA, October 31–November 3, pp. 186–187, 2004.
[37] Barro S, Presedo J, Castro D, Fernandez-Delgado M, Fraga S, Lama M and Vila J, “Intelligent Telemonitoring of Critical Care Patients,” IEEE EMB Mag., vol.18, no.4, pp. 80-88, 1999.
[38] Bruce, E.N.: ‘Biomedical signal processing and signal modeling’ (John Wiley & Sons, Inc., New York, 2001.
[39] G. Bondini, A. S. Brogna, C. Garbossa, L. Colombibi, M. Bacci, S. Chicca, F. Bigongiari, N. C. Guerrini, and G. Ferri, “ An Ultralow-Power Switched Opamp-Based 10-B Integrated ADC for Implantable Biomedical Applications”, IEEE Trans. Circuits Sys, vol. 51, no. 1, pp. 174-178, Jan. 2004.
[40] Medical Instrumentation – Application and Design, John and G. Webster, Eds, Wiley, New York, pp. 258-259, 1998.
[41] J. Goes, N. Paulino, H. Pinto, R. Monteiro, Bruno Vaz, and A. S. Garcao, “Low-power low-voltage CMOS A/D sigma-delta modulator for bio-potential signals driven by a single-phase scheme”, IEEE Trans. Circuits Sys, vol. 52, no. 12, pp. 2595-2604, Dec. 2005.
[42] Andrea Gerosa, Andrea Maniero, and Andrea Neviani, “A fully integrated two-channel A/D interface for the acquisition of cardiac signals in implantable pacemakers”, IEEE J. Solid-State Circuits, vol. 39, no. 7, pp. 1083-1093, July 2004.
[43] Zhijun LU, Yamu HU, and Mohamad SAWAN “A 900mV 66μW sigma-delta modulator dedicated to implantable sensors”, IEICE Trans. INF.& SYST., vol. E88-D, no. 7, pp. 1610-1617, July 2005.
[44] V. Peluso, M. Steyaert, and W. Sansen, Design of low-voltage low-power CMOS delta-sigma A/D converters, Kluwer Academic Publishers, Boston, 1999.
[45] J. Crols and M. Steyaert, “Switched-opamp: An approach to realize full CMOS switched-capacitor filters at very low power supply”, IEEE J. Solid-State Circuits, vol. 29, no. 8, pp. 936-942, Dec. 1997.
[46] J. D. Meindl and A. J. Ford, “Implantable telemetry in biomedical research,” IEEE Transactions on biomedical engineering, vol. BME-31, no. 12, pp. 817-823, Dec. 1984.
[47] T. Akin, K. Najafi, and R. M. Bradley, “A wireless implantable multichannel digital neural recording system for a micromachined sieve electrode,” IEEE Journal of Solid-State circuits, vol. 33, no. 1, pp. 109-118, Jan. 1998.
[48] FCC rules and Regulations, Table of Frequency Allocations, Part 2.106, Nov, 2002.
[49] Jaehoon, K., and Rahmat-Samii “Implanted antennas inside a human body: simulations, designs, and characterizations”, IEEE Trans. MTT., vol. 52 no. 8, pp.1934-1943, Aug. 2004.
[50] C.-M Lee, T.-C. Yo, C.-H. Luo, C.-H. Tu, and Y.-Z. Juang, “Compact broadband stacked implantable antenna for biotelemetry with medical devices”, Electronics Letters, vol. 43(12), pp. 660-662, Jun. 2007.
[51] Soontornpipit, P., Furse, C.M., and You, C.C.: ‘Design of implantable microstrip antenna for communication with medical implants’, IEEE Trans. MTT., vol. 52, no. 8, pp.1944-1951, 2004
[52] D. K. Shaeffer; T. H. Lee, “A 1.5-V, 1.5GHz CMOS Low Noise Amplifier,” IEEE J. Solid State Circuits, vol. 32, pp. 745-759, MAY. 1997.
[53] T. Manku, “Microwave CMOS-Device Physics and Design, “IEEE J. Solid-State Circuits, vol. 34, pp. 277~285, March 1999.
[54] Behzad Razavi, Design of Analog CMOS Integrated Circuits, Mc Graw Hill, 1996.
[55] B. D. Muer, M. Borremans; M.Steyaert and G. L. puma, “A 2-GHz Low-phase-noise Integrated LC-VCO Set with Flicker-Noise Upconversion Minimization,” IEEE J. of Solid-State Circuits, vol.35, NO.7, pp.1034-1038, July 2000
[56] T.H.Lee, The Design of CMOS Radio-Frequency Integrated Circuits, Cambridge University Press, 1998.
[57] Derek K. Shaeffer; Thomas H. Lee, “A 1.5-V, 1.5GHz CMOS Low Noise Amplifier,” IEEE J. Solid State Circuits, vol. 32, pp. 745-759, MAY. 1997.
[58] Joseph J. Carr, John M. Brown, Introduction to Biomedical Equipment Technology, Fourth Edition, Prentice Hall, 2001
[59] W. Y. Liao, Y. G. Lee, C. Y. Huang, H. Y. Lin, Y. C. Weng, and T. C. Chou, “Telemetric Electrochemical Sensor,” Biosensors and Bioelectronics, Vol. 20, pp.482-490, 2004.
[60] S.R. Norsworthy, R. Schreier, and G.C. Temes, ‘Delta-Sigma Data Converters Theory, Design, and Simulation’, IEEE Press, New York, 1997.
[61] Augusto Marques, Vincenzo Peluso, Michel S. Steyaert and Willy M. Sansen, “Optimal Parameters for ΔΣ Modulator Topologies”, IEEE Trans. Circuits Sys, .vol.45, no.9, pp.1232-1241, Sep. 1998.
[62] A.Marques, V. Peluso, M. Steyaert, W. Sansen, “Optimal Peramters for CascadeΔΣ Modulator”, in Proc. ISCAS’97, pp. 61-64, 1997.
[63] C. Renato T. de Mori, P. Cesar Crepaldi, T. Cleber Pimenta, “A 3-V12-Bit second order sigma-delta modulator design in 0.8-um CMOS”, Grupo de Microelectronica-Escola federal de Engenharia de Itajuba, pp.124-129, 2001.
[64] T.Kajita, G.C. Temes and U.-K. Moon, ”Correlated double sampling integrator insensitive to parasitic capacitance”, Electron. Letter, vol.37, no.3, pp.151-153, Feb. 2001.
[65] Piero Malcovati, Simona Brigati, Fabrizio Francesconi, Franco Maloberti, Paolo Cusinato and Andrea Baschirotto, “Behavioral Modeling of Switched-Capacitor Sigma-Delta Modulators“, IEEE Trans. Circuits Sys, .vol.50, no.3, pp.352-364, Sep. 1998.
[66] A. Yukawa, “A CMOS 8-bit high-speed A/D converter,” IEEE J. Solid-State Circuits, vol.SC-20, no.3, pp.775-779, June 1985.