摘要
随着生物医学电子学的迅速发展,其研究领域不断拓宽,地位日益重要,展示了广阔的发展前景。为了更好地解决世界上快速增长、数量庞大的脑血管病人的康复需求和脑血管疾病治疗仪技术落后之间的矛盾,目前,就如何在现有脑血管形态学诊断的基础上,进一步了解和促进脑血管功能变化已成为国际上一个新的研究热点。为此,设计制造出更适合患者需求的脑循环治疗仪已成为学术界和市场共同的迫切需求。
传统脑循环仪的波形发生器由模拟电路产生,其精度低、稳定性差、体积大、灵活性差;目前最流行的脑循环仪其人体适应性差、价格高、无法和其它医疗仪器衔接。为了克服这两类治疗仪的缺点,获得脑血流量调节系统中需要的稳定性好、精度高、频带范围宽、可以方便地和其它医疗设备衔接的任意波形发生器,促进现有功能治疗仪向自动调节能力更强、市场价格更合理发展,本论文重点研究、设计了下述两个脑循环治疗仪波形发生器方案:(1)基于DE2开发系统和QuartusⅡ软件,以“TOP-DOWN”设计方法,采用现场可编程门阵列(FPGA)实现信号的频率合成,以超高速集成电路硬件描述语言(VHDL)形式实现波形存储器、嵌入式锁相环及直接数字频率合成技术(DDFS)各功能模块,并进行系统适配和资源锁定,形成任意波形发生器原型系统;(2)基于单片机和DDFS技术完成任意波形发生器的软硬件设计,包括单片机系统的软硬件设计、双口RAM的FPGA片内实现、FPGA单片机被动串行配置等内容。经调试,这两个系统均已能输出频率范围较宽、稳定性好、精度高的波形。
实验结果表明这两个设计方案都达到了预定的要求,证明了用这两种方案来实现脑血流量调节系统中所需的波形发生器的方法是可行的。
With a rapid development of Biomedical Electronics, the research field has been constantly wide spread and has been playing a more and more important role, all of which display a broad prospect of development. Nowadays, there is a contradiction between the recovering demands of cerebrovascular patients, who actually are increasing fastly in the world, and the disadvanced instruments for cerebrovascular diseases. To solve the contradiction, a new international hot topic, which is about how to further study and promote the variational cerebral blood vessel's function on the basis of present cerebrovascular morphology diagnosis, has come out. Therefore, both the academic and market urge a demand of a new type of device which is more suitable for patients' treatment of circulatory function.
Traditional waveform generator of brain-cycle device forms analog circuits. It is not only poor in accuracy and stability, but also bulky and inflexible. At present, the popular device is poor adaptability , high prices and not linking with other instruments. In order to overcome these shortcomings, this paper designed the following two Programmes.(1)Based on the DE2 development system and the Quartus II software, the prototype system of electrical stimulation waveform generator is designed with the "TOP-DOWN" Design Method. With VHDL, it achieved the functional modules of Waveform memory, embedded phase-locked loop and DDFS. At last, fitting system and locking resources, it formed a prototype system.(2) Based on SCM and DDFS, it is to design hardware and software in AWG, which included SCM system, double-port RAM realization inside the FPA, passive serial configuration between FPGA and SCM. After repeated debugging, the system can output the waveforms with frequency ranges, good stability, highly accuracy.
Through experiments, the two design options achieved the predetermined requirements. It proved the projects viable, which carry out the waves in rCBF system.
引文
[1]中国投资咨询网.2006-2007年中国心脑血管药市场分析及投资咨询报告[R].http://www.ocn.com.cn/reports/2006195xinnaoxueguanyao.htm,2006年9月.
[2]Kralj A,Acimovic R,Stanic U.Enh ancement of hemiplegicpatient rehabilitation by means of functional electrical stimulation[J].Prosthet Orthot Int,1993,17:107.
[3]陈骥,廖科.基于生物反馈的神经康复治疗仪的研制[J].生命科学仪器.2007,5:57-60.
[4]Nedergaard M,Astrup J,Diemer NH.J Cereb Blood Flow Metab,1988:8.
[5]Shamy SM.Ng Christina WY.Hui—Chan,魏妮译 燕铁斌校.经皮电神经刺激在脑卒中康复中的应用:时尚与事实,继续医学教育,2007,21(15):1-3.
[6]方燕南,张艳,黄如训等.电刺激治疗对脑梗死后运动功能及形胶质细胞活性的影响[J].中国神经精神疾病杂志,2000,26(1):9-11.
[7]孙乐蓉,杨红,冯爱玉等.电刺激小脑治疗对脑卒中患者肢体运动功能的影响[J].神经病学与神经康复学杂志,1999,4(3):15-17.
[8]杨波,关方霞,张强等.小脑顶核电刺激对脑外伤患者脑血流速度和颅内压的影响[J].中风与神经疾病杂志,2000,17(3):147-148.
[9]Nakai M,Iadecola C,Ruggiero DA,et al.Brain Res,1983,260:35.
[10]Nakai M,Ladecold C,Reis DJ.Am J physiol,1982,24:H226.
[11]Tang ZS.Endocrinology of heart and lungs[M].Beijing:Publishing House of Science and Technology,1991
[12]李克,黎元.功能磁共振成像的脑血流量调节机制[J],中国医学计算机成像杂志.2004,10(5):314-318.
[13]李强,干敏梁.基于直接数字频率合成技术的脑循环功能治疗仪[J],生物医学工程学杂志,2005,22(1):143-146.
[14]白炳良.数控波形发生器的设计[J].宜春学院学报(自然科学).2007,29(4):49-63.
[15]张玉梅,阔永红,傅丰林.基于DSP和DDS的高精度频率信号发生器实现[J].电子工程师,2004,30(1):43-45.
[16]刘顺英,昂秀芬,李巍译.《锁相环原理、设计及其应用》[M].人民邮电出版社.1988.
[17]陈世伟.《锁相环路原理及应用》[M].兵器工业出版社.1990.
[18]潘宇倩.DDS频率合成器AD9850原理及应用[J]_航天器工程,2007,16(5):85-88.
[19]周义建,游志刚.基于AD9850的多功能信号源的设计[J].电子技术,2001,(06):29-31.
[20]苏健民,付金霞,刘嘉新.基于FPGA的直接数字频率合成器设计[J].自动化技术与应用.2006(08):29-31.
[21]周洪敏,王红玉,顾艳丽.直接数字频率合成技术及其设计方案[J].科技咨询导报.2007,(24):121-122.
[22]李凯,蒋伟荣,程耕国.直接数字频率合成的杂散信号分析[J].湖北汽车工业学报,2007,21(1):47-50.
[23]王辉,殷颖,陈婷,俞一鸣.MAX+plusⅡ和QuartusⅡ应用与开发技巧[M].机械工业出版社2007.
[24]郑燕,赫建国,党建华编著,基于VHDL语言与QuartusⅡ软件的可编程逻辑器件应用与开发[M],国防工业出版社,2007.
[25]李洪伟,袁斯华.基于QUARTUS2的FPGA/CPLD设计[M],北京:电子工业出版社.2006.
[26]周润景,图雅,张丽敏.基于QuartusⅡ的FPGA/CPLD数字系统设计实例[M].电子工业出版社,2007.
[27]徐广辉,程东旭,黄如.基于FPGA的嵌入式开发与应用[M].北京:电子工业出版社.2006.