Sistema multicanal para a aquisição de biopotenciais

Se presenta un sistema compuesto por hardware de adquisición y software de soporte para la medición de biopotenciales en tiempo real desde una PC. El equipo cuenta con 8 canales diferenciales acoplados en continua, muestreados con convertidores analógico-digitales sigma-delta de 24 bits, con ganancia y tasa de muestreo configurables. La resolución del dispositivo está dada por el piso de ruido del sistema que es inferior a 2 µVrms en un ancho de banda de (0.05-100) Hz. Para medidas en un ancho de banda de 1 kHz el piso de ruido resulta menor a 3 µVrms. El coeficiente de rechazo de modo común es de 96 dB, y para lograr medidas de mayor calidad se utilizan electrodos activos y un circuito independiente para reducir la tensión de modo común, lo que posibilita utilizar topologías de medición no diferenciales. La transmisión de datos y de energía para todo el sistema se realiza a través del bus USB. El equipo cuenta con una barrera de aislamiento compatible con normas internacionales de seguridad eléctrica para equipamiento médico. Se relevó la respuesta en frecuencia y se comprobó que cumple con requisitos para dispositivos de electrocardiografía. Se adquirieron distintas señales de biopotenciales para verificar el funcionamiento del equipo y demostrar el uso del software.A biopotential measurement system composed of acquisition hardware and software capable of relaying real-time signals to a PC is presented. The device has 8 DC coupled differential channels sampled by 24 bits sigma-delta analog to digital converters with programmable gain and sampling frequency. The noise floor of the device determines its resolution, and it is less than 2 µVrms in a bandwidth of (0.05-100) Hz. Measurements up to 1 kHz can be carried out with a noise voltage less than 3 µVrms. The common mode rejection ratio is 96 dB. To achieve high-quality measurements active electrodes are used along with a common mode voltage reduction circuit allowing single-ended measurement topologies. A USB connection serves both as data channel and power source. The device includes an isolation barrier in agreement with international standards for the electrical safety of medical equipment. Its frequency response was measured and compared with accepted standards for electrocardiographic devices, and various biopotential measurements were carried out in order to test both hardware and software.é apresentado um sistema composto de hardware de aquisição e software de suporte para a medição de biopotenciais em tempo real a partir de um PC. O aparelho tem 8 canais diferenciais acopladas em contínuo, amostrados com conversores analógico-digital sigma-delta 24 bits. com o ganho e taxa de amostragem configurável. A resolução do dispositivo é determinado pelo nível de ruído do sistema é menos 2 μVrms uma largura de banda (0,05-100) Hz. Para medições em uma largura de banda de 1 kHz o piso de ruído é inferior a 3 μVrms. A razão de rejeição de modo comum é 96 dB, e para se obter medidas de qualidade superior é usado eléctrodos activos e um circuito separado para reduzir a tensão de modo comum, tornando-se possível a utilização de topologias de medição não diferenciais. A transmissão de dados e energia para todo o sistema é feito através do barramento USB. A equipe tem uma barreira de isolamento compatível com as normas de segurança elétrica internacionais para equipamentos médicos. Foi revelada a resposta em frequência e está em conformidade com os requisitos para dispositivos de eletrocardiografia. Se Obteveram diferentes sinais de biopotenciais para vereficar o funcionamento equipamento e demonstrar a utilização do software.Fil: Guerrero, Federico Nicolás. Universidad Nacional de la Plata. Facultad de Ingeniería. Departamento de Electrotecnia. Laboratorio de Electrónica Industrial, Control e Instrumentación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Haberman, Marcelo Alejandro. Universidad Nacional de la Plata. Facultad de Ingeniería. Departamento de Electrotecnia. Laboratorio de Electrónica Industrial, Control e Instrumentación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Spinelli, Enrique Mario. Universidad Nacional de la Plata. Facultad de Ingeniería. Departamento de Electrotecnia. Laboratorio de Electrónica Industrial, Control e Instrumentación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Nano-Watt Modular Integrated Circuits for Wireless Neural Interface.

In this work, a nano-watt modular neural interface circuit is proposed for ECoG neuroprosthetics. The main purposes of this work are threefold: (1) optimizing the power-performance of the neural interface circuits based on ECoG signal characteristics, (2) equipping a stimulation capability, and (3) providing a modular system solution to expand functionality. To achieve these aims, the proposed system introduces the following contributions/innovations: (1) power-noise optimization based on the ECoG signal driven analysis, (2) extreme low-power analog front-ends, (3) Manchester clock-edge modulation clock data recovery, (4) power-efficient data compression, (5) integrated stimulator with fully programmable waveform, (6) wireless signal transmission through skin, and (7) modular expandable design. Towards these challenges and contributions, three different ECoG neural interface systems, ENI-1, ENI-16, and ENI-32, have been designed, fabricated, and tested. The first ENI system(ENI-1) is a one-channel analog front-end and fabricated in a 0.25µm CMOS process with chopper stabilized pseudo open-loop preamplifier and area-efficient SAR ADC. The measured channel power, noise and area are 1.68µW at 2.5V power-supply, 1.69µVrms (NEF=2.43), and 0.0694mm^2, respectively. The fabricated IC is packaged with customized miniaturized package. In-vivo human EEG is successfully measured with the fabricated ENI-1-IC. To demonstrate a system expandability and wireless link, ENI-16 IC is fabricated in 0.25µm CMOS process and has sixteen channels with a push-pull preamplifier, asynchronous SAR ADC, and intra-skin communication(ISCOM) which is a new way of transmitting the signal through skin. The measured channel power, noise and area are 780nW, 4.26µVrms (NEF=5.2), and 2.88mm^2, respectively. With the fabricated ENI-16-IC, in-vivo epidural ECoG from monkey is successfully measured. As a closed-loop system, ENI-32 focuses on optimizing the power performance based on a bio-signal property and integrating stimulator. ENI-32 is fabricated in 0.18µm CMOS process and has thirty-two recording channels and four stimulation channels with a cyclic preamplifier, data compression, asymmetric wireless transceiver (Tx/Rx). The measured channel power, noise and area are 140nW (680nW including ISCOM), 3.26µVrms (NEF=1.6), and 5.76mm^2, respectively. The ENI-32 achieves an order of magnitude power reduction while maintaining the system performance. The proposed nano-watt ENI-32 can be the first practical wireless closed-loop solution with a practically miniaturized implantable device.PhDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/98064/1/schang_1.pd