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Biomedical Circuits and Systems, IEEE Transactions on

Issue 1 • Date March 2008

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Displaying Results 1 - 13 of 13
  • Table of contents

    Page(s): C1
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  • IEEE Transactions on Biomedical Circuits and Systems publication information

    Page(s): C2
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  • Editorial

    Page(s): 1 - 2
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  • A Wireless IC for Wide-Range Neurochemical Monitoring Using Amperometry and Fast-Scan Cyclic Voltammetry

    Page(s): 3 - 9
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1473 KB) |  | HTML iconHTML  

    An integrated circuit for real-time wireless monitoring of neurochemical activity in the nervous system is described. The chip is capable of conducting measurements in both fast-scan cyclic voltammetry (FSCV) and amperometry modes for a wide input current range. The chip architecture employs a second-order DeltaSigma modulator (DeltaSigmaM) and a frequency-shift-keyed transmitter operating near 433 MHz. It is fabricated using the AMI 0.5-mum double-poly triple-metal n-well CMOS process, and requires only one off-chip component for operation. A measured current resolution of 12 pA at a sampling rate of 100 Hz and 132 pA at a sampling rate of 10 kHz is achieved in amperometry and 300-V/s FSCV modes, respectively, for any input current in the range of plusmn430 nA. The modulator core and the transmitter draw 22 and 400 muA from a 2.6-V power supply, respectively. The chip has been externally interfaced with a carbon-fiber microelectrode implanted acutely in the caudate-putamen of an anesthetized rat, and, for the first time, extracellular levels of dopamine elicited by electrical stimulation of the medial forebrain bundle have been successfully recorded wirelessly using 300-V/s FSCV. View full abstract»

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  • Stimulus-Artifact Elimination in a Multi-Electrode System

    Page(s): 10 - 21
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2459 KB) |  | HTML iconHTML  

    To fully exploit the recording capabilities provided by current and future generations of multi-electrode arrays, some means to eliminate the residual charge and subsequent artifacts generated by stimulation protocols is required. Custom electronics can be used to achieve such goals, and by making them scalable, a large number of electrodes can be accessed in an experiment. In this work, we present a system built around a custom 16-channel IC that can stimulate and record, within 3 ms of the stimulus, on the stimulating channel, and within 500 mus on adjacent channels. This effectiveness is achieved by directly discharging the electrode through a novel feedback scheme, and by shaping such feedback to optimize electrode behavior. We characterize the different features of the system that makes such performance possible and present biological data that show the system in operation. To enable this characterization, we present a framework for measuring, classifying, and understanding the multiple sources of stimulus artifacts. This framework facilitates comparisons between artifact elimination methodologies and enables future artifact studies. View full abstract»

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  • A Frequency Control Method for Regulating Wireless Power to Implantable Devices

    Page(s): 22 - 29
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (784 KB) |  | HTML iconHTML  

    This paper presents a method to regulate the power transferred over a wireless link by adjusting the resonant operating frequency of the primary converter. A significant advantage of this method is that effective power regulation is maintained under variations in load, coupling and circuit parameters. This is particularly important when the wireless supply is used to power implanted medical devices where substantial coupling variations between internal and external systems is expected. The operating frequency is changed dynamically by altering the effective tuning capacitance through soft switched phase control. A thorough analysis of the proposed system has been undertaken, and experimental results verify its functionality. View full abstract»

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  • An Active 2-D Silicon Cochlea

    Page(s): 30 - 43
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    In this paper, we present an analog integrated circuit design for an active 2-D cochlea and measurement results from a fabricated chip. The design includes a quality factor control loop that incorporates some of the nonlinear behavior exhibited in the real cochlea. This control loop varies the gain and the frequency selectivity of each cochlear resonator based on the amplitude of the input signal. View full abstract»

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  • A Mini-Invasive Long-Term Bladder Urine Pressure Measurement ASIC and System

    Page(s): 44 - 49
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    A mini-invasive system for long-term bladder urine pressure measurement system is presented. Not only is the design cost reduced, but also the reliability is enhanced by using a 1-atm canceling sensing instrumentation amplifier (IA). Because the urine pressure inside the bladder does not vary drastically, both the sleeping and working modes are required in order to save the battery power for long-term observation. The IA amplifies the signal sensed by the pressure sensor, which is then fed into the following analog-to-digital converter. Owing to the intrinsic 1-atm pressure existing inside the bladder, the IA must be able to cancel such a pressure from the signal picked up by the pressure sensor to keep the required linearity and the resolution for pressure measurement of the bladder urine. The pressure range of the proposed system is found out to be 14.7~19.7 Psi, which covers the range of all of the known unusual bladder syndromes or complications. View full abstract»

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  • Defect-Aware High-Level Synthesis and Module Placement for Microfluidic Biochips

    Page(s): 50 - 62
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1526 KB) |  | HTML iconHTML  

    Recent advances in microfluidics technology have led to the emergence of miniaturized biochip devices, also referred to as lab-on-a-chip, for biochemical analysis. A promising category of microfluidic biochips relies on the principle of electrowetting-on-dielectric, whereby discrete droplets of nanoliter volumes can be manipulated using an array of electrodes. As chemists adapt more bioassays for concurrent execution on such ldquodigitalrdquo droplet-based microfluidic platforms, system integration, design complexity, and the need for defect tolerance are expected to increase rapidly. Automated design tools for defect-tolerant and multifunctional biochips are important for the emerging marketplace, especially for low-cost, portable, and disposable devices for clinical diagnostics. We present a unified synthesis method that combines defect-tolerant architectural synthesis with defect-aware physical design. The proposed approach allows architectural-level design choices and defect-tolerant physical design decisions to be made simultaneously. We use a large-scale protein assay and the polymerase chain reaction procedure as case studies to evaluate the proposed synthesis method. We also carry out simulations based on defect injection to evaluate the robustness of the synthesized biochip designs. View full abstract»

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  • Biomedical Circuits and Systems Conference (BioCAS 2008)

    Page(s): 63
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  • IEEE Transactions on Biomedical Circuits and Systems Information for authors

    Page(s): 64
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  • IEEE Transactions on Biomedical Circuits and Systems society information

    Page(s): C3
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  • Blank page [back cover]

    Page(s): C4
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Aims & Scope

IEEE Transactions on Biomedical Circuits and Systems (TBioCAS) publishes peer-reviewed manuscripts reporting original and transformative research at the intersection between the life sciences and circuits and systems engineering principles.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Gert Cauwenberghs
University of California at San Diego